Blood glucose (BG) is highly variable due to the time of day, the time taken after a meal, stress, and other factors, such as how well they slept. Therefore, BG is not a good marker of metabolic health.
Here is what I copied from Equus Magazine to explain it further: “Glucose. This sugar is an energy source inside the horse’s cells. Serum glucose fluctuates widely in normal individuals, in response to factors such as stress, pain or recent feeding, so an elevated reading on a single test isn’t necessarily significant. However, chronically elevated levels of glucose may also indicate a metabolic disorder, such as insulin resistance (IR).”
A better blood value to look at is blood insulin. A random sample may not be as indicative of metabolic syndrome as a sample taken after fasting or one taken after a glucose load challenge. Both of these are a better marker of IR or “dysregulation.”
ACTH level is another marker associated with “Cushing’s Disease” and should be looked at along with insulin from an oral glucose test (OGT). These values, when compared over time, will give you a better picture as the results are less variable. But most importantly, your evaluation of how the horse is doing is the best indicator of metabolic health. Body fat loss, gain in muscle, and athletic performance (willingness to move, for example), tell more about how healthy the horse is.
Here is another pasted copy of information from Merck: “Horses with EMS respond to high carbohydrate meals with an exaggerated increase in insulin, a higher than expected blood glucose level, and a very slow return of blood glucose concentrations to baseline values. This indicates a resistance to the peripheral effects of insulin (EMS) and/or an inability to metabolize oral carbohydrate normally (insulin dysregulation).”
I think I’ll address this on the next Thursday Zoom meeting. Thanks for this update, and please, let us know if the vet is also testing for these other values or using the OGT. Doc T