Veterinarian’s corner: Dairy beef respiratory vaccine strategies

By Dr. Trey Gellert, Four Star Veterinary Service, LLC
One-day-old dairy beef calves need to be set up for long-term success. Starting these calves with the end goal in mind will lead to a mutually beneficial relationship for the producer and calf. Many important components go into raising these dairy beef calves, such as colostrum management, nutrition, and the environment. The topic of this article will be the importance of targeted vaccine strategies.

It is critically important to vaccinate dairy beef calves because these calves are typically co-mingled and stressed, had unknown colostrum intake and quality, and had unknown dairy farm disease pressure. These make the dairy beef calf unique and different compared to typical cow/calf and dairy operations. Co-mingled calves bring the diseases from many different farms onto one farm, which can combine different diseases. Stressing these calves may weaken their immune systems and set them up for failure from the start.

Vaccines are a tool to help manage diseases present in your cattle. Vaccinating for common diseases is the approach I like to take. In dairy beef calves, respiratory disease typically occurs in two major time frames: at first placement into the barn and after weaning. In our previous article, we talked about scours and dehydration being the number one cause of death in the first 60 days, but respiratory disease is the second leader in cause of death in the first 60 days and the number one cause after 60 days. The goal of a respiratory vaccine program is to help set up this calf not only for the first 60 days, but also the rest of its life.

Two major categories of pathogens may cause respiratory disease in cattle: viruses and bacteria. Respiratory disease in cattle is typically referred to as Bovine Respiratory Disease Complex (BRD). This is due to the multifactorial issues that range from environmental factors to disease pathogens that can all trigger BRD.

Viruses
Viruses that cause respiratory disease in cattle are Parainfluenza-3 virus (PI3), Bovine Respiratory Syncytial Virus (BRSV), Bovine Herpesvirus 1 (IBR) and Bovine Viral Diarrhea Virus (BVDV). Viruses are typically an issue in young, early-placed dairy beef calves that are co-mingled. One factor that plays a role in viral-triggered BRD is proximity to older cattle that may have low levels of viruses present in the herd.
Managing viral pneumonia in dairy beef calves goes back to early intranasal vaccination of the three pathogens: PI3, BRSV and IBR. Intranasal vaccination allows for bypass of maternal antibodies that may decrease efficacy of injectable vaccines and increase of local immunity within the mucosa of the respiratory tract.

Injectable vaccines may be used when calves are older and prior to weaning to help boost immunity to these viruses. Using an intranasal vaccine in conjunction with an injectable vaccine of the same pathogens at a different time allows for prime boosting. Prime boosting is an enhanced antibody immunity response from using two different routes of vaccines.

Bacteria
Bacteria that cause respiratory disease in cattle are Mannheimia haemolytica, Pasteurella multocida, Histophilus somni and Mycoplasma bovis. These bacteria can all be found as normal microflora of healthy calves, but become an issue when stressors induce overgrowth and immune suppression. Stressors range from co-infections with viruses, lack of nutrition, diet changes, ventilation, environment, co-mingling, proximity to older cattle, water availability, and any factor that is a change that requires that calf to adapt. Stressors on an immune-suppressed calf can lead to an over-proliferation of the normal microflora bacteria. Once these bacteria overgrow, they lead to BRD. Antimicrobials may be used to help control the bacteria after growth, but lack 100% effectiveness against all bacteria. Vaccines for bacteria are not 100% effective and should be used prior to calves being stressed.

An intranasal vaccine upon arrival is a good strategy for Mannheimia and Pasteurella coverage. This will also allow for prime boosting later. Prior to weaning, injectable vaccines for Histophilus, Mannheimia and Pasteurella should be used to develop immunity prior to the major stress of weaning. Mycoplasma vaccines are available, but they are relatively new to the market and traditionally have had less success than the other bacteria vaccines.

Timing is important when giving respiratory vaccines. We typically want to develop the calf’s immunity prior to the stressor and potential for BRD to develop. Usually, immunity takes about 14 days to develop after vaccination, so take this into consideration when developing a complete targeted health program. Also, consider not vaccinating calves that are already sick because it typically results in a poorer immune response. Work with your herd health veterinarian to develop an action plan that fits your farm’s unique challenges.