Analyzing Your Animal-Health Program
How are modified-live virus and killed-virus vaccines different? Why do some require a two-dose regimen? And which vaccinations are important for calves?
With the arrival of the preconditioning and weaning period, it's a good time to brush up on animal health and vaccination basics. North Dakota State University (NDSU) Extension veterinarian Charlie Stoltenow and Pfizer Animal Health senior technical veterinarian Gerald Stokka offer these answers to some common calf-health questions.
What's the difference between a modified-live virus (MLV) and a killed-virus vaccine?
Just as its names implies, a MLV is a live-virus vaccine but its virulence has been reduced to a level that shouldn't cause disease. Meanwhile, a killed vaccine is considered safer and more stable because it isn't living.
While MLV and killed vaccines can both be effective against viral respiratory pathogens, Stoltenow says most research indicates the MLV produces a stronger immune response.
Why is it important that calves receive two doses of vaccine?
Since a single dose may not be enough to produce an adequate level of herd immunity, North Dakota's Stoltenow says giving a second dose is a kind of "insurance policy." He emphasizes that two doses are especially important when administering killed vaccines because they don't produce as strong an immune response as MLV vaccines.
What vaccinations are important for calves?
Stoltenow advocates vaccinating calves against what he calls "the big four." These are: infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), bovine respiratory syncytial virus (BRSV) and parainfluenza-3 virus (PI3).
"These vaccinations set it up so calves can better fend off other disease threats," he says. Additionally, he recommends producers consider vaccinating against clostridial diseases and Mannheimia.
What else is needed for an effective animal-health program?
Stoltenow says nutrition is key. "All my health programs start with nutrition," he says. "We can't look at vaccines as a panacea. If an animal doesn't have an immune system, the vaccine can't work miracles."
Stokka believes a ration that attracts calves to the bunk and meets their nutritional requirements is essential. He says new calves aren't likely to have high consumptions of the starter ration in the first week; therefore, the ration must contain enough nutrients in a small amount. Also, while long-stem grass hay is a good appetizer for calves, it isn't likely to fully meet their nutrient requirements.
New calves also are likely dehydrated, Stokka says, so special attention is needed to ensure calves find the water source and actually drink.
Equally important, Stokka maintains, is parasite control. "Don't overlook the interaction of parasites with the immune system. Most calves raised on grass will have some level of parasitism; internal parasites suppress appetite as well as the immune response. For calves to perform well and stay healthy, they must be free of these internal organisms," he says.
Why do vaccines sometimes fail?
Stoltenow says there can be several reasons: the animal may already be incubating the disease or there may be passive transfer interference.
Human error also can be blamed. Sometimes the wrong vaccine is given for the condition, the vaccine experienced temperature abuse or was outdated, or it was incorrectly administered. For instance, if the shot is given at the top of the neck, it can't get into the blood supply.
Most commonly, according to Stoltenow, is that the animal does not have the ability to mount an appropriate response. He says this can be influenced by factors such as stress or poor nutrition.
What causes shipping fever?
When calves leave the ranch and head to the feedlot, we often hear the term "shipping fever." Stokka attributes this stress-induced sickness to risk factors such as partial failure of passive transfer at the ranch, and cattle transportation and marketing that results in additional stress, shrink and commingling.
Stoltenow says the best strategy in treating sick calves is to catch them early and treat them immediately. He suggests this rule of thumb: "The first sign of disease is depressed appetite. If calves are not treated early in the disease cycle and have progressed to the runny-nose stage, it's nearly too late."
For high-risk calves -- those commingled or without proper vaccinations -- Stoltenow proposes "metaphylaxis." This consists of treating animals with antibiotics at label rates before they become ill and as they enter backgrounding or feedlot settings. Stoltenow says, "It's short term. The antibiotics won't do anything to a virus, but they fight bacteria and reduce the chances for the major pathogens to team up with viruses to cause disease."
How are modified-live virus and killed-virus vaccines different? Why do some require a two-dose regimen? And which vaccinations are important for calves?
With the arrival of the preconditioning and weaning period, it's a good time to brush up on animal health and vaccination basics. North Dakota State University (NDSU) Extension veterinarian Charlie Stoltenow and Pfizer Animal Health senior technical veterinarian Gerald Stokka offer these answers to some common calf-health questions.
What's the difference between a modified-live virus (MLV) and a killed-virus vaccine?
Just as its names implies, a MLV is a live-virus vaccine but its virulence has been reduced to a level that shouldn't cause disease. Meanwhile, a killed vaccine is considered safer and more stable because it isn't living.
While MLV and killed vaccines can both be effective against viral respiratory pathogens, Stoltenow says most research indicates the MLV produces a stronger immune response.
Why is it important that calves receive two doses of vaccine?
Since a single dose may not be enough to produce an adequate level of herd immunity, North Dakota's Stoltenow says giving a second dose is a kind of "insurance policy." He emphasizes that two doses are especially important when administering killed vaccines because they don't produce as strong an immune response as MLV vaccines.
What vaccinations are important for calves?
Stoltenow advocates vaccinating calves against what he calls "the big four." These are: infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), bovine respiratory syncytial virus (BRSV) and parainfluenza-3 virus (PI3).
"These vaccinations set it up so calves can better fend off other disease threats," he says. Additionally, he recommends producers consider vaccinating against clostridial diseases and Mannheimia.
What else is needed for an effective animal-health program?
Stoltenow says nutrition is key. "All my health programs start with nutrition," he says. "We can't look at vaccines as a panacea. If an animal doesn't have an immune system, the vaccine can't work miracles."
Stokka believes a ration that attracts calves to the bunk and meets their nutritional requirements is essential. He says new calves aren't likely to have high consumptions of the starter ration in the first week; therefore, the ration must contain enough nutrients in a small amount. Also, while long-stem grass hay is a good appetizer for calves, it isn't likely to fully meet their nutrient requirements.
New calves also are likely dehydrated, Stokka says, so special attention is needed to ensure calves find the water source and actually drink.
Equally important, Stokka maintains, is parasite control. "Don't overlook the interaction of parasites with the immune system. Most calves raised on grass will have some level of parasitism; internal parasites suppress appetite as well as the immune response. For calves to perform well and stay healthy, they must be free of these internal organisms," he says.
Why do vaccines sometimes fail?
Stoltenow says there can be several reasons: the animal may already be incubating the disease or there may be passive transfer interference.
Human error also can be blamed. Sometimes the wrong vaccine is given for the condition, the vaccine experienced temperature abuse or was outdated, or it was incorrectly administered. For instance, if the shot is given at the top of the neck, it can't get into the blood supply.
Most commonly, according to Stoltenow, is that the animal does not have the ability to mount an appropriate response. He says this can be influenced by factors such as stress or poor nutrition.
What causes shipping fever?
When calves leave the ranch and head to the feedlot, we often hear the term "shipping fever." Stokka attributes this stress-induced sickness to risk factors such as partial failure of passive transfer at the ranch, and cattle transportation and marketing that results in additional stress, shrink and commingling.
Stoltenow says the best strategy in treating sick calves is to catch them early and treat them immediately. He suggests this rule of thumb: "The first sign of disease is depressed appetite. If calves are not treated early in the disease cycle and have progressed to the runny-nose stage, it's nearly too late."
For high-risk calves -- those commingled or without proper vaccinations -- Stoltenow proposes "metaphylaxis." This consists of treating animals with antibiotics at label rates before they become ill and as they enter backgrounding or feedlot settings. Stoltenow says, "It's short term. The antibiotics won't do anything to a virus, but they fight bacteria and reduce the chances for the major pathogens to team up with viruses to cause disease."
