Significant losses due to bovine respiratory disease (BRD) occur in the U.S. beef industry with estimated annual losses at $1 billion (Jim et al 1993). BRD accounts for approximately 75% of morbidity and 50% of mortality in feedlots despite significant improvements in vaccine and antibiotic therapy. A rapid and sensitive diagnostic method for BRD is needed to reduce the significant economic loss from this disease. Ekips Technologies, Inc. is devoted to developing a method of assessing respiratory health on the basis of exhaled immune system biomarkers. The objective of this Phase I Project is to adapt our existing technology to demonstrate rapid measurement of ethane in the expired breath of healthy bovine and bovine experimentally infected with a known BRD pathogen. OBJECTIVES: Significant losses due to bovine respiratory disease (BRD) occur in the U.S. beef industry with estimated annual losses at $1 billion (Jim et al 1993). BRD accounts for approximately 75% of morbidity and 50% of mortality in feedlots despite significant improvements in vaccine and antibiotic therapy. Although the medical costs attributed to BRD are substantial (Martin et al 1982; Perino 1992), the economic impact of BRD on animal performance, carcass merit, and meat quality are likely even more devastating. Evidence of subclinical disease at harvest indicates current management techniques are inadequate. A report (Whittum et al 1996) demonstrated that 72% of steers examined (n=469) had pulmonary lesions at harvest, even though only 35% were treated for prior respiratory disease. In another report (Gardner et al 1999), lung lesions were present in 33% of all lungs evaluated at harvest, with lesions distributed almost equally between treated (37%) and untreated (29%) cattle. Additionally, steers with lung lesions plus active lymph nodes had $73.78 less net return, of which 21% was due to medicine costs and 79% due to lower carcass weight (8.4% less) and lower quality grade (24.7% more U.S. Standards). This is additionally supported by the correlation of lower marbling scores in BRD calves with reduced carcass grade and net return per head (Stovall et al 2000) and a 12% greater daily gain and more U.S. Choice carcasses in "healthy" steers versus cattle identified as "sick" at some point during the finishing period (McNeill et al 1996). This negative impact on carcass traits 200 days after receiving at the feedlot illustrates the importance of BRD. A rapid and sensitive diagnostic method for BRD is needed to reduce the significant economic loss from this disease. Current methods of diagnosis primarily involve subjective signs and are clearly inadequate. "Pen riders" monitor cattle for individual changes in animal attitude, appetite, and respiration. Once pulled to the chute for further examination, a body temperature in excess of 40?C is used to confirm diagnosis and antibiotic treatment is initiated. While laboratory tests for bacterial or viral infections could be used help confirm diagnosis, test results are typically unavailable for 24+ hours. As a result, most treatment and management decisions continue to be based on subjective clinical assessments (Gaylean et al 1999). This heavy reliance on visual signs makes early diagnosis difficult and the potential for an incorrect diagnosis high. Identifying at-risk animals before they become sick and confirming disease in suspect cattle are two areas where objective measures of respiratory health can be used to improve management practices. Early detection could reduce growing economic losses from excess medications, decreased weigh gain, lower carcass quality and higher labor costs. A rapid measure of respiratory health has the potential to have a significant impact on the beef industry by assisting with the successful management of bovine during the feeding period. APPROACH: Ekips Technologies, Inc. is devoted to developing a method of assessing respiratory health on the basis of exhaled immune system biomarkers. An important step toward this goal has been the successful measurement of exhaled nitric oxide (eNO) in bovine breath and the demonstration of higher levels of eNO in feedlot calves with BRD versus controls (Roller et al 2006b; Roller et al 2006a). Preliminary results suggest that eNO is a valuable marker for BRD and studies are underway to confirm the validity of this marker. Bovine eNO concentrations are low, however, and animal-to-animal variation could preclude the use of eNO as a sole biomarker for respiratory health. This is currently being addressed through ongoing efforts to identify additional biomarkers of interest in diagnosing and managing BRD. One such marker, ethane (C2H6), has been linked with oxidative stress-induced lung disease in humans (Gutteridge and Mitchell 1999; Phillips et al 1999; Rahman et al 1996). The objective of this Phase I Project is to adapt our existing technology to demonstrate rapid measurement of ethane in the expired breath of healthy bovine and bovine experimentally infected with a known BRD pathogen
