Prevention is the Key to Reducing Respiratory Problems in calves
Respiratory problems take their toll in calves on dairy operations. In fact, their occurrence is second only to diarrhea disease in dairy calves from birth to weaning. You can’t totally shield calves from every virus and bacterium in their environment, but using preventive management strategies, you can reduce the probability they will be affected.
Respiratory problems cause almost 21 percent of all newborn calf losses in the United States. They are also responsible for significant production losses because heifers that survive respiratory disease almost always perform poorly in terms of growth rates, reproductive rates and milk production. To make matters worse, the incidence of respiratory problems has increased 34 percent over the last 20 years.1
Calves are exposed to the viruses and bacteria that cause respiratory disease as soon as they are born. These pathogens are shed from their mothers and other cows and are quite common in their environment. The causative viral agents include bovine respiratory syncytial virus (BRSV), infectious bovine rhinotracheitis (IBR, or red nose), or the bovine viral diarrhea virus (BVDV). The primary bacterial culprits include Pasteurella multocida, Mannheimia haemolytica, Haemophilus somnus and Mycoplasma.
These viruses and bacteria usually work in concert to cause illness and pneumonia in calves, according to Russ Daly, DVM, DACVPM, associate professor and extension veterinarian at South Dakota State University.
“What we typically see is that the virus helps the bacteria gain a foothold in the calf,” he explained. “These viruses damage the lining of the respiratory system, making it easier for bacteria to get down into the lungs and cause clinical symptoms. For example, the IBR virus paralyzes the cilia in the upper respiratory tract, preventing them from performing their normal function of sweeping out bacteria and expelling them from the body. As a result, the bacteria can access and damage the lungs.”
Because these organisms are everywhere—even in the calf’s own body, it’s not realistic to think you can shield calves from their presence, but you can find ways to minimize them and to bolster the calves’ immune systems to fight them off.
Give them a head start.
The first line of defense is the immune-bolstering colostrum that should be administered to calves immediately after they are born. By providing adequate antibody-rich colostrum when the calf’s immune system is immature, producers can provide passive immunity—and stack the deck a little more in their favor. When analyzing any colostrum program, Daly says four things are crucial: quality, quantity, quickness and cleanliness.
Quality. Calves need to take in good quality colostrum to fight off respiratory disease and intestinal disease, he explained. To test the effectiveness of your colostrum you can measure its specific gravity with a colostrometer, which gives you a picture of the antibody concentration in the milk. An even better measure is the protein level of the calf’s blood.
“Often we test the protein level of the blood serum of the calves 2 to 7 days old,” Daly offered. “If the protein levels are good, we know the calves are absorbing adequate colostrum and antibodies. Colostrometer readings only tell us what is going into the calf. With serum blood protein levels, we can see both the quality of the colostrum and how well it is being absorbed. When producers run into problems with calves, the first thing to check is serum protein levels.”
Quantity. According to current guidelines, calves should receive 3-4 quarts of high-quality colostrum during their first hour after birth. Three additional quarts should be administered within 12 hours.2 Colostrum can be administered using buckets or bottles, or with an esophageal feeder if ingestion is inadequate.
Daly added that pooling colostrum, a common labor-saving practice on many dairies, can be helpful in achieving a minimum, consistent level of antibodies, and in helping calves respond to a wide variety of pathogens. However, he cautions that all colostrum that is pooled should be high quality and collected using sanitary practices. Further, colostrum should not be pooled from first-calf heifers or from cows with health problems, such as Johnes disease.
Quickness. Time is also of the essence when it comes to administering colostrum. “By 24 hours of life, the calf is no longer able to absorb the antibodies from the colostrum,” Daly stated. “So, it is very important to get colostrum into them as soon as possible, preferably within the first hour of life.”
