Vaccines Key to Calving Efficiency

3/2/2013 7:00 AM
By Laura Zoeller Southwestern Pa. Correspondent

BELLE VERNON, Pa. — The single most important economic trait in cow herds is reproduction efficiency, and a quality vaccination program can assist in boosting those numbers.

Victoria Baker, a cattle and equine representative for Zoetis (formerly Pfizer) recently discussed vaccination types and label guidelines at the final meeting in this year’s Penn State Extension Beef Cattle Seminar Series.

“An average of 80 percent of cows that are exposed will end up with a calf at weaning,” Baker said, “but 90 percent is a realistic, achievable goal. One way to increase conception rate, and increase the chances of a healthy calf at weaning, is to implement a regular deworming schedule.”

According to Baker, parasite infections affect conception rates, the calving-to-breed-back interval, new calf mortality, bull performance and lifetime production.

“Study after study has shown an increased conception rate following deworming,” Baker said. “Short-acting dewormers used one time can increase the conception rate by 4.3 percent, while long-acting dewormers, or short-acting ones used twice, can increase it by over 8 percent. That can really add up in a short amount of time.”

Diseases such as BVD, IBR, and Lepto can also wreak havoc on a breeding program.

“Lepto can cause abortions, stillbirths, and weak calves, while BVD can cause abortions, early embryo death, infertility, and persistently infected (PI) calves,” Baker said. “PI occurs when the BVD virus gets into the blood stream of a dam when she is between 40 and 120 days pregnant.

“The fetus’s immune system thinks the virus is normal and accepts it as part of its own DNA,” she said. “Once it is born, it continuously sheds the virus by the millions and potentially infects every animal it comes into contact with.”

Vaccinations are available for those diseases, but Baker believes understanding the label may be equally important to any regimen.

“There are grades to vaccines in the same way there are grades to beef,” Baker said. “In the same way that certified’ beef would be the top grade for a steak, a vaccine’s top grade is a claim that it can prevent an infection.

“That vaccine would prevent all colonization or replication of the challenge organism,” she said. “There is only one vaccine on the market today that prevents infection, and that is only if the vaccine has been handled, stored and implemented in the proper way and at the proper time.

“Among other things,” she said, “that means not going off label and vaccinating animals that are not recommended, not allowing the vial to freeze or overheat, and administering it subcutaneously if that is what is advised.”

Beyond that, the best choices will provide “prevention of disease” or will “aid in the prevention of disease.”

“Other things to look for on your label are the duration of the vaccine’s effectiveness,” Baker said. “In order to get a label on a vaccine, a company only has to prove that it works for 28 days. So, if there is no duration listed, you don’t know how long it lasts beyond that amount of time. Do you want to plan to re-vaccinate once a month? I wouldn’t.”

Baker advises working with a veterinarian to keep track of worming and vaccination schedules and to keep records of everything.

“Know the specific disease threats,” she said. “Be aware of when the risk is highest, how long it lasts, and when and how often you need to vaccinate to maintain its effectiveness.

“An enhanced vaccination program will not only improve pregnancy and calving rates,” she said, “but it will also improve colostral immunity for the calf upon birth. And, given that the average cost of a pregnancy loss is $555, if a vaccination program increases your live calf numbers by one, it has more than paid for itself.”


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9/1/2014 | Last Updated: 11:15 AM