Periparturient Changes in Maternal Body Temperature and Colostrum Physicochemical Characteristics in Rasa Aragonesa Ewes.

Accurate identification of the periparturient period is essential for improving reproductive management in sheep. This study evaluated changes in maternal temperature and colostrum physicochemical characteristics during the transition from late gestation to early lactation. Seventeen pregnant ewes were monitored from 36 h before to 36 h after lambing. Vaginal and rectal temperatures were measured by digital thermometry, udder surface temperature by infrared thermography, and colostrum calcium, Brix value and pH were assessed using rapid field methods. Vaginal and rectal temperatures decreased significantly before lambing (p < 0.001), whereas udder surface temperature remained unchanged. Colostral calcium concentration decreased before parturition and increased postpartum (p < 0.001), while Brix values increased significantly before lambing (p < 0.001). No significant changes were observed in colostral pH. These findings suggest that maternal temperature and colostrum physicochemical characteristics may serve as useful physiological indicators of imminent lambing in ewes.