DIGESTIVE AIDS US.qxd:Jerkins feature.qxd
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DIGESTIVE AIDS
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ORSES in training are susceptible to a number of digestive problems, such as gastric ulcers, colitis and colic. Although less severe, chronic loose droppings, which may be associated with a failure to thrive, are also fairly common. The prevalence of these conditions amongst racehorses is likely to be a consequence of our feeding and management practices, given the anatomical design of the horse’s gastrointestinal tract. While the cause of gastric ulcers is fairly clearly defined, the trigger for other digestive issues such as colic or colitis is less easily explained. Likewise, the cause of persistent loose droppings in some horses in training cannot always be found. However, in all of these cases a disruption to the normal microbial balance within the digestive tract may contribute to the underlying issue. Nearly three billion bacteria in the caecum alone The microbial community within the equine digestive tract consists of a vast population of bacteria of many different types, as well as other organisms such as protozoa and yeast. We should not think of this population as being static, as it constantly changes in response to the diet and is also influenced by other environmental and management factors. The microbial population is particularly sensitive to any sudden change in diet, especially where the starch and fiber content of the ration is concerned, e.g. as
E.Coli can contribute to colic, colitis and diarrhea
“The microbial population is particularly sensitive to any sudden change in diet, especially where the starch and fiber content of the ration is concerned” may occur when a horse in full training on full rations is injured and requires box rest with a swift change to a convalescent diet. Veterinary medications including some antibiotics and worming treatments have also been shown to have a detrimental impact on the microbial balance in the gut. A change in environment or travel, as well as racing itself, can also impact on these microbial communities as a result of the response to stress. Balance on the inside maintains health on the outside Disruption to the normal balance of bacteria in the hindgut particularly can have
a profound impact on both short term and long term health in racehorses because they are dependent on the activity of these bacteria for a number of crucial digestive and other functions including: Fermentation of fiber as an energy source Fermentation of starch that escapes digestion in the small intestine Metabolism and removal of lactic acid produced as a result of this starch fermentation Assistance in water re-absorption from the hindgut Synthesis of a wide range of B vitamins crucially needed for energy metabolism Maintenance of a healthy immune system through the constant stimulation by resident bacteria The ability of the bacterial population to ‘do their job’ can be compromised to a lesser or greater extent when the nature of the bacterial population changes. A decrease in the number or activity of the ‘useful bacteria’ can occur because of the environment in the hindgut becoming inhospitable, e.g. when excess starch arrives and is rapidly fermented, making the environment more acidic. As well as shifting the balance of different types of bacteria that are normally present, this can also pave the way for the opportunistic growth of pathogenic bacteria such as Salmonella Sp., Clostridium Sp., E.coli Sp. and other organisms including Cryptosporidium, which can contribute to colic, colitis and diarrhea. Feeds and supplements that incorporate ingredients that function as digestive aids are potentially useful in the ration of horses in training, as they seek to maintain a hospitable environment in the hindgut and hence keep a stable and beneficial microbial balance offering a preventative measure against digestive upset. There are a range of nutraceutical and other ingredients that are commonly found, either in isolation or in combination, in commercial racing feeds and/or supplements. Their worth is dependent on the rationale for their use, as well as the research available to support their efficacy. Prebiotic FOS – a lunchbox for beneficial bacteria FOS prebiotics are ingredients that are often derived from sugar beet or chicory and are commonly referred to as fructooligosaccharides or simply FOS. A FOS prebiotic cannot be degraded by digestive enzymes in the small intestine, but travels to the hindgut where it is selectively fermented by ‘beneficial’ bacteria, helping to retain or restore a healthy microbial balance. The benefit of FOS prebiotic ingredients for horses, such as racehorses that are exposed to an increased risk of colic due to ISSUE 13 TRAINERMAGAZINE.com 43