Calm-natured calves appear to have a better response to vaccination at weaning than temperamental calves, according to scientists with the Texas Agricultural Experiment Station.
This better vaccination response means the calmer calves are less likely develop sickness or die of disease, says Dr. Ron Randel, Experiment Station scientist based at the Texas A&M University System Agricultural Research and Extension Center at Overton.
Earlier work done by Randel and others have proven that cattle that speed out of the handling chute ate and gained less, and even yielded tougher steaks. This study is one the first that looks at the animal's immune response in relation to temperament, Randel says.
Randel, working with other scientists from the Texas A&M system and the U.S. Department of Agriculture, divided 6- to 7-month-old Brahman bull calves from the Overton center's 2004 spring calf crop into two groups: the calmest and the most temperamental.
The calves were grouped based on their "exit velocity," the speed at which they exit a handling chute, and "pen scores," where visual observations about the animal's response to confinement and humans are recorded. In the 11-week trial, the research team measured the calves' responses to clostridial vaccination.
Bacterial in nature, clostridial diseases can cause a range of calf-health problems, including death, before any symptoms are observed, Randel says. The bacteria are spread by spores that are extremely hardy, being resistant to extreme heat and cold. Botulism, a food-borne disease affecting humans as well as animals, is caused by clostridial bacteria.
Clostridial vaccinations are an important part of most calf-health programs, including Texas A&M's VAC-45 program.
As with the VAC-45 program, all calves were vaccinated at the beginning of the trial and given a booster shot six weeks later.
To measure the immune response, team members analyzed blood samples from the calves for the antibody response specific to clostridial vaccinations.
On the sixth day of the study, both groups of calves showed "significant" immune response to the vaccination, Randel says. But by the sixth week, the calm calves had a 50% greater antibody response than the temperamental calves.
After the booster shot on the 42nd day, the peak immunological response was delayed in the temperamental calves compared to the calm calves. Also, the temperamental calves' immune response decreased from day 49 to the end of the study. The calm calves' immune response did not significantly decrease after the booster. At the end of the study, the calm calves had more than a 60% advantage in immune response.
"Not only did the calmer calves have a greater response to the vaccine, they did a better job of sustaining antibody levels previously produced," Randel wrote in a Overton center field day report. "In addition to the benefits of increased vaccination response, the calm bull calves out-gained their more temperamental counterparts by more that 0.3 pounds per day over the length of the study."
In addition to Randel, the research team members were: Ryan Oliphant, graduate research assistant, Dr. Tom Welsh, Experiment Station, Dr. Jamie Laurenz, Texas A&M - Kingsville, and Dr. Jeff Carroll, USDA, Lubbock.
"What we're saying is, if you use VAC-45, you'll get a lot better result with calm calves than with crazy ones," Randel says.