14: Nutrient requirements of exercising horses Flashcards
What is required for bone remodeling? Why?
Moderate exercise with rest causes remodeling of long skeleton bones
bone structure changes with rest (most porous)
What are the risks of exercise?
Risk of microfractures and injury if intensity increases too rapidly
Full bone turnover takes approximately 6 months
Slide 6
Look
3 types of fiber in equine muscles? What are they for/do they do
Type 1: Slow-twitch for endurance
- aerobic
- oxidize triglycerides
Type 2A: intermediate fast twitch
- anaerobic + aerobic
- can use both intramuscular glycogen and triglycerides
Type 2X: fast-twitch for sprints
- anaerobic
- fully reliant on glucose, glycogen for E
- low oxidative potential
Kinetics of gas exchange in equine physiology
- maximum rate of O2 uptake/min is double that of human athletes
- splenic reserve of RBC (carry oxygen; releasing them from the splene increases oxygen carrying capacity of horse)
Factors affecting nutrient/energy requirements of hoses during exercise
- Duration
- Intensity (speed, ground resistance, incline)
- other (number and height of jumping efforts, performance of extended and collected gaits, amount of weight carried/pulled)
Energy is required in an exercising horse for…
maintenance + energy for daily exercise effort
May need additional E for transportation, stress, etc
Energy requirement of a horse varies depending on
- the horse
- level of exercise
- type of exercise
- rider weight and experience
- climate
- ground conditions
Categories of exercise in horses
Light, moderate, heavy, very heavy
slide 11
Oxygen utilization is used to measure… What is it related to?
Used to measure energy expenditure
Closely related to heart rate
Linearly related to speed
Slide 12, 13
How does the energy requirement for exercise calculation change in light, moderate, heavy and very heavy work
Light work
DE = (0.0333 x BW) x 1.20
Moderate = 1.40
Heavy = 1.60
correction factor to support exercise
What nutrient is most used in high intensity exercise?
Carbohydrates
Increased intensity = increased CHO use bc of recruitment of fast-twitch muscle fibers
Anaerobic metabolism
Where does the body get glucose (CHO) for exercise
Muscle glycogen, blood glucose, hepatic glycogenolysis, or hepatic gluconeogenesis
What happens when glycogen levels re depleted? Does CHO loading work in horses?
Fatigue resistance reduced (get tired easier)
A little bit, but they are mostly hindgut fermenters and too much starch for too long = metabolic issues
Look at slide 16
Supplementation of _________________ may spare glucose during _______________
Fats and fatty acids for at least 2-3 months
Low and moderate exercise (beta-oxidation)
Important n-3 and n-6 f.a.
Linoleic acid forms arachidonic acid (n-6’s)
a-linolenic acid forms EPA and DHA (n-3’s)
Why might EPA and DHA supplementation be beneficial?
They alter cell membranes of platelets, erythrocytes, neutrophils and monocytes
- Increase fluidity of RBC
- Decrease inflammatory response
Protein use during exercise? Prolonged exercise reduces…
Protein metabolism estimated to be only 5-15% of E expenditure during exercise
Serum concentrations of branched chain AA are reduced (oxidized for E)