People and facilities

Transcription

1 Calf Rearing Fact Sheet: Getting started People and facilities 1. Get the right person to rear the calves and ensure they have the resources and support to do the job well. 2. Calf sheds need to be draught free but well ventilated at a high level. 3. Maximise sunlight it is a natural steriliser. 4. Bedding needs to be clean and dry. 5. Calves need access to fresh water at all times. Would you swap places with your calves?? Staff Select and invest in the right person - rearing calves requires skill, attention to detail and empathy with the calves. The best rearer is someone who actually wants to do the job, not someone who is directed to do it. Keep trained staff in the calf shed. Ensure they have the time and support they need to do the job well. Facilities The calf shed should be dry and draught free. There needs to be airflow at a high level but no draught at calf height a lighted match shouldn t blow out when lit among the calves. Calf sheds should face towards the sun. Sunlight dries out and helps sterilise the shed. Purpose built calf sheds can have a UV resistant plastic roof and shade cloth/fabric walls which can be rolled up for better ventilation. If building a new shed, consider drainage under the calf shed and design the shed so that milk/colostrum can be piped/gravity fed. Install swinging gates with self-closing latches and a raised collection pen/ramp for loading / unloading calves. Avoid sharp edges, nails, tin or any small gaps where calves can get their heads or hooves stuck. Calves need a minimum of 1.5 m 2 /calf. The smaller the available area per calf, the messier the shed and the more fresh bedding that will have to be added. All calves (including bobbies) must have access to clean fresh drinking water at all times. Bedding This factsheet is one in a series at Published by On-Farm Research, PO Box 1142, Hastings, NZ. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 1.1 Some calf sheds successfully use grating as long is there is no draught coming up through it. Ensure bedding is topped up regularly or replaced with fresh material untreated shavings, sawdust or bark chips are ideal. Concrete might be easy to clean but it is cold and slippery. Regularly (at least weekly) spray surfaces at calf level pen fittings, walls, gates, floors/bedding with a virucide disinfectant. Have a separate area designated for sick calves to minimise disease spread. Clean out the calf shed at the end of the calf rearing season rather than just before the start of the next season. This allows time for sunlight to sterilise the shed.

2 Calf Rearing Fact Sheet: Getting started Building a calf shed 1. Low cost calf sheds can be constructed using UV resistant plastic. This has the advantage of letting in sunlight which acts as a natural sterilant. 2. Site sheds so that shelter belts protect people, calves and shed from prevailing winds. 3. Face calf sheds into the sun for warmth and sterilisation. 4. Ventilation is important - not draughts at calf height but provide air movement at a high level. 5. Decide on your milk feeding system this usually dictates the size, shape and layout of pens. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 1.2 General design A good calf shed is one that meets the needs of both calves and calf rearers. Calves can be reared in a wide range of facilities from converted implement sheds to purpose built calf sheds. Use existing shelter belts where possible. These make the environment warmer for people and calves, while protecting sheds from wind damage. Ventilation is important. There should be air movement above the calf to prevent the build up of ammonia and subsequent problems with pneumonia. Solid partitions between pens prevent draughts. Many sheds now have a UV resistant plastic roof and shade cloth on the walls which can be rolled up for ventilation. Such sheds can be built at much lower cost than traditional sheds because of the lighter materials used. Sheds (and calves) should face into the sun. Sunlight is not only good for keeping calves warm it also dries out and disinfects the pens. If building a new shed, consider drainage under the shed. Ideally, the shed should be higher at the back and have some form of drainage at the front. Consider covered areas for storing feed and mixing milk. Load-out facilities and a race with calf scales are very useful. Have a pen where sick calves can be placed in isolation Avoid sharp edges, nails, tin or any small gaps where calves can get their heads or hooves stuck. Pens, bedding and feeding An area of 1.5 m 2 /calf is a minimum and pens of calves are ideal. In an open fronted shed, pens should be twice as deep as they are wide. Decide on your milk feeding system and design pens to suit. If hanging a feeder on the front of a pen there needs to be sufficient space for all calves to feed. The best systems involve having calves of a similar age together and having a separate quarantine area for new arrivals. The best bedding is whatever is cheapest and most readily available bark chips, post peelings and sawdust are all useful. Bedding should be at least mm deep. Fresh bedding needs to be added as calves get older and pens get messier. Slatted floors and under pen drainage are good provided there are no draughts. Modern sheds feeding whole milk should be designed so that milk is piped (gravity fed) to avoid carting milk. All calves (including bobbies) must have access to clean drinking water. A perimeter guard around each trough (see next page) can prevent fouling.

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4 Calf Rearing Fact Sheet: Getting started Equipment 1. All aspects of the operation from calf pick up to water in paddocks after weaning require attention to detail. 2. Cleanliness is a must. 3. Sharp edges in any equipment can damage calves and people. 4. Check teats in feeders and replace faulty teats. Provide plenty of meal and keep it fresh and clean. 5. Sunshine is a powerful sterilising agent. 6. Wash and drain feeders between feeds. General Site the operation in a sunny well drained area. Be prepared to put shingle down in areas where vehicles travel mud will increase the likelihood of disease. Dirty equipment leads to disease and sickness. That is an animal welfare issue and a bottom line loss to the enterprise. After washing, drain equipment to allow it to dry. Sunshine sterilizes. Repair broken equipment damaged items may cause injury. Calf trailers Shelter from cold wind and rain on the journey to the calf shed is critical to ensure that calves do not arrive weakened and susceptible to disease. Clean trailers after each use and leave to dry in sun. Milk feeders Use compartment feeders if feeding a restricted volume of milk. This means you can check that every calf gets its full milk ration. Replace leaky teats or teats that flow too fast/too slow. There should be adequate room in each pen for each calf to feed comfortably off the feeder. Feeders should be placed such that calf necks are stretched out long and low. Meal feeders This factsheet is one in a series at Published by On- Farm Research, PO Box 1142, Hastings, NZ. While all due care has been taken in preparing this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 1.3 Trough like feeders allow easy access to birds and rodents but calves have good access as well. Allow 35 cm of trough length for each calf. Troughs should be off the ground and protected from the weather. Meal bins can have plastic strips that hang down to deter birds. Start calves with strips tied up and release once calves are used to feeding (next page). Water troughs Protect ball cocks so that calves cannot play and cause flooding. Clean out regularly. Small bowls are good so that water remains clean by frequent refilling. A perimeter guard around a water trough can prevent fouling (next page). Never use teats for providing water to calves as water will then go straight to the abomasum rather than the rumen.

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6 Calf Rearing Fact Sheet: Getting started Calf collection 1. Farm staff must know pick up plan and calf ID system to be used. Plan ahead. 2. Collect calves at least once a day to reduce bonding time with the cow. Ideally collect calves twice per day. 3. Get the calf to a warm dry environment as soon as possible. 4. Treat calf navel with iodine spray before transporting and again at shed. 5. Trailer must be clean and dry. Sunshine is a good steriliser. 6. Don t overcrowd trailers - provide shelter and drive slowly. 7. Treat NEWBORNS with care. 8. All newborns must receive 12% of their bodyweight in fresh warm colostrum within 12 hours of birth. Calf Collection Make sure the calf pick up plan is understood by all staff. The calf identification and tagging system needs to be understood by all involved. Collect calves at least twice each day, more often if practical. The aim is to collect as soon as possible after birth. This reduces the bonding time between cow and calf, enables the cow to get on with eating and producing milk and reduces the risk of metabolic disorders. Calf requirements for colostrum are met in your rearing facility. Collection soon after birth reduces the time calves have to suckle and lessens the chance of the cow contracting mastitis. Aim is to get the calf to a dry warm environment as soon as possible and feed a known quantity of fresh high quality colostrum. Spray navel with 7% iodine solution before transporting and again in shed. Cover the navel completely with the spray solution. Calf Trailer Needs to be CLEAN and DRY and protected from wind and rain. A deep bed of dry clean straw works well. Clean rubber mats are OK as long as it is not too wet and cold. Always place calves gently in the calf trailer. They are NEWLBORN. Calf trailers are a major source of bugs. They must be kept clean and dry. DO NOT place too many calves in the trailer. Drive slowly. Calves standing all over each other is not acceptable. Clean and dry trailer daily, ideally using sunshine to disinfect. Arrival at the shed Feed 12% of bodyweight of high quality fresh colostrum to all calves within 12 hours of birth. To be sure all calves get colostrum it is often easier to tube all calves with 2-4 litres of first milking warm colostrum. Don t assume a calf has had sufficient colostrum from its mother. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Fact Sheet 1.4 A 30 kg calf requires 3.5 litres of colostrum within 12 hours of birth. First milking colostrum has more antibodies (immunoglobulins), fat, protein, minerals and vitamins than transition milk. Antibodies in colostrum are only absorbed for the first 24 hours of a calf s life. Ideally give two feeds of first milk colostrum within the first 12 hours of life. Calves that are weak or cold require extra attention. Use a heat lamp box and tube feed with warm, good quality colostrum.

7 Calf Rearing Fact Sheet: Getting started Guide to calf health 1. Calves need warmth, high quality feed and fresh clean water at all times. 2. Monitor calves regularly. 3. Plenty of colostrum fed early is critical. At least 2 litres in first 12 hours and 4 litres total within first 24 hours. After that, you have missed the boat! 4. Scours are a calf rearer s nightmare. Take action quickly to ensure calves remain hydrated. 5. Take concerns to your veterinarian early. Saving money on vet bills may negatively impact both bottom line returns AND calf welfare. 6. Some practices e.g. tube feeding, dehorning and castration require special skills learn from other professionals. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On Farm Research Calf Rearing Fact Sheet 1.5 Introduction Calf rearing requires a high degree of skill and stockmanship. Calves are new born animals - they are weak and vulnerable. Their digestive and immune systems are only partially developed. Calves need to be checked regularly so twice a day feeding (and twice a day checking) is a good idea for young calves. A calf that won t feed or is slow to come up to be fed has a problem. A good recording system helps detect problems early. Coloured neck bands are a good way of identifying calves with problems. For example, a calf that is a slow feeder can get a coloured band and be checked at the next feed. Have different coloured bands for different issues. Calves that are small, have had birthing difficulties or haven t had adequate colostrum are highly susceptible. Calves need at least 4 litres of colostrum in the first 24 hours. The first 12 hours are the most critical for ensuring maximum benefit from colostrum. The shed needs to be warm and dry with good ventilation and without draughts at calf level. A good layer of bedding is important to keep calves warm and absorb urine. Scouring Scouring is the calf rearer s biggest nightmare. There are a number of causes and identification is often difficult. Young calves which are scouring need to be fed electrolytes immediately to avoid dehydration. The number and timing of calves scouring is often a clue as to the cause. Scouring in older calves is usually easier to deal with than scouring in young calves the challenge is identifying the cause and deciding on treatment. Navel infections These are caused by bacteria entering the umbilical cord. Navel becomes swollen, hot and the calf reacts when it is touched. Prevention is best - all calves should be treated with iodine at pick up. Infected navels need to be treated with penicillin. Dehorning and castration Animal welfare is important and some practices are illegal. Learn appropriate techniques and timing.

