Epi. 229 – Assessing Bull Breeding Soundness Exam Parameters Following Vaccination with Modified-live or Killed Vaccine

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AABP Executive Director Dr. Fred Gingrich is joined by Dr. Chance Armstrong and Dr. Jennifer Koziol to discuss a paper published in the AABP peer-reviewed journal The Bovine Practitioner. The journal is available open-access and the target audience is practicing veterinarians.

Veterinarians performing bull breeding soundness exams are often asked when they can vaccinate bulls, and much of the available research focuses on type and timing of vaccination on females. The objective of this study was to determine if and how multivalent vaccines (modified-live and killed) affect spermatogenesis in bulls, measured by the percentage of normal sperm morphology and progressively motile sperm over a complete spermatogenesis cycle in bulls.

Our guests walk through the results of the study which demonstrated no detrimental effect associated with the use of multivalent modified-live or killed viral vaccines on the sperm morphology of mature bulls over a 61-day period. This suggests that vaccination of mature bulls following a routine bull BSE or at the time of turnout could be performed with limited risk. Our guests emphasize the importance of the veterinarian performing a full BSE 30-60 days before the breeding season starts. Armstrong re-iterates the Society for Theriogenology (SFT) standards for the appropriate evaluation of bulls for breeding soundness. Koziol and Armstrong are the authors of the SFT Manual for Bull BSEs and you can find information at this link. We also review how stress, nutrition and lameness also affect bull fertility and the importance of the veterinarian performing this complete evaluation to identify satisfactory breeders for cow herds.

Finally, we discuss the new AABP Bull Breeding Soundness Examination Position Statement (find it at this link). This statement was developed by the AABP Reproduction Committee which ultimately states that this procedure is the practice of veterinary medicine and requires the expertise and knowledge of the veterinarian to perform. Our guests reiterate that this position statement is advocacy for the practicing veterinarian by AABP. If you are interested in reproduction, Armstrong and Koziol encourage you to join the committee by going to this link to email the committee chair. The email should include your name, veterinary school, grad year and your interest in the committee.

Assessing bull breeding soundness exam parameters following vaccination with modified-live or killed vaccine. (2024). The Bovine Practitioner, 59(1), 1-8. https://doi.org/10.21423/bpj20259038