Some Problems Associated with Artificial Insemination of Beef Cattle

In October, 1964, beef cows were divided into three groups. One group was run with bulls for four months (group 1); another group was kept free of bulls and was observed daily for six weeks and cows detected in oestrus were inseminated using chilled semen (group 2); and the third group was given progestagens to synchronise ovarian cycles and the cows were inseminated after treatment and again at the next observed oestrus (group 3). Bulls were put with groups 2 and 3 in mid-December. The percentages pregnant two months after removal of the bulls were 59.2% (group l), 39.4% (group 2) and 68.1% (group 3), but after correction for differences between groups in lactation status and body condition, the figures were 53.7%, 47.1% and 54.3%. On the basis of relative costs per pregnancy, Group 2 was inferior to the other two because few cows were detected in oestrus and labour costs were high. The paper discusses problems associated with management and identification of cattle, collection of semen and detection of oestrus.