Having trouble getting your mare pregnant? It might be time to take a good look at her weight and metabolic condition. Some veterinarians now believe that metabolic diseases likely have a negative impact on equine reproduction.

At the 2013 Society for Theriogenology Conference, held Aug 7-10 in Louisville, Ky., Peter Morresey, BVSc, MACVSc, Dipl. ACT, ACVIM, presented a lecture on what we know about metabolic diseases and equine reproduction.

Knowledge from Other Species

At the moment, much of what veterinarians know about reproduction-related metabolic disorders in horses comes from human medicine and research in other species, Morresey explained. He touched on research first:

  • Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of child-bearing age, he said, and is characterized by numerous ovarian cysts, high male hormone levels, chronic anovulation (ovulation in which the ovaries do not release an egg), and other metabolic disturbances. Affected women have conditions such as obesity and insulin resistance—which has been characterized as the major risk factor related to PCOS. Additionally, he said, PCOS is associated with gestational diabetes development, and affected women tend to have increased insulin resistance compared to healthy pregnant women. Finally, women with PCOS have an increased risk of first trimester abortion compared to healthy women.
  • Research has shown that obesity in men can negatively affect sperm production, decrease testosterone levels, and suppressed testicular function, among other negativities.
  • Research in mice showed that females fed a hig