Teat sanitisation systems and process

Transcription

1 Teat sanitisation systems and process Teat sanitising is critical for maintaining teat skin health and controlling mastitis during lactation. Mastitis costs money, wastes time and reduces productivity. It is a serious interruption to milking and causes distress to the cows. Longer term consequences include increased use of antibiotic treatments, loss in milk production, and increased chances of culling. Mastitis also increases the risk of incurring a milk quality or inhibitory substance grade. In New Zealand, teat sanitising usually refers to teat spraying or dipping, carried out immediately after cups have been removed. This can be a manual or automated process. Teat spraying looks simple. This probably explains why so many people get it wrong. The effectiveness of teat spraying or dipping relies on complete coverage of the teat. This task takes time and is poorly done on many New Zealand farms. A system should be chosen which suits each farm and its resources, while also ensuring the best possible coverage of teats. Benefits Reduce incidence of mastitis and risk of grades Teat spraying after milking has been proven to reduce the incidence of new mastitis infections by 50%. This means less time and cost spent treating mastitis, and separating milk from infected cows. Minimises risk of BMSCC (Bulk milk somatic cell count) grades from dairy companies, resulting from subclinical and clinical infections. Reduce cow discomfort and poor milking behaviour associated with damaged teats. Reduce teat cleaning time As dirt does not adhere as easily to a well conditioned teat. 1.1 Using teat sanitising products Teat sanitising products must be approved to ensure they won t result in undesirable milk residues. A list of approved chemicals is available on the New Zealand Food Safety website ( or you can contact a Milk Quality Representative from your dairy company. Suggested improvements Actions to take New batches of teat spray should be mixed at regular intervals, ideally every 1 3 days. Use water of drinking quality. Mix according to the label. Some products suggest different dilution rates depending on the stage of the season and the risk of mastitis. Most teat sanitisers also contain an emollient to improve teat skin condition. Extra emollient may be added in spring when teats are most tender, but generally it is best not to exceed 15-20% in the final mixture.

2 1.2 Correct teat sanitisation method Teat spray all teats of all cows immediately after every milking, and throughout the whole lactation period. Cover the whole teat of every cow to maximise effectiveness. Teat spraying before cup attachment increases the risk of milk contamination and there are strict criteria associated with this practice. It is used overseas to control environmental mastitis. Its value is not proven in typical Kiwi systems, but it may be useful in feedpad or very high environmental (coliform) mastitis situations. If you wish to do it contact a Milk Quality Representative from your dairy company and ensure you are carrying out the correct technique. 1.3 Types of teat sanitising systems Teat spray units come in manual and automated forms. Manual spraying and dipping systems generally fall into one of three categories: Teat spraying from a hand pump container. Teat spraying with a wand from a larger, pressurised fixed container of spray solution. Teat dipping using a hand held cup to immerse the teat in the disinfection solution. Automated teat spraying systems include: Spraying teats in an exit race. Spraying teats near the exit bail on a rotary platform. The advantages and disadvantages of the different systems are summarised in the following table (Table 1). The choice of a system will take into account the cost, time involved in using and effectiveness of the technique. System Advantages Disadvantages Manual Hand pump Low cost Portable Regular refilling (tendency to run out during milking) Prone to under-spray* Poor spray from poor plastic nozzles Breakages Heavy to hold for long periods, especially in rotaries Pressurised sprayer Quick Light to use Little refilling More expensive Prone to under-spray* Teat dip Total teat coverage guaranteed if correctly used Low solution usage Slow application Regular refilling Risk of contaminated solution Automated Automated Sprayer Automated (low labour input) Prone to under-spray Prone to missing the target area unless regularly checked High solution usage

3 Need to be maintained and monitored to ensure good application Disinfectant levels need checking regularly *The effectiveness of a spray applicator is greatly enhanced by ensuring the spray nozzle emits a solid cone spray pattern, not a hollow cone spray pattern see Figure 6. Table 1. The advantages and disadvantages of different teat sanitisation systems. Manual systems Manual systems include hand pumps, pressurised sprayers and teat dips. Features of hand pumps Hand-held pressurized containers are used commonly in small dairies and as emergency back-up for larger dairies. They commonly hold litres of spray, sufficient for around 150 cows. They need to be pumped up between rows and fitted with a wide solid cone nozzle for effective and efficient operation. Figure 1. A hand pump is any manually operated pressurized unit with its own reservoir. Source: Mel Eden Figure 2. Using a hand pump to achieve good teat coverage. Source: Mel Eden Features of pressurised spray guns and nozzles Solution is delivered through a pressurised line from a central reservoir (see Figure 3). There are normally a number of nozzles suspended in the milking area for the milkers to use, however some setups use a single drum in the pit with one spray gun. Spray guns and nozzles should be of robust design: The nozzle should extend 300 mm to 400 mm from the handle. An upwards angle of about 90 degrees ensures good coverage of all teats is achieved. Long spray wands reduce the risk of milkers inhaling the fine spray, being kicked and make it easier for the milker to cover all of the teats.

