Effect of high stress and low stress cattle handling on selected blood chemistry parameters in finishing steers

Abstract Text:

Angus cross steers (n = 40; 563 ± 44 kg) were used to examine the effect of handling on blood chemistry and physiology of steers near market weight.  Steers were stratified by backfat thickness and randomly assigned to treatment groups: Low stress handling (LSH) and high stress handling (HSH).  Cattle were then randomly assigned to one of 5 blocks containing 4 steers from LSH and HSH treatments. Steers in the LSH treatment were walked a course of 1,540 m.  Steers in HSH were forced to run the 1,540 m course.  Blood samples were obtained via jugular venipuncture before handling (BASE), and at 770 and 1,540 m, 1 h (1H) and 2 h (2H) after finishing the course.  Blood samples were analyzed for plasma lactate (LAC), creatinine kinase (CK), base excess (BE), blood pH (pH), serum cortisol (CORT) concentrations and venous CO₂ (PCO2) and O₂ (PO2) pressures.  Heart rate (HR), respiratory rate (RR) and rectal temperature (TEMP) were measured at the same intervals. Cattle in HSH treatment had greater (P < 0.05) LAC than LSH cattle at BASE (4.1 vs. 3.0 mmol/L), 770 m (16.5  vs. 2.3 mmol/L),  1,540 m (22.3L vs. 2.4 mmol/L), 1H (7.2  vs. 2.7 mmol/L), and 2H (4.0  vs. 2.5 mmol/L), respectively. Creatinine kinase and RR were not different (P > 0.14) at any sample time.  Blood pH in HSH cattle was lower compared to LSH cattle (P < 0.05) at 770 m (7.25 vs. 7.45) and 1,540 m (7.19 vs. 7.48) but was not different (P > 0.13) at BASE, 1H or 2H. Heart rate and TEMP were increased in HSH cattle compared to LSH (P > 0.01) at all sampling times. Serum cortisol was increased (P < 0.05) in HSH compared to LSH cattle at 770 m (87.5 vs. 58.9 nmol/L) 1,540 m (144.4 vs. 93.1 nmol/L) and 1H (113.5 vs. 53.1 nmol/L). Although RR was not different between LSH and HSH, PCO2 was decreased in HSH compared to LSH (P < 0.05) at 1,540 m (30.6 mmHg vs. 39.3 mm Hg) and PO2 was increased at 770 m (42.7 vs 33.5 mmHg), and 1,540 m (51.5 vs. 36.6 mm Hg). Results of this study show that high stress handling can cause physiologic and blood chemistry changes in steers.  These changes could be potentially detrimental to cattle, emphasizing the need for low stress handling practices for promotion of welfare in cattle.

Keywords: Lactate, Cattle-Handling, Finishing Cattle