Conception rates of beef cattle in Botswana following synchronization of oestrus with cloprostenol

ABSTRACT In three trials conducted in 3 successive years, Africander, Brahman, Tswana, Tuli and crossbred cattle were injected intramuscularly with 500 jug of cloprostenol on two occasions 11 days apart to synchronize oestrus. The cattle were inseminated 72 and 96 h after the second injection. Controls of the same breeds were exposed to natural service for a period of 22 days. In all trials the conception rate to natural service was significantly higher (P < 0·01). Conception rates to both breeding methods were highest in Tuli and crossbred cattle and lowest in the Africander and Brahman. Non-lactating cows showed higher fertility than suckling cows and maiden heifers. Vasectomized bulls used in one trial were shown to be useful in the selection of breeding cows suitable for oestrus synchronization. Further studies are justified to maximize the benefits of a potentially valuable method of breeding beef cattle in ranching conditions.