47. Seasonality of Bovine Respiratory Disease Incidence and Nasal Temperatures in Receiving Beef Cattle: A Potential Early Disease Detection Method

Abstract To determine if nasal temperatures could potentially detect bovine respiratory disease (BRD), crossbred beef calves (n = 389) were purchased from regional auction markets. Cattle were received and housed at the University of Arkansas Stocker Unit and used for various 42-d receiving studies. Cattle were received on 4 separate dates (2 spring, 2 fall) and consisted of heifers (n = 202), steers (n = 67), and bulls (n = 120). On d 0, cattle underwent standard processing and were stratified by initial body weight and sex to be assigned to 1 of 8 or 9 pens (10 to 12 calves/pen). A subset of calves (4 to 5 calves/pen) were selected randomly for sampling procedures. While restrained, 2 types of nasal temperatures were recorded: 1) outside surface of nose (NT), and 2) inside the nasal cavity (NTin). Nasal temperatures were recorded using a 256 × 192 radiometric imager that provides real-time thermal imaging (HIKMICRO®). Nasal temperatures were acquired on days 0, 14, 28, and 42. Cattle were observed daily for signs of clinical BRD. If presenting symptoms of BRD and if rectal temperature was ≥ 40 °C, cattle were deemed morbid and treated with an antibiotic according to a standard preplanned protocol. Weather information was obtained from the weather station nearest (15 km) to where cattle were housed. Available data were downloaded from the University of Arkansas Division of Agriculture Milo J. Shult Agricultural Research and Extension Center. Data were analyzed using Pearson’s product-moment correlations and Chi-squared analyses of R programming (v5.5.0). Significance was declared if P ≤ 0.05 and tendencies were declared if 0.05 < P ≤ 0.10. Categorial data which included season (P = 0.0016) and sex (P = 0.0024) both influenced overall BRD outcomes. There were relationships revealed between humidity percentages within the first 2 weeks of receiving and BRD incidence on d 0 to d 14 being positive (P = 0.0165; r = 0.1949) and d 14 to d 28 being negative (P = 0.0020; r = -0.2490). Environmental temperatures within the first 14 d tended to share a positive relationship with BRD incidence from d 14 to d 28 (P = 0.1022; r = 0.1335). There were no correlations found between NT (P ≥ 0.4726) or NTin (P ≥ 0.4527) and BRD outcomes within the 42-d period. However, there were relationships found between environmental temperatures (P < 0.0001; r = 0.3246), humidity percentages (P = 0.0002; r = -0.2970), and total precipitation (P = 0.0003; r = -0.2894) with NT within the first 2 weeks of receiving. In summary, understanding how the environment influences NT recordings and BRD outbreaks would improve potential risk assessment tools at receiving.