Why should you never starve a horse?

When a horse has insufficient food the body goes into a state of negative energy balance.  This can cause a metabolic disorder called Hyperlipemia. This is when the body tries to maintain the function of essential organs by releasing free fatty acids from its fat stores into the blood.  Large amounts of fat circulating in the blood stream (hyperlipemia) causes other organs to fail (e.g. the liver and kidneys). Horses that are extremely overweight are those most at risk for hyperlipemia. The result is irreversible and often life- threatening.