CALF_News_August_September_2021

39 CALF News • August | September 2021 • www.calfnews.net By Gilda V. Bryant Contributing Editor hipping fever or bovine respiratory disease (BRD) is one of the most compli- cated illnesses to treat in cattle. Several factors, including viral and bacterial pathogens, environmental and weather stress and poor nutrition, increase BRD cases. Smart producers use innovative management strategies to ensure cattle are healthy. Jason Smith, Ph.D., beef specialist with Texas AgriLife Extension, says some common viruses that cause BRD are bovine viral diarrhea virus (BVDV) and infectious bovine rhinotracheitis (IBR). The major bacterial culprits are Pasteurella multocida, Mannheimia hae- molytica and Histophilus somni . Shipping fever symptoms cause animals to display lethargy and droop- ing ears. They hang their heads, cough and pant with open-mouth breathing. Excessive nasal discharge and runny, crusty eyes are other indicators. Cattle lack appetites and usually develop a fever. Early identification of sick animals is crucial to prevent mortality. “Stress, related to management, weather or environment is implicated in almost all occurrences of respiratory dis- ease,” Smith says. “Management stresses often include weaning, processing, transporting and dehydration – all in one day. That’s a huge amount of stress on animals. Stress can overwhelm the animals’ immune systems, making them more susceptible to [illness].” More outbreaks of BRD occur during the fall when hot daytime temperatures cool off significantly at night or when cattle experience extreme summer or winter temperatures. Excessive moisture, mud or large amounts of dust also con- tribute to stress that allows pathogens an opportunity to drive respiratory disease. Intervention strategies can reduce BRD cases. “For most stocker and feedyard operations, that starts at the cow-calf level,” Smith asserts. “Preven- tion includes a comprehensive and effec- tive vaccination program, which protects cattle from the viral and bacterial patho- gens that cause respiratory disease. “It’s critical for the operation’s veteri- narian to be involved in that process. Vaccines need to be handled, stored and administered properly in order to be effective.” Providing good nutrition is another essential practice that aids in preventing BRD. A complete mineral program and feeds that contain protein and energy during pregnancy are vital. An appropri- ate diet maximizes colostrum quality and quantity, which beefs up the calf ’s immune system. Trace minerals, especially copper, zinc, selenium and manganese, enable the animal’s immune system to mount an effective immune response to pathogens. Injectable trace minerals may help cattle of unknown histories that are likely mineral deficient. Injectables boost the animals’ immunity until the feedyard nutritionist can correct trace mineral deficiencies through the diet. However, injectables are not a replacement for good nutrition; producers should strictly follow label instructions. Studies suggest that vitamin E, an antioxidant, also minimizes health issues in newly received feedyard cattle. John Richeson, Ph.D., feedyard research expert at West Texas A&M University, says high-risk cattle, sold through the auction market system, usu- ally arrive from smaller operations and were separated from their dam the day of or day before they were sold. They are lightweight, probably unvaccinated and the males are not castrated. Richeson recommends metaphylaxis, one of the most proven tools producers can use to control a BRD outbreak. This drug management practice utilized in identified high-risk feedyard calves saves money because operators do not have to treat the entire truckload of animals. SMART STRATEGIES PREVENT Continued on page 41 