One of the biggest problems cattle owners face is Bovine Respiratory Disease (BRD), a complex disease that can affect cattle of any age and breed.
In North America, BRD is the leading cause of illness and death in cattle production systems, according to Dr. Matthew Scott, assistant professor of microbial ecology and infectious diseases at Texas A&M College of Veterinary Medicine & Biomedical Sciences’ Veterinary Education, Research, & Outreach Campus in Canyon, Texas.
“Each year, the United States is estimated to lose approximately $1 billion due to treatment costs and production losses attributed to BRD,” Scott said. “Additionally, we can expect that nearly 20% of all cattle raised for beef production will require clinical treatment for BRD at some point in their lives.”
BRD is considered a multifactorial disease complex because several factors play an important role in its development, including genetic susceptibility, immune system suppression, stress, cohabitation with sick cattle, sudden changes in weather/climate and exposure to bacteria, viruses, and/or parasitic pathogens.
“We in the industry understand the risk factors that lead to increased levels of BRD, but we don’t fully understand how these factors convert to BRD in each animal,” Scott said. “Due to the transmissible nature of BRD, both small and large herds are at risk for development and outbreaks of BRD.”
Another challenge associated with BRD is that as a prey species, cattle naturally try to hide signs of disease, making it difficult to detect disease before it causes severe symptoms.
“One of the first signs of illness, especially BRD, is that cattle will tend to fall behind or isolate themselves from the rest of the group,” Scott said. “Other clinical signs may include fever over 104 F, runny nose and eyes, cough, tilted head/ear position, and signs of depression, such as decreased appetite, slow body movements and a reluctance to stand up.”
When treating BRD, veterinarians focus on the health of both the individual animal and the herd as a whole.
“Veterinarians working with cattle examine and treat diseases, including BRD, in individual cattle, but always with the herd in mind,” Scott said. “Due to the difficulty in diagnosing or predicting BRD before clinical signs, historical clinical information and disease rates within herds play an important role in making decisions about the treatment and management of BRD. “
While there are many unknowns with BRD, there are also several known precautions cattle owners can take to reduce the risk of their animals becoming ill. The first of these precautions can begin as soon as new calves are born.
“At birth, calves depend on colostrum (the first milk produced by a cow) to receive passive immunity against many different diseases,” Scott said. “Calves should receive an adequate amount of colostrum, typically 10% of their body weight, within the first few hours of life.”
As calves grow, their immunity can be further boosted with vaccines, dewormers and proper nutrition.
For cattle of all ages, reducing stress is one of the best ways to reduce the risk of BRD. This may include adequate ventilation, minimal pen movements, low-stress handling techniques, clean bedding, and free access to food and water.
“Historically, BRD was often referred to as ‘shipping fever,’ because cattle transported from cow-calf operations to feeding operations were at increased risk of developing BRD,” Scott said.
By striving to improve the health of livestock before moving and providing several days of rest upon arrival, owners can reduce the risk of developing BRD during the shipping process.
Due to the challenges associated with BRD, many scientists and veterinarians, including Scott, are studying the disease in an effort to find better ways to detect, treat, and prevent the disease.
“While no single approach or drug will solve all cases of BRD, advances in disease prediction models and diagnostics could allow us to anticipate the disease process, perhaps before livestock show signs. illness,” Scott said. “Veterinary involvement and research related to these advances could allow us to significantly reduce the negative impacts associated with BRD.”
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