ANS3405 Exam2

Roughage

high fiber feedstuffs (≥ 18% crude fiber)

Grass forage

higher in hemicellulose and NDF

Legume forage

higher in protein, calcium, pectin, lignin, vitamin E, & beta-carotene

Early to Mid-Maturity Hay

lots of leaves, fine stems, few seed heads
growing horses, lactating mares, hard keepers

Mid-Maturity

lots of leaves, small + soft seed heads
performance horses, pregnant mares

Mid to Late-Maturity

stemmy hays, lots of mature seed heads
recreational-use horses, easy keepers, ponies

Early to Late maturity nutrient content

Decrease in: NSC, protein, minerals, DE, digestibility
Increase in: hemicellulose, cellulose, lignin

Advantages of processed forage

less sorting, less waste, reduce gut fill - more can be eaten, less storage space, minimal dust, less chewing (for bad teeth)

Disadvantages of processed forage

eaten faster, boredom, wood chewing, may increase choke chances, may cost more, difficult to evaluate without lab

Minimum amount of forage needed? Ideal level?

minimum amount = 1.5% BW
ideal = 90-100% of diet is forage

High-fiber alternatives to forage

beet pulp (highly digestible), hulls (less digestible)

Cereal Grains

high in starch; low in sugar, fiber, and fat

Grains vs forage

Grains have higher DE, higher starch, lower fiber

Processing grains

alters physical form of grain and improves digestion EXCEPT for oats

Grain byproducts

nutrient composition similar to roughages, all grain byproducts are high in phosphorus

Rice bran

high in fat (other brans are not)

High fat feedstuffs

vegetable oils, flaxseed, heat-processed soybeans

Vegetable oil

provides fat, does not provide any other nutrients

High protein feedstuffs

skim milk, soybean meal, cottonseed meal, whey, whole soybeans

Why is fat and fiber added to commercial feeds over starch?

high starch can cause a digestive upset

Fat-added feed

≥5% crude fat

Fiber-added feed

≥12% crude fiber

Fat and Fiber-added feed

≥5% crude fat and ≥12% crude fiber

Concentrates

needed when forage-only diet does not meet nutrient requirements (ex. growing horses, late gestation mares, lactating mares, moderate to heavy exercise, fed low quality forages)

Maximum amt of daily concentrate intake

< 50% total DM intake/day; 0.5% BW per meal

Complete feed

complete feeds combine roughage + fortified concentrate and are only food source; ≥18% crude fiber

Must add minerals

salt, electrolytes

What vitamins and minerals are made by horse or microbes?

vitamin E, vitamin A; calcium, phosphorous, magnesium, sodium, chloride, potassium, zinc, manganese, copper, selenium

What vitamins and minerals must be supplemented?

vitamin D, C, K; cobalt, chromium, fluorine, iodine, iron, sulfur

Options to supplement vitamins/minerals

mineral blocks, premix vitamin/mineral, ration balancer

When would vitamins/minerals needed to be supplemented?

forage only diet, unfortified grains, insufficient amt of fortified feed

What are dietary sources of energy? And what is their immediately available form?

Starch and sugar = blood glucose, fiber = propionate, acetate, fat = fatty acids, protein = some glucose/acetate

Stored forms of dietary energy

starch/sugar = liver/muscle glycogen + triglycerides, fiber = same as sugar/starch, fat = triglycerides, protein = not stored

How does exercise affect which energy sources are used?

Endurance = mostly fat, some carbs
Middle distance = mostly carbs, some fat
Sprint = carbs
Combo = carbs and fat

Nutrient requirements most affected by exercise

Energy, water, electrolytes, vitamin E

Expected DM intake and hay:concentrate needed for horses in work

Light = 2% BW (70-80% forage, 20-30% grain)
Moderate = 2.25% BW (50-70% forage, 30-50% grain)
Heavy/intense = 2.5% BW (40-50% forage, 50-60% grain)

What is lost in sweat? What affects it?

electrolytes; increased heat + humidity, increased exercise duration

What are some electrolyte replacement strategies?

