Craig A. Payne, DVM, MS
Associate Extension Professor, Veterinary Medical Extension and Continuing Education

Celeste Morris, DVM, MBA, MPVM, DACT-Bovine
Assistant Teaching Professor, Food Animal Medicine and Surgery

The following provides an overview of a vaccine program for a cow/calf operation. It covers the viruses and bacteria of concern, describes the difference between killed and modified live viral vaccines, and provides an example of a vaccine schedule. Ultimately, your herd veterinarian is the best source of advice regarding a vaccine program.

Goals of the vaccination program

Vaccine programs used in breeding animals primarily focus on preventing diseases that lead to reproductive losses, such as embryonic death, abortion and stillbirths. Vaccinating breeding females also boosts antibodies in colostrum, helping protect newborn calves from disease during the first few months of life. In calves, vaccination programs primarily focus on preventing respiratory disease (pneumonia) and clostridial diseases such as Blackleg.

Viruses and bacteria

The viruses and bacteria discussed below are commonly targeted in vaccine programs, though additional vaccines may be required if other diseases pose a concern.

Infectious Bovine Rhinotracheitis (IBR)

This virus can cause reproductive losses in cows and respiratory problems in calves. In pregnant cows, it can lead to abortions, typically after four months of gestation but potentially at any stage. In calves, IBR contributes to respiratory disease outbreaks, causing fever, lethargy, heavy nasal discharge, and open-mouth breathing. It may also cause eye inflammation and cloudiness or neurologic signs, which may or may not occur alongside respiratory disease.

Bovine Virus Diarrhea Virus (BVDV) Type 1 & 2

BVDV affects cattle in variety of ways. In pregnant animals, it can cause embryonic death, abortions, congenital defects, or result in persistently infected (PI) calves depending on the stage of gestation. BVDV also suppresses the immune system and plays a role in respiratory disease outbreaks in calves.

Herds with ongoing BVDV problems usually have PI animals. The formation of a PI occurs during a specific window of gestation, typically between 40 to 125 days, when the fetal immune system is still developing. If the fetus is infected with a non-cytopathic strain of BVDV during this time, this virus may be mistakenly recognized as normal. Consequently, the immune system fails to respond against the virus resulting in a life-long infection. PI animals shed large amount of virus continuously but can appear outwardly normal, posing an ongoing risk to other animals in the herd.

Because PI animals are so detrimental, the standard recommendation in herds where BVDV is suspected is to implement a testing strategy and remove any PI animals detected. Vaccination alone cannot counter the effects PI animals can have.

Bovine Respiratory Syncytial Virus (BRSV)

BRSV plays a role in respiratory disease outbreaks, especially in calves. It specifically targets the lower respiratory tract and predisposes the animal to secondary bacterial infection, often worsening the respiratory symptoms and prognosis.

Parainfluenza (PI3)

This virus causes mild to moderate respiratory disease in calves. It primarily targets the upper respiratory tract and increases the risk of a secondary bacterial infection, exacerbating the symptoms.

Leptospirosis

This bacterial disease that can cause embryonic loss, abortions, stillbirths or weak born calves. Abortions may occur early in gestation, but more often occur in the third trimester. Vaccine programs for breeding animals typically include a “5-way Lepto” product which protects against multiple strains of the bacteria: L. hardjo, L. pomona, L. canicola, L. icterohaemorrhagiae and L. grippotyphosa.

Campylobacter fetus (Vibriosis)

This causes a venereal disease which leads to infertility, early embryonic death and, less commonly, abortion in breeding females. Producers may notice cows being bred multiple times before becoming pregnant. While most cows eliminate the infection, a few will maintain it through gestation, deliver a normal calf and then infect bulls in the next breeding season. Bulls then transmit the organisms to other cows during the mating season, perpetuating the disease cycle.

Clostridial diseases

There a variety of diseases in cattle that are caused by Clostridial bacteria. Some of the common diseases producers are familiar with are Blackleg, Redwater and Tetanus. Symptoms vary depending upon the species of bacteria and organ system affected but in general, clostridial diseases progress so rapidly that producers will often find animals dead rather than showing symptoms of illness.

Vaccines against clostridial diseases are commonly referred to as 7-way, 8-way, or 9-way. A 7-way vaccine should be considered the starting point. However, if diseases such as Redwater (caused by Clostridium haemolyticum) or Tetanus (caused by Clostridium tetani) are a concern, an 8-way or 9-way vaccine is required.

Vaccine choice

Combination vaccines are widely available and eliminate the need for multiple injections. For example, you will find vaccines that contain IBR, BVD Type 1 & 2, BRSV, PI3, Leptosporosis, and Campylobacter, so that only one product is necessary to cover all the major reproductive viruses and bacteria in the breeding herd.

When selecting a vaccine, the viral components will either be killed (inactivated), modified live (attenuated), or a combination of the two. For example, Virashield 6 + VL5 (Elanco) and Triangle 10 HB (Boehringer Ingelheim) contain killed viruses. In contrast, products like Bovishield Gold FP5 VL5 (Zoetis) and Bovilis Vista 5 VL5 SQ CFP (Merck) contain modified live viruses. The vaccine, CattleMaster Gold FP5 (Zoetis), contains a combination of the two. The BVD Type 1 & 2 are killed and IBR, BRSV and PI3 are modified live. "Killed" means the virus is no longer alive, while "modified live" means the virus is alive but has been weakened so it doesn’t cause disease when used according to label directions. The vaccine label will specify the type of virus the vaccine contains.

A question that often arises is, "Which type of viral vaccine should I use?" Each has its advantages and disadvantages. Modified live vaccines (MLV) provide quicker, better, and longer-lasting protection against most viral diseases when compared to killed vaccines. Additionally, one dose of an MLV may provide protective immunity if an animal is being vaccinated for the first time. The main disadvantage of these vaccines is the precautions associated with their use in breeding herds. They should not be administered to pregnant cows or calves nursing pregnant cows if the cows have not received the vaccine within the past 12 months. Labels may also recommend administering the vaccine to breeding females approximately one month before the breeding season if they haven’t been previously vaccinated or if vaccination history is unknown. Even though intranasal vaccines such as Inforce 3 (Zoetis) and Nasalgen 3 (Merck) are classified as MLV vaccines, they do not have these precautions.

The advantage of killed viral vaccines is they do not have the precautions associated with use in pregnant cows or calves nursing pregnant cows. A disadvantage, however, is that animals being vaccinated for the first time require an initial dose followed by a booster 2 - 5 weeks later to achieve protective immunity. Another disadvantage is that immunity established may not be as robust against some viruses when compared to a modified live vaccine. The choice of which type of viral vaccine to use should be made with guidance from a local veterinarian.

Finally, it’s important to note that Leptospirosis, Campylobacter, and Clostridial vaccine components are inactivated (killed), even when found in a combination with modified live viruses. These vaccines typically require a booster 2 – 6 weeks after the initial dose, if animals are being vaccinated for the first time.

Vaccine program

Even though there is not a 'one size fits all' vaccination program, the following provides an example of a common vaccination schedule. Again, the herd veterinarian should be consulted to determine the best vaccine program for your operation.