5a Nutrient Requirements of Horses 2 Flashcards
(39 cards)
How much body weight do horses carry on their front limbs?
60-65%
What are the 3 muscle fibre types and what are they for?
type 1: slow twitch for endurance; beta oxidation of fat
type 2A and 2X: fast twitch for sprint; glucose
Describe the respiration rate during gallop?
1 breath: 1 stride
Why would horses require a reserve of red blood cells?
- blood cells can be released from the spleen during exercise
- higher capacity to carry oxygen, more oxygen to muscles
- natural blood doping
How does exercise affect bones?
- remodelling of long skeletal bones
- risk of micro fractures and injury if intensity increased too rapidly
- full bone turnover takes approximately 6 months
- bone tissue becomes more active and as a result, reduction in bone density
What factors affect exercise?
- duration
- intensity (speed, ground resistance, incline)
- other (number and height of jumping efforts, performance of extended and collected gaits, amount of weight carried or pulled)
Describe the energy requirement of exercising horses?
- energy for maintenance + energy for daily exercise effort
- variable depending on: horse, level of training, type of exercise, rider weight and experience, climate, ground conditions)
Describe the ‘light’ exercise category.
- 1-3 hours/week
- recreational riding
Describe the ‘moderate’ exercise category.
- 3-5 hours/week
- school horses, polo, ranch work
Describe the ‘heavy’ category of work.
- 4-5 hours/week
- frequent show horses, race training
Describe the ‘very heavy’ category of work.
- ranges from 1hr/week of speed work to 6-12hr/week of slow work
- racing, elite 3 day event
What is oxygen utilization closely related to, and what is it used to measure?
- closed related to heart rate
- used to measure energy expenditure
- linearly related to speed
What does oxygen utilization for account for at high heart rates?
- does not account for anaerobic energy
Describe the relationship between heart rate, oxygen utilization and energy utilization.
- HR increases linearly
- exponential increases in oxygen utilization and energy utilization
What are the energy requirement equations for each level of exercise?
- light work: DE = (0.0333 x BW) x 1.3
- moderate: DE = (0.0333 x BW) x 1.4
- heavy: DE = (0.333 x BW) x 1.6
- very heavy: DE = (0.0363 x BW) x 1.9
Why does carb use increase as exercise intensity increases?
- recruitment of fast twitch muscle fibres
Where are carbohydrates derived from during exercise?
- muscle glycogen, blood glucose, hepatic glycogenolysis or hepatic gluconeogenesis
- muscle glycogen depletion related to exercise intensity and duration
Does ‘carb loading’ work in horses?
- muscles have a certain capacity to capture glycogen so only works to a certain extent
At 68 hr post exercise, what percentage of muscle glycogen is replenished?
- 85%
- more desirable to enhance fat utilization and spare glycogen
What feed types would replenish glycogen faster?
- starch digested as glucose
- grains like oats or sugar
How is fat supplementation believed to affect glucose?
- glucose sparing effect
- response may only occur during low and moderate exercise
- requires 2-3 months for full adaptation
- true effects undetermined
What is another name for omega 6 fatty acids and what does it form?
- linoleic acid
- arachidonic acid
What is another name for omega 3 fatty acid and what does it form?
- alpha-linolenic acid
- forms EPA and DHA
What are some of the beneficial responses of supplementation of EPA and DHA?
- alters cell membrane of platelets, erythrocytes, neutrophils and monocytes
- increase fluidity of red blood cells
- decrease inflammatory response
- reduction in omega 6 and increase in omega 3 related to decrease in prostaglandins and dampening of inflammation
