Effect of pasture and feeding systems on hematological traits of ewes and lambs.

Context: Sustainable livestock production depends on efficient pasture management and the continuous monitoring of the health of grazing animals. Objectives: This study investigated the effects of pasture types and sheep production systems on the hematological traits of Karacabey Merino (German Mutton Merino × Kıvırcık) ewes and lambs grazing on different pasture types throughout the year and reared in a semi-intensive system (control group). Methods: In this twenty-six-month study, the hematological characteristics of ewes and lambs grazing on natural pastures and in spring (triticale and oat grass pasture), summer (sorghum Sudangrass and wheat stubble pasture), and autumn (triticale and oat grass pasture) were compared with ewes and lambs reared in a semi-intensive system (no pasture for lambs). A total of 36 ewes (aged 3-4 and 65.2 ± 0.55 kg) and 98 lambs were used. There were 12 ewes in total in each treatment group and four ewes in subgroups. Each subgroup in the pasture was separated by fences. The 12 ewes tagged in the control group were within the unit sheep flock. Blood samples were taken from the jugular vein of ewes and lambs at three to four-week intervals during live weight weighing using 3-4 mL edged tubes and transported in the cold chain to the laboratory for analysis. Results: Pregnant ewes grazing on natural autumn pasture had significantly lower red blood cell (RBC), hemoglobin (HGB), and platelet (PLT) counts ( Conclusions: The hematological parameters of pregnant Karacabey Merino ewes grazing on natural pastures during the autumn season, as well as those of lambs raised in a semi-intensive system during the post-weaning period, should be carefully monitored. Additionally, appropriate feed supplementation, along with vitamin and mineral support, should be provided to maintain animal health and physiological balance.