Influence of two-stage weaning with subsequent transport on body weight, plasma lipid peroxidation, plasma selenium, and on leukocyte glutathione peroxidase and glutathione reductase activity in beef calves.

An experiment was conducted to assess the effects of two-stage weaning and subsequent transport on oxidative stress markers in calves. Thirty-six crossbred Angus steers (243+/-20.8 kg; 221+/-19.7 days) were allotted to control, fenceline (FL), and nose-clip (NC) weaning groups. Steers were weighed and blood samples were collected on days -7, 0 (pre-transit) and 7 surrounding transport. Leukocytes were analyzed for glutathione peroxidase and glutathione reductase activity, whereas malondialdehyde and Se were measured in plasma. Data were analyzed using PROC MIXED with the Tukey-Kramer adjustment applied post hoc. No treatment effects were detected for blood variables or weights. Glutathione peroxidase activity was not altered by time (P = 0.27). Glutathione reductase activity, Se, and malondialdehyde declined (P<0.001) from day -7 to 7 in all steers. Treatmentxdate interaction was detected for malondialdehyde (P<0.02). Control and FL steers gained weight (P<0.03), whereas NC steers did not gain weight between days -7 and 0 (P = 0.81). All weaning treatment groups gained weight between days 0 and 7 (P<0.05). Results suggest that two-stage weaning has little effect on examined markers of oxidative stress.