By Associate Professor & Texas A&M AgriLife Extension Specialist Thomas B. Hairgrove, DVM, PhD., DABVP
To begin, I do not believe it is appropriate to recommend “cookie cutter” vaccination programs. Your vaccine program must be developed with your risks and expectations in mind. Vaccines are tools that go into your herd health tool chest. What are your risks for disease introduction? Do your neighbors have cattle and, if so, what type of cattle? A neighbor engaged in a stocker operation that grazes high-risk cattle could well expose your herd to viral respiratory pathogens such as Bovine Viral Diarrhea (BVD) or Bovine Herpes Virus (IBR). Both viruses can be associated with respiratory disease, eye lesions, and even nervous conditions in stocker or feeder cattle. When introduced into your cow herd they may show none of the mentioned lesions, but can be disastrous to your herd’s reproduction. Unfortunately, infection might not be detected until after you have experienced massive abortions, or weak or stillborn calves.
Your large animal veterinary practitioner is the best resource to assist you in developing a vaccination program. Development of a vaccine program necessitates some knowledge of disease, an understanding of how the vaccine works, and its effectiveness. For example, when using a BVD vaccine as an aid in controlling bovine respiratory disease (BRD), the desired result is protection against disease after contact with the virus. The virus may invade the animal’s body but not cause clinical disease. When vaccinating cows, the vaccine must prevent the virus from reaching the fetus to prevent fetal loss. A vaccine licensed for fetal protection must meet a higher standard than a vaccine for respiratory disease.
Vaccines are not perfect, and no vaccine is 100 percent effective. For example, not every person vaccinated against the flu is spared. Keep in mind, there are some minimal risks with all vaccines. Proper vaccine handling is important to your cattle being properly immunized. Purchase vaccines from reputable suppliers and maintain at the temperature specified on the label. Protect vaccines, in the bottle or in the syringe or other delivery device, from extreme heat or cold and sunlight and only mix enough vaccine to be used in an hour. To avoid contaminating vaccines, never use a needle that has been placed in an animal to draw vaccine into a syringe. Always use a new needle to fill syringes. You can find detailed information on proper vaccination placement, vaccine handling, and more, at www.bqa.org.
The process of giving a shot does not ensure that animals have been effectively immunized. Factors that interfere with immune function include nutritional stress, weather stress, stage of pregnancy, and cattle temperament. Cattle in adequate body condition are more likely to mount an immune response, because lack of energy or protein will lower immune response. The lack of proper trace minerals has been associated with immune failure. Bad temperament has been associated with decreased immune response, so handling cattle with minimal stress is important. Elevation of ambient temperature has been associated with poor immune response, as well as more adverse vaccine reactions. Do not vaccinate cattle in times of heat stress, and remember it takes cattle a while to cool back down after being exposed to heat.
The future of the cow herd is the heifers and a good vaccination program that focuses on establishing immunity and maintaining immunity. Blackleg and other clostridial diseases are not contagious. Rather, they are normally found as spores in the soil and even in a normal animal’s gastrointestinal tract; they cause disease when they invade other tissues. These vaccines are referred to as seven ways or eight ways, but one must understand what is in the product. For example, some eight ways include tetanus whereas in other eight ways Clostridium haemolyticum, or red-water, is the addition. If your operation is subject to liver flukes, then consider a vaccine with red-water added. Clostridial vaccines are usually recommended annually to cows to provide immunity to their offspring through the colostrum.
There is controversy concerning the use of modified live (mlv) versus killed vaccines, and one must be careful when just evaluating one research study. Both mlv and killed are reasonably safe and effective when used according to label. There is a risk to using mlv products in pregnant cows, contrary to label, so always read labels carefully. There are products labeled for pregnant cows, which assume label directions were followed and animals were properly vaccinated with the product within a specified time period. Pre-breeding heifers are usually managed separately from cows and can be given a mlv product initially, followed by killed products once they are bred and become part of the cow herd. When using mlv products in pregnant cows as per label, try not to vaccinate cows in the late stages of gestation, which may be associated with some stress. I can’t overstress the role of your veterinarian’s expertise in designing a vaccination protocol.
Leptospirosis is another disease that causes reproductive loss in cattle. There are several serovars, or kinds of leptospirosis, that cause disease in cattle and clinical signs are related to serovar. Cattle are the natural host of Lepto Hardjo Bovis, the most commonly documented Leptospira among cattle in the United States. This serovar colonizes the reproductive tract both of cows and bulls and can be passed by natural breeding or through consumption or contact with contaminated water. Lepto Hardjo Bovis has received much attention in the last 15 years, because the vaccines available in the U.S. prior to that time were not effective against this agent; however, current vaccines on the market appear to be effective. Lepto Hardjo Bovis causes early reproductive loss with few other clinical signs and is difficult to definitively diagnose in the laboratory. Leptospira Pomona, on the other hand, can cause abortions, as well as clinical sickness and death in adult cattle and calves. Swine and skunks are the natural host for this pomona and, again, contaminated water is often a source of infection. In areas with high lepto prevalence, some veterinarians recommend vaccinating more often than indicated on the label.
Campylobacter (vibrio) and bovine trichomoniasis (trich) are both sexually transmitted diseases of cattle that show very similar clinical signs and require laboratory confirmation. Vibrio is caused by a bacterium and trich by a protozoan, but both diseases cause early fetal loss and some late-term abortions as well as a non-uniform calf crop. Vaccines are available for both diseases and, when given according to label, will reduce reproductive loss. These vaccines need to be given pre-breeding and not at pregnancy check. It is important to remember that vaccination is only part of the disease control program and management is key to controlling these two costly diseases. Understand there is a risk of adding infected females when you do not have knowledge of the herd of origin and even pregnant cows can be infected and introduce disease into your herd. Most states have regulations requiring all bulls in commerce to be tested for bovine trichomoniasis, but testing for vibrio is not regulated and a definitive laboratory diagnosis is difficult.
Other disease conditions not necessarily related to reproduction can cause loss in your cow herd and vaccination for these conditions may be warranted. A pink eye vaccine is available and is sometimes helpful; however, bovine pink eye has been associated with multiple organisms. Producers should contact their veterinarians to identify infective agents involved. Often an autogenous vaccine tailored to your disease situation may be indicated. There are vaccines available for foot rot and bovine anaplasmosis that can sometimes aid in control of these diseases. The bovine anaplasmosis vaccine is not licensed by the United States Department of Agriculture, but its sale as an experimental vaccine to licensed veterinarians is allowed in states that approve its use.
I have conducted numerous producer surveys where I ask, “Who is your most trusted resource concerning animal health?” Every survey ranks the producer’s veterinarian as that resource, yet often they depend on others to recommend a vaccination program. A vaccination program tailored to your herd requires extra time and effort, but it may prevent a catastrophe down the road. Understand the utility of your vaccines, as well as their limitations, when developing your program. No vaccine is perfect, but when used correctly they can be an asset to your operation.
For more information regarding news from the Department of Animal Science, College of Agriculture and Life Sciences, Texas A&M University, please contact Maggie Tucker at firstname.lastname@example.org or (979) 845-1542.