Re: Concerned and Seeking Advice
Eleanor Kellon, VMD
It will make your feeding decisions a lot easier if you can convince one of your vets to test her insulin. On the current diet and in work she should test normal (work is the best insulin-buster there is). If it is still high, you will need to still be restrictive. If normal, she can move to the diet for EMS horses/ponies in work where she can get something to help replenish her glycogen stores after work. What usually works well is a combination of 50:50 beet pulp and oats (by dry weight measure). This should only be fed within an hour of stopping work, when muscle is very glucose hungry.
Do you know anyone who is diabetic? If you can borrow a glucometer, the easiest test for whether she needs her diet liberalized a bit as above is to check her blood sugar before and 10 minutes after stopping work. You only need a drop of blood. If it goes down, she needs glycogen replenished.
Glycogen is the storage form of glucose in liver and muscles. When levels drop too low you see issues of poor work tolerance/endurance and power. Muscle bulk may decline because glycogen and the water stored in muscle because of it contribute to bulk. That said, most areas of obvious muscling, like the back and rump, have a generous layer of fat over them so simply losing fat can look like loss of muscle. The best area to watch for actual muscle loss is the upper leg. Very little fat there.
She will still be able to lose fat if you liberalize her diet a bit as long as total calories are not too high.
She's a beauty!
Eleanor in PA