Study suggests vaccination at fall pregnancy checking may increase immunity against pneumonia during the first 30 days of life.

Respiratory disease in pre-weaning beef calves is a growing problem among Midwestern cow-calf herds. In recent studies, prevalence of pre-weaning calf pneumonia has been observed affecting as many as 20%-30% of calves in some operations.

The main factors in determining disease or health in young beef or dairy calves are the transfer of maternal immunity and the duration of maternal immunity.

Dr. Manuel Chamorro, clinical assistant professor with Kansas State University’s College of Veterinary Medicine Livestock Services, recently completed research as part of a team investigating the effectiveness of vaccinating pregnant heifers at 6-8 months gestation to prevent pre-weaning respiratory disease.

The study
Dr. Chamorro, together with Dr. Emily Reppert and Dr. Lacey Robinson, Livestock Services; Joyce Wick, fourth-year veterinary student; and Dr. Natalia Cernicchiaro, Department of Diagnostic Medicine and Pathobiology; are in the process of publishing the study results.

First-calf heifers vaccinated prior to breeding with a modified live virus (MLV) multivalent vaccine containing BVDV 1, BVDV 2 and BHV-1 were split into two groups. One group received two doses of a killed virus multivalent vaccine 21 days apart between 6.5 and 8 months gestation. The second group received a shot of saline solution. The group then measured the total serum IgG and neutralizing antibodies to BVDV 1, BVDV 2 and BHV-1 in newborn calves.

“The question is, ‘Is the just the total IgG level from colostrum enough,’” Chamorro asked, “or are there other factors? We believe it doesn’t matter the amount of antibodies but their specificity. You can have a high level of antibodies, broad spectrum, but if you are lacking specific antibodies against respiratory disease, your calves may still have it.”

The findings
Serum samples collected from dams revealed higher antibody titers to BVDV 1, BVDV 2 and BHV-1 in heifers vaccinated with the killed virus vaccine during gestation than the control group. Similarly, the mean serum antibody titers to BVDV 1, BVDV 2 and BHV-1 of calves at 24 hours old born to heifers vaccinated during late gestation were also higher.

Ultimately, the group’s study found that vaccinating beef cows during 6-8 months of gestation would reflect an increase in specific antibodies in maternal colostrum and would result in better antibody uptake in young calves. Higher serum antibody titers to the specific disease might result in prolonged duration of maternally derived immunity and better protection against respiratory disease during the pre-weaning period.

“It’s a good idea,” Dr. Chamorro said of vaccinating pregnant cows and heifers against common cattle respiratory pathogens during fall pregnancy checking. “It’s affordable and we’ve seen results.”

Abstract: BVDV and BHV-1 antibody levels in colostrum of beef heifers vaccinated or unvaccinated during gestation with a multivalent killed viral respiratory vaccine

Abstract: Maternally-derived BVDV and BHV-1 antibodies in calves born to dams vaccinated or not during gestation

Dr. Manuel Chamorro is a clinical assistant professor for Livestock Services with the Kansas State University College of Veterinary Medicine. Dr. Chamorro’s research interests are concentrated on respiratory viruses of cattle with specific emphasis in BVDV and in the effect of colostrum-derived immunity on clinical protection and immune response to vaccination in calves. Another area of interest for Dr. Chamorro is the use of bovine colostrum or colostrum replacers as an alternative to reduce disease and the use of antibiotics in calves.