Kenny Barrett, Jr: Why vaccinated calves get sick | TSLN.com

Kenny Barrett, Jr: Why vaccinated calves get sick

Kenny Barrett Jr., DVM, MS

The thought of smothering a choice cut of beef in herbs has never appealed to me. I prefer the simple time-tested dry rub of garlic salt and freshly ground black pepper. As a result, I ordered seafood and pasta while dining with friends at a local Italian restaurant. The conversation was mixed and unscripted but eventually centered on beef production and animal health.

One person commented that it didn’t matter which modified-live viral (MLV) vaccines a producer chose. This was a statement they had heard another individual make. I can assure you the pharmaceutical companies would like to argue differently.

However, between the MLV vaccines, it would be unlikely for the average rancher to observe a difference between vaccines. That does not mean there is no difference. I think it indicates all the MLV vaccines are pretty good in the ranch setting.

Range cattle make poor pneumonia studies because ranchers rarely have serious pneumonia outbreaks due to management methods. During the course of the average year it is pretty hard to determine a difference between five and seven sick calves.

To reach an evidence-based recommendation we rely on feedlot studies to help us determine the true difference between these vaccines. Unfortunately it is all too easy to allow historical averages of disease events to pervert scientific reasoning.

Ranchers occasionally make the mistake of blaming the chosen vaccine for a disease outbreak when the problem is much more complicated.

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“Doc, I gave all the shots you recommended and I still had sick calves.” Eventually, every veterinarian hears this comment from a frustrated client.

Why do vaccinated cattle get sick? Sometimes vaccinated animals don’t respond to vaccines the way we want. As a veterinary friend of mine likes to say “you can vaccinate a watermelon but you can’t immunize one.” In other words, just because an injection is given doesn’t mean the animals are protected.

The outcome of disease challenge is the result of the animal, environment and pathogen interacting together. Vaccinations need to be appropriate, timely and administered correctly. Ranchers need to assure the animals have all the tools they need to respond to both the vaccine and any potential disease challenge. Vaccination needs to occur in a low-stress environment using low-stress technique.

From the animal’s perspective they need all the pieces of the puzzle. The immune system requires a specific sack of groceries that includes proteins, energy, vitamins and trace minerals. The puzzle can still be put together with pieces missing – but is still lacking in the end.

Ranchers can expect the same outcome when vaccinating cattle that don’t have adequate nutrition. With a nutritional deficiency we might see twelve sick calves when proper nutrition may have limited the illness to three.

Environmental stress also has a negative effect on response to vaccination. Increased levels of cortisol resulting from stress hamper the immune system’s response to disease and vaccination both. It is like putting the puzzle together with boxing gloves.

Common stressors include weaning, shipping and commingling. Ranchers should vaccinate three to four weeks prior to weaning to limit the effect of these stressors. Whenever possible, castration and dehorning need to occur at branding or before. Separating vaccination from these common stressors allows the animal to more fully respond to the vaccination.

When vaccines have to be given at weaning, we need to be aware of environmental conditions. Dust, high wind, temperature extremes and large temperature fluctuations are stressful and impede the immune system. Many weaning techniques have been investigated. Typically the least stressful methods require the strongest fences and the most labor. No system will work the same from one producer to the next. It is important to work with your veterinarian to devise the optimal system for you.

Timing of the vaccinations and any boosters injections is critical. An obvious example is summer pneumonia. We can’t expect a preweaning shot to have any impact on summer pneumonias that occur one to two months prior to weaning. In that case we need to rely on vaccines administered at branding.

A more obscure example is with Pasturella vaccines. In my experience it is pretty difficult to get any immune response to Pasturella vaccines during the first four months of life. You can thank your cows’ colostrum for that. In contrast, modified-live 5-way viral vaccines given at branding don’t produce much of a measurable immune response. But, they do create a priming effect and stimulate a memory that greatly improves the immune response to a viral challenge.

The vaccines you choose to administer to your cattle are important. How and when those vaccines are administered is just as important. Ranchers need to consult their veterinarian to fully develop and implement an effective herd health plan. With weaning underway, try to remember these principles when administering your fall vaccines. Immunize the calves and avoid vaccinating a watermelon.

