Horse Digestion

horse esophagus

meter to a meter & half long

small intestine

gall bladder, pancreas, duodenum, jujuenum, illium;

gall bladder

secrete bile acids to break down fats

pancreas

secretes insulin and enzymes

villi

finger like projections on the wall of the small intestine to increase surface area for more absorptionc

cecum

at junction btn small and large intestine; ~6ft long in horse; holds 20 L; has microbes & enzymes that break down cellulose/other plant cells, release nutrients and multiply, die, and produce VFAsla

large intestine

composed of colon and rectum; mainly absorbs water with a little bit of nutirents

copraphagia

the act of eating your own poop; allows access to extra vitamins that were produced by bacteria; horses do this when vitamin deficient

pica

when animals selectively chew on bones because they are rich in calcium and phosphorus; in captivity can use a salt lick

factors that affect the amount a horse eats

stress, growth, size, breed, bodyweight, daily activity, stage of life, gaits

maintenance

the animal is sitting idle and not expending addition energy for biological (lactation) or physical (running) activities

National Research Council (NRC)

an encyclopaedia with studies from all over that calculates nutrient requirements for all animals and what to feed them

mega colories

million calories

lactating mares

have the highest energy requirements; highest protein, calcium, & phosphorous requirements

Fed on a DM basis

measure horse feed on calories per kg of DM; calculate DE (digestible energy)

flakes

compressed bail of hay; not a consistent measure

hay

measured in DM; sometimes it is soaked to wash away some of the sugars

gross energy

all of the feeds energy; the raw energy content; contains fecal energy and digestible energy

digestible energy

gross energy - fecal energy; comprises of urinary energy and metabolizable energy

metabolizable energy

comprises of heat energy and net energy

net energy

separated into maintenance and production

colic

collective term for digestive problems; treateable can be fatal; costs $10-15k

gascolic

accumulation of gas in intestinal tract which can lead to rupture; the cecum is filled with fermentation products

idiopathic colic

sever bellyachei

interceptive colic

intestine layers over itself; disrupts the flow of digestion and backs up gastroestinal tracts

sand colic

horse eats more dirt/sand; it piles up and blocks gut; cecum gets inflames

signs a horse has colic

change in behavior; paw at stomach; sweat; roll and not able to get up

how to avoid colic in horses

slow and steady amounts of high quality feed; consistant feeding routine

coffin bone

it extends all the way down into the base of hoof; it takes 1 year to grow out; completely grows 1cm/month

lamina

the layer of hoof wall connected to underlying sensitive tissues

laminitis

aka founder; the blood flow in the hoof is disrupted because of low ph or digestive disruption; this causes laminate to start to separate and the bone can push through sole of hoof; avoid through consistent diet and no excess grain

horse placenta

diffuse placenta

melanocortin receptor (MCR)

responsible for making black pigment in skin; this decides base coat color

eumelanin

the normal sequence of allele in horses; is the black pigment in the skin; "E"

mutation in eumelanin

the mutated sequence of allele in horses; there is no black pigment in the skin; "e"

gene

nucleotides in a certain arrangements; the ATCGs

locus

a region of dna

homozygote

extension gene; "EE"; black hair color; normal MCR (make eumelanin)

heterozygote

Ee; will still make eumelanin; dominant will override the non-working allele; black coat color

hemozygote

ee; recessive allele

Agouti locus

gene that regulates whether eumelanin is produced and what cells it gets produced in; can change the expression of black coat color to specific points (ex mane and tail)

modifier genes

genes on other regions of the genome or on other chromosomes that affect can influence other traits and alleles

gene sequencing

used for pedigree analysis; to find out what genes they have, to check their health (disease risk)

horse base coat color

black or red