Equine Nutrition

Question 1

What is the biggest driver of equine diet

Answer 1

owner preference/perception

Question 2

How to visually assess horse nutrition

Answer 2

BCS: /9
Estimating body weight:
* Scale/weight tape/calculations
* Differentiate muscle wasting and ‘weight loss’

Question 3

Function of the stomach?

Answer 3

digest protein
no absorb

Stomach: small relative to body size
* Storage/physical mixing and chemical digestion
* Gastric emptying time (if fibrous meal) can be up to 1d, if higher carb it can be 20 min

Question 4

Function of the sm int and how is it clinically relevant

Answer 4

digset Fat
absorb Fat/carb/protein

Small intestine: fast rate of passage
* Protein digest: trypsin/chymotrypsin/carboxypeptidase
* Carb: amylase
* Fat: lipase

• Excess carb diet: overwhelm system and can overflow carb into large intestine (change microbial content and cause gas production

Question 5

Function of the lg int and how is it clinically relevant

Answer 5

Fibre fermentation

Large intestine: fermentation – slow rate of passage
* 75-90kg ingesta – important when treating colic (can be colicking and still pass manure, and can still pass manure while fasting while being treated for colic)
o Up to 5d of manure
* Cellulose fibers
* Absorb: water and salt
* Form VFA
o Heat source and carbohydrate source

Question 6

Function of the mouth

Answer 6

Mouth: mastication/chewing = break down particles
* Amylase – digest starch
* Incisors: function is prehending, if damaged = may not be very impactful
* Cheek teeth – function is mastication, if damages = higher risk of choke

Question 7

What are the factors that inform nutritional requirements for adult horses

Answer 7

Informed by…
* Forage requirement
* Energy requirement (Dietary energy)
* Protein requirement (CP)
* Nutrient composition

Question 8

What are the forage requirements of an adult horse

Answer 8

• Forage requirement
  o Should be eating 15h a day, 3-5 acres per horse in summer
  o Good forages are usually adequate
  o Most horses eat 10kg of feed (DM) per day – 2% body weight
   Can weigh the bale/bag of hay to determine how much is being fed

Question 9

What is the average energy requirement of an adult horse? what are the factors that impact it

Answer 9

o Average energy requirement = 17Mcal/day
 most is basal metabolic energy
 also basic activity
 temperature regulation
 maintenance of weight

Question 10

How to manipulate energy requirements to change the weight/BCS of adult horses and how is it used clinically

Answer 10

o 25kg of weight is required to increase of decrease BCS by 1 score
o 20 Mcal above maintenance is required to increase by 1kg
o Should make changes slowly (60-180d)
 Except in crisis situations: endocrine laminitis
o Rule of thumb: feed to ideal BCS and adjust for work/activity

Question 11

How should protein be used practically

Answer 11

• Protein requirement (CP)
  o Must meet energy requirements to fully utilize protein
   Or else protein will be used as energy (not as efficient)

Question 12

How is fat utilized in adult horse diets

Answer 12

o Fat supplementation: max = 20% diet
 Efficient way to increase caloric intake
 Ration is debated
* Omega 6 > arachidonic acid > prostaglandin (pro-inflam)
o Corn oil (main), canola/soy/rice
o Still needed in the body though
* Omega 3 > EPA and DHA (compete with prostaglandin = anti-inflam)
o Flax/marine oil

Question 13

How is fat utilized in adult horse diets and how is it clinically relevant

Answer 13

o Salt/vitamin/mineral:
 Free access salt blocks or added to diet
* Feeding salt can reduce colic risk because it will increase water intake (especially in winter because they don’t want to drink if cold)
 Forage only diets may need supplement
 VitE/Se: regionally differing levels in soil – may need to supplement

Question 14

How is water utilized in adult horse diets and how is it clinically relevant

Answer 14

o Water: requirement = 24L/day (snow is not enough)
 Depends on temp/exercise/lactation (requirements can double)/fed quality/forage
 If not enough – impaction colic

