Equine Nutrition Flashcards
VFAs
acetate + propionate + butyrate
Horses are:
grazing herbivores
GI track well adapted to trickle feeding 🡢 naturally forage 10-15 hr/day
Anatomy
Mouth
- lips enable selective grazing
- saliva only when chewing 🡢 no enzymes
- chewing cycle complex
Stomach
- 8-15 L capacity
- meal size influences emptying
Small Intestine
- relatively short
- bile continually produced
- limited capacity for starch digestion
- minerals + trace elements absorbed
Hindgut
- few mucosal enzymes
- intense fibrolytic activity
Water
- most important nutrient
- inadequate intake can cause impaction colic
- 2 quarts per lb of hay 🡢 5-15 gallons/day
- optimal temp for drinking 🡢 68-78F
- high temps, hard work, lactation 🡩 3-4x
- thirst 🡣 feed intake
How do horses use feed?
- energy = 85%
- protein = 10%
- minerals = 4%
- vitamins = 1%
Forages
digestible fiber necessary as energy source for microorganisms in cecum + lg colon
minimum 1lb forage/100 lbs BW daily
indigestible fiber required for normal GI motility, pH, function
1) Grazing
- most meet needs from cool season grass
- 1 horse/acre
2) Preserved
quantity 🡢 target 2% of BW/day
change forages slowly 🡢 2-3 wks for adaptation
Sources of Energy in Diet
Carbohydrates
- fiber (structural) 🡢 fermentable in cecum, 6-8% starch
- starch/sugar (non-structural) 🡢 absorbed as glucose in SI
Fat:
- 🡩 energy density of any ration
- 2-6% in premixed feed
Protein
- secondary source
- very inefficient
Hay
Legumes
Grass
Cereal Grain 🡢 must be preserved at DM > 85%
Legumes
Alfalfa
- higher nutritional value 🡢 if at < 20% bloom
- no bloat
Grass Hay
- timothy
- orchard
- brome
- bermuda
- bahia
Cereal Grain Hay
- oats
- wheats
- corn
When can foals eat hay?
fiber degrading capacity established by 2 mo
Cereal Grains
Oats
- most popular/palatable
- higher fiber/lower DE
Corn
- 2x DE as oats
- low fiber
Barley
- hard hulls 🡢 needs processing
- moderate fiber + DE
Oats
- most palatable
- safest
Corn
high energy
low fiber
less digestible in SI
Barley
in between corn + oats
less palatable
What is key when it comes to grains?
NFC (starch + sugar) 🡢 non fiber carbs
Starch/Sugar
Digestion:
- begins in mouth
- continues in stomach/SI
Starch:
- creates problems in cecum d/t fermentation
-** overload can cause colic**
Protein
Requirement 🡢 8-10% of ration
- important for muscle dev/exercise
alfalfa hay
soybean meal 🡢 most common supplement
unabsorbed AA/peptides
- 🡩 fecal odor
- substrate for bacterial fermentation 🡢 putrescine + cadaverine, ammonia, phenols, sulfur compounds
Fat Supplements
vegetable oil
- common fat source
- start at 0.25 cup/feeding 🡢 max 2 cups/day
rice bran
Feed Guidelines
- feed by weight
- forage based diets 🡢 1.5-2% of BW
- small stomach for grain 🡢 0.5% BW/feeding
- Ca:P 🡢 2:1
- set schedule
- gradual feed change
Complementary Feeds
variable forms
- straight feed stuffs
- complementary balancers
- supplements
Maternal Feeding
overnutrition v undernutrition
- overfeeding more likely
- affects glucose + insulin metabolism
- precursor to metabolic syndrome
- produces oxidative stress
Overfeeding
- results in lower foal serum IgG
- not failure of passive transfer
Gestating Mares
first 7-8 mo fetus grows at 0.2lbs/day
last 90 days fetus gains ~1 lb/day
- fetus takes up more room leads to 🡣 in forage intake
- 🡩 nutritional demands leads to need for nutritionally balanced concentrated grain mix
Supplements:
- selenium
- vitamin e 🡢 booast foal’s immune system
- copper 🡢 beneficial to foals
- arginine 🡢 may moderate neg effects on foal metabolism
