Impact of Vaccine Choice
on Immunity and Abortion Risk
STILLWATER, Okla. (Oct. 8, 2014) — Cow-calf producers often have questions about how different types of vaccines and the timing of vaccination may affect reproductive performance in their breeding herds. According to John Gilliam, a veterinarian and assistant professor at Oklahoma State University (OSU), they typically ask about products used to immunize cattle against infectious bovine rhinotracheitus (IBR) and bovine viral diarrhea (BVD). Gilliam talked about choosing and using these vaccines during the Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium hosted Oct. 8-9 in Stillwater, Okla.
Regarding the relative need to immunize breeding animals against IBR and BVD, John Gilliam said vaccination can reduce pregnancy losses associated with these diseases, as compared to non-vaccinated animals.
Regarding the relative need to immunize breeding animals against IBR and BVD, Gilliam said vaccination can reduce pregnancy losses associated with these diseases, as compared to non-vaccinated animals.
“There is solid evidence that reproductive vaccination can improve reproductive performance,” stated Gilliam. “Vaccination has significant value.”
Questions then arise regarding whether it is best to use a modified-live virus (MLV) vaccine vs. a vaccine containing a killed virus. Gilliam explained that, in theory, MLV products offer a quicker, more robust and longer-lasting immune response. A second administration, or booster shot, may not be required in some cases. By comparison, a killed-virus vaccine is considered safer and less apt to prompt an undesirable reaction, but a booster is required to achieve immunity.
Most reproductive-disease vaccine labels indicate that prebreeding is the optimum time for administration. For the sake of convenience, however, many producers would prefer to vaccinate at the same time cattle are undergoing pregnancy examination. Gilliam said the timing of vaccination can influence choice of vaccine type.
“Prebreeding vaccination offers optimum immunity during the period of highest risk to reproductive loss, and there is no abortion concern, but it may require additional handling of cattle,” said Gilliam. “Vaccinating during pregnancy (at preg-check) minimizes handling, but the period of optimum immunity may not match the period of highest risk.”
Gilliam said it is difficult to find clear-cut evidence regarding the risk of abortion following vaccination, relative to type of product used. Neither is there definitive evidence of passing colostral immunity to the calf after vaccinating a pregnant cow.
However, Gilliam said there is enough evidence suggesting heightened abortion risk that producers have “cause for pause” when considering vaccination of pregnant animals with an MLV product. Additionally, the safety of MLV vaccine is a concern when vaccinating too close to breeding time. Administering the vaccine less than 28 days prior to breeding is an extra-label use and can have negative effects on fertility.
“Vaccines are safe when given according to label directions,” stated Gilliam, reminding producers that no vaccine offers 100% protection every time.
Gilliam spoke during Wednesday’s ARSBC session focused on impact of environment and management on cow herd efficiency. For more information, visit the Newsroom at www.appliedreprostrategies.com to view his PowerPoint or listen to his presentation.
Comprehensive coverage of the symposium is available online at www.appliedreprostrategies.com. Compiled by the Angus Journal editorial team, the site is made possible through sponsorship by the Beef Reproduction Task Force.
Editor's Note: This article was written under contract or by staff of the Angus Journal. To request reprint permission and guidelines, contact Shauna Rose Hermel, editor, at 816-383-5270.