The thought of smothering a choice cut of beef in herbs has never appealed to me. I prefer the simple time-tested dry rub of garlic salt and freshly ground black pepper. As a result, I ordered seafood and pasta while dining with friends at a local Italian restaurant. The conversation was mixed and unscripted but eventually centered on beef production and animal health.

One person commented that it didn’t matter which modified-live viral (MLV) vaccines a producer chose. This was a statement they had heard another individual make. I can assure you the pharmaceutical companies would like to argue differently.

However, between the MLV vaccines, it would be unlikely for the average rancher to observe a difference between vaccines. That does not mean there is no difference. I think it indicates all the MLV vaccines are pretty good in the ranch setting.

Range cattle make poor pneumonia studies because ranchers rarely have serious pneumonia outbreaks due to management methods. During the course of the average year it is pretty hard to determine a difference between five and seven sick calves.

To reach an evidence-based recommendation we rely on feedlot studies to help us determine the true difference between these vaccines. Unfortunately it is all too easy to allow historical averages of disease events to pervert scientific reasoning.

Ranchers occasionally make the mistake of blaming the chosen vaccine for a disease outbreak when the problem is much more complicated.

“Doc, I gave all the shots you recommended and I still had sick calves.” Eventually, every veterinarian hears this comment from a frustrated client.

Why do vaccinated cattle get sick? Sometimes vaccinated animals don’t respond to vaccines the way we want. As a veterinary friend of mine likes to say “you can vaccinate a watermelon but you can’t immunize one.” In other words, just because an injection is given doesn’t mean the animals are protected.

The outcome of disease challenge is the result of the animal, environment and pathogen interacting together. Vaccinations need to be appropriate, timely and administered correctly. Ranchers need to assure the animals have all the tools they need to respond to both the vaccine and any potential disease challenge. Vaccination needs to occur in a low-stress environment using low-stress technique.

From the animal’s perspective they need all the pieces of the puzzle. The immune system requires a specific sack of groceries that includes proteins, energy, vitamins and trace minerals. The puzzle can still be put together with pieces missing – but is still lacking in the end.

Ranchers can expect the same outcome when vaccinating cattle that don’t have adequate nutrition. With a nutritional deficiency we might see twelve sick calves when proper nutrition may have limited the illness to three.

Environmental stress also has a negative effect on response to vaccination. Increased levels of cortisol resulting from stress hamper the immune system’s response to disease and vaccination both. It is like putting the puzzle together with boxing gloves.

Common stressors include weaning, shipping and commingling. Ranchers should vaccinate three to four weeks prior to weaning to limit the effect of these stressors. Whenever possible, castration and dehorning need to occur at branding or before. Separating vaccination from these common stressors allows the animal to more fully respond to the vaccination.

When vaccines have to be given at weaning, we need to be aware of environmental conditions. Dust, high wind, temperature extremes and large temperature fluctuations are stressful and impede the immune system. Many weaning techniques have been investigated. Typically the least stressful methods require the strongest fences and the most labor. No system will work the same from one producer to the next. It is important to work with your veterinarian to devise the optimal system for you.

Timing of the vaccinations and any boosters injections is critical. An obvious example is summer pneumonia. We can’t expect a preweaning shot to have any impact on summer pneumonias that occur one to two months prior to weaning. In that case we need to rely on vaccines administered at branding.

A more obscure example is with Pasturella vaccines. In my experience it is pretty difficult to get any immune response to Pasturella vaccines during the first four months of life. You can thank your cows’ colostrum for that. In contrast, modified-live 5-way viral vaccines given at branding don’t produce much of a measurable immune response. But, they do create a priming effect and stimulate a memory that greatly improves the immune response to a viral challenge.

The vaccines you choose to administer to your cattle are important. How and when those vaccines are administered is just as important. Ranchers need to consult their veterinarian to fully develop and implement an effective herd health plan. With weaning underway, try to remember these principles when administering your fall vaccines. Immunize the calves and avoid vaccinating a watermelon.

kenny barrett jr. is a veterinarian at the belle fourche veterinary clinic in belle fourche, sd. do you have questions you would like to see addressed in an upcoming installment of cow tales? send kenny a note at bfvc@live.com with “cow tales” in the subject.

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