Some comments on the nutrition posts :
Creatine : I am not surprised that creatine loading is of no benefit in
horses - I would agree with Beth that this could be because even sprint
events go for longer than creatine is going to help supply muscle energy.
Somewhere I remember hearing/reading that horses have a greater aerobic
capacity than humans and require aerobic glycolysis to provide much of the
energy for even these short sprints. While accumulation of creatine could
potentially improve explosive power, this is going to be of little benefit
over all. And of no benefit to endurance horses, that I can see.
Fat : It is very interesting that the racehorses do well for a while with
increased fat in their diets, then decrease their performance. Maybe the
trainers should then enter the horses in an endurance event?! Researchers at
Sydney University looked at supplementary fat and high intensity exercise
and concluded that "provision of an increased proportion of the diet in the
form of fat increased high intensity exercise capacity and the maximal
accumulated oxygen deficit (MAOD) during intense treadmill exercise. Resting
muscle glycogen depletion during the MAOD test was not altered by the
dietary manipulation." Their High fat diet was 12% fat - I think you are
spot on in your recommendations, Tom. This would appear to be an appropriate
level of fat feeding for endurance horses, also, with other researchers
finding muscle glycogen sparing in horses trained aerobically and fed 10%
added fat. Suitable training appears to be important in conjunction with any
changes in diet.
However, while glycogen may well be spared during exercise in fat fed
animals, I have yet to see any work that agrees that this results in
improved endurance performance. Logically it should be so, in that the
horses have an increased ability to use fat for energy and therefore have a
greater effective store, and can conserve glycogen for longer. I guess it is
hard for researchers to jog a horse for 100 treadmill miles!
What have riders found with their horses when they have fed fat, versus not?
There was one message from Linda that seemed to indicate better performance
when her mare was receiving added fat.
Carnitine supplementation : carnitine is needed for effective metabolic use
of fats. Anyone know of information regarding provision of extra?
Great discussion, thanks,