8 Calf Rearing Fact Sheet: Getting started Welfare and euthanasia 1. Good calf welfare is non-negotiable for all calf rearers. 2. The Dairy Cattle Code of Welfare (2010) sets minimum standards around calf welfare. Ensure all those involved in calf rearing are familiar with this code. 3. It may be necessary to humanely destroy calves - follow correct procedures. Ensure there Are good practices around dead calf disposal. Calf Welfare Good calf welfare underpins all successful calf rearing enterprises. Investing in excellent welfare will pay dividends with low calf deaths, good growth rates and calves which grow into cows that are good to handle. The Dairy Cattle Code of Welfare (2010) is very specific regarding the minimum care of calves. Some key points are: All calves must be fed colostrum within 24 hours of birth. All calves require a warm, sheltered environment with access to good quality water at all times Handle all calves gently and with care. Euthanasia There will be times when it is necessary to humanely destroy calves. It is unacceptable to leave a calf suffering. On some farms it is policy to euthanase unwanted calves. It is important that there is a person on farm trained and capable of humane slaughter of calves. Approved methods of euthanasia are: Approved method Rifle Approved method Frontal Target 5-10 cm Blunt force trauma is not preferred as a method of killing calves This factsheet is one in a series at Published by On-Farm Research, PO Box 1142, Hastings, NZ. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Fact Sheet 1.6 Approved method Rifle Approved method Captive Bolt

9 Follow up to ensure death Bleeding out : Note - throat cutting is not an approved killing procedure. When eyes are touched, dead animals have no blink reflex and no rhythmic breathing. It is important to confirm death after slaughter and re-check and confirm death again 5 minutes later. Note: a heartbeat may be felt 2-3 minutes after brain death. Dead calf disposal - have a plan. Most calves are disposed of in an offal hole/pit or in some regions a collection service operates. Dead calves may be worth selling to a slinky buyer. Know what is available in your region. Bobby Calf Welfare There are some good Best Practice Guidelines available refer Painful Procedures Disbudding and de-horning and castration must be done in ways that minimise pain and distress. Disbudding is best carried out by a veterinary or appropriately trained personnel using a gas or electric cauterising iron with appropriate pain control (sedation/anaesthetic). It is best carried out as young as possible once the buds can be felt, usually at about 3 weeks. Dehorning without pain relief must be done before 9 months of age. Consult your local vet and plan well ahead. Castration is best carried out as early as possible before 6 weeks (preferable 7-21 days) using a standard rubber ring. Using elastrators apply the rubber ring to the neck of the scrotum. Ensure both testicles are in the scrotum below the rubber ring. Calf Rearing Fact Sheet 1.6

10 Calf Rearing Fact Sheet: Getting started Guide to feeding 1. Planning before the rearing season starts makes things easier. 2. Attention to detail is important. 3. Decide how and what you are going to feed your calves. 4. Create a routine and stick to it. 5. Ensure all calves have adequate colostrum in the first 24 hours. 6. Have a plan in place for when things go wrong. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 1.7 General Calves are baby animals so need to be fed milk at the start until their rumen develops sufficiently for them to obtain adequate energy from grass to maintain good growth rates. How fast the rumen develops depends on the feeding system used. You need to choose a system that suits you and follow it carefully (see Fact Sheets ) You need to know how much milk each calf is getting as both underfeeding and overfeeding calves can affect calf health and growth rates. Underfeeding a calf can reduce their future performance in terms of growth rate and lactation. Overfeeding is expensive, can cause scours and actually delays rumen development. Set up a routine so the calves are fed at the same time each day. Have a plan for what to do if something goes wrong. Planning Before calf rearing starts, decide what equipment you are going to use, how much milk you are going to feed and how you will provide it. Make sure you have every thing ready before the first calves arrive in the shed. On entry to the shed the calves should be fed colostrum as this is critical to producing healthy calves Calves need to be trained to drink off a calf feeder. This can take time and patience and some calves will take longer than others. Initially calves should be fed twice a day. The length of time calves are fed twice a day depends on the feeding system used and the size and health of the calf. Twice a day feeding also enables you to check each calf twice a day. Make sure all calves come up and drink their milk ration at every feed. Make sure every calf has room to get on the feeder. Feed at the same time each day. Monitor what is happening is every calf drinking well, are they alert, full of energy etc? Identify any calves that are not and act to sort out their problems. Calves are fussy eaters especially when they are young so it is important to ensure that everything you feed milk, calf pellets / meal, hay and grass is fresh, clean and appealing. Milk and pellets must be high quality. It is important that the milk feeders are kept clean and teats are replaced as they become worn. Calves need water as well as milk particularly if they are eating meal. Keep water troughs clean as calves won t drink fouled water. If you wouldn t drink it, don't expect them to!

11 Immunity acquired Percent antibody absorption Calf Rearing Fact Sheet: Calf health Colostrum and immunity Calves need to get 4 litres of high quality colostrum within 24 hours of birth. The sooner the better. Calves with inadequate immunity are more likely to die, have lower weight gains and poorer feed conversion efficiency than those getting enough early colostrum. Up to 40% of day old calves in NZ herds have had insufficient colostrum. Colostrum is obtained from the first milking of a cow. Subsequent milkings provide transition milk which has a lower concentration of immunoglobulins. A calf should receive 4 litres of first milking colostrum within 24 hours of birth General Failure of calves to get sufficient colostrum and acquire early immunity is a world-wide problem. NZ studies have shown 25% of day old calves have had no colostrum and up to 40% have received inadequate colostrum. It is critical that a calf gets high quality colostrum within the first 24 hours and preferably within the first 12 hours. Calves with inadequate immunity are four times more likely to die and those that survive will have lower weight gains, poorer feed conversion efficiency and a higher incidence of scouring than calves with good levels of immunity gained by feeding colostrum in their first 24 hours. Development of immunity Calves are born with a very immature immune system and immunity is transferred from cow to calf through immunoglobulins in colostrum. These immunoglobulins are large protein molecules which can only move through the calf s intestinal wall in the first 24 hours after birth. At this point the wall of the small intestine matures and these immunoglobulins can no longer pass. In addition, the secretion of digestive enzymes starts 12 hours after birth, meaning more and more immunoglobulins are digested and rendered useless. The young calf has no resistance to diseases like E. coli and Salmonella and its only protection in the first few days is from colostrum (this is called passive immunity). A calf with no immunity can get sick when challenged with just 500 Salmonella bacteria, whereas one that has received a good level of passive immunity can withstand 10 billion Salmonella bacteria. By the end of the first week the calf is building up its own immune system and is producing its own antibodies in response to being challenged by pathogens. Within a few weeks the calf is well on its way to being able to fight off disease. Development of passive and active immunity in the calf Calf age (hr) Passive immunity via colostrum this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.1. Active immunity built up by the calf itself Age (w ks)

12 Immunoglobulins (mg/ml) Why do calves miss out on colostrum from their mothers? Many calves do get colostrum from their mothers but a lot don't. The practice of removing calves from dairy cows for generations has undoubtedly reduced mothering instinct in cows. Dairy cows are apt to wander off soon after calving. Calves can go under hot wires and be separated from their mother. Selection for milk production means that udders are often low and difficult for calves to access. Around 25-30% of calves have not suckled 6 hours after birth and 20% have not suckled within 18 hours. Daily calf collection (if not twice daily collection) is the right thing to do - but it cannot be assumed that the calf has had enough colostrum from its mother. New arrivals at the calf shed need to be fed colostrum if there is any doubt as to whether they have had colostrum from their mother. Waiting until the next day when they will be hungry is too late. If necessary the calf should be tube fed although this reduces the efficiency of absorption of the antibodies. The amount of protection a calf obtains is determined by the amount ingested and the amount that is absorbed. The amount ingested is affected by the volume of colostrum consumed and the concentration of the antibodies in the colostrum. The calf should get 5-6% of its bodyweight as colostrum in the first six hours and the same amount 12 hours after birth to ensure that at least 100g of antibodies are consumed. This equates to about 2 litres of colostrum per feed for a 40 kg calf. Factors affecting the quality of colostrum The level of antibodies are highest in the first milk produced after calving and then drop rapidly so colostrum fed to calves in the first 24 hours should be first milking colostrum only. Calves appear to be better protected if they are fed better quality colostrum than a larger volume of lower quality colostrum. Antibody concentration varies widely between cows. A Dairy NZ study showed an average of 48 g/litre with a range from 20 to 100 g/litre. Ideally a calf should be fed first milking colostrum from a mixed age range of cows to give the calf a wider range of antibodies. Cows which have been vaccinated (e.g. against Rotavirus) will produce more antibodies. Cow breed and nutrition will also affect quality and volume of antibodies. Feeding energy deficient diets prior to calving reduces both production and quality of colostrum. Dairy breeds produce more total immunoglobulins than beef breeds but it is more concentrated in beef breeds. Older cows produce more immunoglobulins than heifers as they have been exposed to more diseases. TAKE HOME MESSAGE - Ensure new born calves get fresh colostrum as soon as possible Note the rapid decline in immunoglobulin levels in milk from all cows in the study and the big variation between cows Source :Sally-Anne Turner (2003) Day of lactation Calf Rearing Fact Sheet 2.1

13 Calf Rearing Fact Sheet: Calf health Pre-weaning animal health plan 1. The 3 P s - Planning, Preparation and Procedures provide the framework for successful calf rearing. 2. Prevention is better than cure 3. Preparation of the shed and maintaining hygiene all reduce risk. 4. All the rest Procedures- 5. Know your calves how do they normally behave? 6. Act quickly as health issues caught early are easier to deal with. 7. Know what to look for and how to treat it. 8. When in doubt, be prepared to ask your vet. Farm Research, PO Box 1142, Hastings, NZ this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.2 Planning Have a plan in place for dealing with sick calves including recording of issues. Decide how you are going to identify calves that need to be watched e.g. use a range of neck bands with different colours e.g. white for calf needs to be watched, blue for a calf on a course of antibiotics, yellow for a calf that needs electrolytes. Strips of cloth for tying up plants make ideal neck bands - get a range of colours from a hardware store. Set aside an area as a sick bay. Talk to your veterinarian about what you should be looking out for. Calf arrival If your calves have travelled a long distance, feed 2 litres of electrolytes on arrival. If your calves are straight out of the paddock they should be fed colostrum for their first feed. On arrival at the shed, navels should be sprayed with iodine. Navels should be checked regularly for the first week. Calves with wet or swollen navels should be monitored. If the navel is hot, tender to touch or pus is present then the calf should be treated with antibiotics (penicillin). Early treatment will prevent later problems with things like joint ill. Signs of a healthy calf Nose no discharge, moist and cool. Ears alert and responsive. Coat shiny, supple (if pinch and release - the tent of skin should return to position fast. If it doesn t the calf needs fluids as it is dehydrated). Normal temperature is around 38 C Respiration normal (56 breaths / min 4 days of age and drops to 50 breaths / min by 14 days of age). Week 1-3 Calves should be alert, active and behaving normally. Any change in behaviour, appearance or feeding should be treated as an early sign that something is wrong. During this early period it is essential to get the calf feeding well. Careful observation of calves morning and night and quick intervention when a problem arises is critical. Check for wet tails and make sure all calves are drinking well. Calves with issues should be recorded or the calf marked so that they can be re-checked at the next feed. Calf scours can kill rapidly and any sick calves should be isolated to make treatment easier and reduce any cross contamination.

