Body reserves (BR) are vital for ruminants, enabling them to adapt to energy demands during key physiological stages (PhySt) and changing environments. This study assessed how farming systems (FS; indoor vs. outdoor) affect BR dynamics in Romane meat ewes with shared genetics. We monitored body weight, body condition score, subcutaneous backfat and muscle thickness, and plasma metabolites and hormones such as non-esterified fatty acids, β-hydroxybutyrate, insulin, triiodothyronine and insulin across 5 key PhySt: mating (M), mid-pregnancy (P), before-lambing (bL), after-lambing (aL), and weaning (W). The FS alone did not significantly affect these BR traits. However, FS interactions with PhySt, parity, and litter size revealed significant differences in BR dynamics, including variations in body weight, body condition score, and plasma biomarkers. Both FS showed similar BR profiles and rates, with BR mobilization (from P to W) and accretion (from W to the next P), highlighting the importance of matching nutrition to energy demands. These findings suggest that, irrespective of the FS, tailoring strategies to factors like age, litter size, and PhySt can add value to animals’ adaptive capacities to put them at the service of FS resilience and productivity in the face of climate variability and rising production costs.

Read the full article in the Journal of Animal Science.