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Bovine respiratory disease in cow-calf herds

Heather Smith Thomas for Progressive Cattleman Published on 24 January 2018
A calf with BRD and nasal discharge.

Often called pneumonia or shipping fever, bovine respiratory disease (BRD) is costly for the livestock industry, especially in feedlot cattle, but also a concern in cow-calf herds.

Producers seek better ways to prevent, diagnose and treat BRD.

Prevention

Dr. Andi Lear, food animal field services, University of Tennessee, says minimizing stress is very important, along with a good vaccination program. Using appropriate vaccine protocols to prevent BRD, blackleg, etc., in calves is crucial, along with trying to minimize stress when working them.

“Take care of castration, dehorning, pouring for parasites, etc., prior to weaning. Never wean on diesel fuel – meaning don’t wean, vaccinate and haul calves away in a truck on the same day. Make sure calves have been exposed to vaccine and have some immunity prior to getting on a truck,” says Lear.

If you do all stressful procedures while they are still on the cow, it’s not nearly as stressful because Mom is there to comfort them after they come out of the chute. “Cold-turkey weaning on top of vaccinating can result in more sickness,” she explains.

Dr. Chris Chase, department of veterinary and biomedical sciences, South Dakota State University, says to prevent pneumonia in young calves, we need to immunize the cow so the cow can provide good colostrum, with adequate antibodies for infectious bovine rhinotracheitis, BVD and bovine respiratory syncytial virus.

“Vaccinating at preg-check time or closer to calving with inactivated vaccines that have a little more antigen may be better in terms of improving colostrum than using MLV vaccines,” says Chase. Once calves are born, make sure they get colostrum on time.

“Most cow-calf producers don’t use intranasal vaccines on baby calves because, unless they have a major problem with pneumonia in very young calves, they can wait and give calves their first vaccinations at branding age,” he says.

With a pneumonia problem, accurate diagnosis is important to find out if it is caused by viruses like bovine respiratory syncytial virus, bacteria like mannheimia or some other pathogen to determine the best approach for prevention. Don’t just shoot in the dark.

“If we know there’s a problem with mannheimia, we can vaccinate for that at branding. Otherwise, there is no sense in giving calves that vaccine at that age,” he says.

The important thing is to have the cows well vaccinated. This is crucial for two reasons. The cow can then produce antibodies in its colostrum and also has good immunity itself and won’t be susceptible to transmission from a calf if you vaccinate calves while they are still on the cow.

“We’ve seen cases where people vaccinated calves that were suckling poorly vaccinated cows, and the cows got sick. Any time you vaccinate calves prior to weaning, there will be some exposure for their mothers, even though there isn’t much shedding from the calves.

We documented one case in North Dakota where the cows had poor vaccination history; the producer gave the calves MLV vaccine at weaning, and then the calves went through a fence and got back with the cows. About 25 percent of those cows aborted from IBR [infectious bovine rhinotracheitis] from the vaccine given to their calves,” Chase says.

When cattle are stressed, it’s not a good time to vaccinate. With high-risk calves, some people use intranasal vaccines, and some use an immune-boosting product. “But it’s better to wait until they are over the stress, eating and drinking well, and then vaccinate.

Dehydration is another risk factor, especially in transported cattle. Cattle are four times more likely to suffer respiratory disease if they are dehydrated,” he explains.

In baby calves stressed and dehydrated from scours, we also see higher incidence of BRD. “This is why having adequate colostrum is important, to give young calves some protection. We also know that when a calf is chilled at birth, ability to absorb colostrum is diminished. Then, if the calf gets diarrhea and becomes dehydrated, it is more vulnerable to pneumonia as well,” he says.

Keep young calves from getting chilled with shelter (out of the wind), adequate bedding in cold weather, etc. This doesn’t mean an enclosed barn with inadequate ventilation. The air is then saturated with ammonia and pathogens. The ammonia is irritating to airways and lungs.

Treatment

“The important thing when calves get sick is to be able to recognize it early,” says Lear. “This is sometimes challenging because prey animals like cattle tend to look alert when they see someone and may not show as many signs of being sick.” If you can observe them before they see you, there’s more chance you’ll be able to notice if one is dull and droopy or hanging back from the herd.

“If you see one or two with droopy ears, lethargy, snotty nose, etc., immediate treatment is important. The choice of antibiotic is something you should discuss with your veterinarian, however,” she says. You’ll need an accurate diagnosis (to know if pneumonia is viral or bacterial and what type of bacteria might be involved).

Antibiotics will not treat a viral infection, but the calf will need good supportive treatment and possibly an antibiotic to head off secondary bacterial infection.

“The best way to deal with viral pneumonia is try to prevent it with low-stress handling and vaccination, and good supportive care if a calf does get sick. Antibiotics can help take care of any secondary bacterial infection that often follows the viral infection,” Lear says. The viral pneumonia weakens the calf’s immune system, and the animal is more vulnerable to opportunistic secondary bacterial infection.

Keep the calf warm and dry, eating and drinking, and discuss treatment with your veterinarian. The calf will probably need antibiotics and possibly an anti-inflammatory. If anti-inflammatory medication helps the calf feel better enough to eat and drink, this is a big help.

“There is a huge interaction between the gut and respiratory system,” Chase says. If the gut is healthy, and the calf is eating and drinking, the immune system is stronger; the calf is more able to handle challenges to the respiratory system. Some studies have shown beneficial results using probiotics since gut health and respiratory health go together.

Dehydration makes pneumonia worse. “Immune cells must be able to move from point A to point B in the body; if they can’t get there because there’s not enough fluid, you have a serious problem.” Every bodily function depends on adequate fluid in and around the cells. Keeping the animal eating and drinking is crucial.

diseased lungTreatment for respiratory disease may include medication to reduce pain, fever and inflammation. If the animal can keep eating and drinking because it feels better, it can fight off disease better. “There are some types of oral aspirin and also a drug called Meloxicam that can be used in cattle as an anti-inflammatory,” says Chase.

“We’ve learned a lot about the benefits of anti-inflammatories. When an animal hasn’t eaten for a while and suddenly loads up, flora in the gut changes.” Sometimes they produce harmful compounds, and if their cell walls are gram-negative and a lot of those microbes die, they may release toxins that cause inflammation in the gut.

“If that inflammation spills over into the rest of the body to cause inflammatory response, this has an effect on the lungs. The advantage of oral products like Meloxicam or aspirin (versus Banamine, which is injected) is that you are actually getting it into the area where it is needed if there is gut inflammation.” Banamine can be helpful, however, in lung tissue.

“When dealing with bacterial pneumonia, we use antibiotics,” says Chase. “Many producers today use Draxxin or one of the other broad-spectrum antibiotics. It is crucial to identify the pathogen so you have an idea what it would be sensitive to, and pick the right antibiotic,” he says. You should be working with your veterinarian on diagnosis. For viral pneumonia, the best strategy is just supportive treatment – keeping the calf warm and dry, and hydrated.

“If we just pump antibiotics into sick calves, they may not do very well,” he says. Antibiotics may adversely affect the gut microbes, and the calf may need probiotics or even ruminal transplant (in an older calf) to get things back on track again.  end mark

PHOTO 1: A calf with BRD and nasal discharge.

PHOTO 2: A diseased lung removed from a calf at necropsy. Photos provided by Dr. Andi Lear.

Heather Smith Thomas is a freelance writer based in Salmon, Idaho. Email Heather Smith Thomas.

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