14 Check for wet tails and make sure all calves are drinking well. Calves with issues should be recorded in the shed notebook or the calf marked with raddle or collar so that they can be re-checked at the next feed. Calf scours can kill rapidly and any sick calves should be isolated to make treatment easier and reduce any cross contamination. Calf scours at this age are commonly nutritional" due to over feeding or a change of diet (e.g. milk to milk powder). Nutritional scours don't last long but can affect a large number of calves at one time. Take the calves off milk and feed electrolytes for 24 hours. It is important that electrolytes are fed in large volumes as a scouring calf can dehydrate rapidly. If calves are active, electrolytes should be freely available for the calves to help themselves outside the feeding period. Infectious scours (caused by microbes) can be difficult to manage. Most commonly they are caused by Rotavirus, Salmonella, or Cryptosporidia. Large numbers of calves are progressively affected, and they require significant nursing care to prevent deaths. With infectious scours, milk and electrolytes are fed alternatively. Electroloytes should be fed at least 4 hours after a milk feed. It is important to keep up the fluid intakes of calves to avoid dehydration. Isolate sick calves in an isolated sick bay and have separate equipment for healthy and sick calves. Rearers should make sure boots and clothes are clean and disinfected when moving between the two groups of calves. Do not return recovered calves to their pen mates as they will still be shedding the pathogens (bugs) that cause the scours and will remain infectious to other calves. Dehydration is the main cause of calf death. It occurs because too much water and electrolytes are lost from the body in the scour. Sick calves need large volumes of a high quality electrolyte replacer in the first 24 hours (6-10 litres depending on the degree of dehydration). This may require tubing with a calf feeder. Remove the top layer of dirty bedding as often as possible, or spread clean fresh sawdust on top daily. Spray all surfaces of all calf pens at least daily with disinfectant. Managing a calf scours outbreak is time consuming, stressful and can be heart-breaking. It requires professional support. Develop a working relationship with your veterinarian. If the calves are placed outside ensure they have access to good shelter and that they are all feeding well. Week 3-5 If calves are kept inside, build up of ammonia from the calf urine can cause pneumonia. Ensuring the shed is well ventilated and adding fresh layers of bedding regularly will reduce this risk. Signs include lethargy, rapid breathing, rise in body temperature and coughing. Early recognition and treatment with antibiotics will help prevent losses due to deaths and reduced growth rates. Watch out for any signs of arthritis, ear tag infections and abscesses particularly around the mouth. Dehorning Should either be done with a dehorning paste at 4 days of age or with gas disbudders at 4 to 6 weeks of age. Vaccination Colic This is to prevent clostridrial diseases like blood poisoning and tetanus. Inject the calf with a 5 in 1 injection at 6 to 8 weeks of age followed by a booster 4 to 6 weeks later. Often the result of rapid drinking - the calf shows signs of distress within an hour of feeding - kicking its stomach and even falling over. Monitor teat flow rate. If caused by over-eating grain - give sodium bicarbonate dissolved in water. Weaning Time of weaning off milk will depend on the feeding system used. Ensure calves that are being weaned are up to target weights and are fit and healthy. Keep feeding them meal/pellets and or good quality green leafy grass. Calf Rearing Fact Sheet 2.2

15 Calf Rearing Fact Sheet: Calf health Nutritional scours 1. Nutritional scours are related to stress, over feeding or a change in feed. 2. Early detection and treatment are important to minimize negative impact. 3. Problems are dehydration and acid imbalance 4. Take off milk for 24 hours and feed large volumes of electrolytes. 5. If calves are alert, leave electrolytes in a feeder in the pen between feeds. 6. If calves are unable to drink administer electrolytes with a tube feeder (below). this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.3 Introduction Calf scours (diarrhoea) is the single most important cause of death in milk-fed calves. Scours can be classified into two types, nutritional and infectious. Nutritional scours is usually caused by stress to the calf due to a change in management routines. Nutritional scours can progress to an infectious scour. Depending on the severity of the scours, rearers will see some or all of the following: bright yellow or white faeces depressed calves which are reluctant to feed or suck lack of energy and lethargy dry muzzle wet under the tail calves with sunken eyes and/or a temperature dehydration Nutritional and stress scours The initial digestion of milk occurs in the abomasum (or fourth stomach) and then in the intestines. Nutritional scours is due to an inadequate milk digestion in the abomasum due to overfeeding, stress, too rapid change in diet or the milk not curding. This means the milk leaves the abomasum too early and overloads the intestine with lactose. This results in a watery scour and the fluid loss results in a very dehydrated calf. Environmental stress can also cause scours - e.g. over-crowding, a sudden change in the weather or cold, damp, draughty or humid conditions inside calf sheds. Even changes in staff and hygiene can increase the likelihood of scours. The stress of transporting calves from the sale yards or from one farm to another may be sufficient to lead to scours if calves are offered milk on arrival. Newly arrived calves should be fed an electrolyte solution. Symptoms Scouring calves can lose up to 5 litres of fluid each day including minerals salts essential for normal body function. With most scours, it is the dehydration and acidosis, that kills the calf. With nutritional scours, a calf may still look healthy and have a good appetite so early detection is critical. Treatment Stop feeding milk to calves with nutritional or stress scours for 24 hours. Feed electrolytes instead of milk. The more dehydrated a calf is the more electrolytes it needs. For example if a 40 kg calf has lost 10% of its body weight it will need 4 litres of electrolytes to replace it. A dehydrated calf may need 6-10 litres. Feed at least three times a day. If a calf will not drink, feed electrolytes using a tube feeder.

16 Calf Rearing Fact Sheet: Calf health Rotavirus Rotavirus is spread via faeces and can even be airborne. Infected calves scour out huge numbers of virus particles and the level of contamination may increase very rapidly. It cannot be controlled by antibiotics. Control strategies involve vaccinating cows, ensuring calves get colostrum and maintaining good spraying regimes and hygiene within the shed. Critical to identify and start treatment early. Signs include a pale yellow scour and reluctance to feed. Isolate sick calves if possible. Feed milk and electrolytes with at least two hours between a milk feed and feeding electrolytes. If necessary tube feed electrolytes. Disinfect pens regularly. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.4 General Rotavirus is the biggest animal health issue facing calf rearers with some experiencing death rates as high as 30%. It can be devastating and demoralising. Rotavirus is persistent in the environment, and can remain infectious for many months at room temperature. It can withstand low temperatures and high humidity on non-porous surfaces like plastic and concrete. What is it and how does it kill calves? Rotavirus infects and destroys mature cells from the tip of the villi, which are the tiny, finger like projections on the surface of the small intestine that help absorb nutrients. Absorption of milk and electrolytes is reduced and the damage to the intestinal cells means that fluid is lost from the intestine, further compounding the dehydration. It is this dehydration that generally kills the calf. Scouring continues until the villi inside the small intestine are again covered with mature cells that allow normal digestive-absorptive processes to resume. Rotavirus also increases the concentration of calcium in the intestinal cells which acts like a toxin and leads to the characteristic pale yellow scour of Rotavirus. How is it spread and what are the signs? Rotavirus usually affects calves less than 3 weeks old and is primarily spread by infected calves shedding large quantities of the virus. Other calves ingest faecal matter or inhale virus particles. Incubation time depends on the level of environmental challenge the calf is exposed to but is typically between hours. The most obvious sign of Rotavirus in calves is a pale yellow scour, often rancid smelling. This scouring leads to fluid loss, electrolyte loss and dehydration. Initially Rotavirus will need to be confirmed with a lab diagnosis but experienced rearers generally make a diagnosis very quickly. The key to managing an outbreak is early identification of infected calves so that they can be treated promptly with electrolytes. During each feed it is important to cast an eye over each calf to identify any potential signs of illness. These may include- Hanging back from the feeder/reluctance to come in and feed, Reluctant to drink, fussing with teat, coming off teat, Drinking slower than normal, Wet tail, Pale yellow scour can sometimes be watery and/or bloody.

17 Most calves that die, do so from loss of water and electrolytes, rather than from direct action of rotavirus itself. This means rapid treatment with electrolytes is critical. Animals may continue to shed the virus in their faeces even if they are not showing clinical signs. Calves do not become immune to rotavirus so they can get re-infected. However, because calves are older, the second infection is usually less severe. Treatment Treatment with large volumes of electrolytes is labour intensive and time consuming- and not always effective particularly with younger calves. Even if the animals do recover, they will still shed large numbers of virus particles into the environment, potentially infecting healthy calves. Recovered calves may have slower growth rates and be more susceptible to other diseases. Feed large volumes of electrolytes but don t stop feeding milk as it is important to keep the calf s energy levels up. Many electrolytes contain sodium bicarbonate that alter the ph in the digestive tract and adversely affect milk absorption, so milk and electrolytes should be fed at least two hours apart. As a general rule, calves in the sick pen need as much electrolytes as you have time to get into them. While only small numbers of calves are infected isolate the calves being careful to disinfect any equipment used with sick calves. Don t go straight from the pens with sick calves to pens with healthy calves clean boots and overalls. Spray pens with a virucide if sick calves have been removed. This should help protect the remaining calves in that pen. How do we prevent Rotavirus? Unfortunately there is no silver bullet although vaccinating cows against rotavirus and then feeding calves with colostrum and milk from these cows certainly helps. The risk period for the incidence of Rotavirus infection generally occurs between 5 and 14 days of age when the passive immunity from the dam is wearing off and the calves own immune system has not fully developed. Antibodies in colostrum can continue to provide limited local immunity in the gut (even though they can t be absorbed through the calf s gut) so feeding of colostrum from vaccinated cows will help prevent the development of rotavirus. The timing of rotavirus on dairy farms often coincides with stored colostrum running out. Ensure the shed is thoroughly cleaned out at the end of each season and sprayed with a virucide solution. To reduce the virus contamination to a minimum, spray the shed every 3-4 days with a virucide solution throughout the risk period (i.e. until the youngest calves are at least two weeks of age). Many solutions are suitable for spraying over calves. Maintain a high standard of cleanliness in the shed and thoroughly clean and disinfect equipment such as feeders, especially equipment used in the sick pen. Avoid visitors to the calf shed. If calves are coming from a number of sources, pen calves from the same farms together and group calves according to age. Our experiences One year we experienced a rotavirus outbreak on the 13 th August. There were 435 calves in the shed ranging in age from new arrivals to calves which had been in the shed for 21 days. Within 3 days of the first case of rotavirus being diagnosed it had spread through the shed, with calves in all pens affected. Younger calves were hit the hardest but even the oldest calves were affected. However, older calves recovered and we had no deaths in the calves aged two weeks or older. In total, 46% of the calves were affected and at the peak we were treating over 80 calves. The shed was so contaminated that it became impossible to isolate calves so we stopped trying and concentrated on dealing with the problem. Most calves were on once a day milk feeding and we continued to feed milk in the mornings. At the morning feed, any suspect calf received a coloured neck band which meant it needed close monitoring. Any calf that had a wet tail got a different coloured neck band and was fed electrolytes in the evening from a bottle. In some cases, most calves in a pen had coloured bands and it was just as easy to feed electrolyte to all the calves in those pens. Any calf that was wobbly or couldn t feed received a different neck band and was taken to the sick pen. In total, 8% of calves were relocated to the sick pen and overall shed mortality was 5.4%. Calves in the sick pen were fed milk in the mornings and electrolytes at midday and in the evening (either by tube or bottle). Within 10 days we had worked our way through the worst of the outbreak but any new calves which were brought into the shed still went down within 48 hours in spite of regular spraying of the shed. We felt that we had a level of contamination within the shed which was even swamping good healthy calves. The only solution was to put new arrivals into a completely different shed. It is worth noting that in the same year we had 3 outbreaks of Salmonella. This was quickly recognised as being a different disease. Affected calves were treated with antibiotics and there were no Salmonella related deaths. Calf Rearing Fact Sheet 2.4

