CALF_News_Feb_March_2019

23 CALF News • February | March 2019 • www.calfnews.net 3-5 percent is common in high mountain ranges. Additionally, PH-related death loss has doubled in feedlot cattle over the last decade. Dr. Bob Hough, in a July 2018 Western Livestock Journal article, said losses are coming at the end of the feeding period, when animals are close to ready for harvest. Why do we see more? There are two important factors that figure into the increasing feedlot problem. One is the additional weight the industry is currently targeting for fed cattle. Cheap gains, efficient cattle and an acceptance of heavier carcasses line up to make a fed animal far larger than only a few years ago. According to Hough, increased carcass weight is being supported by rela- tively stable-sized organs. Lung capacity becomes proportionally smaller in rela- tionship to body weight, stressing organs and increasing the risk of PH. Second, genetics is becoming a larger factor in PH deaths since the advent of successful branded-beef programs. The industry is using ever-increasing numbers of straight-bred British cattle, which were developed at low elevations. The decrease of heterosis, along with heavier fed weights, is helping increase the number of PH deaths. The susceptibility to PH is, indeed, highly heritable. It is a complex trait influenced by a large number of genes. Pulmonary arterial pressure (PAP) is being studied at the University of Wyoming and Colorado State University (CSU). CSU has determined that PAP’s heritability is greater than heritability for weaning and yearling weights. That’s an amazing discovery, considering the repercussions of PH. The good news is, there is a push to develop an EPD for susceptibility to PH. Finding a solution With an increasing number of fed cattle that are straight-bred Angus, the American Angus Association has been working with CSU to develop calcula- tions for a PAP EPD. PAP tests are available and highly recommended for bull buyers running cows in high altitude areas. Tim Holt, a CSU veterinarian, says tests are ideally done at a minimum of one year of age on cattle that have spent three to six weeks at 6,500 feet elevations. A catheter is inserted into the jugular vein, threaded into the heart’s right ventricle and into the main pulmonary artery. A score lower than 41 is considered acceptable. Of course, it is recommended that high-scoring animals not be used for breeding stock. Because PH is a somewhat localized problem, federal research grant coor- dinators have been reluctant to fund studies, slowing progress in solving this growing dilemma. Elimination of expanding diseases may never totally come about, but we can be grateful for private businesses, breed associations, educational and research institutions that never give up searching for better health for our nation’s cattle herd.  The Cellerate Yeast Solutions ® portfolio of products is only as good as our understanding of your operation. That’s why Phibro offers more than just high-quality yeast products. We build lasting relationships with our customers, provide extensive expertise and offer solutions that are backed by science. Practical solutions for healthy animals and a healthy bottom line. the most POWERFUL supplement is PARTNERSHIP Talk With a Phibro Expert 800-677-4623 | pahc.com ———————— Also providing you ———————— Terramycin ® AB20 ® GemStone ® Bloat Guard ®