Patterns of stallion sexual behaviour in the absence of mares.

In the first experiment the response of 93 adult stallions to stimulated and natural sexual stimuli was observed just before and 2 weeks after the breeding season (December and July respectively). About 72% of the stallions reacted the same before and after the breeding season (P less than 0.01) while 9% behaved similarly and 19% differently. Also, 72% of the stallions reacted with sexual arousal (mounting) to one of 3 successive simulated sexual stimuli; 25% to a dummy, an additional 44% to a gentle stallion and another 3% to a dummy smeared with mucus and urine from a mare in oestrus. In another experiment, the sexual behaviour of 4 young stallions and 3 older stallions was observed while they were in the stable. Erection was observed an average of 7.4 times in 24 h, a full erection 3.8 times and attempts to masturbate 4.1 times. Complete masturbation with ejaculation was only sporadically noted. The total time of erection averaged 38 min/24 h. The peak of erection time occurred in the morning and the low point during the night and at 05:00-08:00 h. No significant differences were found between the young and older stallions; differences occurred only between individual stallions.