18 Calf Rearing Fact Sheet: Calf health Salmonella Salmonella is caused by a gram negative bacteria that causes acute intestine infections in the calf and humans. The bacteria can survive in the calf shed environment for long periods of time. Predisposing factors for calves are stress and poor immunity in intensive rearing units. Prevention ensures calves get colostrum, minimising stress and maintaining good hygiene and spraying regimes within the shed. Salmonella can appear in calves from 2-12 weeks of age. Younger calves are much more vulnerable than those older than 12 weeks. Speed of treatment is critical to survival of the individual calf and to stop the spread of the disease through the shed. Treatment of clinical cases involves antibiotics and aggressive electrolyte replacement. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.5 General Salmonella is a gram negative, non spore forming bacteria that causes acute intestinal infection in both humans and animals. In extreme cases, calf rearing facilities can experience high levels of morbidity (sickness) and death rates as high as 100%. Because it can spread to humans, care needs to be taken when handling sick animals. The Salmonella bacteria is capable of surviving in the environment, and can remain infectious for many months in semi-dried faecal material that frequently gets left behind when calf sheds are not cleaned out properly. However, Salmonella are susceptible to drying and sunlight. The main varieties are S. typhimurium and S. brandenburg. S. brandenburg was identified in New Zealand in 1999 and is a particularly aggressive variant which is infective at much smaller doses and spreads more rapidly than S typhimurium. Salmonellosis is increasing in New Zealand, largely as a result of intensification. The disease is usually endemic with sporadic outbreaks. Stress on the calf and low levels of maternal antibodies (inadequate colostrum) are factors that lead to outbreaks of the disease. Diagnosis of the disease is by laboratory analysis of faecal samples (from at least 5-6 calves) and is important in establishing an effective treatment and management plan. How is it spread and why does it kill the calf? Salmonella usually affects calves from 2-12 weeks old and is mainly spread when infected calves ingest bacteria present in the environment, or in feed or water. After ingesting the bacteria, incubation time is typically 1-5 days. The Salmonella bacteria produce enterotoxins that are very invasive and damaging to the gut lining. This damage causes severe loss of fluids and electrolytes into the gut lumen resulting in dehydration and death. The enterotoxins create inflammatory changes which also result in the bacteria entering the bloodstream and circulating through the body. This results in septicaemia which allows bacteria to lodge in other organs of the body like the brain, bone, lungs and liver causing blood poisoning and death. Scouring causes fluid and electrolyte loss and severe dehydration resulting in death. Initially Salmonella will need to be confirmed with a lab diagnosis to determine the treatment plan with your veterinarian. The key to managing an outbreak is early identification of infected calves so that they can be treated promptly with parenteral antibiotics and supportive fluid replacement.the disease is aggressive and calves die from dehydration. Mortality rates are high and intensive care and treatment is needed to prevent losses.

19 What are the signs of the disease? During each feed it is important to cast an eye over each calf to identify any potential signs of illness. These may include- Hanging back from the feeder/reluctance to come in and feed, Reluctance to drink, fussing with teat, coming off teat, Drinking slower than normal, Wet tail, Pale yellow scour can sometimes be watery and bloody. Septicaemia can occur in newborn calves that are >1 week of age. The illness can be very sudden in onset and calves are often found dead in the pen. Calves have a marked depression in appetite a lack of enthusiasm to suckle is often one of the first symptoms. Calves can have a high temperature ( C) with death occurring in hours. The faeces may range from profuse to moderate diarrhoea. Central nervous signs, ocular lesions and polyarthritis may be seen and these animals may also suffer from pneumonia. Mortality rates may reach 100%. Acute enteritis is the most common form of the disease in older calves (2-6 weeks of age). Initially there is a fever ( C), followed by a brown pasty scour that leads to a severe watery diarrhoea. The temperature often returns to normal at the onset of diarrhoea and can be subnormal at the time of checking. The calf is anorexic and depressed. The faeces have a putrid, foul odour and may contain shreds of mucous membrane and clots of blood. The calf may be hunched with abdominal pain and straining. Affected calves rapidly become dehydrated, quickly lose condition and become weak and emaciated. Calves that die do so within 2-5 days, become more and more dehydrated. In less severe cases or chronic enteritis, the faeces may merely become a pasty consistency, yellowish-grey in colour but with little evidence of the dramatic changes that accompany the acute form of the disease. These animals commonly grow slowly and potentially become carriers by shedding the bacteria in the faeces. What are post-mortem findings? Post-mortem examination can be important in diagnosing Salmonella. Most animals exhibit marked haemorrhagic enteritis, often accompanied by severe necrosis of the ileum and large intestine. Gut contents are smelly, watery and contain mucous or blood. There is often a pseudo-membrane in the lumen of the intestine. The lymph nodes around the mesentery are congested, enlarged and may be haemorrhagic. What is the prognosis and treatment? Definitive diagnosis is by demonstrating the presence of salmonella in a bacterial culture of the faeces. However in calves, excretion of the bacteria is often intermittent, even in those animals that show symptons. This means it is advisable to sample the faeces from 5-6 animals to obtain a good diagnosis. The key to managing an outbreak is early identification of infected calves so that they can be treated promptly with antibiotics and electrolytes. Delays result in irreversible damage to the gut and the animal becoming severely dehydrated at this stage death can occur even with appropriate antibiotic and fluid therapy. Antibiotic treatment is usually sufficient provided it is initiated at an early stage. Salmonellosis is aggressive and mortality rates can be high if antibiotic treatment is not initiated early. Intensive care and feeding with quality electrolytes are needed to prevent losses. How do we prevent it? Ensure the shed is thoroughly cleaned out at the end of each season and sprayed regularly with a disinfectant. Maintain a high standard of hygiene in the shed and thoroughly clean and disinfect equipment such as feeders, especially equipment used in the sick pen. Minimise all stress on the calves especially during transport. Avoid overcrowding during transport and in calf sheds. Ensure calves have received adequate colostrum at birth. Vaccination of cows, 8 and 3 weeks before calving will help protect the calves via their mothers colostrum. Calf Rearing Fact Sheet 2.5

20 Calf Rearing Fact Sheet: Calf health Cryptosporidiosis 1. Crypto is a small protozoa parasite which causes diarrhoea in young calves. 2. The disease can be quickly controlled with aggressive oral rehydration tube feed with electrolytes. 3. Rapid rehydration avoids complications with secondary intestinal infections and reduced growth rates. 4. The protozoa is not host specific and can infect humans, especially children. It results in abdominal pain and cramping with watery diarrhoea, nausea, loss of appetite and weight loss. What is Crypto? Crypto can be a major problem in the calf shed causing diarrhoea in young calves usually seen between 4-28 days of age. Cryptosporidia are very small parasites called protozoa. The main problem species are C. parvum which infects the small intestine and C. muris which damages the abomasum. Infected oocysts are excreted in the faeces of infected calves. The parasite has a complex life cycle and persistent infections can be established in the calf. Infection spreads rapidly between animals and persists in the environment. The intensity of the infection increases as the calf season progresses due to increased contamination of the environment. Cryptosporidiosis usually originates from a point of infection (maybe one calf) and rapidly spreads to susceptible animals. Initially the incidence is low and peaks within 2-3 weeks. Morbidity (sickness) is very high but mortality (deaths) are usually low. The calf can get other infections (viral and bacterial) at the same time and this can result in severe illness and increased death rates. What does it look like? The parasite causes cell destruction and atrophy of the villi (lining of the small intestine and abomasum) resulting in reduced digestion and absorption of milk and fluids. The resulting diarrhoea can last from 4-13 days. Calves may be hunched and reluctant to suckle milk due to gastric discomfort. Faeces may be watery and yellow resembling rotavirus infection or may be mucoid, grey and slimy. Growth rates can be markedly impaired depending on the amount of damage to the villi. Poor growth rates are common for several weeks following recovery. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.6 How common is Crypto? Crypto is present on about 30% of dairy farms. Over 30% of calf scour samples are positive for Crypto The death rate from affected scouring calves is typically 10% in uncomplicated infections, but may be as high as 30% in septicaemic (dehydration, shock, and hypothermia) calves with secondary infections.

21 How can I tell if my calves have Crypto? It is very difficult to distinguish it from other causes without lab testing of faecal samples. Many calves with Cryptosporidia, Rotavirus and Salmonella scours lose their appetite. Scours from combined infections have a more severe effect. Typically scouring is 5-6 days but can be up to 12 days. There are now tests which are available for use on-farm. Consult your vet on how to interpret any results. Alternatively, ask your vet for sample pottles, and take samples from a minimum of 4 scouring calves. Ask your vet to test to identify crypto, and to also test to exclude Rotavirus, Coronavirus, E coli and Salmonella. Many calves will have multiple infectious agents so veterinary advice will be important. How do my calves get infected? From cows on infected farms. Some cows (typically 15%) may be shedding crypto at the time of calving (winter only). Calves are infected via contaminated faecal matter. This can be on tractor trays used to carry calves, calf rearing sheds, implements used to feed calves. Anything calves may find to lick or suckle may help to spread Crypto. Are all calves at risk of developing Crypto scours? Typically, Crypto scours will only occur up to about 25 days of age but this is much the same with other causes of calf scours. Most calves show signs from 6-21 days with the highest numbers showing signs of scours about 8-10 days. Many calves will become infected without scouring. An outbreak of Crypto will typically affect up to 30% of the calves being reared. What is the treatment? Remove from milk and feed electrolytes for 24 hours. Continued feeding of electrolytes between milk feeding is often required for a few days to support the calf. This allows the damaged gut to heal and helps hydrate the calf and restore the electrolyte balance. Halocur is a new drug which can be used to prevent and manage outbreaks of Cryptosporidiosis by reducing the number of oocysts excreted in the faeces. The use of high quality electrolytes enhanced with the carbohydrate- betacyclodextrin (Kryptade) have been shown to reduce the convalescence period. Hygiene and cleaning of equipment, feeders and people (clothing, boots, hands) is very important. Spraying the calf shed with disinfectants can help reduce the level of infection. What are the actual costs of Crypto? Many costs cannot be identified easily. We do know that experienced calf rearers work under tight time and budgets constraints and hospital mobs take a disproportionate amount of calf rearers time. Because scouring continues for a number of days, and younger calves seem to take longer to recover, treatment is extremely time consuming. This process is really tough on calf rearers. The delay in reaching weaning weight targets means the number of calves being fed increases, further increasing staff work loads. Crypto infections by themselves are not associated with high mortality rates, only prolonged recovery periods from scours. When calves have mixed infections e.g. crypto and rotavirus, mortality rates can climb alarmingly to 25-30% of calves being reared. This is particularly the case in calves who have had inadequate colostrum. These calves can make up 75% to 80% of the total calf deaths, primarily due to bacterial infections leading to blood borne infections. This group may get significant benefit from antibiotic treatment. Calf Rearing Fact Sheet 2.6

22 Calf Rearing Fact Sheet: Calf health Post-weaning animal health plan 1. Keep monitoring your calves after weaning. 2. Vaccinate calves and monitor parasites. 3. Know what the risks are in your area for facial eczema and copper deficiency. 4. Be proactive and act fast when issues arise. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.7 General It is still important to monitor calves after weaning. The earlier health issues are detected, the less effect they will have on live weight gain. Post-weaning diseases Internal parasites: Once calves have been on pasture for about 4 weeks they can become vulnerable to gastro-intestinal parasites. Cooperia is the main parasite at this age and causes scouring. The best treatment is a combination oral drench. Lice can appear from six weeks of age. Treatment usually involves a pour-on but consult your vet. Oral drenches do not contain an endectocide for lice. Pink eye: This is a highly contagious bacterial infection of the eye. The first sign is a discharge from the eye, the eye becomes reddened, an ulcer develops and finally the eyeball looks white. Most affected animals recover with treatment - see your Vet for remedies. Coccidiosis: This is caused by a protozoa (coccidian) and causes scouring and can result in rapid weight loss. It is generally seen in calves that have been taken off meal suddenly. Calves need to be put back on meal and weaned off gradually to allow for gradual exposure to the pathogen and for immunity to develop. Clostridial diseases: Prevention is the best option. Vaccinate with a 5 in 1 injection at 6-8 weeks of age and give a 2nd booster injection 4 6 weeks later. Hair loss can occur for a number of reasons ring worm, facial eczema or eczema. Ring worm is seen as small circles of lost hair. Facial eczema usually occurs in autumn and is caused by a fungal toxin on the grass causing liver damage and results in areas of hair loss/sunburn. Spring eczema is similar in appearance to facial eczema and appears to occur in calves with well developed rumens that are transitioning to high quality forage. Polio-encephalomalia (polio, vitamin B1 or thiamine deficiency):- This is seen as a sudden onset of a nervous condition - initially showing up as blindness and/or lack of coordination. Animals can fit and die if left untreated. Cattle normally produce sufficient vitamin B1 and the reason why this process is disrupted in calves is unknown. The disease is most common in late spring or early summer after weaning. Early treatment with a vitamin B1 injection is needed. Ryegrass staggers:- Occurs in summer and is caused by a fungal toxin in perennial ryegrass. The symptoms are staggering and lack of coordination- similar to polio except that develops more slowly and more calves are affected. Symptoms tend to disappear when the calf is relaxed. It is not life threatening move calves slowly, remove hazards like electric fences and move onto non ryegrass paddocks or feed hay or other supplements. Copper deficiencies:- In areas of deficiency calves often benefit from copper supplementation between 3 and 6 months of age. One symptom is a rough coat but confirmation should be through a blood test or liver biopsy

