An observational study of the breeding soundness examination of beef bulls.

摘要

Mail surveys were used to identify practicing veterinarians to cooperate in the study and to establish the variability in breeding soundness examination (BSE) methods among veterinarians. A spermatozoal morphology slide and corresponding BSE information for 2900 beef bulls were submitted from 29 practicing veterinarians.;One hundred spermatozoa were classified as normal or having one of nine morphologic defects. This morphologic data, combined with the cooperators' reported scrotal circumference and spermatozoal motility information, was used to form the research classification (pass or fail) for the BSE. There were variable levels of inter-observer agreement (Kappa) between the cooperator and the research classification. Intra-observer agreement was moderate. Veterinarians differed in their use of the BSE methods recommended by the Society for Theriogenology (SFT). Those with moderate Kappas performed BSEs consistent with SFT recommendations.;The revised BSE criteria was evaluated by comparing the 1976 research classification to the 1992 research classification. A higher proportion of all bulls passed the 1976 BSE (86.2%) than the 1992 BSE (60.9%). For the 1992 BSE the influence of scrotal circumference decreased and the impact of spermatozoal morphology increased.;Nearly 71% of spermatozoa were classified as normal. Less than 1% of spermatozoa had acrosome, distal coiled tails, or midpiece defects. Approximately 3.8% of spermatozoa had distal droplets (DD), 1.6% tightly coiled tails, 1.6% head defects, 8.4% proximal droplets (PD), 5.5% separated heads, and 6.7% distal midpiece reflexes. As bull age increased, the percentage of normal spermatozoa increased and the percentage and number of bulls with cytoplasmic droplets (PD, DD) decreased.;Semen samples from 8 bulls with seminal vesiculitis syndrome (SVS) and 11 control bulls were examined by light microscopy and sperm chromatin structure assay (SCSA). Semen from SVS bulls had a higher percentage of spermatozoa with abnormal chromatin structure and morphologic defects, and a lower percentage of motile spermatozoa. SCSA traits were moderately correlated to BSE attributes.