Effects of Exogenous Oxytocin on Embryonic Survival in Cows

Abstract

The aim of this study was to evaluate the effect of oxytocin on embryonic survival in dairy cows. Pregnancy was verified using the early pregnancy factor (EPF) activity on Day 4 after artificial insemination (AI). Pregnant cows were randomly allotted to two groups: treated (n = 8) and control (n = 8). Oxytocin (100 IU, 5 ml, DIF Turkey) was administered twice daily by intravenous injections to treated cows and sterile saline (5 ml) to control cows immediately before milking on days 4 to 7 after AI. Blood samples were taken via jugular vein every day from day 4 to 8 and every other day until Day 20 following insemination to evaluate the effect of oxytocin on embryonic survival. The embryonic loss was diagnosed in 3 of the 8 cows treated with oxytocin, and embryonic survival rate was 62.5% in this group versus 87.5% in controls. Short cycles occurred in 37.5% of oxytocin-treated cows. At the same time their serum progesterone concentrations rose more slowly than in controls. It was concluded that cows administered oxytocin on days 4 to 7 after insemination are at a higher risk of pregnancy loss.