23 Calf Rearing Fact Sheet: Calf health Internal parasites 1. Larvae are ingested in pasture and as adults attach themselves to the intestinal wall and cause tissue damage. 2. Calves are susceptible to worms after weaning and the damage they cause to the wall of the intestine means that calves can have significantly reduced weight gains. Usually shows up on calves as a dirty backside. Can be mistaken for Coccidiosis (see Fact Sheet 2.9). 3. Drench before faecal egg counts get too high. 4. Oral combination drenches are generally the most effective in young calves. 5. Ensure you know how to drench effectively and when you should be drenching to avoid resistance. 6. Minimise worm burdens by feeding well, grazing good covers and graze clean pasture. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.8 Introduction Gastro-intestinal parasites (worms) are common in cattle and those commonly seen in cattle include Ostertagia, Trichostrongylus and Cooperia. Females lay thousands of eggs which are excreted in the faeces. When environmental conditions are favourable the eggs hatch into the L3 stage. L3 larvae are ingested along with the pasture, swallowed and then develop in to adult worms which attach themselves to the wall of the intestine. Damage to the intestinal wall can be measured in the blood by the amount of pepsinogen present. Adult worms start the cycle again by laying eggs which are excreted in faeces. Optimum conditions for hatching are moist grass with temperatures above 10 0 C The highest contamination levels on pasture generally occur between October and May. Once calves start eating pasture they can ingest larvae but intestinal parasite worm burdens tend to remain low until after weaning. Younger animals are more susceptible to worm burdens than older animals. The more larvae present on the pasture the more likely you will have problems. Ideally calves should be grazed on pasture that is fresh and has not been recently grazed by calves. Even low levels of infection can reduce growth rates in calves. Symptoms Low appetite, weight loss or reduced weight gain, Watery diarrhoea, Dehydration, Poor dull coat, Low energy, Faecal egg counts (FEC) above 1000 epg (eggs per gram of faeces) indicate significant adult worms, In calves, plasma pepsinogen concentrations above 1 IU/ml indicate infestation. Treatment Reduce exposure to parasite burdens by moving calves onto paddocks that have not been grazed for a long period. Avoid too much grazing pressure higher pasture covers reduce the number of larvae consumed as most larvae live close to the ground. Calves which are healthy and well fed will be less susceptible to gastro-intestinal parasites than weaker calves. Grazing paddocks with adult cattle or sheep after calves will reduce the larvae load on the pastures. Calves need to be drenched before worm burdens get too high. Can be administered as a pour on, oral or injection. Oral combination drenches tend to be the most effective drench in young calves. Talk to your vet re avoiding drench resistance - factors include using the correct dose, returning treated stock to contaminated pastures, not treating healthier animals, only drenching when necessary based on faecal eggo counts (FEC) and symptoms. Make sure that the volume of drench administered is based on the size of the largest calves being treated as under-drenching increases the potential for drench resistance. Provided resistance is not present, drenching should result in a rapid cessation of the diarrhoea.

24 Calf Rearing Fact Sheet: Calf health Coccidiosis 1. Coccidiosis is an increasingly common disease that affects animals from 4 weeks to 8 months. It is often associated with the end of meal feeding. 2. The parasite causes severe intestinal damage and affected animals can take a long time to resume normal growth rates. 3. Infection is by ingestion of oocysts which survive well in moist conditions. 4. Clinical signs include dysentery containing mucous and blood and faecal staining of the hind quarters. 5. Definitive diagnosis is difficult from faecal oocysts as the association between onset of diarrhoea and shedding is not consistent. 6. Response to treatment is the common method of diagnosis. 7. Best prevention is gradual weaning off concentrates (containing rumensin) alternate day feeding of concentrates and then once-weekly feeding coupled with rotational grazing to prevent ocyst build up. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.9. General Coccidiosis is an intestinal disease caused by a protozoa which occurs primarily in young calves aged 3-8 months of age. In heavily contaminated environments calves may show clinical signs as early as 4 weeks of age. Typically Coccidiosis has high morbidity (sickness) and moderate mortality with long term affects on production in animals which survive. The incidence of this disease is increasing and the detrimental effect on dairy beef performance is considered significant. This condition can be controlled by inclusion of a coccidiostat in the rations and strategic grazing management. What is Coccidiosis? Coccidia are intracellular, protozoan parasites which co-exist in the intestinal tract of cattle. Eimeria zuernii and Eimeria bovis are host specific and infect the ileum and large intestine. The life cycle is complex, including both asexual and sexual reproduction. Sexual reproduction results in the formation of oocysts which are passed in the faeces. The source of infection is the faeces of clinically infected animals. The calves ingest oocysts from contaminated pasture, feed and water or by grooming each other. Dry conditions and high temperatures in the pasture will destroy oocysts within a few weeks. However under moist conditions they can survive for up to 2 years. Clinical disease occurs when there is damage from heavy infestations or the calves have lowered resistance through stress, poor nutrition or concurrent diseases. The gut mucosa becomes denuded and stripped of villi which results in severe haemorrhage and impaired water absorption. This leads to diarrhoea, dehydration and death. In lighter infections, mal-absorption is a consequence of villi atrophy resulting in poor growth rates and ill-thrift. What circumstances influence the disease? Initially, there is a build up of infection on the pasture that the calves are grazing. This is often caused by continual use of the same calf paddocks each year. Seasons that are mild and moist speed up the contamination. The cessation of meal feeding is also often associated with coccidiosis. Calves that have had lots of meal have been protected by the coccidiostat (often rumensin) in their feed and so haven t had the need or opportunity to build up immunity against the parasite. The incubation time is 2-4 weeks and then Coccidiosis is seen as a sudden onset of diarrhoea, usually in many animals in the group.

25 What are the presenting signs? The incidence and severity of this disease ranges from low grade to acute, severe and often fatal. This is directly related to the level of stress the animals are under. Animals often appear unhappy and uncomfortable and may exhibit severe unproductive straining while defecating. Temperature is mildly elevated ( degrees C.) Dehydration and lack of appetite are common. The passage of blood and mucous stained faeces is often the first sign of disease. Faecal staining of the tail, hind quarters and hocks is a strong indication of the presence of Coccidiosis. This is known as the Coccidiosis flag or windscreen wiper effect. Affected calves rapidly lose condition. Moreover, because parasites damage the gut lining, regaining condition takes a long time. Severely affected calves typically undergo a convalescence of many weeks, during which feed intake and weight gains are reduced. Animals can become unthrifty. Mild and chronic cases show up as weight loss, anaemia and mild or no diarrhoea. Calves appear weak and listless with droopy ears and rough coats. There is a continuous re-infection in a heavily contaminated environment together with a partial immune response struggling to hold the parasite in check. How do I know it is Coccidiosis? Laboratory tests for Coccidia oocysts are done using a salt flotation method. Oocysts counts > 5,000 /g are significant. The interpretation of results is complicated by non-pathogenic oocysts which can also be present in large numbers. Likewise, diarrhoea can also occur before the oocysts are shed in the faeces, thus false negative results are possible. Also oocysts numbers may be under-estimated because of the dilution effect of fluid faeces. Blood tests are of limited value, though they may confirm a calf is anaemic. A definitive diagnosis can only be made at post-mortem examination by collating gross findings with histology and impression smears. The best diagnosis is often a rapid recovery from treatment. What is the treatment and how do I control the problem? In an outbreak the sick animals should be isolated and given supportive oral fluid therapy and treated with coccidiocidal drugs. Preferential feeding may be needed to obtain satisfactory growth rates. Severe cases may recover. The remainder of the animals should be removed from the infected pasture and the stocking rate reduced. Place calves back on meal containing a coccidiostat and then gradually remove the meal from the diet. This allows the calf to build up its immunity gradually. Minimise stressful procedures during an outbreak. What is the prevention? Gradually weaning calves from concentrate feeds containing a Coccidiostat to 100% pasture allows a calf time to build up its own resistance to the protozoa. Feeding the concentrate with Coccidiostat on alternate days, progressing to weekly feeding is beneficial. Rotational grazing during the post weaning period prevents levels of infection building up whilst the calf is building up immunity. Supplementation with a concentrate containing a coccidiostat can be strategically effective in breaking a cycle of infection when the challenge is high, especially warm moist climatic conditions. Regularly clean and move feed and water troughs. Calf Rearing Fact Sheet 2.9

26 Calf Rearing Fact Sheet: Calf health Skin diseases 1. Lice in young calves may indicate underlying stress or poor nutrition. 2. Ringworm is a Zoonosis which means it can be transmitted to humans. Animals usually recover without treatment. 3. Spring eczema usually occurs when calves with well developed rumens are transitioned onto grass and augmented by application of pour-on treatments at this time. 4. Facial eczema occurs in late summer and autumn and results from liver damage caused by a fungal toxin in pasture. Monitor spore counts and prevent with zinc treatment. Lice Lice are biting and ecto-parasites that live on the skin of calves. Lice populations tend to be lower in summer. Calves that are poorly fed or under stress may become heavily infested with lice, secondary to the primary condition. Biting lice cause intense irritation leading to rubbing against all kinds of objects, resulting in hair loss Lice can be seen on the skin and eggs appear as white specks attached to the hair shaft. Examine the areas around the neck, shoulders, back line and tail. Treatments for lice are usually a pour-on insecticide to the animals back. Ringworm Dermatophytosis or ringworm is very common in young cattle. It is a highly infectious and contagious fungal disease caused by Tricophyton verrucosum. The disease is more prevalent in warm and humid climates. Lesions occur anywhere on the body but are most common on the head especially around the eyes. They are thick, round, greyish, crusty areas of often several centimetres in diameter which are raised above the skin surface. Spontaneous recovery usually occurs so treatment is not normally undertaken. The lesions may persist for 1-4 months. Ringworm is a zoonosis which means it is transmittable to humans. Care with handling infected calves and washing hands with an iodine based soap is important. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 2.10

