Equine Nutrition

Question 1

VFAs

Answer 1

acetate + propionate + butyrate

Question 2

Horses are:

Answer 2

grazing herbivores

GI track well adapted to trickle feeding 🡢 naturally forage 10-15 hr/day

Question 3

Anatomy

Answer 3

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

Question 4

Water

Answer 4

• 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

Question 5

How do horses use feed?

Answer 5

• energy = 85%
• protein = 10%
• minerals = 4%
• vitamins = 1%

Question 6

Forages

Answer 6

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

Question 7

Sources of Energy in Diet

Answer 7

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

Question 8

Hay

Answer 8

Legumes
Grass
Cereal Grain 🡢 must be preserved at DM > 85%

Question 9

Legumes

Answer 9

Alfalfa
- higher nutritional value 🡢 if at < 20% bloom
- no bloat

Question 10

Grass Hay

Answer 10

• timothy
• orchard
• brome
• bermuda
• bahia

Question 11

Cereal Grain Hay

Answer 11

• oats
• wheats
• corn

Question 12

When can foals eat hay?

Answer 12

fiber degrading capacity established by 2 mo

Question 13

Cereal Grains

Answer 13

Oats
- most popular/palatable
- higher fiber/lower DE

Corn
- 2x DE as oats
- low fiber

Barley
- hard hulls 🡢 needs processing
- moderate fiber + DE

Question 14

Oats

Answer 14

• most palatable
• safest

Question 15

Corn

Answer 15

high energy
low fiber
less digestible in SI

Question 16

Barley

Answer 16

in between corn + oats
less palatable

Question 17

What is key when it comes to grains?

Answer 17

NFC (starch + sugar) 🡢 non fiber carbs

Question 18

Starch/Sugar

Answer 18

Digestion:
- begins in mouth
- continues in stomach/SI

Starch:
- creates problems in cecum d/t fermentation
-** overload can cause colic**

Question 19

Protein

Answer 19

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

Question 20

Fat Supplements

Answer 20

vegetable oil
- common fat source
- start at 0.25 cup/feeding 🡢 max 2 cups/day

rice bran

Question 21

Feed Guidelines

Answer 21

• 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

Question 22

Complementary Feeds

Answer 22

variable forms
- straight feed stuffs
- complementary balancers
- supplements

Question 23

Maternal Feeding

Answer 23

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

Question 24

Gestating Mares

Answer 24

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

Question 25

Foal Nutritional Needs

Answer 25

3% BW in DM/day
- energy
- protein 🡢 lysine + threonine
- minerals 🡢 Ca, P, Zn, Cu

Question 26

Maximal v Optimal Growth

Answer 26

• bone mineralization lags bone growth
• developmental orthopedic disease occurs
• 3-9 mo is greatest risk

Optimal Growth 🡢 60% concentrate
- 1 lb conc./100 lbs foal
- 1 lb/mo of age
- not to exceed 7-9 lbs/day

Question 27

Performance Considerations

Answer 27

Forage only diets 🡢 lactate 🡣, venous pH, blood glucose 🡩

Question 28

Fescue

Answer 28

cool seaso perennial
drought resistant
high quality/yield