Proper practices increase vaccine efficiency

A veterinarian says many factors are involved in disease control, and timing of vaccination is one of the most important

DRUMHELLER, Alta. — Timing is important to provide the best vaccine protection for beef cattle.

Producers might think that when their animals become sick, they need better or new vaccines, said veterinarian Rob Tremblay at the recent Canadian Angus Association annual meeting held in Drumheller.

However, disease control is multi-faceted and other factors can play a role, he said.

“What matters for best protection is when you vaccinate. Of all the changes that you might make in your program, when you vaccinate will be the most important,” he said.

“Some diseases are either seasonal in occurrence or related to some other events that are pretty critical,” he said.

Vaccines come in different forms and for the most serious problems like bovine viral diarrhea, inactivated and modified live vaccines are available.

Cows need at least 150 days of protection after conception to prevent the fetus from picking up the disease in-utero and being born persistently infected. Considering it takes 42 to 60 days to get all cows pregnant during a breeding season, the cow needs 190 to 210 days of protection.

Bulls represent a special risk from BVD, said Tremblay.

If they are not vaccinated, the virus can appear in their testicles. The infection does not affect their fertility but BVD may be shed in their semen for a long time. Bulls should be vaccinated with a modified live vaccine, ideally before they go through puberty.

Other diseases to watch for include infectious bovine rhinotracheitis (IBR), which causes respiratory infections, infertility, abortion, and stillbirths. Long-term vaccine coverage is needed.

Leptospirosis also causes infertility and abortions.

“If you are worried about these diseases, you vaccinate them to the time you are going to turn out the bulls,” he said.

Vaccinating during pregnancy checks works if the cows are checked at the same time every year.

Scours vaccines protect the cow and calf but are unlikely to work if they are administered at the wrong time.

Timing is also important when vaccinating calves.

Vaccines don’t protect against all the microbes that could cause pneumonia, and immunity from colostrum might block vaccine efficacy. Intranasal vaccines at birth work but they are not long lasting.

Colostrum or first milk can protect against scours for about 10 to 14 days while protection against pneumonia lasts for about four to seven weeks, Tremblay said.

When calves are vaccinated at processing time, some may receive protection and others are left vulnerable. Calves are at various ages depending when they were born so their immune systems are at different stages.

At this time, they will receive a wide spectrum of vaccines and clostridials. It is not known how much these different products might interfere with each other. If the calf needs two shots, a hand width between injection sites is recommended.

The vaccines need to be handled properly to make sure they work.

“The modified live vaccines can only work if they are alive. They start to die as soon as you mix them,” he said.

They die faster if exposed to heat and sunlight and should be used within an hour of mixing. Mix the live vaccine gently but thoroughly with rolling rather than shaking. Viruses are fragile and shaking damages them.

Products should be stored in a functioning refrigerator and use a thermometer to make sure the temperature is right.

Clostridials settle quickly, so mix them well.

Ask a veterinarian if epinephrine should be on hand in case the cattle have a reaction to the vaccine.

Clean equipment with warm soapy water and then rinse it and let it dry. Do no use alcohol or other disinfectants.

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