27 Spring eczema Spring eczema is a well recognised problem that occurs in recently weaned calves. Most cases occur in calves that have been reared intensively on grain and low milk diets to promote early rumen development. These calves have a large rumen capacity and their liver is not able to cope with the enormous supply of chlorophyll and it s metabolite, phytoporphyrin. This accumulates in the bloodstream and skin. The reaction with sunlight results in an acute photosensitisation producing sunburn-like lesions. Treatment with chemicals to combat lice and worms at this critical time (i.e. when calves are introduced to pasture) can predispose calves to this condition. This is because metabolising the drug places additional demands on the liver. Calves develop a swelled, reddened, flaky or scabby skin on the white areas of the skin, usually along the back. This can become thick and leathery which eventually peels and leaves red, inflamed tissue underneath. Affected calves should be housed out of direct sunlight or have access to shade. Allowing them to graze at night helps to prevent further damage to the skin. Treatment with anti-inflammatory drugs and anti-histamines can be beneficial. Application of zinc based ointments (Filtabac) can be used to block out the effects of the sun. Facial eczema Facial eczema is caused by the ingestion of a toxin (sporidesmin) which is contained in the spores of the fungus Pithomyces chartarum. This fungus grows and produces large numbers of toxic spores in conditions of high humidity and warm overnight temperatures in late summer and autumn. The fungus grows on the dead litter of pastures, with highest concentrations of spores in the base of the sward. The disease tends to be associated with perennial ryegrass because of its ability to produce dead litter. Clover, kikuyu, paspalum and tall fescue are safer than ryegrass dominant pastures. The toxin causes damage to the liver resulting in an obstructive jaundice. Phytoporphyrin accumulates in the bloodstream and skin and results in photosensitisation. This photosensitisation tends to occur 2 weeks after exposure to the toxin and is characterised by irritation, reddening and swelling of exposed hairless (eyes/ears/nose/inside hind legs) and nonpigmented skin. The calves rub the affected area on branches or posts and large areas of skin may fall off. Most calves are affected sub-clinically and have poor growth rates. Diagnosis is made by blood tests for elevated liver enzymes indicating liver damage. The control of facial eczema involves monitoring spore counts on grasses to identify danger periods; spraying pasture with fungicides to prevent growth of the fungus, grazing management to avoid high risk pastures; administering zinc as a preventative to minimise the toxic effect of sporidesmin on the liver. Calf Rearing Fact Sheet 2.10

28 Calf Rearing Fact Sheet Feeding - colostrum, milk, milk powder 1. The best calves will be those reared on ad libitum milk. But rearing costs will be higher and rumen development will be slower this is likely to reduce post weaning growth rates. 2. Calves fed on colostrum and whole milk will generally have less health issues than calves reared on milk powder. 3. Milk powders which do not curd are generally not suitable for very young calves (less than 2 weeks). The labelling on milk powders is not helpful and we suggest a curd test to ascertain the suitability of milk powders. This fact sheet is one in a series available at this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.1 General The best calves will inevitably be reared on ad libitum milk. However, milk energy is expensive and the more milk that is fed to a calf, the slower the rate of rumen development. This means that weaning is delayed, further increasing the rearing costs. Calves reared on ad libitum milk powder often grow poorly after weaning because they have poor rumen development. Colostrum Colostrum is the best feed source available to newly born calves. Technically, colostrum comes from the first milking and subsequent milkings produce transition milk. First milking colostrum has more fat, protein and minerals than milk and contains 22% solids. The quality of colostrum declines rapidly after the first milking and by day 3 after calving, transition milk is very close to milk in composition. Although the antibodies in colostrum are only absorbed for the first 24 hours of a calf s life, continued feeding of colostrum and transition milk can still have huge benefits. Even slightly higher immunoglobulin levels appear to have beneficial effects within the gut and can offer some protection against pathogens such as rotavirus if the cow has been vaccinated. Colostrum has a higher feed value than milk and, depending on the size of the calf, 3-4 litres daily is usually sufficient for the young calf if it is also being fed meal. Colostrum that has blood in it should be fed fresh. Colostrum can be fermented with yogurt and stored (chilled for up to one month or frozen). Whole milk Cows milk contains around 12.5% solids, has a high energy value and the correct balance of nutrients. Calves fed on whole milk generally have fewer health issues than calves fed on powdered milk. There is plenty of on-farm evidence that the best feed for calves is fresh, warm whole milk. Whole milk and colostrum can be preserved by acidification with formalin (20 ml/10 litres) or citric acid (1.5 g powdered citric acid/10 litres) or adding yoghurt before storage. Use l sachet or 1litre to 20 litres of colostrum, let it age and then use to seed the next batch of colostrum.

29 Milk powders Calf milk replacers are generally fed when whole milk is not available (or is too expensive to feed). Milk powder is used to rear many of the 500,000 Friesian bull calves reared each year and sometimes used to finish off the rearing of heifer calves once colostrum and transition milk has finished. Milk powders usually contain 24% protein and On-Farm Research product surveys have shown this can range from 22 to 29%. The fat content is typically 22% but with a range from 17 to 23%. Unfortunately the labelling on NZ milk powders is poor, with many indicating minimum rather than actual specifications. It is difficult for rearers to make value judgements on milk powders as there is no information on the actual ingredients used. Phrases like proven blend, leading brand, premium product are not very helpful to the discerning calf rearer. By contrast, European labelling requirements provide much more detail as shown below. Composition 24% Protein 19% Fat 6.8 % Minerals 0.01% Crude fibre 1.8% Lysine 0.6% Methionine 0.25% Cystine 1.12% Threonine 60.25% Milk Powder Most New Zealand made milk powders are formulated from by-products of dairy processing (e.g. whole milk powder, skim milk powder, whey powder, butter milk powder) along with added fats, vitamins and minerals. Milk powders containing a reasonable percentage of skim milk powder or whole milk powder will contain casein proteins and should curd. In recent years, whey milk powders have been imported from Europe. These have had the casein proteins removed as cheese and will not curd. Skim milk powders which have had excessive heat treatment have had their casein proteins denatured and will also fail to curd. Although these non-curding milk powders are generally cheaper, they are not really suitable for very young calves. Non-curding milk powders are suitable for older calves (e.g. 2-3 weeks old ) and for feeding once colostrum and transition milk has finished. Curd Test Because labelling on milk powders is poor, it is often difficult to determine whether milk powders are made of casein or whey proteins. For this reason we suggest a curd test - a milk powder is unlikely to curd unless it contains a significant amount of skim or whole milk (probably 60-70%). Make up 500 ml of the milk powder you wish to test, as per the instructions on the bag. Keep at 39 C (set the oven and use a thermometer) and add 5 ml of rennet. A good curd should have formed within 20 minutes. Do the same with some blue milk so you can see what a really good curd should look like - though it is very unlikely that any milk replacer will curd as well as whole milk. Calf Rearing Fact Sheet 3.1

30 Calf Rearing Fact Sheet: Feeding Milk feeding systems 1. Understand the strengths and limitations of the different systems. 2. It is the combination of the system and the people and farm resources that determine the success of a system. 3. Choices include once a day or twice a day, low or high milk volumes. 4. High milk volume systems require twice a day feeding but calves can be outside early and fed in larger mob. 5. With high volume milk system calves are older before they can be weaned. 6. Low milk systems require calves to be kept inside until weaning and the feeding of pellets or meal. But these calves can be weaned between 5 and 7 weeks. 7. Colostrum and whole milk are generally preferred on dairy farms. 8. Calf pellets or meal encourage early rumen development. General There are many systems for rearing calves. Each system has advantages and disadvantages and principles that need to be followed to be successful. It is the combination of the feeding system and the rearer that determine the success of a system. Attention to detail and good observation skills are critical. Calves are born with a non-functioning rumen and it is the development of the rumen that controls the age at which calves can be weaned. Calves with a poorly developed rumen cannot digest grass. Pellet or meal intake encourages rapid rumen development and enables earlier weaning. Grass is a very bulky feed so even though a calf might have a well developed rumen, it is still relatively small and pellets or meal will still be required until the calf s rumen is large enough for it to digest adequate quantities of grass to provide the nutrients required for optimum growth and good health. Options Once a day or twice a day feeding? Twice a day feeding requires a higher labour input but means that each calf can be individually checked twice each day (see Fact Sheet 3.3). On a high volume milk system calves are usually fed twice a day to reduce the risk of nutritional scours from the large milk volumes used. On a restricted milk system, calves are fed for 7-10 days on twice a day feeding although small calves and Jersey calves are fed for longer (see Fact Sheet 3.4). Pellets or meal and clean drinking water must be available when calves are fed once a day. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.2 Low or high milk volumes? Low milk volumes require compartmentalised feeders, housing of calves until weaning and the feeding of calf pellets/meal but calves can be weaned off milk between 5 and 7 weeks of age. High volume milk systems mean calves can go outside earlier and can be fed using large calf trailers. Less calf pellets or meal are fed. Rumen development is slower in high milk volume systems and calves cannot be weaned until they are about 9-10 weeks old. A lot more milk is fed in these systems and reduced rumen development can result in a post weaning check.

31 Inside or outside? Calves on high volume milk systems can be placed outside from as early as one week of age as long as they have access to sheltered paddocks. However cold will increase the energy demands of the calf. A Friesian calf will begin to shiver at 5 C when there is no breeze or rain. However shivering commences at 12 C when it is windy and wet. Calves being fed a low milk system need to be kept inside until they are weaned off milk at 5-7 weeks of age. Colostrum, milk or milk powder? Quality colostrum is best followed by milk, followed by calf milk powder. Generally, whole milk or colostrum are the preferred feeds on dairy farms because they are readily available and easy to feed. They are cheaper than CMR (calf milk replacer) and there is no extra work with mixing. If a calf milk replacer is fed it is important to feed a high quality milk powder for at least the first two weeks. High quality milk powders are those containing skim milk powder and which curd (see Fact Sheet 3.1). The advantage of calf milk replacers is that calves can be fed away from the milking shed without having to transport milk to the calves. Calf milk replacers are often the only option for bull calf rearers without access to whole milk. Concentrates or not? Concentrates include calf meals and pellets. They increase the rate of rumen development and allow calves to be weaned earlier reducing costs. It can be difficult to get calves to eat concentrates when they being fed ad lib. milk. They aren t hungry so don't bother with the meal. Rather like filling a child up on ice cream and then suggesting they eat cereal. If calves are being fed restricted milk and not eating the concentrates, they may be unpalatable. Calves do not like meal/pellets containing palm kernel. The most appropriate choice will depend on:the facilities available, amount and skill set of labour available, the required performance and the cost. When reviewing costs it is important to remember that the protein and metabolisable energy in concentrates generally cost only 40 and 60%, respectively, of those in whole milk. It therefore makes good economic sense to have a high proportion of calf diet made up of concentrates. Calf Rearing Fact Sheet 3.2

32 Calf Rearing Fact Sheet: Feeding Feeding - high volume 1. Traditional system used on dairy farms. 2. Good live weight gains achieved up until weaning. 3. Calves weaned at around 9-10 weeks kg for Friesians and 70 kg for Jerseys. 4. Uses a lot of milk (average 400 litres/ calf) and generally requires a much longer period of twice a day feeding. 5. Good growth rates can be achieved. 6. High milk volumes can delay rumen development and can result in a postweaning check if the calf cannot digest enough grass to meet its energy requirements. 7. Hard to monitor calves in large groups. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.3 General Traditionally, high volume milk systems are used on dairy farms. Colostrum or vat milk is readily available, mixing is not required and is seen as a cheaper option. High live weight gains can be achieved. To rear a 37 kg calf gaining 0.80 kg/day to 90 kg at weaning at 10 weeks of age on milk requires approximately 400 litres of milk. Typical system There are many variations in terms of how much milk and for how long it is fed, when calves go outside and age at weaning. On arrival at the calf shed feed calves 2 litres of first day colostrum and a further 2 litres later. Calves also need to be trained to drink off a feeder. Calves are fed an average of between three and four litres of colostrum or vat milk twice a day. Best to feed milk warmed to degrees C. Some people feed milk ad libitum - meaning that milk is always available. Large quantities of milk can be consumed using this method. Calves can go outside from a week old if suitable shelter is accessible and the weather is good. There are benefits in the calves having access back to the sheds as these very young calves are vulnerable to the cold. Once outside they are generally fed in large groups on a cafeteria pulled behind a vehicle - usually a motorbike. Need to check all calves are feeding well and this is often difficult with 50 calves to a feeder. Calves consume minimal amounts of other feeds, in particular concentrates, whilst milk intake is high. Rumen development is delayed as a consequence. On average, calves are weaned off milk at 9-10 weeks of age. Advantages Can be put outside early. Only a small amount (if any) concentrates are fed. As calves are outside early there is reduced exposure to high levels of pathogens. Disadvantages Can get post weaning growth check due to poor rumen development. Feed a lot more milk with less control so easier to get nutritional scours as some calves can drink more than their share and is more expensive than some other options. Less hands on so harder to closely monitor individual calves in larger groups. Wean later and feed twice a day longer so higher labour input for longer.

