Bovine respiratory disease (BRD) in calves and feedlot cattle is responsible for enormous losses in the beef industry — $900 million annually, by some estimates.1,2,3,4 A combination of factors come together to cause the disease: environmental factors (climate, management practices), the status of the calf (nutrition, stress) and pathogens, which include respiratory viruses such as bovine viral diarrhea (BVD) 1 and 2, infectious bovine rhinotracheitis (IBR), bovine respiratory syncytial virus (BRSV) and parainfluenza3 (PI3). Any of these viruses alone can cause BRD and also open the door for bacteria to launch their own assault on the host’s immune system, making the illness even more severe.
Of the two bacteria — Mannheimia haemolytica and Pasteurella multocida — most often involved with BRD, the first gets most of the blame with beef cattle. “Mannheimia haemolytica is the cause of the most severe and fatal forms of shipping fever,” says Anthony Confer, D.V.M., Ph.D., professor of veterinary pathobiology at Oklahoma State University. “It’s the first bacterial pathogen that really takes off in stressed cattle.”
Common — and complicated
It’s also prolific; Mannheimia haemolytica is found even in healthy calves on pasture. “It’s pretty much in all of them,” Confer says. “They get it very early in life and carry it in their nasal passages.” The bacteria wait for an opportunity — the stress of weaning and shipping, viral infections — to start growing. Then the bacteria are inhaled into the lungs, where the trouble starts. Down in the lungs, the bacteria multiply rapidly and begin secreting leukotoxins, their toxic defense mechanism. Leukotoxins kill white blood cells as they rush to fight the invading bacteria by binding to a white blood cell and punching a hole in the cell wall. “The white blood cell dies, deflates and loses its contents,” says Brett Terhaar, D.V.M. and Elanco beef technical consultant.
Those contents do further damage to the lung tissue. Because the job of white blood cells is to engulf and digest bacterial invaders, when their walls are punctured, the destroyed white blood cells then contribute to lung damage as well. The effect on the calf is devastating. “Pneumonia caused by M. haemolytica has a distinctive look that veterinarians should be able to easily identify during a necropsy,” Terhaar says.
“When we vaccinate, we’re priming the immune system, setting up calves so they can protect themselves before the stress of weaning and shipping,” Terhaar says. But to be effective, the vaccine used must contain an inactivated version of the leukotoxin, which is known as a leukotoxoid. The leukotoxoid poses no threat and stimulates the immune system response the calf needs. “Those vaccinated calves will make antibodies against the leukotoxin,” Terhaar says. “The antibodies will bind to the leukotoxin so it can’t attach to the white blood cells.” That effect is lasting: Even after the initial antibody response diminishes, the vaccine has trained the immune system to respond to that particular threat. “Once the animal is shipped and bacteria start proliferating, the bacteria should stimulate a stronger antibody response in those cattle that have been vaccinated than those that weren’t,” Confer says.5
Research shows that a vaccine dose must provide adequate quantities of antigens at the injection site in order to stimulate an effective response.5 One product tested delivered a dose that was less than the recommended level and relied on bacterial replication to produce the remaining needed antigens.5 “The research out there shows us that when a product without a leukotoxoid relies solely on stimulated antigen growth, needed levels of protection may not be consistently reached, making the calf vulnerable,” Terhaar says.5
But the leukotoxoid alone is not enough. The calf needs antibodies to additional parts of the bacteria, which also attack the immune system. “You can’t just give a leukotoxoid and have good protection,” Terhaar says. “There’s a lot of different components to the bacteria that we want the calf to make antibodies to.” Those antigens also need to be included in an effective vaccine. That protection is crucial, and that’s what Titanium® 5+PH-M offers. It contains an M. haemolytica leukotoxoid and delivers an effective immune response against the viruses and both types of bacteria most often associated with BRD — BVD 1 and 2, IBR, BRSV, PI3, Mannheimia haemolytica and Pasteurella multocida — to help the calf fight health challenges it is likely to face. 6,7,8,9 “Respiratory disease is a big, big deal,” Terhaar says. “Vaccination is essential.”
The label contains complete use information, including cautions and warnings. Always read, understand and follow the label and use directions. Do not vaccinate within 21 days of slaughter.