Providing nutrition for sick foals

Transcription

1 Vet Times The website for the veterinary profession Providing nutrition for sick foals Author : Nigel Woodbine Categories : RVNs Date : June 1, 2008 Nigel Woodbine reporter, reviews a presentation given at BEVA Congress on the importance of correct feeding of sick foals to avoid causing further complications HEALTHY foals drink an extraordinarily large amount of milk, but there are a number of differences in sick foals that can lead to either an increased or decreased requirement. Although healthy foals will drink every 20 to 30 minutes and can consume up to 20 per cent of their bodyweight voluntarily, these volumes should not be given to sick foals, according to Celia Marr from Rossdales Equine Hospital in Newmarket. Speaking at BEVA Congress 2007 in Edinburgh, Dr Marr explained how - when based on a generic foal model (thoroughbreds) - these figures mean an average 50kg foal would require around 10L of milk, representing an envyinvoking daily calorie requirement of approximately 6,000 (the same as 20.4 Mars bars or, more disappointingly, 240 satsumas). Dr Marr said: The main point is that normal healthy foals have a massive demand for milk, so if we re going to have to take that job over for them, it s going to be pretty time-consuming and important that we keep giving milk extremely frequently. However, she warned that differences between sick and healthy foals meant that the ill animals requirements could be either increased or decreased. She said: Things like septicaemia and hypoxia, which are common in foals, may in fact increase the metabolic rate - and by the same token, sick foals may not be able to use their nutrients as efficiently. 1 / 14

2 If they re ill they may have lost their suckle reflex and their appetite - and they re very frequently too dim to realise that they need to eat anything. Problems One major problem in sick foals is that, regardless of their underlying problem, they will frequently have gastrointestinal motility problems, or will very quickly develop them - a reason why, according to Dr Marr, it is extremely important that you never attempt to give any foal that is cold and collapsed any sort of oral feeding. Recalling her days in general practice, Dr Marr spoke of the times when she was called to see a sick foal on farm where she would discover it lying in the middle of the stable with various people standing around staring at it. She said: The first thing they want you to do is give it colostrum - everybody knows that foals need colostrum, and that s what they want you to do: get a stomach tube and give it colostrum. That is, in fact, a very wrong thing to do. Instead, Dr Marr said it was more important to get those people who were "standing around" to place the foal in sternal recumbency so it could breathe more efficiently, before starting to warm it up. She said: Feeding is something that is put aside until later. You may find that you ve missed the window of opportunity for colostrums to get into the foal, but you can easily address that with plasma. Nutrient delivery When attempting to deliver nutrients the routes available are oral, intravenous, or a combination of both. According to Dr Marr, the oral route is the most physiological and - as well as being the least hassle - has one big advantage in that the nutrients supplied to the cells that line the gut (enterocytes) come direct from the lumen. She explained: If you just give them nutrition intravenously, it s not going to sustain those enterocytes but you have to balance that against the fact that the gut may not be working. If the gut is not working you may not be able to use the oral route at all, or you may have to deliver only very small amounts of nutrition that way. This means you have to consider the option of the intravenous route, which may be your only option. 2 / 14

3 The white stuff When considering oral feed types there are a variety of options available, and Dr Marr claims that the best method is simply to take the milk straight from the dam. Unfortunately, this is not always possible so, as an alternative, milk from another mare may be used. Dr Marr said: We tend to find that the dams in our intensive care unit often make more milk than their foals are drinking, so we will freeze that milk if the mare has been vaccinated against rotavirus. Another useful alternative is powdered milk replacer, which is available from several companies. The important thing about powdered milk, however, is to ensure that it is made up consistently and hygienically. To ensure the best quality, Dr Marr suggests that you weigh the powder precisely each time you make it up to ensure the exact quantity, and use boiling water from the kettle rather than water from the hot tap. She said: You must boil the water. Hot water from the tap has come out of a standing tank and therefore is not suitable and might have bacteria in it. Another important factor to consider is consistency. You don t want it lumpy because you don t want it plugging up your tubes, she said. What I usually do is weigh up my milk powder and make it into a paste with boiling water - a bit like making a roux - and then you dilute it out to the full amount. If you just chuck the whole litre of water into the milk powder, it will end up lumpy and may plug up your tubes, which might cause your clinicians to use bad words. No matter how well prepared you are though, it is always possible that you may not have mare s milk or powdered milk to hand when you most need it. Not all practices have ready supplies, and there are always occasions when emergency strikes - times when your local supermarket may just be a lifesaver. If you are stuck at the weekend where, perhaps, the mare has died and you haven t got any mare s milk, don t forget that you can just go down to Tesco and buy some goat s milk, she said. As powdered milk replacer hasn t always been the high quality it is today, Dr Marr freely admits to having used goat s milk regularly in the past, although now she would only advise its use in emergency situations. Sometimes I ll get a call on a Saturday night from a colleague who doesn t usually deal with foals and who has an orphan to contend with. What are they going to do? I would say the answer is to just buy some goat s milk, she explained. 3 / 14

