Equine nutrition Flashcards
If in ruminants the hydrolysis of organic matter takes place mainly in the rumen then in horses it takes place in
the stomach and in the hindgut
The part of the digestive tract that is most important in digestion depends on
the ration / type of feed
If a horse’s ration is concentrate-rich the hydrolysis of organic matter takes place mainly in
the stomach, if hay-rich then in the hind gut.
How long do horses spend eating if allowed to graze freely?
Usually, when horses are grazed, they spend 16-17 hours per day for eating.
Biggest difference between ruminants and odd-toed ungulates is that
– in ruminants the hydrolysis of nutrients first takes place by microbial fermentation and secondly by endogenous enzymes
– in odd-toed ungulates this is vice versa, first endogenous enzymes act and then microbial fermentation takes place
In horse nutrition, carbohydrates can also be divided into two parts
– hydrolysable (digested by endogenous enzymes)
– fermentable (digested by microbial enzymes)
examples of hydrolysable carbs (3+)
disaccharides,
some oligosaccharides (e.g. maltodextrin)
and starch (amylose, amylopectin)
examples of fermentable carbs (3+)
cellulose, hemicellulose
and some oligosaccharides (fructans, galactans etc.)
an abundance of fructans can cause
issues in fermentation in the hindgut so,
need to be limited
hindgut acidosis, laminitis etc.
e.g. pasture-associated laminitis from lush young grasses containing fructans
Generally, starch digestion in horses is similar to that in
monogastric animals (like pigs)
Starch digestion takes place mainly where with what
in the small intestine where the enzyme α-amylase enters and acts with pancreatic juice
α-amylase hydrolyses what exactly?
amylose α-1,4 glycosidic bonds,
but not the C-skeleton terminal α-1,6 glycosidic bonds (until only disaccharides are left)
Small intestine enzyme isomaltase hydrolyses what exactly?
α-1,6 glycosidic bonds
The final digestion of starch takes place where by what
in the small intestine by disaccharide enzymes (maltase, sucrase, lactase) which are produced in the small intestine
The activity of lactase is remarkably high not only in foals but also in
adults, and therefore the grown up horses can easily digest lactose
What is the first thing we need to take into account In the case of a starch-rich ration
The amount and activity of the produced α-amylase is limited, and the chyme passage rate in the digestive tract is high.
NB! Starch can remain partly undigested in the small intestine and enter to the hind gut, where active microbial fermentation takes place, which may cause acidosis.
What is the max percentage of concentrates you can feed
No more than 0.2% (max 0.4%) concentrates of body weight per feeding time,
e.g. 1kg for a 500kg horse
Due to the morphology of the horse GI tract, microbial fermentation of a starch-rich ration already begins in the
Due to the morphology of the horse stomach, some fermentation occurs in the highest part of the stomach.
The uppermost portion of the stomach is nonglandular.
Are there lactic acid utilising bacteria or lactic acid producers or both in the equine stomach?
There is no lactic acid utilising bacteria in the horse stomach -> are only producers.
What compound is a major cause of gastric ulcers?
Lactic acid is absorbed with great difficulty, and therefore, together with stomach HCl, it
destroys the mucosa cells of the stomach non-glandular region, which leads to gastric
ulcers.
Horses use feed protein less effectively compared to
ruminants
Horses also need much less protein in their rations. Less than even dry cows.
Why is hydrolysable protein important for covering a horses’ protein requirements?
Although, in horses, effective carbohydrate fermentation and microbial protein synthesis occurs in the hind gut, the horse cannot use the produced microbial protein.
Feed fermentation also occurs to some extent in the stomach, in which case it is possible that some of the microbial cell protein can be digested, but this is negligible in feeding practice.
Therefore hydrolysable protein is important to cover horses’ protein requirements.
Horses, compared to cattle, are more sensitive to easily hydrolysable feed protein.
For example: when lucerne hay, rich in protein is fed, they..?
excrete most of the digested feed protein via urine when lucerne hay is fed
Excessively fed feed protein increases horses’ what (5)
– energy requirement
– water requirement
– sweating
– heart beat rate
- Reduces the speed endurance of racing horses
Problems occur when the fed protein requirement is exceeded by?
Problems occur when the protein requirement is exceeded by 20-30%.
Protein requirement of dressage and show-jumping horses is almost equal to
their maintenance protein requirement – 8% in DM is sufficient
Protein requirement for physically hard working horses is
10-12% – a lot of protein is excreted with sweat