Arkansas research just published in the journal Professional Animal Scientist tries again to get at the question facing anyone offloading high-risk stockers: Vaccinate and implant them now, or rest them a few days (or weeks) before running them through the chute?
The thinking is that holding off respiratory vaccination on those typically unvaccinated, unweaned, commingled calves may reduce taxation of an already stressed immune system, which should eventually improve both vaccine effectiveness and response to the implants.
To add more information to the decision mix, the Arkansas researchers bought a total of 393 high-risk crossbred 5-weight beef calves from a northern Arkansas auction market and shipped them to background on pasture. Upon arrival, calves were weighed, tagged, randomized and then assigned to one of four treatments:
- Vaccinated and implanted right off the truck.
- Vaccinated off the truck but not implanted.
- Vaccinated and implanted two weeks after arrival.
- Vaccinated two weeks after arrival but not implanted.
Their results showed no statistically significant difference for average daily gain during the 42 days of the test based on any of the treatments, suggesting no advantage to implanting the high-risk calves or holding off vaccination. The lack of response to the implants was likely due to the high degree of BRD sickness in the calves, the authors suggest: More than eight out of 10 calves were pulled for initial antibiotic treatment; 12 percent of them were eventually pulled four times for treatment. Vaccinating immediately off the truck did significantly increase the amount of circulating BVD antibibodies for the calves in the group; however, the difference in pull rates to treat BRD didn't differ as a result.
Because, in this case at least, the stressed calves didn’t respond to implants, their results indicate that when lightweight calves are being preconditioned for a subsequent grazing period, it may be beneficial to delay implantation until turnout on grass to extend the implant payout longer into the grazing period.
View All Blogs »