Freedom’s pasture-mate, Willow, was recently diagnosed with Equine Metabolic Syndrom (EMS) or Insulin Resistance (IR).

 What does that mean?

According to the Department of Animal Science at the University of Connecticut,

Glucose (sugar) normally functions to fuel many metabolic processes in the body and is the primary energy currency of the body. Insulin is normally produced in response to elevated blood glucose and is key to the regulation of blood glucose concentrations and glucose utilization. Insulin promotes glucose uptake by cells and promotes formation of glycogen or fat. Insulin resistance is defined as a reduced sensitivity of the body’s cells to insulin’s facilitation of glucose uptake.

Basically what happens in insulin resistance is that the cells become resistant to the glucose uptake action of insulin. Initially, this just means that more insulin is needed (hyperinsulinemia) to keep blood glucose concentrations within normal limits after a starchy or high sugar meal. If it is severe enough even super high insulin concentrations are ineffective and blood glucose may also be abnormally high. The problem is that not only does this limit energy availability to the cells but insulin also has other effects on the body that may be detrimental when it is higher than normal for prolonged periods of time. Unlike humans, horses rarely go into the second stage, where the pancreas becomes “exhausted” and no longer can secrete adequate insulin.

In practical terms, this means that Willow, who only gets enough concentrate to mask her vitamin/mineral supplement, must wear a grazing muzzle because too much sugar could cause an episode of laminitis. In fact, it was because her owner felt digital pulses that she ran a blood panel and got the diagnosis.

It didn’t take Willow very long to figure out that this is NOT FUN. She is getting less tolerant about putting it on, although putting a tiny bit of grain in the muzzle is still enough of a temptation to overcome her reluctance. Unfortunately for Willow the new barn has a lot of grass and she’s mighty peeved that her access is now restricted.

I tried using a muzzle on Freedom when I first got him – not because I need to restrict his eating, but as a way to stop him cribbing. That lasted about 5 minutes. He destroyed two or three grazing muzzles in short order and then refused to let me near him him with a halter.

Have you had to use a grazing muzzle on your horse or pony?