The flock-mating of progestagen-synchronized ewes. 1. The influence of ram-to-ewe ratio upon mating behaviour and lambing performance

Abstract

SUMMARYSixteen Suffolk rams, 8 previously assessed as High libido and 8 as Medium libido, were mated to groups of 6, 12,18 and 30 ewes whose oestrous cycles had been synchronized using progestagen-impregnated vaginal sponges.Observations over a 3-day mating period indicated that no differences occurred in mating behaviour between High and Medium libido rams. As number of ewes per ram increased, the rams achieved a greater mean total number of mounts and services, but mated a smaller mean percentage of ewes. Also the time taken and the number of services required to mate with all ewes served increased substantially.As the number of ewes per ram increased the ewes had, on average, to wait longer for their first service and were served less often. There were no statistically significant differences between treatments in the ratio of ewes lambing to ewes served.