4 Figure 3. Pressurized spray unit as a permanent fixture. Source: National Milk Harvesting Centre, Australia Teat spraying technique Teat spraying is more widely used than teat dipping as it can be speedily implemented. However, it still takes time to do it properly. An effective spraying technique involves: For maximum coverage, sprays should be applied from directly under the tips of the teats, not from the side. All sides of each teat should be covered and a drop should form on the end of each teat (see Figure 4). Approximately 20 ml of diluted teat spray should be used per cow per milking i.e. every 100 cows will require 4 litres of diluted teat spray per day. Spraying whilst moving the wand or gun in a circular pattern - adjust the angle of the spray gun to ensure good coverage. Spraying continuously - avoid spraying jets intermittently as coverage will not be complete. Testing Spraying Effectiveness Check the volume of spray used - aim for 20 ml per cow per milking. Test the effectiveness of your teat sprayer by spraying against a white surface. The spray pattern should be a solid cone of spray, not a hollow spray pattern (see Figure 6.) Adjust or replace the nozzle if necessary. Test the effectiveness of the spraying technique by taking a clean paper towel and wrapping it around the teat. There should be even coverage all the way around and at the tip (see Figure 5). This is a good way to check how you are doing it and to test the competency of new staff.

5 Figure 4. Teat spray should cover all of the surface and form a drip on the end of each teat. Source: National Milk Harvesting Centre, Australia. Figure 5. Checking teat spray coverage over the whole teat using a paper towel. Source: CountDown Down Under. Figure 6. Checking the effectiveness of a teat sprayer. The sprayer should make a solid cone shape (left hand image) not a hollow one (right hand image). Source: Mel Eden. Teat dipping Teat dipping is very effective as it gives good coverage of teats without exposing milkers to mists of the disinfectant (see Figure 7). Squeeze cup applicators ensure that at least the lower portion of teats is completely covered every time. The trade off is that it can be time consuming. Suggested improvements Actions to take Aim to use 10 mls per cow per milking. Squeeze type cups or an anti-spill teat dip unit will reduce spillage. Replace the solution frequently throughout milking - avoid just topping it up or use more than one dip cup. Replacing the solution reduces contamination by milk from cow to cow. Contamination reduces the efficacy of the mixture. Cup design will also help to reduce contamination.

6 Having several cups strategically positioned in the dairy means there will always be a teat dip handy. Figure 7. Teat dipping cup. Source: National Milk Harvesting Centre, Australia. Automated systems There is increased interest in automated teat spray systems because of the potential to remove operator error or reduce labour input. Some systems are available commercially while others are home built. The systems can be broadly categorised into two types: spraying teats in an exit race; spraying teats on the milking platform. At this stage, these systems do not achieve 100% coverage of all teats as udders vary in height and shape and the movement of cows and positioning of legs make it difficult to get a direct hit. However, many operate more effectively than a poor manual operator and they are useful if the milker is stretched at cups off or if this position has been fully automated. The following comments are offered to help farmers explore their options. Bear in mind that these systems are typically designed to operate with no human supervision other than to refill the disinfection solution. Exit race spraying Exit race spraying is the most common form of automated teat spraying in New Zealand. These units are all based around cows moving over one or more nozzles fixed in a narrow section of the exit race with the spray activated by motion sensors (See Figure 8). The units require steady, even cow flow to achieve effective teat spray coverage and so will often incorporate some sort of obstacle to ensure this. This can be achieved by making cows step over pipes on the ground or walk over some sort of leg spreader. There is debate about the best height for the spray nozzle(s). One argument is that a higher nozzle is more likely to achieve delivery of the liquid to the teats. The counter argument is that a lower nozzle will give a greater fan effect and so give a broader coverage at the base of the udder. There is general agreement however, that the more spray heads and the better they are arranged to cover all teat surfaces, the more successful the spraying will be. One issue on which there is consensus is that the spray should be triggered from the rear of the cow, rather than from the head of the cow, to improve the timing and reliability of spray application to the teats. Another factor to consider is wind drift - the unit must be shielded from the wind to achieve consistent spray patterns.

7 Although perfect coverage is still some way off, these units are considered to do a better job than a bad manual operator. The units usually use around 20-25ml per cow per milking, which is in line with Smart SAMM recommendations but more than manual systems commonly use. Figure 8. An automatic teat spray unit in the exit race. On-platform spraying On-platform spraying is usually only used on rotary platforms or by robots (see Figure 9). An automated spray system on a herringbone is not currently practical. The rotary platform sprayers typically have one spray head that uses electronic eye beams to detect the bail position, to check if the bail contains a cow and to determine if the cluster is removed. The better designs move via an arm to a position under the udder when spraying. Having the cow stationary in a bail is a great advantage but the true benefit of these systems can only be achieved if waves are installed to keep the cows legs apart while spraying. Figure 9. Automated teat spray units with waves in bails. Action points Visit other farms and see how effective their teat disinfection systems are. Test the operator s competency by wrapping a paper towel around teats just sprayed to check if disinfectant covered all surfaces. Test the nozzle performance by checking the spray pattern. Spray upwards onto a sheet of paper and a solid cone of spray should be achieved. Site automatic teat spray nozzles downwind of work areas. Having spray units at conveniently placed locations around the dairy means time is not wasted walking to pick up the spray unit. Avoid inhaling fine mists of chemical. Some people become sensitised to them.