Postpartum Changes in Colostrum Protein Composition and Lamb Growth Performance

This study investigated the relationship between colostrum composition and lamb growth performance by monitoring temporal changes in key colostrum components during the first 144 hours postpartum. Colostrum samples were collected at 24-hour intervals from 60 ewes of the Morkaraman, Awassi, and Tuj breeds and analysed for protein composition, with particular emphasis on immunoglobulin G (IgG) heavy chain, β-lactoglobulin, κ-casein, total protein, and density. Lamb growth performance was assessed based on live weights recorded at birth, 33 days, and 66 days of age. A marked decline in colostrum IgG and β-lactoglobulin concentrations was observed after the first 24 hours postpartum, with IgG heavy chain levels decreasing from 2.55 ± 0.096 g/dL at 2 hours to 0.61 ± 0.059 g/dL at 144 hours. In contrast, α-lactalbumin concentrations increased over time. Correlation analyses indicated significant positive associations between colostrum IgG heavy chain, κ-casein, and total IgG measured at early postpartum sampling points and lamb live weights at 33 and 66 days of age. These findings suggest that early colostrum protein composition may be associated with subsequent growth performance, underscoring the importance of appropriate colostrum management practices in sheep production systems.