Feeding the Performance Horse

Question 1

How are horses adapted to nutrition

Answer 1

• utilise diets high in fibre, low in nutrients/energy
• trickle feeders
• satisfy energy requirements from forage based diet
  ~ ferment fibrous feed in large intestine
  ~ microbial ferm produce VFA predominant energy source
• feeding innate behaviour (up to 18 hours a day)
• when diet differes = problems (e.g. high starch = colic, ulcers, laminitis)
• maintain gasterointestinal health primary requirement for equines = struggle perform long/stay healthy

Question 2

Fiber based diet

- min fiber recommend

Answer 2

• require fibre basisi of all diets regardless workload
• 1.5g DM/kg BW/d as forage or grass (1.5% BW)
• 1.1g DM/kg BW (1%) for ‘at risk’ overweight equids as minimum (Rendle et al., 2018)
  ~ Under veterinary advice
  ~ If excess energy = reduce concentrates not forage
  ~ still receiving excess energy = provide lower energy forage (straw, bagged chaff, lower quality hay)
  ~ dont starve horses = colic
• only feed conc when horse cant consume enough fibre to satisfy energy needs

Question 3

Concentrate feeds

• calculating energy requirments
• starch limits
• considerations

Answer 3

• When calculated requirements show that more energy dense feeds are required = replace some of forage in the ration with a concentrated form of energy
• BW is an easy indication if DE requirements should +/- (condition score with tape)
• Select feeds with an appropriate DE and crude protein (CP) content and consider the starch levels
  ~ 1g starch/kg BW/meal
  ~ 2g starch/kg BW/day
• need to consume amount of feed given within feeding time available
  ~ riding school, endurance horse out all day = consider eating time
• not all starch processed if feed too much
  ~ excess energy to fat
  ~ bypass where utiised in stomach and SI, to LI fermented rapidly in hind gut = colic, laminitis

Question 4

Crude protein

- limiting effect

Answer 4

• protein requirements can be met if the animals energy requirements are being met
  ~ Due to the need for energy to synthesise non-essential amino acids
• Does not account for the limiting effect of essential amino acids
  ~ not provided in the diet = synthesis of protein within the body will be negatively affected - lysine is the first limiting amino acid
• NRC (2007) daily CP and lysine requirements
• CP requirements increase with exercise but not as much as DE requirements
• Increase considerably during lactation and growth

Question 5

Types of exercise
DE calculations
Crude protein

Answer 5

• in poerpoint slides week 15

Question 6

Approtpriate diets

• basis
• nutrients and how fed

Answer 6

• Forage basis for all horses diets (GIT health and VFAs)
• important role in hydration and therefore helps with performance
  ~ water holding capasity large intestine = reduce dehydration
• not feeding a concentrate = feed fortified with vitamins and minerals need to provide a source of these nutrients
  ~ Balancer – includes proteins
  ~ Vitamin and minerals supplement
• Consider the environment the horse exercises/competes in
  ~ Forage has a high heat increment (microbial ferm)

Question 7

Appropriate diets endurance

- energy requirements

Answer 7

• competitive level horses need increased energy req
• conc provide energy from starch
  ~ Formulated for slower release energy by inclusion of oil
  ~ Starch levels vary considerably (<10% - >30%)
  ~ Must stay within the 1g starch/kg BW/meal recommendation
• concs provide protein and some vits/minerals
• high starch diet yield glucose then glycogen storage BUT horse use fat/VFAs main energy source for slow exercise

Question 8

Appropriate diets endurance

- oil

Answer 8

• provide energy in form of oil
  ~ 38MJ = energy rich
• Metabolised via β-oxidative pathway = aerobic metabolism
• Horses fed high fat diets have preference for FA metabolism
  ~ Glycogen sparing effect
  ~ utilising FA not glycogen in muscle
• Feed 100ml/100kg BW (up to 20% of ration)
• Add to diet gradually over 10-12 weeks
• not provide protein or other nutrients
• not palatable
• Reduces volume of concentrate feed required = good for fussy feeders
• Reduced heat production = good for hot climates

Question 9

Appropriate diets endurance

- protein

Answer 9

• fed at recomended levels
• excess = increase urine output and water requirements
• ensure lysine requirements met (1st limiting AA)
  ~ 0.8-0.1g lysine/kg BW/d for horses in hard exercise
• feed electrolyte supplement daily for training horses
• Feed according to level of training, not specific days exercise
• Feed according to manufacturers guidelines

Question 10

appropriate diets endurance

- timing of feeding

Answer 10

• timing of feeding influence performance
• Starch based meals (cereal grains) should be avoided in the 3-4 hours before aerobic exercise
• Starch causes insulin secretion and uptake of glucose form the blood
• Promotes glucose metabolism and decreases fatty acid metabolism
• Muscles also want to use the glucose
• Can cause blood glucose to drop (hypoglycemia)
• Reduces performance due to lack of energy substrate (glucose)
• Should continue to provide forage as this will provide some VFAs and promote hydration

Question 11

appropriate diet endurance

• glucose before exercise
• muscle glycogen

Answer 11

• use muscle glycogen during exercise
• need some glucose to maintain blood glucose levels and muscle glycogen levels
  ~ brain only use glucose energy source
• replenishing muscle glycogen levels is slow process = 2-3 days
• during endurance rides = need to replenish glycogen and retain blood glucose levels
  ~ cant be acheived through slow fibre and fat route
  ~ feed glucose source small quantities as part of ration
• withdrawn from compertition if too low glucose

Question 12

Appropriate diets sprint exercise

- respiration type

Answer 12

• working anaerobically = speed muscles use energy
• resp sys dont respond quick enough to enable aerobic metabolism
• glycogen main energy source
• if continue work at speed = lack oxygen leads to pyruvate convert to lactic acid/fatigue
  if resp sys catch up level of exercise = pyruvate enter citric acid cycle, process continue as aerobic metabolism

Question 13

Appropriate diets sprint

• type of racing
• feeds

Answer 13

• flat racing = speed
• some very short races = perform anaerobically
• diet/training = promote glycogen metabolism
• traditionally = cereal grains and forage
• ration high ceral grains, low forage (60:40)
  ~ GIT health compromised
  ~ over 90% race horses have gastric ulcers
• feeds based on provding starch

Question 14

Appropriate exercise combination exercise and other influence of nutrition

Answer 14

• Most disciplines require horses to work aerobically and anaerobically, with only very fast work leading to anaerobic metabolism
• Showjumper will use both: spurts of speed and more controlled work
• Feeding is also influenced by animals temperament, health, trainability, sensitives and genetics
• Consider the competition environment – how long will the horse be travelling, climate, ground conditions, facilities