For more than 200 years, vaccines have saved millions of lives and prevented human diseases like polio, measles, mumps and many others. Most people don’t realize that dairy cows are responsible for this life-saving invention. In 1796, Sir Edward Jenner noticed that milkmaids who developed cowpox lesions on their hands also were resistant to smallpox. To prove his theory, Jenner infected an orphan boy with the cowpox virus, and he too was fully protected from the deadly virus. This discovery led to the development of the smallpox vaccine.
Advancements in vaccine technology have changed the course of modern agriculture. Our first cattle vaccines were developed in the late 1880s to protect against blackleg. Today, there are more than 50 different disease-preventing antigens approved for use in cattle vaccines, and the U.S. dairy herd is healthier and better protected from diseases than ever before.
To maximize the health of your herd and the success of its vaccination program, there are several best-management practices to understand and apply.
All things considered
Several critical factors ensure vaccines are going to provide the protection we expect, both pre- and post-vaccination. Prior to vaccination, consider the following:
• Selection of disease antigens
• Timing of administration
• Vaccine handling and storage
• Content of endotoxin (for some vaccines)
After vaccines are administered, there are many factors that contribute to the response an animal mounts against the diseases for which it is vaccinated. This response requires a healthy immune system, which is impacted directly by:
• Disease exposure
• Other environmental conditions
First things first
The first question to ask is what diseases to vaccinate against. Make these decisions with your veterinarian who is familiar with diseases unique to your operation and potential disease threats in your area. Provide protection for diseases considered to be endemic to cattle, such as infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), IBR-PI3, bovine respiratory syncytial virus and leptospirosis. Beyond endemic diseases, evidence-based medicine should be practiced. Confirm that the disease already is in the herd or that the potential risk of infection is great enough to justify the expense of an additional vaccine.
Timing is critical
Timing in a vaccine program is absolutely critical. The first step in achieving success is to develop an animal flowchart to determine where disease protection is needed. Once the risks are identified, the appropriate management, housing and husbandry solutions should be implemented. If it is determined that a vaccination could be helpful, it should be administered at least 2 to 4 weeks prior to the time of challenge. Because of their developing immune systems and the potential for colostral interference, calves always should be revaccinated for endemic diseases after 4 to 6 months of age.
Put it in writing
Farms should have a written vaccination program that can be referenced by any farm employee involved in the administration of products. There also should be an adequate system of vaccination documentation to ensure each calf’s protection.
Handle with care
Proper handling and storage is vital to ensure the safety and efficacy of vaccines. Allowing a vaccine to freeze or overheat can damage the vaccine. Modified live vaccines can be inactivated and become useless if mishandled, and killed vaccines can be damaged in a way that harms the cattle injected. Bacterial gram-negative vaccines, such as Pasteurella, Brucella or E. coli vaccines, can become harmful to livestock if mishandled. So be sure to follow the manufacturer-recommended storage procedures. Always use clean needles, and never use disinfectants that could inactivate modified live vaccines.
One of the greatest challenges of developing a successful vaccine program is the management of endotoxins in gram-negative bacterial vaccines. Cattle can overload on endotoxins for several reasons, and the use of multiple gram-negative vaccines can create a significant health risk, known as “endotoxic stacking of vaccines.” To protect your cattle from endotoxic overload or stacking, there are several rules of thumb to follow:
• Properly store vaccines – never freeze or overheat
• Use new, clean needles (subcutaneous administration causes the least reaction)
• Limit gram-negative vaccines to two at a time
• Wait one week if more gram- negative vaccines are necessary
• Work with your veterinarian to better understand and manage vaccine endotoxins
Colostrum and nutrition
One of the greatest ways to ensure the success of your vaccination program is an effective colostrum management program. Developing a strong immune response starts with getting the right amount of colostrum into the calf at the right time. Newborn calves should receive a gallon of colostrum as soon as possible after birth, and another gallon 12 hours later. The healthier your calves, the more responsive they will be to vaccines, and ultimately the more productive they will be in the future.
Stress can have a negative effect on vaccine response. It drives up the cortisol levels in animals. This in turn decreases the critical function of immune cells, such as white blood cells and lymphocytes. Animals should not be vaccinated during times of stress, such as extreme environmental conditions (heat, cold and dust). Vaccine administration also should be avoided during housing changes that create social stressors on calves. We would never vaccinate our son or daughter on the first day of kindergarten, so we shouldn’t vaccinate dairy calves on the same day as weaning or movement from hutches.
Parasites can have a devastating effect on the immune response. They can drive the immune response in a direction that is counterproductive to a viral vaccine response. They have been shown to reduce both the humoral response that creates antibodies, as well as the cell-mediated response that combats intracellular organisms. Parasites compete for the nutrients needed to mount an immune response, and they suppress appetite. To maximize vaccine response, cattle should be dewormed at least two weeks prior to vaccination and coccidia should be controlled.
Even with the best vaccine program in place, good immunity can be compromised by poor management practices. An immune system in a calf or cow can be overwhelmed by extraordinary challenge. If milk bottles are not cleaned properly and salmonella bacterial counts build in the environment, no vaccine or colostral immunity will withstand the challenge. If a farm has numerous persistently infected calves shedding the BVD virus to their herdmates, these calves will have difficulty responding adequately to the virus. Regularly review and evaluate your management protocols, records and employees for signs that your vaccination program may be at risk.
For more than 200 years, vaccines have benefitted human and animal health. Every year we benefit from new technology and new information to make our vaccination programs even better. Especially in a world that wants assurance that we are caring for animals and producing milk responsibly, it’s important we are committed to the best practices in vaccine management. This commitment not only will benefit the health and productivity of your animals, but the image of the dairy industry as a whole. PD
Your herd vaccination checklist
1. Choose vaccines backed by product research and a reputable manufacturer.
2. Work with your veterinarian to select the appropriate disease antigens and develop vaccine protocols.
3. Train employees on vaccine protocols and document vaccine administration.
4. Follow storage and handling guidelines on the product label.
5. Understand and manage endotoxins in gram-negative bacterial vaccines.
6. Feed newborn calves a gallon of colostrum as soon as possible, and another gallon 12 hours later.
7. Work with your nutritionist to ensure proper calf nutrition.
8. Vaccinate calves 2 to 4 weeks prior to challenge.
9. Revaccinate calves for endemic diseases after 4 to 6 months old.
10. Minimize stress and do not vaccinate during weaning or transition.
11. Control parasites by deworming and treating coccidia.
12. Review all calf-management practices to identify any risk factors that would negatively impact the success of your vaccination program.