Changes

The horse is a monagastric hindgut fermenter. The horse evolved for grazing and it does so for up to 17 hours a day. A high proportion of the horse's dietary carbohydrate is in the form of '''starch'''. A mature horse eats 2-2.5% of it's body weight in dry matter every day, 1.5-1.75% of this should be fibre (hay/haylage). This is to prevent a rapid drop in pH in the large intestine and also to stimulate peristalsis in the gut and prevent build up of gas.

The horse is a monagastric hindgut fermenter. The horse evolved for grazing and it does so for up to 17 hours a day. A high proportion of the horse's dietary carbohydrate is in the form of '''starch'''. A mature horse eats 2-2.5% of it's body weight in dry matter every day, 1.5-1.75% of this should be fibre (hay/haylage). This is to prevent a rapid drop in pH in the large intestine and also to stimulate peristalsis in the gut and prevent build up of gas.

Undigested material spends a long time in the caecum and large intestine being digested by microbial fermentation, mainly cellulose (95% after 65 hours). Most microbial fermentation occurs in the colon (as opposed to the [[Hindgut Fermenters - Rabbit - Anatomy & Physiology|rabbit]], where most occurs in the caecum).

Undigested material spends a long time in the [[Caecum - Anatomy & Physiology|caecum]] and [[Large Intestine|large intestine]] being digested by microbial fermentation, mainly cellulose (95% after 65 hours). Most microbial fermentation occurs in the [[Colon - Anatomy & Physiology|colon]] (as opposed to the [[Hindgut Fermenters - Rabbit - Anatomy & Physiology|rabbit]], where most occurs in the [[Caecum - Anatomy & Physiology|caecum]]).

In the hindgut of the horse,  

In the hindgut of the horse,  

*30% of protein digestion.

*30% of protein digestion.

A lot of absorption of VFAs and water occurs in the large intestine which pass readily into the blood. Electrolytes are also absorbed in the large intestine; 95% of sodium and chloride and 75% of potassium and phosphate.

A lot of absorption of [[Volatile Fatty Acids - Anatomy & Physioogy|VFAs]] and water occurs in the large intestine which pass readily into the blood. Electrolytes are also absorbed in the large intestine; 95% of sodium and chloride and 75% of potassium and phosphate.

To mix the contents of the large intestines, the taenia and circular muscle of the tunica muscularis contract. This also transports the ingesta through the large intestine and brings the products of fermentation in contact with the epithelium.

To mix the contents of the large intestines, the taenia and circular muscle of the tunica muscularis contract. This also transports the ingesta through the large intestine and brings the products of fermentation in contact with the epithelium.

==[[Small Intestine - Anatomy & Physiology|Small Intestine]]==

==[[Small Intestine - Anatomy & Physiology|Small Intestine]]==

*Arrangement is similar to that of the dog's small intestine, but the position of the jejunum is influenced by the large ascending colon and caecum.

*Arrangement is similar to that of the dog's small intestine, but the position of the [[Jejunum - Anatomy & Physiology|jejunum]] is influenced by the large ascending colon and caecum.

**The jejunum is restricted to the left dorsal part of the abdomen.

**The jejunum is restricted to the left dorsal part of the abdomen.

**The ileum opens directly into the caecum.

**The [[Ileum - Anatomy & Physiology|ileum]] opens directly into the caecum.

*Transit time of food in the small intestine is quite rapid.

*Transit time of food in the small intestine is quite rapid.

**25% of a liquid marker has reached the caecum within 1.5 hours.

**25% of a liquid marker has reached the caecum within 1.5 hours.

*The microbial population is dependant on diet and frequency of feeding, as different microbes are suited to digesting different things.

*The microbial population is dependant on diet and frequency of feeding, as different microbes are suited to digesting different things.

**The number of microbes can change 100 fold in a 24 hour period.

**The number of microbes can change 100 fold in a 24 hour period.

*VFAs produced are absorbed across the intestinal wall.

*[[Volatile Fatty Acids - Anatomy & Physioogy|VFAs]] produced are absorbed across the intestinal wall.

*Urea from the blood is transported to the intestinal lumen to be used by microbes, which also use nitrogen from the diet.

*Urea from the blood is transported to the intestinal lumen to be used by microbes, which also use nitrogen from the diet.

*Environmental factors of the caecum and ventral colon can influence fermentation of microbial population.

*Environmental factors of the caecum and ventral colon can influence fermentation of microbial population.