Controlling reproduction in selection schemes of dairy goats

Abstract

Reproductive seasonality observed in all breeds of goats originating from temperate latitudes and in some breeds from subtropical latitudes can now be controlled by artificial changes in photoperiod. Short days stimulate sexual activity, while long days inhibit it. This knowledge has allowed the development of photoperiodic treatments to control sexual activity in goats, in both the buck and doe. In the French intensive milk production system, goat artificial insemination plays an important role in controlling reproduction and, in conjunction with progeny testing, in improving milk production. Most dairy goats are inseminated out of the breeding season with deep frozen semen, after induction of oestrus and ovulation by hormonal treatment. This protocol provides a kidding rate of about 65%. New bree-ding strategies based on the buck effect associated with artificial insemination are being developed to reduce the use of hormones. With the development of insemination with frozen semen, a classical selection program was set up, including planned mating, progeny testing and the diffusion of proven sires by insemination in herds. Functional traits have become important for efficient breeding schemes in the dairy goat industries. Emphasis on functional traits related to udder morphology and health resulted from the knowledge established du-ring the last decade. New windows have been opened based on new molecular tools allowing the detection and mapping of genes of economic importance in farm animals.