The Basenji Annual Estrus: Controlled by Short-day photoperiod

Introduction Man from the earliest time has observed biological cycles in animals. The daily light cycle and the change in the length of day control these cycles. For birds the increasing day length (long-day photoperiod) begins the process of migration and mating. In mammals the reproduction cycle can be activated by the long-day or short-day photoperiod. Domestic animals have shown a trend in not needing the photoperiod to regulate the reproduction cycle and for breeding anytime during the year (Lofts, 1978). The Basenji is an exception.