Comparison of stress-related physiological and behavioral changes in beef cows subjected to 3 weaning methods.

OBJECTIVE

This study evaluated physiological and behavioral responses to weaning stress in beef cows using 3 weaning methods, comparing pre- and post-weaning changes within cows, determining correlations between sensor ear tags and visual data, and exploring associations between fecal glucocorticoid metabolites (FGM) concentrations and behavioral indicators of stress.

ANIMALS AND PROCEDURE: Cow-calf pairs were weaned and assigned using abrupt (AW), nose-flap (NF), or fenceline (FL) methods, in consecutive groups of 30 pairs per method. Data were collected from 3 d before weaning (D-3) to 7 d post-weaning (D7). CowManager (Agis Automatisering) ear tags measured time spent on behaviors, whereas in-person observations identified vocalization, eating, walking, pacing, standing, and lying conducted in 30-second instantaneous samplings at 40-minute intervals, 6× daily. Saliva and fecal samples were collected from D-1 to D3 for cortisol and FGM analyses. Statistical analyses were based on within-cow behavioral changes (Δ) between pre- and post-weaning and analyzed using multilevel regression models, depending on outcomes.

RESULTS

Abruptly weaned cows had increased Δtime eating, whereas NF cows had decreased Δtime eating on D1 and D2 compared to pre-weaning (P < 0.01). In addition, AW and FL cows spent increased Δtime being active on D1, unlike NF cows (P < 0.001). Fenceline-weaned cows had increased Δtime spent being active, Δfrequency walking, and pacing post-weaning compared to pre-weaning (P < 0.01). On D0 and D1, AW and FL cows exhibited higher Δvocalizing frequency, unlike NF cows. Abruptly weaned cows had lower FGM concentrations on D1, D2, and D3 compared to D0 (P < 0.001). However, FL cows had higher ΔFGM concentrations on D1 compared to D0 (P = 0.002). Nose-flap-weaned cows had increased ΔFGM concentrations only on D3 compared to D0 (P < 0.001).

CONCLUSION AND CLINICAL RELEVANCE: Cows subjected to NF weaning generally exhibited smaller deviations from baseline in activity, walking, and vocalization, whereas cows in the FL weaning group had increased activity and elevated FGM concentrations on specific post-weaning days. Behavioral and physiological indicators did not consistently align. This and limited agreement between CowManager-derived data and visual observations underscores the importance of methodological considerations but provides opportunities for management decisions aimed at weaning-related stress reduction. Because weaning methods were implemented sequentially, without treatment-level replication, findings represented cohort-specific group trends rather than definite evidence of treatment superiority, and should be interpreted cautiously.