Q.My veterinarian diagnosed my 20-year-old mare with PPID (pituitary pars intermedia dysfunction) and prescribed medication. He didn’t recommend changing her turnout arrangements, which involve time in a grassy paddock each day. But a friend said grass is bad for PPID horses. Can horses with PPID be turned out on pasture?

—Sally, via e-mail

A.The short answer: It depends!

It depends largely on the PPID horse’s endocrine status—whether or not this horse has insulin dysregulation (abnormally high blood insulin levels) or equine metabolic syndrome (EMS), as well as having PPID. Why do we care? When a horse is EMS or insulin dysregulated, they likely cannot tolerate pasture. In fact, pasture will likely exacerbate the insulin dysregulation (i.e., it causes the horse to have even higher levels of circulating insulin in the blood, which contributes to these horses developing laminitis)