Q: What is the correct age to breed a mare for the first time? I have strongly considered breeding my Pure Polish Arabian filly before she begins a serious dressage career. I would keep and train the foal. The filly is currently 3 years old. I have been told many ages of when I should first breed her: 4, 5, 6, and even 10! I would like a professional’s opinion and would really appreciate what you have to say.

Jasmine, California

A: I’ll start by commenting on behavioral considerations and share what I know about natural horse reproduction and behavior. Dirk Vanderwall, DVM, PhD, Dipl. ACT, from our reproduction center here at New Bolton Center, will comment from the veterinary reproduction specialist’s perspective.

Under natural herd conditions mares that are in good nutrition typically start cycling, are bred, and become pregnant in their yearling spring, often even before their first birthday. Some of these young mares will lose their pregnancies, but most go on to foal at about the age of 2. Their first foal might be small, reflecting the dam’s not yet fully grown size. The milk of a 2-year-old filly can be a bit slower to come in than that of older maiden mares, but it usually comes in strong within a day or so after the foal is born. Similarly, maternal behavior is variable and often a bit delayed in some 2- and 3-year-old first-time dams