HORSE DIGESTIVE SYSTEM :–The horse is a non- ruminant herbivore. Herbivore means that horses live on a diet of plant material. The equine digestive tract is unique in that it digests portions of its feeds enzym-atically first in the fore gut and ferments in the hind gut. The horse’s digestive system really two sections. The first section has similarities to caecal digestive system of a mono gastric animal such as the dog, man or pig. The second section is more like the rumen of a cow.
In the horse unlike in the ruminant the microbial fermentation occurs after the ‘mono gastric’ like section rather than before. This has a great impact on how we should feed a horse and explains in part why the horse and cow differ so much in their nutritional efficiencies and requirement
MOUTH= Horses grasp food using a combination of the lips, tongue and the teeth.and Feeds are mix with saliva in the mouth to make a moist bolus that can be easily swallow. Three pairs of glands produce saliva parotid, the sub maxillary, and the sublingual. Horses will produce between 20–- the 80 litres of saliva per day. Saliva contains bicarbonate which buffers and protects amino acids in the highly acidic stomach. Saliva also contains small amounts of amylase which assist with carbohydrate digestion
ESOPHAGUS= In horse digestive system This is a simple muscular tube that takes food from the mouth to the stomach. and The esophagus is around 1.5m in length in a mature horse
STOMACH = The stomach of the horse is small in relation to the size of the digestive system or animal and makes up only 10% of the capacity 15 litres in volume. In the stomach, feed is mixed with pepsin (an enzyme to digest proteins) and hydrochloric acid to help break down solid particles. The rate of passage of feed the stomach is highly variable, depending on how the horse is fed
SMALL INTESTINE = digesta passes from the stomach into the small intestine. the small intestine is approximately 28% of the horses’ digestive tract, is 1522m long and has a volume of 5570 litres. This is the major site of digestion in the modern performance horse. The small intestine is broken into 3 sections; the duodenum, jejunum and the ileum.The saliva of a horse contains only small amounts of amylase and there is little actual digestion that occurs in the stomach of most horses.
Most digestion therefore occurs in the small and large intestines. Although the intestine itself secretes some enzymes, the pancreas releases by far the greatest amount. In the small intestine the digestive processes (enzymatic breakdown of proteins, fats, starches and sugars) are similar to those of other mono-gastric animals .but the activity of several of the enzymes in the chyme (food mix), in particular amylase, are lower than in other mono gastric animals and.Microbial protein, which is synthesise in the large intestine, cannot be utilise to any great extent by the horse.
THE HIND GUT = Digestion in the hindgut is largely microbial rather than enzymatic. Digestion in the hind gut is perform by billions of symbiotic bacteria which efficiently break down plant fibres and un-digest starches into simpler compounds call volatile fatty acids (VFA’s) which can be absorb through the gut wall. Compare with the digestive tract of ruminants the horse is not as well suit to digesting products of grass with high crude fibre content, low grade protein and low levels of carbohydrates, starch and fat.
Caecum=The caecum is a blind sack approximately 1.2m long that can hold around 2836 litres of feed and fluid. The caecum is a microbial inoculation vat, similar to the rumen in a cow. The microbes break down feed that was not digest in the small intestine, particularly fibrous feeds like hay or pasture.
Feed will remain in the caecum for about seven hour. Allowing bacteria time to start breaking it down using the fermentation process. The microbes will produce vitamin K, B complex vitamins, proteins, and fatty acids. The vitamins and fatty acids will be absorbed,but little if any protein will be absorbed.
LARGE COLON= The large colon consists of the right and left ventral colons and dorsal colon is about 33.5m long and will hold 86 litres.
Microbial digestion (fermentation) continues, and most of the nutrients made through microbial digestion are absorb here as well as B group vitamins produce by the bacteria and some trace minerals and phosphorus.
SMALL COLON= , Rectum and Anus The small colon is approximately the same length.and The large colons but only has diameter of roughly 10cm.
By now the vast majority of the nutrients have been digest and what is left can not be digest or use by the horse.and The main function of the small colon is to reclaim excess moisture and return it to the body. This results in fecal balls being form These fecal balls, which are the un-digest. and Mostly indigestible portion of what was fed some 3672 hours ago. Then passes the anus to the rectum and expel as manure through.