ANGUS BEEF BULLETIN EXTRA
February 8, 2022 | Vol. 15 : No. 2
Congestive Heart Failure in Fed Cattle: It’s Something Different
Brisket disease affects the heart’s right ventricle; congestive heart failure, the left.
During the past several years, there has been an increased incidence of bovine congestive heart failure among feedlot cattle. The disease is pretty much untreatable, and the outcome is fatal. That’s bad enough, but what really frustrates cattle feeders and their veterinarians is that no direct cause has been identified. According to University of Nebraska veterinarian Brian Vander Ley, however, researchers are narrowing the list of suspects. Investigation is underway to determine if susceptibility is linked to genetic risk factors.
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Clinical symptoms of feedlot congestive heart failure are much the same as those associated with brisket disease and typically include edema under the jaw and in the abdomen, but particularly in the brisket area. |
Vander Ley spoke during the Range Beef Cow Symposium, hosted Nov. 16-17, 2021, in Rapid City, S.D., explaining how the congestive heart failure seen in feedlots appears to be something other than brisket disease. Sometimes called high-mountain disease, brisket disease is a malady that affects genetically susceptible cattle managed at elevations above 5,000 feet (ft.). It can lead to congestive heart failure, but Vander Ley thinks the disease now found more frequently in feedlot animals is something different.
There are multiple ways that congestive heart failure can occur, but Vander Ley said they typically fit within one of “three big buckets.”
No. 1: Diastolic dysfunction is the inability of the heart to fill with blood when resting between heartbeats, and not enough blood is pumped to meet metabolic needs of the body. This most often happens because the sac around the heart becomes filled with fluid due to hardware disease or because that space is occupied by a cancerous growth.
No. 2: Systolic dysfunction is a weakening of the heart’s ability to pump. It can be caused by ionophore poisoning or Histophilus somni infections that damage the heart muscle.
No. 3: Constriction of the pulmonary blood vessels and resistance to blood flow overloads the heart. Examples include resistance to blood flow through the lungs of cattle that are exposed to low-oxygen environments like those found at elevations above 5,000 ft. (brisket disease) and in calves that have chronic bovine respiratory disease (BRD).
“But the disease we’re seeing in feedlots doesn’t quite fit any of those buckets,” stated Vander Ley.
Clinical symptoms of feedlot congestive heart failure are much the same as those associated with brisket disease and typically include edema under the jaw and in the abdomen, but particularly in the brisket area. Affected animals often exhibit lethargy and weakness, and the jugular vein becomes distended. Vander Ley said caretakers typically report a “broken behind the withers” sway-backed appearance, along with a tell-tale “orange Kool-Aid®” diarrhea.
“The heart failure we’re seeing in feedlots affects the left ventricle, and that’s different from [brisket disease], which results in right heart failure. That’s why we suspect that what we’re seeing in feedlots is not the same thing as what we see at high elevation.” — Brian Vander Ley
“But the heart failure we’re seeing in feedlots affects the left ventricle, and that’s different from [brisket disease], which results in right heart failure. That’s why we suspect that what we’re seeing in feedlots is not the same thing as what we see at high elevation,” explained Vander Ley, also noting that heart failures have occurred in feedlots located well below 5,000 ft. of elevation.
According to Vander Ley, there has been much speculation associated with feedlot heart failures. Early impressions were that it occurred only late in the feeding period, but it has been seen in newly arrived cattle, too. It was thought that susceptibility might be related to animal heart and lung capacity, cattle nutrition management resulting in animals being “pushed too hard,” or prior respiratory disease, but none of those suspected predisposing factors have been proven. One consistent observation among these cases of feedlot heart failure is that they tended to occur among cattle from the same sources over time, strongly suggesting that genetics might be involved.
Vander Ley said investigation has subsequently identified two potential genetic risk factors. One factor is thought to increase the odds of disease by eight times and the other by seven times. Animals inheriting both genetic factors are 15 times more likely to develop heart disease, but carrying both factors does not guarantee it.
“One factor is very prevalent among Angus, both red and black; and the other is prevalent among all British breeds of cattle,” reported Vander Ley. “The genetic factors show recessive inheritance patterns, which is encouraging. They should be manageable.”
While management of bovine congestive heart failure occurring in fed cattle seems likely, Vander Ley said research continues to validate using potential tools for genetic selection.
Editor’s note: Troy Smith is a cattleman and freelance writer from Sargent, Neb. Photo by Matt Caldwell.
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