Vaccine use rises in western Canadian cow-calf herds

Recent measles outbreaks in North America and Europe have occurred as vaccination rates of children drop off due to anti-vaccination movements.

I’m glad we don’t have a major anti-vaccination movement in the beef industry. In fact, we now have some evidence that the opposite trend is occurring.

A recent study in the latest issue of the Canadian Veterinary Journal highlighted the current state of vaccine use in cow-calf herds.

Dr. Cheryl Waldner and other colleagues from the Western College of Veterinary Medicine at the University of Saskatchewan authored the paper that surveyed herds enrolled in the Western Canadian Cow Calf Surveillance Study. This research network was funded by the Beef Cattle Research Council of the Canadian Cattlemen’s Association along with funding from Saskatchewan Agriculture.

The network involved periodic surveys from a group of cow-calf herd managers across Manitoba, Saskatchewan and Alberta on a variety of management topics, as well as tracking productivity and the levels of production-limiting diseases.

The objective of the study was to describe when and how vaccines are administered to cow-calf herds in Western Canada. In all, 93 herd owners responded to the study: one from eastern British Columbia, 46 from Alberta, 29 from Saskatchewan and 17 from Manitoba. The average herd size was about 230 cows and 37 percent of the respondents had more than 300 cows.

The good news from the study was that 97 percent of respondents vaccinated their cows with at least one type of vaccine, most common being infectious bovine rhinotracheitis virus (IBR) and bovine viral diarrhea virus (BVDV).

Ninety-one percent of the herd managers reported that they vaccinated their cows with a combination vaccine that contained antigens against these two diseases.

Both of these viruses are important causes of abortion in cattle and they are both relatively common in our cattle populations. It is extremely encouraging to see vaccination rates at a much higher level than was reported in previous studies.

In 2002, a similar survey also authored by Waldner examined vaccine use in 200 cow-calf herds in Western Canada and only about 45 percent of producers reported using these vaccines in cows at that time. Both studies recruited herds through veterinarians and so the results are at least somewhat comparable. As a result, it appears our vaccination rates in cows are trending upward.

This good news is probably somewhat attributable to the realization of the importance of these diseases on reproductive success.

Another recent scientific paper summarized the results of a number of clinical trials and suggested that vaccinating for BVD would reduce abortions by 45 percent and increase pregnancy rates on average by five percent. Vaccinating for IBR would cause on average a 60 percent decrease in abortion rates. The economic benefits of these vaccines are obvious and practicing veterinarians have been promoting their use for years.

The timing of the use of BVD vaccines in cows was also examined in the survey. Fifty-seven percent of herd owners reported using BVD vaccines before breeding, 22 percent used them at pregnancy testing and 15 percent reported using them before calving.

The timing of these vaccines is highly important because they are primarily designed to protect the fetus from abortion, but timing of vaccination also depends on other herd management factors and the type of vaccine being used. It is highly recommended that producers speak to their veterinarians before they decide on a vaccine protocol for their herd.

Scours vaccines for calf diarrhea were also used by about half of the herds surveyed. Scours vaccines are administered to the pregnant cow before calving to ensure that the dam’s colostrum contains antibodies to some of the bacteria and viruses that can cause diarrhea in young calves.

While these vaccines are an important method of control of calf scours, there may be herds that largely limit this disease through environmental management of the calving area and other forms of biosecurity. However, there are probably more herds that could achieve an economic benefit from including these vaccines with their herd management protocol.

A major gap in our vaccine protocols identified in the survey was the vaccination of bulls. While more than 90 percent of producers reported vaccinating cows for IBR and BVDV, only 55 percent of producers reported using these vaccines on their bulls.

Bulls can become infected with these viruses and there is some evidence that with BVD virus in particular, that bulls can harbour longer- term viral infections within testicular tissue, which might then spread to cows during the breeding season. It would seem to be a simple, yet prudent recommendation to make sure bulls are also vaccinated when vaccinating the cow herd.

It looks like we’ve made some major strides in our vaccination coverage in cow-calf herds, but there are still some gaps. There are still almost 10 percent of herds not vaccinating cows regularly for IBR and BVD, two very important causes of reproductive loss.

All herds in these studies were owned by producers who worked regularly with veterinarians. The rate of unvaccinated herds is probably higher if we surveyed herds that didn’t have as close a relationship with a veterinarian.

In addition, it would appear that many bulls aren’t adequately vaccinated against diseases such as IBR and BVD. I encourage producers to work closely with a veterinarian to develop a vaccination protocol to provide the most cost-effective protection for their herds and one that fits with their management practices.

John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.

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