by Tamara Scully
“There are some costs you do not cut corners on. And those are pastures, bulls, and herd health. Spending less on these items often leads to reduced productivity and thereby often raises your costs,” Kathy Larson, Beef Economist with the Western Beef Development Centre (WBDC) in Canada, said.
Vaccinations are important tools in maintaining herd health. Using them properly, and following established protocols for cows, calves and bulls, is central to preventing disease concerns. While vaccinations don’t prevent all disease occurrences, they are a tool for reducing the severity and duration of diseases, as well as the population of animals impacted by contagious diseases.
In 2014-2015, the Western Canada Cow-Calf Survey found that of 400 producers surveyed, the average calf death loss was seven percent. Thirty-six percent of that loss was attributed to scours, pneumonia or other disease. Proper herd vaccination can help to keep these losses to a minimum.
“It’s important to talk about how vaccination can lend a hand in limiting those losses,” Larson said.
The WBDC treated its cattle herd in 2016 with a vaccination protocol of invermectin parasiticide in the fall/winter for cows and bulls; June vaccinations for the clostridial disease blackleg, bovine viral diarrhea (BVD), infectious bovine rhinotracheitis (IBR), parainfluenza 3 (PI3), anthrax, and bovine respiratory syncitial virus (BRSV) for all groups — and again in September for calves; and March vaccination against footrot for bulls and scours for cows calving in April.
This protocol resulted in 27 cows, or eight percent, becoming ill despite vaccination, Larson said. For calves, 13 percent still became sick, while 10 percent of the bulls required treatment of diseases for which they had received vaccination.
The total cost for the vaccination program was $25/cow. This amount is much less than the economic cost of not vaccinating the herd, she said. Not vaccinating can cause decreased conception rates, result in cows with long-term health impacts, and cause death.
Producers need to know “how to get the most out of your vaccination protocol, and what we should expect out of our vaccination protocol,” Dr. Nathan Erickson, University of Saskatchewan, said.
The goals of any vaccination program are: to reduce the number of animals shedding pathogens; to reduce the quantity of pathogens being shed; to reduce the period of time in which pathogens are shed; and to increase the number of pathogens needed to cause new infections.
Vaccination “does not prevent 100 percent of disease,” he emphasized. Instead, vaccination will reduce “the number of new cases that one sick animal is going to create.”
This control of disease, rather than absolute prevention, begins with proper vaccinations. However, other factors play a role in maintaining herd health, and in the herd’s response to any vaccination protocol.
“Well-fed animals will respond well to a vaccination program, and well-fed animals are less likely to get sick,” Erickson said.
Other factors impacting vaccination efficacy include: vaccination timing; handling of the vaccine; technique in administering the vaccine; the equipment used; the disease pressure in the herd; and the virulence of the pathogen. Or, if the vaccine does not target the correct pathogen, results will be poor. In some circumstances, the pathogen can mutate, and the vaccination will no longer be as effective.
Timing of vaccinations in relation to the disease action is critical. Pathogens which can cause abortions require pre-breeding vaccination protocols to be most effective. Vaccinating against these pre-pregnancy or pre-calving won’t have the same results.
When booster shots are given to a previously vaccinated animal “we’re going to have an increase in the level of immunity,” he said. “Over time, this immunity is going to start to wane. There is a potential for a missed opportunity” if vaccinations are not administered at the optimal time.
The immune system needs time to respond to any vaccination in order to provide maximum immunity during the high-risk period for the disease. BVD, PI3 and any abortions tend to occur in the first three months of gestation. IBR and other diseases tend to occur later in gestation, for example.
For a booster shot, the immune system requires about two weeks to respond fully. For an animal being vaccinated the first time, four weeks are required.
Producers mishandle vaccinations. Particularly with modified live vaccines, the effectiveness can be impacted by the environment. Direct heat, freezing temperatures — including being placed directly next to ice packs — and light exposure can all cause vaccines to fail.
“They are live. They really don’t like extreme temperature changes,” Erickson said.
Proper injection sites, as well as whether the vaccine is given sub-cutaneously or intravenously, is important. If a vaccine is injected into the wrong site, “you won’t get proper absorption of that vaccine,” he said.
Syringes should be cleaned in warm water and soap, and not disinfected, which could kill off the beneficial vaccine microbe. Syringes should be pulled apart and allowed to thoroughly air dry, and vegetable oil used to lubricate the rubber rings. Syringes should be replaced regularly, and cleaned periodically during use. Needles need to be changed every time before storing the vaccination, and after every 10 animals during administration.
Pathogen misidentification is a common occurrence. Some diseases may present with similar symptoms, but assuming that the same disease agent is causing all the herd health issues is not wise. Post-mortem identification and “doing appropriate diagnostics is really important,” Erickson said.
Knowing your herd’s health history and potential risks, and working with your veterinarian to develop the best vaccination protocol to address concerns, is the best approach. Beginning with a healthy, well-fed herd and practicing effective vaccination protocols can minimize costs through increased reproduction, lower lifetime effects of disease, and reduced treatment costs.
The webinar presentation by Larson and Erickson was presented by the Beef Cattle Research Council, and can be viewed here: www.beefresearch.ca/resources/webinars.cfm.