Evaluation of Metabolic Parameters in Karya Ewes During the Transition Period

Background: The transition from pregnancy to lactation involves substantial metabolic adjustments in ewes. However, information on periparturient biochemical changes and their association with litter size in prolific Karya ewes remains limited. Objective: This study aimed to characterize changes in serum metabolic parameters during the transition period in Karya ewes and assess differences in maternal biochemical profiles and colostrum Brix values associated with litter size. Methods: Twenty multiparous Karya ewes aged 3–5 years were monitored from prepartum week 3 to postpartum day 15. Blood samples were collected at prepartum weeks 3, 2, and 1, at parturition, and on postpartum days 3, 7, and 15. Serum energy metabolites, protein indicators, minerals, and enzyme activities were measured. Colostrum collected immediately after lambing was assessed using digital Brix refractometry. Longitudinal data were analyzed using linear mixed models, with Benjamini–Hochberg adjustment for pairwise comparisons. Colostrum Brix values were compared between litter-size groups using Welch’s independent-samples t-test. Results: Serum glucose peaked at parturition (82.6 ± 11.2 mg/dL) and declined to 53.5 ± 4.4 mg/dL by postpartum day 15 (adjusted p = 0.006). Triglyceride and cholesterol concentrations decreased around lambing and early lactation, whereas mean aspartate aminotransferase and gamma-glutamyl transferase activities were higher during early lactation; all four parameters showed significant overall time effects (p < 0.001). Time effects were also significant for total protein (p = 0.003), magnesium (p = 0.029), and phosphorus (p = 0.035), but not calcium, albumin, blood urea nitrogen, non-esterified fatty acids (NEFA), or beta-hydroxybutyrate (BHBA). Twin-bearing ewes had lower calcium (p = 0.019) and total protein (p = 0.038), higher BHBA (p = 0.021), and higher colostrum Brix values (p < 0.001) than singleton-bearing ewes. The litter-size effect on NEFA was not significant (p = 0.407). Conclusions: Karya ewes exhibited parameter-specific metabolic changes during the periparturient period. Differences associated with twin pregnancies support closer monitoring of maternal metabolic status, although these findings alone do not establish subclinical metabolic disease.