Cleanliness. To minimize contamination, colostrum must be collected from cows that are clean and have clean udders, Daly emphasized. “Any contamination from bacteria, along with inadequate storage techniques, can cause bacteria to proliferate rapidly, which can have adverse effects on the health of the calves, especially their digestive systems.”
He added that colostrum generally keeps for about a week under proper refrigeration. It can also be frozen.
Boost their immune systems further.
There are many vaccines on the market to prevent or reduce respiratory disease in calves. Daly said there are many choices … killed virus versus modified live virus vaccines … intramuscular versus intranasal vaccines … in addition to the many choices of pathogens that are included. That’s why it is important for producers to work closely with their veterinarians in choosing the right products and timing for their specific situations.
Don’t forget the creature comforts.
Such environmental factors as ventilation, bedding, cleanliness and density can also contribute to the calf’s risk of developing respiratory problems.
“We often try to keep the calves in closed-up barns so that we can keep them warm, but we do need air moving through so that respiratory agents don’t stay too long,” Daly asserted. “It’s a fine line we walk. We don’t want to create a drafty or chilly environment, but we need to allow for plenty of fresh air. The design of the barn can be important in allowing adequate ventilation. Increasing the depth of bedding can help by allowing the calves to burrow into it and protect themselves from drafts.”
Three other environmental factors that affect a calf’s risk of developing respiratory problems are pen size, housing temperatures and shared housing, according to Daly. Increasing the pen size can reduce the concentration of microorganisms calves are exposed to, and as a result reduce their risk of contracting respiratory disease. Cold-temperature housing creates a less friendly environment for bacteria and thus can be advantageous if managed properly. Shared housing with older animals (more than two months difference in age) during the first week of life also increases their risk of respiratory infection, as does leaving calves with dams for more than 24 hours post calving. And, of course, providing clean, dry environs for all calves is extremely important to respiratory health.
Ferret it out. Treat it.
Observation is the best way to detect respiratory disease in calves, according to Daly. Look for signs of cough, nasal discharge, runny eyes and fever—even problems in the inner ears, such as infections and drooping ears. Early detection is the key, he explained. .jpg)
“Once the problems have stayed around the lungs for long periods of time, we have less opportunity for the calf to respond to treatment.”
He also emphasized that the disease can develop after calves have been commingled, a fact that is sometimes forgotten.
“It’s important to watch for respiratory signs even after the calves have been removed from their hutches. Sometimes producers think they are out of the woods once calves are put with others, but commingling creates stress. They have to create a social order and find water and feed; that’s one of the triggers we see for disease.”
Respiratory diseases are treated with antibiotics, some of which can provide long-lasting antibiotic levels in treated calves. The regimen is typically 3-4 days; the effects last as long as 7-9 days, Daly said.
“If they still have symptoms after that time, we can assume that the disease has become chronic and is probably not going to respond to treatment very well,” he elaborated. “That’s why early detection and prevention are so important.”
References: 1. Respiratory Disease in Young Dairy Calves. Alvaro Garcia and Russ Daly, South Dakota State University. 05/04/2010. 2. Ibid.
The Do’s and Don’ts of Respiratory Disease in Calves
√ Do provide high quality colostrum
√ Do administer colostrum within an hour of birth
√ Do use proper sanitation in collecting, storing and pooling colostrum
√ Do work closely with your veterinarian to develop a vaccine program
√ Do provide adequate ventilation
√ Do provide adequate bedding to keep calves warm
√ Do provide solid dividers between animals
√ Do observe calves closely
√ Do measure specific gravity of colostrum and blood serum protein in young calves
√ Don’t create an environment with stale air
√ Don’t allow drafty or chilly air to prevail
√ Don’t overcrowd animals
√ Don’t allow nose-to-nose contact
√ Don’t pool colostrum from first-calf heifers or unhealthy animals
√ Don’t skimp on bedding—or pen size
√ Don’t forget to observe calves after they are commingled
√ Don’t wait to administer colostrum
√ Don’t house calves with older animals during their first week of life