Previous studies reported that the sexual performance of rams did not improve following observation of heterosexual behaviour, which was in contrast to effects on male cattle, goats, pigs and horses. The purpose of this study was to investigate the possibility that exposure to a recently mated ram may increase sexual performance. Eight sexually experienced rams (1 year of age) were assigned to either mated ram stimulus (MRS) or non-mated ram stimulus (NMRS) conditions in a switchback design. The rams in the MRS condition were briefly (10 min) exposed to a penmate that had mated a ewe immediately beforehand. The males in the NMRS condition were exposed to a penmate that had been placed in an empty pen. The rams were allowed to freely investigate their respective stimulus penmate and then each male was placed with an oestrous ewe for 15 min. The frequencies of anogenital sniffs, leg kicks, flehmen lip curls, mounting attempts, mounts and ejaculations were recorded. Ejaculatory latencies were also recorded. Mean courtship (anogenital sniffs and leg kicks) and mounting (mount attempts and mounts) behaviour frequencies were higher for the MRS condition (P=0.01 for both traits). Similarly, the individual mean frequencies of anogenital sniffs, leg kicks, mount attempts and mounts were higher for the MRS condition (P=0.046, 0.016, 0.048 and 0.029 for the 4 traits respectively). Mean flehmen lip curl and ejaculation frequencies were not different between the MRS and NMRS conditions (P=0.900 and 0.700 respectively). The results suggested that an odour cue associated with the ewe or mating per se was emitted by the penmate which was allowed to mate, and this cue then enhanced the sexual performance of rams in the MRS condition.
|Publication Title||Applied Animal Behaviour Science|
|Author Address||Department of Animal Sciences, Rutgers, State University of New Jersey, New Brunswick, USA.|
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