Abstract

Background:
Parturition is one of the most critical and economically important phases in ewe production systems.

Aim:
This study evaluated physiological and behavioral changes in sheep during the peripartum period to identify practical indicators associated with impending lambing.

Methods:
Seven primiparous sheep were monitored for physiological parameters, including heart rate, respiratory rate, rectal temperature, plasma cortisol concentration, and neutrophil-to-lymphocyte ratio (NLR), before lambing. Behavioral activities, including eating, lying, standing with or without rumination, and urination frequency, were continuously recorded. The data were analyzed to determine temporal changes relative to lambing time.

Results:
The heart rate steadily increased, reaching a notable high on the day of lambing (D-0; 100.1 bpm; p < 0.05), and the respiratory rate was also elevated on that day. Meanwhile, the body temperature showed a significant drop as lambing approached. The NLR remained consistent until D-2 but saw a sharp rise on D-1 and D-0, reaching 2.18. Cortisol levels were significantly elevated on D-0 (45.8 ng/mL; p = 0.0012). Feeding time notably decreased as lambing approached, while lying behavior increased, peaking with rumination at D−0 (34.1%; p < 0.05). Other behaviors showed no significant changes.

Conclusion:
Increased heart rate, respiratory rate, cortisol concentration, and NLR, together with reduced body temperature, eating activity, and altered rumination behavior, were associated with impending lambing in sheep. These indicators may support closer monitoring and timely intervention during the peripartum period.

Key words: Lambing prediction; Peripartum behavior; Cortisol; Sheep; Stress indicators.