Standardization of a non-invasive methodology to measure cortisol in hair of beef cattle

摘要: A study was conducted to (a) determine if beef cattle hair contains cortisol at measurable concentrations, and (b) identify the effect of location collection method on concentrations. Hair samples (0.5 g) from head, neck, shoulder, hip, switch were collected twelve Angus cross bulls (313.1714.7 kg BW) using two sampling methods: plucking, ensure follicles; clipping, an electric razor as close possible skin. After washings with isopropanol, ground a ball mill for 5 min 22 Hz, sonicated methanol 30 min, incubated shaker 18 h, 50 1C 100 rpm. The supernatant pipetted off evaporated in block heater, 45 under stream nitrogen. Samples reconstituted phosphate buffered saline before quantification competitive immunoassay. described successful detecting all samples, concentrations ranging 0.30 5.31 pg/mg. intra-assay coefficient variation (CV) ranged 3.6% 6.0%, while inter-assay CV 5.4% 11.2%. concentration greater (Po0.05) tail (1.9970.189 pg/mg) compared head shoulder (1.14 0.8270.189 pg/mg, respectively), neck hip (1.50 1.5970.189 respectively) (0.8270.189 pg/mg). Cortisol (Po0.01) by clipping (2.3570.176 than plucking (1.7570.176 There