33 Calf Rearing Fact Sheet: Feeding Milk feeding - low volume/restricted milk 1. Milk energy is expensive whereas pasture energy is cheap. However pasture is an inadequate diet for young calves. 2. Pellets or meal (20% Protein) need to be available from day one to promote early rumen development and to transition calves from milk to pasture if early weaning is desired. 3. Feeding restricted volumes of milk to housed calves (i.e. not fed grass) encourages them to eat larger volumes of pellets or meal. 4. Using this system calves can be weaned off milk if they are healthy and have put on at least 20 kg live weight since arriving in the shed and are eating at least 1 kg of pellets per day. This is generally between 5 and 7 weeks. 5. Need to use a compartment milk feeder (see below) to ensure all calves are getting sufficient. 6. Pellet feeding continues after weaning and until the calves are at least 12 weeks old. General Milk is the most expensive component of a calf s diet whether it is removed from the vat or purchased as milk powder. Reducing the amount of milk fed and getting the calf onto pasture faster will reduce rearing costs. However, grass does not meet the nutritional requirements of a young calf because the calf s rumen is small and not well developed. Because grass is bulky and can be up to 85% water, it is hard for the calf to consume enough. Feeding calf pellets or meal encourages early rumen development and provides the nutritional bridge between milk and pasture in a low volume/restricted milk system. Milk feeding Sort and group the calves on weight and feed accordingly. Calf milk replacer concentrated at 200g milk replacer/litre from Day 1 (see table) or feed whole milk 2 litres morning and and again late afternoon for 10 days and then switch to 3 litres of milk fed once a day for a further 5 weeks. Where restricted milk diets are fed it is essential that compartment feeders are used and calf feeding is supervised so that all calves get their ration. Twice a day feeding can be carried out for longer by spreading the amount over two feeds but it increases labour requirements. Day Small <37kg * Medium 37kg 43kg Large >43kg x 1 litre 2 x 1 litre 2 x 1 litre x 1 litre 1.50 l 2.00 l x 1 litre 1.75 l 2.25 l l 2.00 l 2.50 l l 2.25 l 2.50 l l 2.50 l 2.50 l l 2.50 l 2.50 l l 2.50 l 2.50 l l 2.50 l Weaned l Weaned Weaned Total milk replacer/ calf (kg) this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.4 * These are typically Jersey calves. From day 1 have fresh 20% protein calf pellets (or meal) available ad libitum (i.e. always have some left in the feeder). Have fresh straw or low quality hay available. Always have clean drinking water available. A good test of this is whether you would drink it!

34 Weaning off milk Calves are best kept in the shed until after weaning. If they are on pasture they will eat pasture rather than the pellets and this will slow down both the rumen development and their rate of growth. Calves can be weaned off milk if they are healthy, have gained at least 20 kg live weight since arriving at the shed and are eating at least 1kg of pellets or meal per day. Calves should be kept inside for a couple of days after weaning off milk so that any calves not eating enough pellets are detected. These calves can then be placed back on milk. Post weaning Pellets can be changed from 20% protein to 16% (protein) calf pellets if the calves have access to and are consuming reasonable amounts of high quality pasture (green, leafy, clover, growing well). If there is good quality pasture available the amount of pellets being fed/ head can be slowly reduced as follows:- Up to the end of week 8 Up to the end of week 10 Up to the end of week kg/head day 1 kg/head/day 0.5 kg/head/day After week 12 stop feeding pellets if calves are meeting growth targets. If there is not enough quality grass then more pellets will need to be fed for longer. Over summer an alternative feed source may be needed if pasture quality or quantity is limited. Advantages Calves in small groups so easy to closely monitor health. Calves can be weaned early. Feed less milk in total. If done properly reduced likelihood of nutritional scours. Disadvantages Calves need to be kept inside until weaning. Keeping calves inside for longer means higher risk of a disease outbreak if hygiene is poor. Requires the feeding of calf pellets or meal to encourage early rumen development. Calf Rearing Fact Sheet 3.4

35 Calf Rearing Fact Sheet: Feeding Rumen development 1. The newborn calf can only digest milk it needs to move to a fully functioning ruminant which can digest a complex diet like pasture. 2. Milk does not develop the rumen. Grain causes much rapid rumen development than pasture because it stimulates papillae development. Top photo - calf fed milk and hay Bottom photo calf fed milk and grain This factsheet is one in a series at Published by On-Farm Research, PO Box 1142, Hastings, NZ. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.5 Digestion in the new born calf At birth the young calf has a simple digestive system with only one of the four stomachs (abomasum) functional. The abomasum in a 40 kg calf can hold 1.5 litres but it expands rapidly to a capacity of litres within a week. Since the calf can only handle a highly digestible milk diet when it is born it has to undergo major changes before it can handle a less digestible diet like pasture. Digestion in the adult Diets such as pasture and silage contain fibre that cannot be absorbed directly - it needs to be broken down by microbial fermentation before it can be absorbed. To deal with this fibre, adult ruminants have a large fermentation vat (rumen) which operates at a neutral ph and where microorganisms can digest complex carbohydrates/fibre. The lining of a fully functioning rumen is covered in papillae which are finger like projections which greatly increase the surface area for absorbing the nutrient produced by microbial fermentation. Developing the rumen The rumen is small at birth and milk causes no rumen development at all as it by-passes the rumen and goes straight to the abomasum. Soon after birth, the rumen begins to develop a population of microbes which enter the rumen when the calf nibbles on grass, straw or bedding. The microbes that develop will be those that best digest whatever dry feed the calf is eating. Water is important for the growth and multiplication of these microorganisms and if it is not provided, rumen development is restricted. As well as growth in size, the rumen papillae need to develop in order for the rumen to become functional. Calves fed grain (or meal) will develop a functional rumen much more quickly than calves fed on milk, grass or hay. This is because grain produces butyrate and proprionate when fermented and these products develop the rumen papillae. Calves fed on milk and grass will eventually develop a functional rumen but the process will take much longer. This makes for a longer milk feeding period and a higher rearing cost. To optimise rumen development, and achieve early weaning, calves need to have a palatable grain based ration on offer as soon as possible (Note: palm kernel is not palatable for young calves).

36 Calf Rearing Fact Sheet: Feeding Weaning 1. Base your weaning decisions on calf weights (scales are more accurate than guess work). 2. Transition calves onto clean high quality pasture once meal intake is greater than 1 kg/calf/day. 3. Calves must have access to clean water. 4. Access to shelter for young calves on pasture reduces health risks. 5. Ensure adequate meal intake prior to weaning. 6. Gradually reduce milk over a week. 7. Keep other practices the same during the process of weaning 8. Check animal health procedures vaccination, parasites, minerals. Consult your vet if necessary. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.6 When to Wean Prior to weaning, calves need to be growing well and be on a combination of milk and meal. Weaning age will depend on the feeding system used. Calves on a typical high volume dairy farm system (see Fact Sheet 3.3) will have slower rumen development and need to be weaned at much heavier weights. Dairy NZ targets are 100 kg for Friesian calves, 90 kg for crossbred calves and 80 kg for Jersey calves. On a low volume/restricted milk (an early rumen development system - see Fact Sheet 3.4) calves will be able to be weaned a lot earlier. For example, Friesian calves can be weaned at 65 kg, crossbred calves at 60 kg and Jersey calves at 55 kg. These are minimum weights, not the average of the group. And all calves need to be eating 1 kg of meal before they are weaned. It is important to remember that if a mob of 20 calves are eating 20 kg of meal, some individuals will only be eating 0.5 kg and will not be ready for weaning. Watch out for these individuals - they will be hollow looking and noisy - and put them back onto milk. Weaning Ensure pasture the calves are going onto is clean and of high quality. Often paddocks close to the rearing facility are weed infested and used for effluent. Plan ahead and prepare high pasture quality for calves. The aim is to encourage intake. Access to clean water is also essential. Access to shelter is important. If calves are introduced to pasture at an early age a sudden change in weather or lengthy periods of adverse weather increases the susceptibility to health problems like pneumonia Gradually reduce milk over about a week. Do not water down the milk given. The aim is to encourage the calf to replace milk with meal and/or pasture. Increase meal feeding to 2 kg/head/day. Then after 2-3 weeks, slowly reduce the meal available to 1 kg/head/day and down to 0.5 kg/head/day after 4-6 weeks. Continued feeding of small quantities of meal or crushed maize through the summer will maintain calf growth rates. Reduce the stress by keeping other things the same and choose your timing regards weather conditions. It is of course best to have a few fine days postweaning. Once weaned calves are settled, they can either be in one mob and moved around the farm ahead of cows to ensure access to high quality pasture. Animal health (see Fact Sheet 2.7)

37 Calf Rearing Fact Sheet: Feeding Managing the summer Achieving target growth rates is often difficult over summer because of poor summer feed quality. Calves reared on a high milk volume system fare worst because of insufficient rumen development. Silage is just a substitute for pasture and is often of insufficient quality to maintain summer growth rates in young calves. High energy supplements can be used but must be introduced slowly. Calves fed 1 kg of palm kernel and 1 kg of crushed grain grew at 0.9 kg/day compared to calves fed pasture alone which grew at 0.6 kg/day. Calves on forage rape (Winfred) can grow at 1 kg/day provided they have 3 weeks to adapt to the crop and they are not forced to eat into the stems. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.7 What is the problem? Milk feeding is only part of calf rearing. After weaning a young calf needs high quality feed well beyond weaning as the rumen is simply not big enough to cope with much roughage and roughage is often what they have to contend with over their first summer. Feed which is drying off and going to seed is rapidly declining in energy. The end result is slower growth rates. Calves which have been reared on high milk volume systems with little meal often fare even worse over their first summer (than those reared on low milk volume/high meal). This is because milk is a great energy source but it does not actually stimulate rumen development. On the other hand, the grain in meals encourages the growth of the papillae which line the rumen wall and which absorb the products of rumen digestion. Calves with good rumen development may not be as heavy or look as round as calves which have been fed a lot of milk but they are better placed to handle poorer quality feed. Many high milk volume calves go backwards after weaning because their rumen is not sufficiently developed to digest low quality feed. The same issues apply to bull calves and many bull finishers hold off their calf purchases until the autumn so they can buy calves that someone else has battled through the summer. With bull calves there is an obvious gap between when calf rearers need to sell their calves (late spring) and when finishers want to buy (early autumn) which creates ongoing problems in the bull beef supply chain. Calves can potentially grow at 1.3 kg/day over their first summer to achieve this requires an impractical ration of ad lib. lucerne hay and pellets containing by-pass protein. Nevertheless, it shows what is possible. Yet even on good quality summer pasture, calf growth rates are typically kg/day. A Friesian dairy heifer weaned at 100 kg on the 30th November should be 185 kg on the 1st April. But if it only grows at 0.5 kg/day over the summer it will be 25 kg behind its target weight. Live weight penalties incurred over the first summer can be recovered before mating but not without very good management and supplementation. Brassicas Feeding a brassica crop is probably the most cost effective way of ensuring good calf growth rates - particularly in a summer dry area. Forage rapes provide the best fit as they can be grazed early yet are capable of carrying a bulk of feed into the summer. There are cultivar differences in growth and animal performance but Winfred has consistently given good animal performance and can be grazed 85 days after sowing.

