Management of insulin resistance might lower the risk of laminitis, and one of the cornerstones of management is diet. “Think of these horses as being in a prediabetic state,” said Nicholas Frank, DVM, PhD, Dipl. ACVIM, associate professor of large animal clinical sciences at the University of Tennessee, at the 2006 AAEP Convention. “They need to exercise more and take in less sugar.”

He made these recommendations:

• Take obese horses off sweet feed, they don’t need it anyway.
  
• Consider a grazing muzzle.
  
• Don’t overfeed them.
  
• Feed hay lower in nonstructural carbohydrates (NSC; forage testing labs can tell you a hay’s NSC content).
  
• Induce weight loss by feeding hay initially at 2% of the horse’s current body weight, decreasing to 1.5% of current body weight, then finally dropping to 1.5% of ideal body weight.
  
• Consider pergolide treatment in horses with EMS to stave off PPID.
  
• Exercise horses to decrease weight.

If an insulin-resistant horse develops laminitis, Frank recommended the following management practices:

• Take the horse off pasture entirely–remove some horses permanently, but most temporarily.
  
• Keep the horse in a dry lot.
  
• Hand-walk him for exercise once his feet are stabilized.
  
• If he’s obese, feed low-sugar hay.
  
• If he’s lean, feed hay plus a low-NSC feed.

Consider strategic use of levothyroxine (generally used as replacement therapy in reduced or absent thyroid function) for three to six months in obese horses