Comparison of hematological parameters between single and twin pregnancies in Dorper ewes during gestation, lambing, and postpartum

ABSTRACT: The hematopoietic system changes during the pregnancy to carry fetal development and maternal needs. This study compared the hematological parameters between ewes with single and twin pregnancies during gestation, delivery, and postpartum. The experiment was conducted on 60 healthy pregnant Dorper ewes that were divided into two experimental groups: Group 1 (G1), with single pregnancies (n=30), and Group 2 (G2), with twin pregnancies (n=30). Blood samples were collected from all ewes at different times: immediately before fixed-time artificial insemination (AI); on day 30, 90, 120, 130, and 140 of pregnancy; immediately after delivery; and at 24h and 48h postpartum. Statistical analysis compared the two groups at different times (P<0.05). Mild, normocytic, and hypochromic anemia was detected in all ewes from AI time and throughout pregnancy from both groups, but did not prove to be of clinical relevance. In the peripartum stage (from the 140th day of pregnancy to 48h postpartum), the ewes with twin pregnancies (G2) exhibited higher erythrogram values and neutrophil:lymphocyte ratio than did ewes with single pregnancies (G1). This indicated a greater hematopoietic adaptation in the body during the development of two fetuses. Except for the eosinophil numbers, all leukogram parameters were influenced by pregnancy in a similar way in both groups, and was characterized mainly by leukocytosis with neutrophilia during peripartum due to the high presence of endogenous cortisol at delivery. Thus, these findings showed that pregnancy was a stressful physiological event that increased the leukocyte count with a slight alteration in the erythrogram of Dorper ewes.

摘要：造血系统在妊娠期间会发生适应性改变，以满足胎儿发育与母体生理需求。本研究针对妊娠、分娩及产后阶段的单胎妊娠与双胎妊娠杜泊羊（Dorper）的血液学参数展开对比分析。本实验选取60只健康妊娠杜泊羊，将其分为两组：单胎妊娠组（G1，n=30）与双胎妊娠组（G2，n=30）。分别于以下时间节点采集所有受试母羊的血液样本：定时人工授精（Artificial Insemination, AI）前即刻、妊娠第30、90、120、130及140天、分娩后即刻，以及产后24h与48h。采用统计学方法在各时间节点对两组参数进行比较（P<0.05）。两组受试母羊自定时人工授精阶段至整个妊娠周期均检出轻度正细胞低色素性贫血，但该变化未达到临床相关程度。在围产期阶段（妊娠第140天至产后48h），双胎妊娠组（G2）母羊的红细胞参数及中性粒细胞与淋巴细胞比值均显著高于单胎妊娠组（G1），这表明双胎妊娠时机体为适配双胎儿发育需产生更强的造血适应性应答。除嗜酸性粒细胞计数外，两组母羊的其余白细胞参数均受妊娠进程的相似影响；围产期阶段因分娩时内源性皮质醇水平升高，主要表现为白细胞增多伴中性粒细胞增多。综上，本研究结果表明，妊娠对杜泊羊而言是一种应激性生理事件，可导致白细胞计数升高，并伴随红细胞参数的轻度改变。