Mating behaviour of rams in pens

Abstract

Two experiments were carried out to measure the mating behaviour of rams in pens. In the first, rams were tested for 1 or 3 h in a large number of tests, and records were taken of the number of mounts per test, serves per test, the ratio of mounts to serves, and the various time intervals between sexual activities. The number of serves per test was the most highly repeatable measure (0.66 ¦. 0.16 (¦ s.e.) for tests of 1 h and 0.66 ¦ 0.18 for tests of 3 h). Up to two introductory tests were required to allow rams to overcome apprehension and then to demonstrate their true serving behaviour. Tests of 20 min did not always detect differences between rams in serving behaviour. In the second experiment, the above results were validated on a large number of rams. It was further shown that the heritability of the number of serves per test was 0.33 ¦ 0.62. The frequency distribution of serves per test was shown to be skewed to the right.