High Mountain Disease & PAP Testing
THE FACTS ABOUT PAP AT T-HEART
- We PAP test at our lowest elevation on the ranch at 7,680 feet
- We PAP test our bulls twice, once at weaning and once at yearling, to ensure the best accuracy. If they pass twice in our elevation and environment, we feel more confident they will work for you
- We are dedicated to being your trusted supplier for TRUE HIGH ALTITUDE bulls
High Mountain Disease (HMD) also known as Brisket Disease or Dropsy, is one of the Rocky Mountain region’s most costly diseases. The disease is the result of elevated pulmonary arterial pressure caused from lack of oxygen, and generally affects animals at elevations above 5,000 ft. Cattle differ in how they respond to oxygen shortage. Some are able to tolerate high pressures for a long period of time while others die quickly. HMD is not limited to one sex or breed, and has been found across all breeds including crossbreds.
Dr. Tim Holt, Fort Collins, CO is the consensus world expert on HMD. He’s an Assistant Professor at CSU’s veterinary hospital and also has a private veterinary practice. Dr. Holt is known as the guru of PAP testing. Pulmonary arterial pressure (PAP) scores are obtained by a procedure called ‘rightheart catheterization’. In this procedure, a fine plastic catheter is passed through a needle in the jugular vein, with blood flow into the upper right side of the heart, through a valve into the right ventricle, through another valve, and into the pulmonary artery just short of the branches to the lungs. Pressure waves are observed on a heart monitor and the monitor gives a direct readout of the true average pressure.
“This disease is stimulated by hypoxic stress secondary to high altitude,” Holt explains. “Therefore, it’s impossible at this time to conduct accurate PAP tests in lower elevations.” That’s not to say it’s not done at lower elevations, but this should be kept in mind at all times when testing cattle in lower elevations. The test at lower elevations should be used only to evaluate the cattle in that herd, Holt explains. “It’s not a ‘sellable’ test,” he says. In other words, cattle he’s tested at lower elevations, regardless of how low their PAP score, have still developed HMD or scored a high PAP test when taken to high altitude. Research has shown that the heritability of HMD can be quite high, ranging from 42% to 84%. This indicates that cattlemen can successfully select against the disease by culling cattle with high PAP scores. In efforts to cut losses to HMD, cattlemen should identify those animals, specifically bulls, with high PAP scores and cull them from the herd or avoid adding them to the herd. Dr. Holt assures us that the higher the elevation, the more accurate the test.