Physiological Factors
Reproductive failure can result when hormones are not produced in the correct amount or in the right pattern or if no egg is produced and released from the ovary. Ovaries can become cystic (both follicular and luteal, so either before or after ovulation). In does with follicular cysts, which are rare, the follicle with the egg grows but there is failure of ovulation, or release of the egg. This type of cyst usually results in females that are always in heat. This may be related to problems with the hormone that causes ovulation known as luteinizing hormone. Even though this type of cyst is hard to treat, large doses of LH/hCG or GnRH followed by a dose of prostaglandin 10-14 days later, might be effective. See your veterinarian for use of drugs not labeled for goats.
Luteal cysts can occur when the corpus luteum (CL) fails to regress (go away) and becomes filled with fluid such that hormone secretion is altered. Poor uterine health resulting in low prostaglandin secretion could cause this problem. Luteal/CL cysts can lead to pregnancy loss, a dead, mummified fetus, infection, and even pseudopregnancy (fake pregnancy). Luteal cysts usually go away eventually, but prostaglandin (available commercially as Lutalyse©) administration might be used to lyse the CL.
Reproductive failure can also occur if external factors causing anestrus (no estrus/heat). These factors include season, low nutrition, lactation and disease. However, proper management or care can be used to overcome or lessen the impact of these types of reproductive failure.
It is also important to understand that females might undergo silent estrus, which is ovulation without visible signs of estrus. The incidence of a silent estrus occurring is high during transition periods in goats, such as the onset of puberty and transition into and out of the breeding season. In addition, reproductive failure can occur from females having shorter cycles, which has been associated with lower fertility. Females with longer cycles appear to be as fertile as females with normal cycle length.
For addiitonal reading on other factors that cause reproductive failure, please click on the link: http://www.extension.org/pages/19373/goat-reproduction-reproductive-failure
For more information about Reproduction in goats see: http://www.extension.org/goat
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