The repeatability of seminal characteristics of stallions
Pattie, W.A.; Dowsett, K.F.
Journal of Reproduction and Fertility. Supplement 32: 9-13
1982
ISSN/ISBN: 0449-3087 PMID: 6962907 Document Number: 184527
15 semen characters were measured for 4 laboratory stallions and 164 commercial stud stallions. Data were avilable from 531 ejaculates obtained over 4 breeding seasons (1974/75-1977/78); 9 breeds were represented. Stallions at commercial studs each produced 1-13 ejaculates at an av. interval of 4 wk (range = 1 h to 1 yr). Significant between-stallion variation occurred in all characters except pH of gel-free semen. Low repeatabilities (<0.3) were found for gel-free volume, pH of gel-free semen and the percentage of abnormal mid-pieces. Moderate repeatabilities (about 0.6) were found for total volume, gel volume, motility, percentage of dead spermatozoa, sperm concentration, total sperm number and the percentages of sperm head abnormalities, tail abnormalities, loose heads and cytoplasmic droplets. It is suggested that if a semen examination shows characteristics below or near recommended min. levels, an additional 1 or 2 samples should be examined before a stallion is classed as likely to have doubtful fertility.