Studies in flock mating of sheep. 4. The relation of libido tests to subsequent service activity of young rams

Abstract

Seventy-five Merino rams, l 1/2 years old, were tested for libido in pens and were later observed while mating in flocks. The total number of services performed in three pen libido tests was the parameter most highly correlated with service frequency during flock mating. For the 58 rams that mounted ewes in the libido tests, the total number of services in the three tests was highly correlated with the number of services performed during the first three hours in flocks of 40 ewes containing only one ram (r56 = 0.853, P<0.001). Subsequently, pairs of rams were joined with flocks of 66 or 125 ewes. With these rams, the number of services in the pen libido tests was highly correlated with the number of services performed in three hours immediately after introduction of the rams (r20 = 0.717, P<0.001) or seven days later (r14 = 0.709). It is concluded that the number of services performed by young rams during a simple form of libido test could provide an indication of their subsequent service activity during flock mating.

The ram as a model for behavioral neuroendocrinology

“…The serving capacity test was first developed by Mattner and colleagues in Australia (Mattner et al, 1971). These scientists defined serving capacity as "the number of matings with estrous ewes a ram achieves in a specific time period when confined to a pen of limited size."…”

Flock mating in sheep

“…Australian work with Merinos has shown that two-tooth rams mate with fewer ewes and sometimes are not as fertile as older rams (Lightfoot & Smith 1968;Croker 1970;Croker & Lindsay 1972;Mattner et al 1971Mattner et al , 1973. Two ram age groups joined with different numbers of ewes per ram were compared in two experiments to provide information on the Romney breed.…”

Flock mating in sheep

“…Pen libido tests (Mattner et al 1971) were conciucted with all rams in Experiments 2 and 3 a few days before joining and 17, 34, 51, and 72 days after the start of mating. Each test consisted d 20 min continuous observation of a single ram with five oestrous ewes in a small pen, all mounts and services being recorded.…”