Quality of semen collected by transrectal massage in bulls restrained in the presence of a cow

The purpose of this experiment was to determine the effect of PGF and GnRH treatment and exposure of bulls to estrus-cows on semen quality collected by transrectal massage. Three fertile, pure Frisian bulls, 2-3 years old, were followed up weekly for four periods of treatment (control, exposure to estrus-cows, PGF and GnRH). The bulls exposure to a cow in estrus showed high semen volume (3.3±1.3 ml), percentage of progressive motility of sperm (73.3±12.0 %; P<0.05) and sperm concentration (996.6±141.6×106/ml; P<0.05) compared to other treatments. The pH (8.2±0.3; P<0.05) and morphological abnormalities (18.1±4.5 %) were higher in the control animals compared to other treatments. Live sperm percentages were higher in GnRH treatment (72.8±3.7%) than other treatments. However, the difference was not significant. We conclude that transrectal massage was very effective for producing semen and acceptable when the bulls exposure to a estrus-cow was >60 minutes before collection of semen. The lower quality semen after treatment by PGF and GnRH requires further investigation.