However, protection from disease isn’t guaranteed simply by the administration of quality vaccines.
A host of factors impact the immune response of cattle and the level of protection developed from vaccination.
Vaccines can do what they are intended to do if we minimize factors that detrimentally affect the ability of cattle to respond to the preventive treatment.
While we tend to focus the most attention on quality of vaccine response against bovine respiratory disease, response to pinkeye, Clostridial and Brucella (Bangs) vaccines is affected in much the same way.
Your veterinarian is the best source of information on the various factors of vaccine response and vaccines.
Nutritional condition of cattle
For vaccines to work the way they are designed to work, the cattle being vaccinated – whether calves, yearlings or adults – must be nutritionally sound.
Immune response is a complex chain of events that requires energy and other nutrient components. We cannot ask vaccines to perform well at any level of nutritional deficiency.
Vaccine care
If vaccines are stored improperly, immune response is jeopardized before the vaccine is ever administered. Vaccines should be stored and handled at all times according to label directions.
Most vaccines require refrigeration, so check your refrigerator regularly to ensure it works properly. Ultraviolet waves in sunlight can damage vaccines, particularly modified-live viral (MLV) vaccines, because the waves kill the live vaccine organisms.
While being used to inject MLV vaccines, syringes should be shielded from direct sunlight and kept cool between vaccinated animals.
Proper storage temperature of vaccines containing killed gram-negative bacteria (a certain class of bacteria including Mannheimia, Pasteurella and Histophilus) helps diminish the release of endotoxins, which are natural components of gram-negative vaccines.
Endotoxins can cause subtle, subclinical effects that may negatively impact the immune response or, at their worst, cause a cascade of harmful events in calves, including decreased blood pressure, increased respiration and even shock or death.
Use chute-side coolers, including those with syringe “holsters,” during warm-weather processing.
Conversely, vaccines should not be allowed to freeze in cold weather, since freezing alters the biological compounds and may prevent the immune system from responding effectively.
When mixing MLV vaccines, it is important to thoroughly mix the dry “plug” with the liquid diluent (or the liquid bacterial component of combination vaccines).
When mixing killed vaccines, use only moderate shaking in order to diminish the effects of endotoxins. Planning for adequate vaccine mixing and preparation well in advance of the rush of processing is time well spent.
When to vaccinate
The timing of vaccination is important to the success of any vaccination program. This includes both the age of the cattle to be vaccinated and the timing for the necessary protection.
Research demonstrates the ability of calves as young as 1 day old to respond to certain vaccines, particularly MLV products.
This kind of vaccination-driven, cell-mediated immunity should take place early in life to protect the calf before temporary maternal antibodies from colostrum have declined to non-protective levels.
Talk to your veterinarian about vaccines that have proven cell-mediated immunity against various viral organisms, such as IBR (infectious bovine rhinotracheitis), BVD (bovine viral diarrhea) Type 1 and Type 2 and BRSV (bovine respiratory syncytial virus).
Producers should consult with their veterinarian to assure safety from abortion of any pregnant cows when use of MLVs is going to occur in calves.
In many spring-calving beef operations, vaccination may coincide with turnout onto summer grass. In fall-calving operations, it may occur when cattle are gathered off summer range.
Vaccination with live or killed bacterial vaccines such as Mannheimia and Pasteurella, and the killed (inactivated) Clostridial (blackleg-type organisms) vaccines should start early in life as well.
Vaccinating calves 2 to 4 weeks pre-weaning is less stressful than vaccination at weaning, and it allows the immune system to respond to the vaccine by the time weaning occurs.
As a result, calves are better prepared for weaning. The stress of weaning causes the release of corticosteroids, substances that suppress immune function.
Corticosteroids decrease immune functions and may decrease vaccine response as well as increase susceptibility to diseases.
Timing also is important when it comes to the environment and weather. Hot, ambient temperatures and high humidity at processing can have a negative impact on vaccine response.
Hot temperatures are magnified when calves are closely grouped together waiting to be processed, generating increased body heat and decreased air movement.
It is better to vaccinate calves during the cooler times of the day on multiple days than extending processing into the hot times of the day.
Clean up the worms
Pre-weaning use of dewormers that will effectively kill internal parasites can both improve weight gains and improve the ability of the calf’s immune system to respond to vaccines and the stress of weaning.
When calves are carrying nematodes, the calf’s immune system tends to focus on worms rather than vaccine organisms. By significantly reducing nematode numbers, calves are better able to respond to respiratory disease vaccines.
Sometimes less is better
A calf’s immune system responds to any and all foreign proteins, regardless of whether or not they stimulate immunity against disease.
This response requires energy that could otherwise be used for maintenance or gain.
Since vaccines are made up of the inoculating organisms and sometimes an adjuvant (a certain type of carrier) designed to stimulate immune response, it’s important to choose vaccines carefully.
You are selecting not only effective vaccines, but you are choosing vaccines with appropriate adjuvants. Your veterinarian can help you make these decisions.
In addition to the energy requirements of a vaccine, excessive endotoxins can have a negative impact on cattle. This typically occurs because too many gram-negative bacterial vaccines are administered simultaneously.
Talk to your veterinarian about what vaccines are required in your area and what vaccines will produce effective immunity without creating excessive demands on the animal.
It may be best to administer all the necessary vaccines on more than one day, with a minimum of 10 days to two weeks between vaccination days. Other processing demands, such as branding and castration, also create additional stress.
Work with your veterinarian to produce a balanced vaccination program that not only includes appropriate vaccine products, but also includes a plan of when and how to administer vaccines. 
Dr. Bill Burdett is a technical services manager for Merck Animal Health. He lives in Nebraska and can be contacted at (308) 379-3261.
PHOTO
Top: The quality of vaccine response can be determined by timing, temperature and nutrition of cattle at the time of administration. Staff Photo
Bill Burdett
Technical Services Manager
Merck Animal Health
bill.burdett@merck.com
