Benefits of early vaccinations carry on through calf’s life: research

NASHVILLE, Tenn. — Recent research suggests beef calves should be vaccinated early to guard them against the risks of scours and pneumonia.  

Most receive an adequate amount of antibody-rich colostrum from their mothers but sometimes a newborn calf is not able to nurse soon enough to get the full benefit, said Vic Cortese, a researcher and veterinarian with Zoetis.

The cow loses three to five percent colostrum power for every hour the calf does not nurse, he said at a special session during the National Cattlemen’s Beef Association convention held Feb. 1-3 in Nashville, Tennessee.

“The time to stand and the time to nurse are important numbers to know,” he said.

The first 60 days of life are critical to the lifetime health of an animal. It should double its birth weight by day 56 but if it was sickly, it may fail to achieve that.

“By 60 days, we have set what the animal is going to do. We have got to do a better job with these calves,” he said.

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“The more the calf grows in the first 60 days of life, the better that calf will do in weight gain, feed efficiency and reproduction.”

Disease often strikes calves at two to six months of age as maternal antibodies wane.

Calves that had to be treated for respiratory disease one time before three months of age are 2.5 times more likely to die after three months of age and 2.4 times more likely to die up to 2.5 years of age.

“That calf that had mild pneumonia when he or she is young never catches up,” he said.

“We can totally screw up that genomic potential if that calf had pneumonia,” he said.

Heifers that got sick as very young calves are often 2.4 times more likely to have dystocia problems and may struggle to rebreed.

New research shows calves re-ceiving vaccinations early on do better throughout their lifetimes.

Intranasal vaccination in the first week of life can be effective against a range of respiratory diseases. However, the effect is not long lasting so boosters are needed.

“The basic prime boost strategy is, how do I start the baby, maintain it as a teenager and maintain it as an adult?” Cortese said.

He suggested producers start by giving an intranasal vaccine, followed by a vaccine delivered in a different way, to better stimulate the animals’ immune systems.

Research has looked at a combination of intranasals followed by injectable vaccines in young calves. Those receiving the intranasal seemed to respond better.

Canadian studies show similar results.

Maternal antibodies start to decline by half every three to four weeks, said researcher Claire Windeyer of the University of Calgary faculty of veterinary medicine.

“Often when that starts disappearing, you’ll get outbreaks of summer pneumonia because their maternal protection is leaving and they haven’t started making protective antibodies or had exposure enough to be protected,” she said.

Sometimes vaccinating baby calves may not show a good immune response the first time. However, there appears to be a memory response in the body and when the booster shot is administered, stronger immunity usually results.  

When and how to vaccinate is always under debate among researchers, she said.

Giving an injectable form may not be effective because of the pre-existing immunity the calf received from its mother.

“The maternal antibodies from the cow in the colostrum, those can interfere with the response of the calf to some types of vaccines specifically the injectable ones given in the muscle or subcutaneous,” she said.  

“Those are consistently blocked by maternal antibodies at least in terms of our traditional ways of evaluating the immune response,” she said.

A better understanding of intranasals is still under assessment.

Calves receiving an intranasal vaccine with high levels of maternal antibodies still respond well because the immune response in the nose is not blocked in the same way as the maternal antibodies circulating in the blood.

It may also do them some good if they did not get that first dose of colostrum.

“We are trying to assess whether beef calves are getting enough colostrum. We have a false sense of security in that regard,” Windeyer said.

Past studies from the Western College of Veterinary Medicine in Saskatoon found 30 percent of calves born in Western Canada had low levels of passive immunity because they did not get enough colostrum.

While vaccination has benefits, it can also be stressful, said Cortese.

Studies have shown new feedlot calves can be off feed and showing general signs of not feeling well, especially if they received an intranasal and five-way vaccination at the same time.  

Stress of vaccination occurs about 24 hours after the procedure, but by day six, animals are usually back to normal if they arrived in good shape.

 However, vaccination stress may last for 21 days among less healthy calves that are upset from weaning, transportation and are adjusting to eating from a new feed bunk.

Among replacement heifers, priming the immune system improves their reproductive protection later.

When heifers are primed with a modified live vaccine and receive a single dose of killed vaccine, the protection was shown to be much higher than two doses of the killed vaccine for protection against bovine viral disease and infectious bovine rhinotracheitis.

The timing of vaccinations in  commercial operations can be tricky.

“Fall pregnancy check is not the optimum time to vaccinate these animals. I know it is easy because it fits in with management, but in all species of animals pregnancy is an immunosuppressive period,” Cortese said.

The immune system regulates so there is limited response when cows are vaccinated in early pregnancy.

There is also a risk  the vaccine may cause abortions.


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