Influence of sex on activated partial thromboplastin time (aPTT) and prothrombin time (PT) in sheep

Haemostasis is a physiological process that prevents excessive blood loss. In laboratory, the prothrombin time (PT) and the activated partial thromboplastin time (aPTT) are used to examine clotting systems. However, the influence of sex on PT and aPTT values is unknown. The present work aimed to determine the values for PT and aPTT in adult sheep and to evaluate their dependence on the sex of the animal. Blood samples were collected from 40 adults (1-6 years old) of mixed breed sheep (20 males and 20 females) via jugular venepuncture conducted using vacuum tubes containing 3.8% sodium citrate as an anticoagulant. PT and aPTT were determined by visual detection of clot formation. The mean PT and aPTT values for all sheep were 7.71 ± 0.87 s and 35.7 ± 3.57 s, respectively. The aPTT values showed a significant difference (P = 0.0013) between male and female samples, while the difference in PT values was not significant (P = 0.0565). Thus, the animal sex influences the function of the plasma blood-clotting system in sheep. In contrast with table 1 data, in particular, aPTT values are significantly higher in female sheep than in males.