Los fenómenos de bioestimulación sexual en ovejas y cabras

The introduction of males and estrous females among anestric goats and ewes induces synchronous ovulations in the following 3-5 days (the male and female effect). The signal of males is partly pheromonal, and this leads to an increase in the frequency of pulses of the luteinizing hormone (LH). The percentage of responding females to the male odor is lower than for females in direct contact with males, and it indicates that all senses are probably involved in the response but none is necessary. In spite the small evidence, it appears that the female effect produces the same mechanisms. The first induced ovulation is silent in a variable percentage of females, and followed by a short luteal phase. A second LH peak is then released, inducing a second ovulation and the formation of a normal corpus luteum. Depth of anoestrous and sexual activity of males affect the response too: increasing the percentage of silent ovulations and of short ovarian cycles when the anoestrus is deep and the male is sexually inactive. Depth of anoestrus affects the female effect response. In this review, all senses and factors that are probably involved in the response to the male and female effect are discussed.