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In today's economic environment, you cannot afford excessive morbidity or mortality, but neither can you afford to indiscriminately spend money on treatments. That is why it is smart business to evaluate cattle at time of arrival for relative risk of contracting Bovine Respiratory Disease (BRD). When it comes to effectively controlling BRD, a control strategy can be more cost effective than treatment programs for two reasons. First, cattle may be ill, but are not showing easily identifiable clinical signs. Therefore, control should begin early in high-risk calves, such as on arrival to a new facility, to minimize the development of chronic animals. Second, BRD can cause lung damage without the cattle showing obvious clinical signs of BRD. In a cooperative study conducted by the USDA-Meat Animal Re-search Center and the University of Nebraska Great Plains Veterinary Educational Center, Louis Perino, DVM, PhD, found 68 percent of calves that had never been diagnosed with BRD had lung lesions at slaughter that indicated pneumonia. Researchers also found that the presence of lung lesions at slaughter was associated with a significant negative impact on average daily gain. (See related story on page 16). The key to controlling BRD is learning to properly evaluate cattle on arrival, according to Kelly Lechtenberg, DVM, PhD, a practitioner and veterinary consultant with Midwest Feedlot Services Inc. in Oakland, Neb. He uses the following criteria to help determine if a BRD control program should be considered: Commingling - if cattle are from multiple sources like auction barns. The more sources, the higher the risk for BRD. Physiologic and Metabolic Status - if calves are newly weaned. Cattle weaned within 14 days are at the highest risk for BRD. The greater the time from weaning, the less the risk. Cattle that have been weaned at least 45 days prior to shipment to a feedlot seldom develop BRD infections, in Lechtenberg's experience. Environmental Stress - if the weather is cold and wet. The more miserable the weather, the greater the likelihood cattle will get sick because they are diverting energy from their immune systems to maintain body heat. In addition, when cattle are huddled and listless because they are fighting the elements, it is harder to spot the ones that are sick with BRD, which can further delay needed therapy. Pregnancy Status - if they have recently aborted a calf. Since their immune systems are compromised through the pregnancy or abortifacient used, they are at increased risk for BRD.
Bulls in Arrival Group - if cattle were castrated on arrival or at shipping. Lechtenberg says his experience has been that recently castrated bulls are nearly four times more likely than steers to develop BRD. Cattle Shrink - Lechtenberg says another way to evaluate cattle is percent shrink. But even though this is an objective measure, using it to evaluate risk for BRD requires a thorough knowledge of the cattle's history. Cattle may exhibit shrink, yet have no noticeable effect on the immune system, he says. But if you use shrink, along with environmental factors, history and management practices to evaluate cattle on arrival, you can make a better clinical assessment of cattle and help determine if they are in early stages of BRD. Facility design, processing delays and availability of labor to properly observe and treat sick cattle may also influence the need for early control of BRD. In order to do a better job of consistently evaluating the risk level of a group of cattle, or to learn more about controlling BRD, consult your veterinarian. The information contained in this article is courtesy of Elanco Animal Health |
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