The role of body weight changes and other factors in the control of fertility of rangefed beef cattle

Abstract

A study of factors affecting calving interval of the Boran, small East African Shorthorn Zebu and their F1 Progeny from Heresford bulls was conducted on a Kenyan Acacia wooded grassland. The target mating weight was around 318kg. Fertility was highly seasonal and short calving intervals were attained when conception occurred between Nov and Jan followed by the period from May to July. Animals that gained weight or suffered a smaller body weight loss during the month prior to conception had a higher fertility. Fertility improved progressivey with dams age but declined after about ten years.