Comparison between the Sperm Morphology in Semen Samples Obtained from Yearling Beef Bulls by Transrectal Massage of the Ampullae and Cauda Epididymal Dissection

As electroejaculation (EEJ) is prohibited for use on unanaesthetized animals in Sweden, there is a need for an alternative method of semen collection from bulls in the field. The aim of the present study was to evaluate the use of transrectal massage (TM) of the ampullae to collect semen from yearling beef bulls under field conditions in Sweden. Transrectal massage was performed on 52 yearling beef bulls. Volume of semen collected, duration of procedure, percentage progressively motile sperm, and sperm concentration were measured. Smears were prepared for sperm morphology examination. Semen samples were obtained from 47 of 52 bulls. Mean volume was 3.2 ml (SD +/- 3.7), mean duration of collection was 7.4 min (SD +/- 2.8), mean percentage progressively motile sperm was 43.5% (SD +/- 29.2) and mean concentration was 201.9 x 10(6) spermatozoa/ml (SD +/- 278 x 10(6)). Twenty-three of the 52 bulls were slaughtered 3-4 days after semen collection and aliquots of the cauda epididymal contents were collected for sperm morphology examination. The percentages of proximal droplets, abnormal tails and abnormal midpieces were significantly higher (p < 0.05) and the percentage of detached heads was significantly lower (p < 0.05) in the post-mortem samples compared with those in the TM samples. However, importantly there was no significant difference between the two sample types in the percentages of abnormal heads. This study demonstrates that semen can be collected from yearling beef bulls by TM. We think that TM constitutes a useful tool, when semen collection with EEJ or artificial vagina (AV) is not possible under field conditions, when included in the bull breeding soundness evaluation (BBSE) protocol. However, further studies are needed, and presently being carried out, to evaluate if semen samples collected by TM are comparable with semen samples collected by AV.