Replace them as they are lost, add to water, salt, top dress feed, oral paste; horses cannot store electrolytes

What are benefits of adding fat to diet?

decreased excitability, decreased dust, energy source, shiny coat

Is a high protein diet harmful to most horses? What happens to excess protein?

not generally harmful as long as adequate water is supplied; BUT will increase ammonia excretion which is bad for respiratory system in stalled horse

What happens when horse eats grain meal? How long do effects last? How does it impact fuel availability?

Insulin increases with blood glucose, decrease in fat mobilization for 4 hours; puts body in storage mode and reduces fuel available to muscle

What happens when horse eats large hay meal? How long do these effects last?

decreased blood volume, increased gut fill and weight; lasts about 4 hours

How would a large hay meal affect exercise? How does this change with a small hay meal?

gut will compete with muscles for blood and increased body weight negatively affects exercise; small hay meal reduces this effect

What is a good pre-exercise feeding strategy?

Small grain and hay meals with continuous hay intake; decreases risk of colic and negative effects on fuel availability

What is a good post-exercise feeding strategy?

replenish muscle glycogen with starch, do NOT feed until body temp drops below 102, use good quality hay + small grain meal 60-90mins after exercise, then grain again 2-3hrs later

Difference between RER and PSSM

RER - defective calcium regulation
PSSM - excess of abnormal muscle glycogen

How does high NSC trigger RER and PSSM?

RER - indirect effect - excitable behavior
PSSM - direct effect - glycogen synthesis

How should RER/PSSM horses be fed?

RER - low to moderate NSC with added fat concentrate, low NSC hay/pasture
PSSM - low NSC with added fat concentrate, low NSC hay/pasture

How is nutrition connected to sporadic vs chronic tying up?

Sporadic - deficient in electrolytes, vitamin E, selenium
Chronic - high starch/sugar

How does nutrition affect reproductive performance?

deficient DE and protein can result in messed up fertility and pregnancy loss

How does body condition affect reproductive performance in broodmares?

thin = lower pregnancy rate, low milk production
obese = low milk production, risk of metabolic disease

What is the ideal body condition score for broodmares? Why?

BCS 6-7; she will need fat stores for weaning and lactating

What type of mare would the practice of "flushing" going into the breeding season be most effective?

may help improve fertility in thin mares

When is the most opportune time to improve the body condition of a broodmare? Why?

in early gestation; her nutrient requirements are similar maintenance which will allow her to put on weight

How much weight gain is needed to move up 1 BCS level?

20kg

How many extra Mcal DE are needed for 1kg of weight gain?

20Mcal DE

Maximum safe weight gain in mature horses

0.5kg/day

How does gestation and lactation affect the mare's requirements?

all nutrients affected by lactation; DE increase 90%, protein increase 45%, minerals increase 25%(TM)-200%(Ca + P)

How does stage of pregnancy or lactation affect how we feed mares?

early gestation = forage usually sufficient, concentrate only needed if mare needs to gain weight
late gestation = forage 70-80% diet, concentrate 20-30%
lactation = forage 50-60% diet, concentrate 40-50%

How should we manage mares consuming tall fescue? Why?

remove mares from infected fescue 30 days before foaling and mow pastures; fescue can increase length of gestation, stillborn foals, retained placenta

How should you handle the mare's diet around the time of weaning? Why?

feed normally up to weaning; post-weaning gradually reduce concentrate

What is the ideal body condition score for stallions? Why?

BCS 5-6; need energy stores for breeding season

What affects stallion's requirements?

temperament and psychological response to breeding

How should stallions be fed during non-breeding and breeding seasons?

non-breeding = "high" maintenance, 90-100% forage and 0-10% concentrate
breeding = light work, 70-80% forage and 20-30% concentrate