Antibiotics and vaccines
Antibiotics have significantly lowered mortality rates of many bacterial diseases, suggesting that antibiotics fill a void when the cow’s innate and adaptive immunity fails to optimally protect against mortality.
“Furthermore, some classes of antibiotics are known to accumulate inside phagocytic cells of the innate immune system and, in so doing, help the phagocytic cell more efficiently kill an ingested bacteria,” Kehrli explains.
However, the cow’s innate immune response is also critical for antibiotics to be useful as evidenced by the fact that animals with defects in innate immune function, such as defects in neutrophil function, develop repeated bacterial infections that cannot be effectively controlled long-term with antibiotics. “So, I would say that antibiotics and the innate immune system work hand-in-hand to fight off bacterial infection,” Woolums says.
Kehrli adds, “We already know quite a bit about the effects of various physiological stressors on neutrophil and lymphocyte functional activities, as well as the reduced ability of an immune-suppressed animal to respond to vaccination.
“However, we don’t know all of the underlying causes of poor responses to vaccines,” he adds. “Hence, it is critical that we invest in research to provide a better understanding of which components of the innate immune system are necessary for effective vaccine responses.” (See “Get the most out of vaccines” on page 24 of the February issue of Dairy Herd Management.)
Geni Wren is editor of Bovine Veterinarian, a sister publication of Dairy Herd Management. Portions of this article appeared in the July-August issue of her magazine.
Get the most out of vaccines
When Vic Cortese goes out to a farm, he makes it a point to check the farm’s refrigerator.
“A majority of the time, the refrigerator is set either too cold or too warm,” he says, adding that he actually measures this with a thermometer. He would like to see the temperature around 40 degrees F to optimize performance of the vaccines stored there.
And, he says, he would rather see the vaccines stored on the shelves of the refrigerator rather than the door. Not only do the vaccines get jostled on the door when the door opens and closes, they are also subjected to greater temperature extremes since the door is the first place receiving warm air when the refrigerator is opened.
“It’s amazing how much dairies pay for (the vaccines) and then place them in an old refrigerator that got taken out of the house that doesn’t maintain temperatures correctly,” says Cortese, who serves as director of the Veterinary Specialties Group at Pfizer Animal Health.