4 Do not, however, use cow s milk, she warned: Frozen bovine colostrum is a useful back-up source for IgG, but bovine milk is not suitable for feeding foals. If the foal is unable to tolerate milk because it is bilious or has diarrhoea, then - providing it isn t refluxing - it is still important that something is going into its gut. She said: If you take them off milk, I would usually recommend giving something like a mixture of Lectade with a little bit of glutamine in it. Glutamine is a nonessential amino acid that becomes essential in some diseased states, and is the major fuel for the enterocytes. You can buy it in all sorts of health and sports type shops. It s available as part of sports drinks because athletes like to take a lot of glutamine. See Table 1 for feeding types. How much milk you should give a foal depends entirely on its clinical status, said Dr Marr. Certainly with sick foals you would never go in and give the 20 per cent that they would drink if they were healthy, so start gradually at about five per cent and build it up according to how quickly the foal is getting better, she said. You need to feed them at least every two hours, and more frequently if possible. The more frequently you can feed them, the better - because obviously it s small amounts going in constantly. See Table 2 for guideline feeding amounts. Oral feeding routes If you only remember one thing from this article, Dr Marr wants it to be this: bottle-feeding is a lifethreatening situation for foals. Although bottle-feeding is an obvious choice, weak or resisting foals are at high risk of aspiration pneumonia with this method. Dr Marr recalled a situation where a healthy foal had been brought to her from a well-known stud farm. A very experienced member of the farm staff had tried to bottlefeed it with colostrum and, somehow, some of that colostrum ended up in the foal s chest. Of such a situation, she said: This is a dead foal basically - there is no way that we were going to get it to recover from this really severe aspiration. As I was alluding to previously: everyone wants you to get the foal on the bottle, everyone wants you to give them colostrum - but just be careful because it can end up as a disaster. I think the trick is to just wait. If you re dealing with a sick foal that is not very keen on eating, don t worry about it - you can give it its nutrition in other ways. If the foal is not feeding, then don t force it. 4 / 14

5 Suggested bottle-feeding method To bottle-feed correctly the foal needs to be in a standing position. Feeding a sick foal in sternal recumbency is not recommended, although there are occasional orthopaedic cases where the method may be considered - for example, when an otherwise healthy foal cannot physically stand up. Dr Marr said: You want to hold the bottle, tilt it downwards and attempt to get in a posture where the foal is reaching up the way it would under an udder. A neat way to do that is to get into a semi-crouching position to encourage the foal to drink through your armpit. You land up in a position that is similar to how the foal would reach up into the mare s udder. When dealing with healthy orphan foals that are willing to feed, it is often better to forget about bottles and use bowl feeding. This method is much more convenient, and is far safer as foals are less likely to aspirate milk than they are with a bottle. Intermittent nasogastric tubing can also be used, although Dr Marr claims this method is only practical if one or two feeds are needed. Sick foals should not be given more that 500ml at a time with this method, while foals less than one week old should not receive more than one litre at a time. Alternatively, Dr Marr suggested the use of indwelling polyurethane nasal feeding tubes, which are less traumatic than ordinary stomach tubes and, if required, can be kept in place for several weeks. Prior to use, radiographs should be taken to confirm that the nasogastric tube is correctly placed in the foal s stomach, after which the tubes can be sutured to the nose and taped to the foal s face. Dr Marr said: When you are giving milk via the gastric tube or using the naso-oesophageal tube, it is essential to check the reflux first. Ideally, the foal should be standing, but at the very least it needs to be held in sternal recumbency. If more than 50ml of reflux is obtained, do not administer the feed. However, if all is well, the feeding solution should be introduced slowly. Dr Marr claims that kangaroo bags are ideal as they allow the milk to go in by gravity. At the end, the tube should be flushed with 20-30ml of water. Total parenteral nutrition In cases where oral feeding is impossible, Dr Marr suggests the use of total parenteral nutrition (TPN) - the practice of feeding a foal intravenously in situations where the gastrointestinal tract is non-functional or because its absorptive capacity is impaired. She said: This is essentially 5 / 14

6 delivering a mixture of glucose, amino acids and lipids intravenously. However, it s a whole big step up in terms of level of care, because once you start TPN, you ve got to keep it running - you can t stop it and start it the way you would another sort of drip. The key thing here is that sudden swings in energy delivery are extremely dangerous and very threatening. You should never ever allow your supplies to run out and it is essential that you control the rate. With TPN, Dr Marr said she could not over-emphasise the importance of keeping everything clean. She warned that there was a much higher requirement for asepsis and monitoring when using IV nutrition as there was a higher risk of iatrogenic infection. Another disadvantage of TPN is that the foal has to be separated from its mother, which Dr Marr claims can sometimes cause problems. She explained: Some mothers will stand there for days on end focusing entirely on their foals and ignoring all the paraphernalia and junk round them, but other mothers just can t cope with it and have to be sent home. Ultimately, though, Dr Marr claimed that everything possible should be done to attempt to maintain the bond between mare and foal. We re all hoping to have a healthy foal at the end of it, and the best outcome is that we can send that foal home with its mother, because its mother is obviously an important ongoing source of nutrition. She added: Regardless of how you rear orphan foals, you will always have issues with their social interaction and their interaction with humans - they learn all that discipline and how to behave like a horse from the mother. They can t learn that from you. Acknowledgements With thanks to Celia Marr. This article was was based on her presentation How to provide nutrition for sick foals from the Advances in Critical Care Nursing stream at BEVA Congress Thanks also to Niamh Collins for the Rossdale Equine Hospital guidelines for enteral feeding of foals. 6 / 14

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9 Bottle-feeding using Dr Marr s under the armpit method. PHOTO CREDITS: Rossdale and partners 9 / 14

10 Aspiration pneumonia in a foal. Weak or resisting foals are at high risk of contracting aspiration pneumonia when bottle-fed. 10 / 14

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12 A naso-oesophageal tube in place, and a double lumen catheter attached for total parenteral nutrition in a sick foal. 12 / 14

13 Oral feed types Guideline for feeding mare s milk/ milk replacer to healthy foals (which are not also drinking from a mare) 13 / 14

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