Question 15

Can horses be outside in the winter and how

Answer 15

yes

time to adjust (grow coat/acclimate)
water
high fibre

Question 16

What factors would contribute to poor thermoregulation in the winter

Answer 16

• Less efficient thermoregulation
  o Old/poor BCS
  o MSK problems
  o Inadequate hair coat
  o Inability to chew

Question 17

What is the thermoneutral zone

Answer 17

• Thermoneutral zone: range of temperatures when metabolic heat production doesn’t change

Question 18

How does heat impact nutritional requirements? What host factor impacts heat thermoregulation?

Answer 18

Thermoregulation in Heat
* Increased energy requirement (activity/temp regulation)
o Fly swatting
* Increased electrolyte and water requirement
* Obesity is a factor – less circulation through adipose tissue

Question 19

how does diet impact thermoregulation

Answer 19

• heat increments of feed: hay > grain > fat (fibre > protein > starch > fat)

Question 20

What factors impact the nutritional needs of an adult horse

Answer 20

Factors affecting nutritional needs – individual
* size/body type/weight
* age
* work (production – lactation takes lots of energy)
* breed
* environmental
* health status

Question 21

How do the nutritional needs of performance horses change and how is it clinically relevant

Answer 21

• require more digestible energy (non-structural carbs) – grain (oats – fast and easy digestion, corn – not broken down as easily)
  o corn increases risk of colic – increases risk of colonic acidosis (broken down in the colon due to cellulose shell)

Question 22

How do the nutritional needs of stallion horses change

Answer 22

Stallion
* ideal BCS is considered 5 ,6/9 (over conditioned)
* varied supplement use (omega 3)
* adjust for level of breeding and work

Question 23

How do the nutritional needs of brood mares change and how is it clinically relevant

Answer 23

Brood Mares
* Often over conditioned (most of fetus growth in late gestation)
* Early gestation should be 5/9
* Increase nutritional needs late gestation and lactation
* Will lose weight while lactating

Question 24

How do the nutritional needs of lactating mares change and how is it clinically relevant

Answer 24

• Increase to 28-31 Mcal/d
• Milk takes precedent – energy requirement high
  o Can lose 2-4% body weight per day
• High water intake and feed intake

Question 25

What is the typical timeline of a foal from birth to weaning

Answer 25

• 0-3mo – baby drinking milk
  o Observe growth rates (if growing too fast = developmental abnormalities like osteochondral dystrophy OCD)
• 4-6mo – reduced milk intake, eating forage/concentrates
• Weanling/yearling – forage/concentrate only

Question 26

What is creep feeding? what are the goals?

Answer 26

Creep Feeding
* Begin at 8 weeks of age – milk still a part of diet, gradual transition to solid food
* Use feeders that adult horses can’t eat
* 0.45 kg/d for each month of age
* Goal
o Accelerate GI maturation
o Allow consistent growth
o Reduce weaning stress
o Provide adequate nutrients

Question 27

Compare old vs geriatric horses

Answer 27

• Old = healthy and over 20yo
• Geriatric = old + senescent changes +/- concurrent dz

Question 28

what are the challenges and factors associated with feeding a geriatric horse

Answer 28

• Challenges: reduced digestion and microbes = reduced ability to digest fibre
  o Reduced ability to make vitamins (B/C)
  o Poor dentition
  o Often over or under weight
• Factors that cause reduced feed intake
  o Less active
  o Dental dz
  o MSK pain/reduced movement
  o Hierarchy challenges
  o Health challenges

Question 29

What to feed a geriatric horse

Answer 29

• What feed
  o Highly palatable
  o Easy to chew and swallow/dust free
• Strategies
  o Highly digestible/extruded pellets
  o High quality fibre
  o Chopped hay/hay cubes/pellets
  o Soaked feed/mash