North American Veterinary Licensing Examination (NAVLE) Practice Test

What condition can be caused by fescue grass toxicity in mares during late pregnancy?

1. Retained placentas

2. Mastitis

3. Fescue toxicity

4. Placentitis

The correct answer is: Fescue toxicity

Fescue grass toxicity occurs when pregnant mares consume fescue that contains a fungus (Neotyphodium coenophialum) that produces ergot alkaloids. These alkaloids can lead to several reproductive issues, particularly during the late stages of pregnancy. One of the most significant risks associated with this toxicity is the potential for retained placentas. When mares are affected by fescue toxicity, the ergot alkaloids can lead to prolonged gestation periods and an increased likelihood of complications during and after parturition. This can result in a retained placenta, which is a serious condition that can lead to infections and other complications for the mare postpartum. While mastitis and placentitis are important conditions to consider in equine health, they are not the direct result of fescue grass toxicity in this context. Mastitis primarily affects lactating mares and is not directly linked to fescue consumption. Placentitis, on the other hand, can occur due to infections or other factors but is not specifically attributable to fescue toxicity. Instead, retained placentas are specifically recognized as a condition linked to the consumption of toxic fescue during late pregnancy.