Cattle producers preparing to work spring-born calves should be taking steps now to protect their animals from the respiratory diseases, infectious bovine rhinotracheitis and bovine viral diarrhea virus.

By vaccinating calves now, the first vaccination against IBR and BVDV takes place at a time when there is comparatively less stress on a calf.

“This gives the animal an excellent opportunity to begin the development of cell-mediated immunity,” said Glenn Selk, Oklahoma State University Cooperative Extension cattle reproduction specialist. “The calf then is re-vaccinated at weaning time.”

Selk cites the July 2008 issue of the Journal of American Veterinary Medical Association, which details a study comparing a “calf-working” vaccination program with the traditional “pre-weaning” vaccination schedule.

OSU veterinary medicine scientists, in cooperation with scientists at the Samuel Roberts Noble Foundation in Ardmore, studied the timing of modified-live virus vaccinations in beef calves.

For years, the recommendation for the timing of modified-live vaccines called for the vaccine to be administered after maternal passive immunity antibodies had decreased to negligible levels in the blood of the calf.

“It was thought that maternal antibodies received in the colostrum would interfere with the effectiveness of the modified-live virus vaccine,” Selk said. “Therefore most viral vaccines were not administered until the calves were 4 months to 5 months of age or older.”

However, the OSU-Noble Foundation research demonstrated otherwise. The scientists vaccinated calves at 67 days of age and re-vaccinated them at weaning – 190 days – and then compared those animals with others vaccinated at 167 days of age and given a second vaccine at 190 days, at the time of weaning.

“There was no difference in the percentage of calves protected by the vaccine due to the timing of the first vaccination,” said Dr. John Kirkpatrick, OSU emeritus professor and veterinarian who worked on the study. “The result with both vaccination schedules was improved serum antibody titers compared with un-vaccinated control calves.”

Kirkpatrick said it came as no surprise that the vaccinated calves had lower treatment costs and less mortality in the feedlot than the non-vaccinated control calves.

Before the study was initiated, all cows and replacement heifers were vaccinated after calving and 30 days before breeding with a modified live vaccination for IBR and BVDV types I and II, as well as bovine respiratory parainfluenza-3 and bovine respiratory syncytial virus, commonly referred to as PI-3 and BRSV.

“The research suggests that the first vaccination with a modified-live virus vaccine can be administered at normal ‘calf-working’ time, provided a booster is given at weaning,” Kirkpatrick said.

Following all vaccine label directions, cows that nurse these newly vaccinated calves should have already been protected with a modified-live vaccine against the same respiratory diseases.