Lecture 15: Equine Nutrition 3

national research council (NRC)

represents minimum requirements for nutrients; based on mature BW

equi-analytical website

• type of horse, age

• current body weight and condition

• physiological state → repro status, exercise/fitness level

maintenance stage crude protein requirement

8%

pregnant stage crude protein requirement

10%

lactating stage crude protein requirement

11-13%

growing stage crude protein requirement

14%

what if protein is deficient?

• young animals → decreased growth

• mature animals → decreased feed intake, decreased body condition, poor hoof and hair growth

key concept of protein requirements of horses

protein quality is critical in growing horses

calcium and phosphorus requirements for maintenance stage

Ca = 0.24, P = 0.17

calcium and phosphorus requirements for lactation stage

Ca = 0.6, P = 0.3

calcium and phosphorus requirements for growth stage

Ca = 0.8, P = 0.4

benefits of supplemental fat for endurance horses

• increases energy density

• reduces reliance on grain

guidelines of supplemental fat for horses

• up to 10% of diet

• adapt over 8-10 weeks to higher fat diet

• balance protein and minerals

sources of supplemental fat for horses

vegetable oils, rice bran

water requirements for horses

• 8-10 gallons/day

• increase with lactation and exercise

• warm water encourages intake in winter

after exercise, what should you do to help the horse cool down?

allow small drinks every 5-10 minutes

key management of water requirements in horses

• always provide clean water

• provide salt to encourage intake

body condition scoring in horses

• 1-9 scale

• ideal = 4-6

• 50 lb per BCS score

performance horse ideal BCS

4-5

pleasure horse ideal BCS

5-6

managing starved horses

• start with low quality forage

• begin at 50% maintenance based on ideal BW

• gradually increase over 10 days to 100% maintenance

• introduce grain slowly over 10 days to full amount

reduce nutrient drains

• deworm

• blanket for warmth

• stable to reduce exercise

• make sure no competition for food

managing general dietary changes

• change diet over at least 10 days when increasing feed amount

• introducing grain to starving horse or after colic → add ¼ of full amount every 2-3 days to achieve 10-d minimum (start at ¼ → ½ → ¾ → full)

• do not increase concentrate by more than 0.5kg per day

common issues for geriatric horses

• poor dentition

• reduced digestion

• PPID/Cushing’s disease → abnormal glucose and fat metabolism

nutritional management for geriatric horses

• senior complete pelleted feeds

• higher protein (12-16%)

• smaller, frequent meals

• fat supplementation if needed

• limit grain and pasture with fructans

ponies vs horses

• greater fat mobilization when insulin low or in negative energy balance

• higher risk of hyperlipemia → leads to fatty infiltration of liver and high TG

why should you never fast ponies?

high risk of fatal hyperlipemia

what is the cause of hyperlipemia?

negative energy balance

management of hyperlipemia

• provide energy (carbohydrates)

• frequent feeding

• may require IV support → glucose and amino acids

• may take 5-10 days to resolve

what is the minimum time period over which a horse’s diet should be changed?

10 days

developmental orthopedic disease

bone cysts, valgus/varus, OCD, physitis

causes of DOD

excess energy (grain), rapid growth, mineral imbalances

key nutrient imbalances

calcium, phosphorus, copper, zinc

contracted tendons in foals

• may occur at birth due to malpositions in utero

• may occur in the rapid growth phase following a period of nutritional restriction

• avoid by ensuring diet will always support growth

obesity risks

• development of insulin resistance

• laminitis

• susceptible to metabolic syndrome → insulin insensitive

dietary management of obesity

• gradually reduce feed intake over 3-4 weeks

• feed 2% of current body weight for 2 weeks, then 1.5% of current body weight for 2 weeks, then 1.5% of target body weight for 2 weeks

• do not decrease feed intake below 50% of maintenance

• do no underfeed lactating mares or mares in last trimester

dietary management of obese horses

• restrict pasture (use grazing muzzle)

• feed low-quality hay and weigh hay

• remove grain

• increase exercise

• commercial “complete feed” type pellets based on alfalfa and straw for weight loss are available

thyroid hormone for management of obese horses

• levothyroxine

• feed 3x normal dosage

• increases metabolic rate

insulinwise for management of obese horses

• supports healthy BW, normal fat distribution, and healthy laminae

• blend of polyphenols and amino acids

exertional myopathy

• syndrome of muscle fatigue, pain, or cramping associated with exercise

• discolored urine → myoglobin from damaged muscle

• clinical signs → sweating, tachypnea, tachycardia, very firm and painful lumbar and gluteal muscles

recurrent exertional rhabdomyolysis

• abnormal regulation of intracellular Ca in skeletal muscle

• management strategies → decrease trigger factors for excitement, feed high fat, low starch diet

what is the issue with high starch when trying to manage recurrent exertional rhabdomyolysis?

it is readily available and contributes to excitability

types of supplements

• joint → glucosamine, chondroitin

• anti-inflammatory → omega-3 fatty acids

• hoof → biotin, methionine

• electrolytes → performance horses

• reproductive → DHA, L-carnitine

key concepts of supplements

• widely used

• variable evidence for efficacy

• not tightly regulated

omega fatty acids

• omega-6 → pro-inflammatory

• omega-3 → less inflammatory

sources of anti-inflammatory supplements

fish oil, algae, flaxseed (limited conversion to EPA)

increase omega-3 intake to

reduce inflammation

reproductive aids

• omega 3 fatty acids → docosahexaenoic (DHA) → fish oil

• L-carnitine → role in sperm energy metabolism

hoof supplements

• contains biotin and DL-methionine

• farrier’s formula

biotin

essential role in fatty acid metabolism → affects skin integrity and hoof growth

DL-methionine

sulfur containing amino acid to add strength to connective tissue proteins

balancer pellet

• high protein → 25-35% protein

• high in minerals and vitamins

• often top dressed to supplement deficiencies in regular diet

salt

• trace mineralized salt block → brown

• salt block → white

• loose salt → more consumption than block

supplemental electrolytes

• replace sweat losses during exercise → encourage water intake

• important → always provide water when supplementing

• can use paste form if horse is not eating