Abstract
This study evaluated the effects of chronic cold stress on metabolism, colostrum quality, and early lamb performance in two environmentally resilient sheep breeds: Morkaraman and Awassi. The study included 20 ewes (10 each breed) and their lambs (10 per breed). This study evaluated serum biochemical parameters and colostrum quality and composition in sheep and assessed the growth performance of lambs during the first seven days of life under cold environmental conditions. Findings indicated that Morkaraman lambs exhibited higher birth weights and superior growth rates compared to Awassi lambs under cold conditions. Cold stress significantly influenced serum biochemical parameters, with Morkaraman ewes showing higher triglyceride and gamma-glutamyl transferase (GGT) levels. Colostrum quality declined over time in both breeds; however, immunoglobulin G and GGT concentrations decreased more rapidly in Morkaraman ewes. In conclusion, Morkaraman sheep demonstrated better lamb growth performance under chronic cold stress, but this advantage was accompanied by a faster deterioration in colostrum quality, indicating breed-specific physiological responses to cold environments.