On-Arrival Vaccination vs Delayed Vaccination
By : JILL J. DUNKEL
It’s common practice to vaccinate newly arrived cattle coming in to a feedlot or backgrounding operation. These calves – especially if they are of a mixed or sale barn origin – are at high risk of infection after stressful events such as weaning, transport or going through a sale barn. It makes sense to get a vaccination program started immediately in an attempt to head off illness.
Or does it?
Brian Vander Ley, DVM, PhD, DACVPM, is a veterinary epidemiologist at the Great Plains Veterinary Educational Center, University of Nebraska. He said research shows it might be time to reconsider this standard practice.
“It’s interesting if you read labels, the general directions on most vaccine bottles say ‘vaccination of healthy cattle recommended.’ A lot of times we don’t take the time to read the small print on a vaccine label. Almost every vaccine we can put in cattle carry a statement like this,” Vander Ley said.
In other areas of medicine, particularly human and small animal, practitioners go to lengths to make sure vaccine recipients are healthy before giving a vaccine. “We don’t do that for cattle because we vaccinate or process cattle in mass. The question is, are they really healthy enough to receive it?” he asked. “Stress in transport, comingling, weaning, exposure to pathogens, physiological stress…do these cattle fit the definition of healthy animals?”
Don’t misunderstand – cattle absolutely need to be vaccinated. A sound vaccination protocol at the ranch is preferred when stress is at a minimum and cattle experience limited exposure. When vaccines are administered correctly, that scenario sets up the best immune response from the vaccination.
“Let’s consider our expectations of a vaccine. Vaccination is in preparation for the body dealing with an infection. It’s like insurance. It’s used as a tool for an infection a calf might encounter in the future,” Vander Ley said. “But on arrival, the calf has already been exposed to a lot of pathogens, and then add stress.”
The question then becomes is an animal, on arrival, too stressed for the vaccine to work to its potential? Vaccines need time to build an immune response, and if administered during a stressful time, is the immune response adequate? Vander Ley said the assumption is vaccination is, at worst, the loss of dollars used to purchase the vaccine.
A study conducted at the University of Arkansas looked at on-arrival vaccination and vaccination delayed until 14 days after arrival on 528 highly comingled, high risk calves. No metaphylaxis was administered. Average daily gain in the first 14 days in the delayed cattle was 1.16 pounds compared to .88 pounds in the on-arrival cattle. By 42 days, the on-arrival cattle had gained some ground but still were gaining 0.1 pounds less on average.
After 42 days, there was virtually no difference in BRD treatment cost and no difference in death loss. Essentially all respiratory disease happened in the first 14 days – the timing of the vaccine didn’t change the overall morbidity, Vander Ley said.
Looking at IBR titers, the calves vaccinated on day 14 were substantially more prepared to respond to the vaccine than those vaccinated on arrival.
“Those receiving the vaccine on arrival did not respond like we would hope,” Vander Ley said.
Other, larger study was conducted and included an immunostimulant and metaphylaxis in the processing protocol. Although first treatment numbers were similar, the delayed treatment cattle showed a 4 to 5% decrease in BRD retreatment risk.
“What we see in these studies is there is no harm in delaying the vaccination,” said Vander Ley. Delaying vaccination until the calves are settled and stress is reduced did not impact morbidity. He said further studies have been conducted and results are due to be published soon.
“It’s important to consider the stress level of these calves and their risk.”