38 Brassicas (continued) On all brassica crops, calves need time to adapt to what is a complete change of diet (3 weeks seems sufficient). This means that growth rates will be slow initially after calves are introduced to a crop. In two different experiments, calves on Winfred grew at 0.6 and 1.0 kg/day over the first 3 weeks and 1.1 and 1.2 kg/day over the second 3 weeks. To achieve this level of performance, calves need to be rotationally grazed and moved once they have eaten the leaf off the crop. If they are pushed to graze into the stem they won t grow as fast and brassica re-growth will be compromised. Feeding supplements at pasture Calves can be fed silage but this is just a pasture substitute. Higher growth rates often require higher energy supplements. The advantage of supplements is that they can be used on an as-required basis whereas brassica crops require planning and having land that can be taken out of grass. In a series of experiments feeding supplements to pasture fed calves, growth rates were typically increased from 0.6 kg/ day on summer pasture to 0.75 kg/day with 1 kg of supplement (25% of total ration) and to 0.9 kg/day with 2 kg of supplements (50% of total ration). Supplements used were typically a mix of 50% crushed maize and 50% palm kernel. While palm kernel has palatability issues for very young calves, this does not appear to be an issue once calves are older than 3 months. Calves need to be adjusted to supplements gradually to avoid dietary upsets and potential acidosis. However this is not an issue if the summer feeding supplementation is simply a continuation of the rearing and meal feeding programme. Calf Rearing Fact Sheet 3.7

39 Calf Rearing Fact Sheet: Feeding Nurse cows 1. Staff need patience and a high level of management and stockmanship. 2. Plan ahead and ensure suitable facilities are available. 3. Good calf weights can be achieved with a relatively low cost system. 4. Cows can be bought as budget in-calf cows and some people breed their own self-replacing nurse cow herd. 5. Can successfully raise 3-4 calves per batch and 2-3 batches per season. A total of 10 calves per cow. 6. There are various methods of mothering on foster calves all involve time, patience and monitoring. 7. Calves can very quickly go down with scours from over feeding. Do not overfeed cows in the early stages. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 3.8 Staff Staff must be patient and enjoy the challenge of mothering on (difficult) calves. Staff must be committed with a high level of management skill to be successful. Without the right staff this system will fail. General Mothering on and multiple suckling of calves on cows is a low cost way to rear calves and calves reared on nurse cows normally grow very well. However, nurse cow reared heifers have had less contact with people and are often more difficult to train to be milked. A high producing Friesian cow, which is well fed, can raise 3-4 calves at a time and then rear another 2 or 3 sets of calves during the season. Alternatively, the first set of calves can be left on and weaned at 200+ kg at the end of summer. The cow and her calves require lots of high quality feed (20 kg DM/cow/day). Need suitable facilities for mothering on and shelter for calves while they are very young. Obtaining Cows Friesian cows are usually preferred if planning on retaining for the next season as a Jersey cow s own calf is not usually of high value. Purchase in-calf cull cows. Arrange to take on carry over cows that are still producing well. These may raise fewer calves than a cow purchased in early lactation. Three calves on a cow at a time and three sets of calves over a season can often be raised. e.g. Autumn calves, end of July and again early October although the last group may be hard to procure. Purchase cows with high somatic cell count early in the season. Mothering on It is possible to raise 2-4 calves on one cow depending on her milk supply. Remove the cow s own calf and place this calf with the foster calves together in a covered pen. Ideally keep each calf set together. When choosing foster groups, aim to group similar calves together same weight, temperament, age. Run cow in night and morning initially, allow calves to suckle for minutes ensuring all calves get adequately fed. Once the cow is relatively accepting of her new family they can be left together and placed by themselves in a slightly larger enclosure for the cow to access some feed and water. DO NOT over feed cows at this stage.

40 More keys to success 8. Only mob up with other cows and calves when well bonded. 9. Calves weaned too early will suffer from a check as the rumen is insufficiently developed. 10. A cow with 3-4 calves will need to be fed as a fully lactating cow at least 20 kg DM/day. 11. DO NOT forget about these cows and calves once the mothering on is finished. Mothering on Closely monitor your cows and calves. OBSERVE often. Once let out of the shed the cow s own calf may overfeed, resulting in scours. Increase intake of cows gradually. Very high intakes too soon can result in calves overfeeding, resulting in scours. Calves with scours can go down very quickly. Treat for dehydration promptly. Once cow and her foster family are bonded they may be joined to a larger group. In large mobs, cross suckling often occurs. Watch for tail-enders. Growing and Weaning A cow raising four calves will require at least 20 kg DM/day as these cows are producing large quantities of milk. Nurse cow reared calves cannot be weaned early as the rumen is insufficiently developed. Calves can normally be weaned at 10 weeks when another batch of young calves can be mothered on. Transitioning the weaned calves onto ad lib meal prior to weaning is beneficial to minimise post weaning check. If pastures dry out, 1-2 calves per cow can be weaned to reduce the feed demand of the cows with remaining calves. Monitor cow live weight and take appropriate action if live weight is dropping, especially if planning to mother on another batch. Summer Management Calves on nurse cows, grazing adequate high quality pasture maintain good growth rates over summer. Weight gains of 1 kg/ calf/day are achievable. Ensure all normal animal health procedures are carried out and mineral status is adequate. DO NOT forget to monitor these cows and calves! Water and shade are important. Calf Rearing Fact Sheet 3.8

41 Calf Rearing Fact Sheet Why targets, benefits of weighing 1. Set live weight targets specific to the cows in your farm system. 2. Setting targets allows you to know what you are aiming for to ensure optimal cow performance. 3. Setting targets and monitoring progress means you can be proactive in making sure you achieve targets. 4. Weighing is more accurate than either weigh band or eye-o-meter. General Setting targets in the context of this fact sheet involves identifying goals for the live weight of dairy animals at a specific time or age. Within the dairy industry, targets are often referred to as a percentage of mature live weight. Mature live weight is significantly affected by breed but also varies between farms and farm systems. Know the mature live weight of your herd and then establish target live weights for stock starting at weeks. To establish the mature live weight of your herd either weigh 10% of your 6-8 year olds in Dec/Jan (Spring calving herd) or use the following formula:- Expected mature live weight = Live Weight Breeding Value Note Live Weight Breeding Value can be obtained from your herd improvement organisation. Monitoring progress towards established targets is important as it allows you to have confidence that you will arrive at the destination (Mature live weight) on time and reap the benefits OR be alerted early on and be able to take remedial action to get back on track. See Farm Fact Sheet on setting targets 4.2 and on. Scales are by far the best option for weighing calves, however weigh bands are certainly a big improvement on an imprecise eye-o-meter. this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 4.1 Visually assessing live weight is unreliable. Calves can be healthy, have a shiny coat and appear to be doing all the right things except growing at the required rate to achieve targets. Poukawa weighed 500 calves and compared their weight and girth measurements with a commercially available weigh band. The commercial weigh band used was not a good predictor of weight and had obviously been calibrated from weaner beef calves and extrapolated back to lighter (dairy calf) weights. Ideally heifers should be weighed every month or bimonthly. Target weights are the weights to be achieved by ALL individuals. It is not an average of the group.

42 Calf Rearing Fact Sheet: Targets Dairy heifers 1. Failure to achieve target live weights will affect cow lifetime performance and result in higher wastage rates. 2. Establish live weight targets for your heifers based on mature cow live weights in your herd. 3. Monitor, review and adjust feeding and animal health plans to achieve targets. 4. Targets are weights for ALL heifers to achieve, not a group average. 5. Electronic scales are more accurate than eye-o-meter or weigh band for assessing live weight. General Failure to achieve target weights at mating and pre-calving will result in: Lower conception rate of heifers, Later calving heifers and consequently lower conception rate of first calvers (rising 3 Year Olds), Lower milk production in first lactation, Failure to achieve adequate mature live weights, affecting lifetime production. Target live weights are set to ensure heifers reach adequate weights to be mated and calve at or before their herd planned start of calving. Puberty occurs when heifers reach 42-47% of mature live weight. Achieving target mating weights minimises the incidence of non-cycling heifers and ensures heifers are mated and consequently calve early. This allows for more days post calving before mating starts for the herd. Higher conception rates are achieved if first calvers are mated during their 2nd or subsequent heat. Achieving target pre-calving heifer weights will result in higher, first lactation milk yield. Replacement heifer live weights As outlined in Farm Fact Sheet 4.1 replacement heifer live weight targets are often referred to as a percentage of mature live weight. Age % mature weight (kg) 6 months 30 9 months months (mating) months 90 this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet 4.2 Recommended targets are outlined below: Achieving target calving weight starts with achieving target weights at weaning. To reach target pre-calving weights Friesian calves will need to grow at 0.75 kg/day, cross breed at 0.6 kg/day and Jerseys at 0.54 kg/day. Later born heifers will have to grower faster to achieve target mating and calving weights. Poor growth rates or poor animal health will reduce the likelihood of achieving these targets.

43 Table 1: Target live weights of young stock based on mature cow live weight and Live Weight Breeding Value Mature Cow Live weight 400 kg 450 kg 500 kg 550 kg 600 kg Live Weight Breeding Value (LW BV) months (fully weaned) months (30% mature live weight) months months months (60% mature live weight) months months (90% mature live weight) Reference: The In Calf Book for New Zealand Dairy Farmers, DairyNZ. Page 43. Putting plans into action Establish target live weights for the young stock in your care. This is an individual farm decision based on mature liveweight of cows in your herd. Monitor progress. Weigh calves every second month and assess progress against targets. Are you going to reach the mating target? Scales are more accurate than eye-o-meters or weigh bands. It is important that ALL heifers reach target - it is not a group average. Weigh at a similar time of day, preferably in the morning to minimise the effect of gut fill. If targets are not being achieved take action and if necessary preferentially feed lighter heifers. If targets are consistently not achieved review the animal health status of heifers and in particular review the parasite control programme and mineral status of heifers. Discuss issues with your vet. Calf Rearing Fact Sheet 4.2

44 Calf Rearing Fact Sheet: Targets Bull calves 1. Set target growth rates. 2. Monitor live weight gain to ensure you are meeting these targets. 3. If not meeting your targets work out why you are not and fix the issue. 4. Failure to meet targets is usually because they are not eating enough quality feed or there is an underlying health issue. General Whereas dairy farmers are often seeking to grow their dairy replacements as fast as possible, bull calf rearers are often operating on tight margins. Bull calves are typically purchased off calf rearers at 100 kg in Nov/Dec with early calves sought after as they tend to finish earlier. Early born calves often only have to be taken through 1 winter, later born calves will generally have to be taken through 2 winters. Feeding through this second winter is expensive with associated treading damage (pugging) particularly on heavy soils. The target weight for a typical 40 kg calf at 4 days of age is 100 kg at 12 weeks of age. This is considered a good compromise between growth rate and cost. Whilst it is possible to achieve live weights of 100 kg some 2-3 weeks earlier than this, the input costs (milk and meal) are significantly greater. Monitoring will allow you to determine whether your calves are growing at the desired rate. Wk Friesian bull LWt (kg) this document, On-Farm Research and Dairy NZ accept no liability. People acting on this information do so at their own risk. On-Farm Research Calf Rearing Fact Sheet