Pre-weaning ewe-lamb separation stress training alleviates vigilant watching behavior, increases relaxation-type behaviors, and lowers catecholamine levels in early-weaned ewes.

Lambs are typically weaned at 3-5 months of age, while early weaning (e.g., at one month of age) can readily induce ewe-lamb separation stress. Although improvements in weaning methods have shown some effectiveness in alleviating stress associated with early weaning, previous studies have mainly focused on stress responses in lambs, with relatively little attention given to ewes. Stress training is a method in which animals are exposed to specific stressors in advance to reduce their sensitivity to subsequent stimuli. This study aimed to investigate whether 1 h of pre-weaning ewe-lamb separation stress training (PWLSST) applied to ewes scheduled for early weaning (Day 35) could reduce post-weaning stress responses, improve behavioral performance, and explore the underlying mechanisms. The results showed that, compared with normally weaned ewes, ewes in the PWLSST group exhibited significantly reduced vigilant watching behavior and markedly increased relaxation-type behaviors (lying, exploring after weaning (P < 0.05). Concurrently, catecholamine (CA) levels in the PWLSST group were significantly decreased (P < 0.05). In summary, 1 h of PWLSST significantly reduced vigilant behavior and increased the proportion of relaxed behaviors in early-weaned ewes, which may indicate a marked reduction in stress levels. These improvements may be associated with decreased CA levels, which are related to chronic stress responses. These findings suggest that appropriate ewe-lamb separation stress training before weaning can help alleviate stress responses in early-weaned ewes, improve behavioral performance, and thereby enhance ewe welfare. This study provides a valuable reference for developing appropriate early-weaning protocols in meat sheep production.