Gestation
The average gestational period in goats is 150 days, or five months. During early gestation, embryonic losses are usually 20 percent to 30 percent higher than later in gestation. There are a number of extrinsic factors that can contribute to embryonic mortality, including environmental stressors such as heat and nutrition, and doe age. During early gestation, the embryo is also extremely sensitive to a wide range of drugs and mineral deficiencies.
Gestation is usually characterized by high levels of progesterone from the placenta that help inhibit uterine contractions until kidding. However, in goats, the placenta does not provide sufficient progesterone and is dependent on secretions from an active corpus luteum to support pregnancy. Hence, spontaneous (non-infectious) abortions resulting from luteal insufficiency are more common in goats. Undernutrition, vitamin and mineral deficiencies, toxic plants and certain drugs such as levamisole can contribute to non-infectious abortions. Multiple late abortions ('abortion storm') usually suggest an infectious source such as chlamydiosis and toxoplasmosis. To properly diagnose the cause of an infectious abortion, the fetus, portions of the placenta and a blood sample from the doe should be collected for testing.
References: Whitley, N.C. and D. J. Jackson. 2004. An update on estrus synchronization in goats: a minor species. J. Anim. Sci. 82: E270-276E (Proceedings); http://www.luresext.edu/goats/training/reproduction.html
