The effect of collection procedure on the sperm output and copulatory behavior of AI stud boars

Sixteen mature boars in routine use at an artificial insemination (AI) facility were subjected to routine semen collection (Control) or were sexually stimulated either by penile diversion prior to collection (DIV), by collection with a non-estrous gilt in the dummy sow (WG) or by collection with a non-estrous gilt in the dummy sow following physical contact with a non-estrous gilt for 2-h periods daily over the 3 days prior to collection (HWG). Each boar was subjected to all four collection procedures over a 4-week experimental period. While slight increases in sperm concentration and in the total yield of sperm were observed following sexual stimulation, neither of these parameters differed significantly (P > 0.05) from those observed during Control collections. Boars on the HWG treatment produced a significantly larger (P < 0.05) ejaculate volume than that recorded on the Control treatment. Boars on the WG treatment spent a significantly longer (P < 0.05) time on the dummy compared to the Control treatment, with all other comparisons being non-significant. Boars when on WG and HWG treatments showed a greater degree of sexual arousal (P < 0.05) compared to when collected on the Control treatment, as measured by the shorter interval from mounting to the initiation of pelvic thrusting, but other components of the copulatory behavior complex were not influenced by treatment. It is concluded that stimuli, additional to the visual stimulus of the dummy sow, produce only slight changes in the copulatory behavior and ejaculatory process of AI-experienced boars and that the provision of such stimuli is unlikely to enhance the short-term semen output of such boars.