Implications of recent advances in reproductive physiology for reproductive management of goats

The control of reproduction in goats is interesting for technical reasons ( synchronization of kiddings, adjustment to forage availability or to econom y), and for genetic reasons (identification and dissemination of improved g enotypes). The use of short-light rhythms leads to markedly increased produ ction of semen per buck and prevents occurrence of a 'resting' season. Rece nt identification of a bulbourethral lipase in goat spermatozoa opens new p erspectives in sperm preservation. Light plus 'short day' treatments also a llow induction of out-of-season oestrous cycles and ovulations leading to e nhanced fertility. Repeated use of eCG provokes the production of antibodie s, delays the timing of ovulation and causes a reduction in fertility after fixed-time artificial insemination. All steps of embryo production, freezi ng and transfer are now controlled and allow the attainment of satisfactory numbers of kids born per donor female, which are compatible with the devel opment of the technique for exchanging genotypes between countries. In vitr o production of embryos allows high development rates to be achieved after in vitro maturation and fertilization of oocytes, and will ensure the produ ction of synchronous populations of one-cell zygotes at the stage required by new biotechnologies.