Bovine Abortion Syndrome (Bas) has a significant impact on commercial dairies. Abortion rates vary between 2 and 20 % and there is little information regarding non-infectious factors affecting fetal stages. We analyzed the joint relationship of infectious and non-infectious factors with the probability of abortion in dairy cows. We used dairy cows from the Nuble province of Chile (n = 148) at 42 days of pregnancy. We then took monthly blood samples until abortion or calving. We determined plasma concentrations for the following: amino transferase, albumin, cholesterol, globulin, fibrinogen, beta-hydroxybutyrate, retinol, alpha-tocopherol, calcium, phosphorus, glutathione peroxidase, total proteins and urea. Serology was performed for infectious diseases and body conditions were recorded. Our study used a multivariable logistic regression model and proportional hazard regression. There was an (P < 0.05) association with abortion, (OR = 4.27) for Neospora caninum and (HR = 94.35) for Leptospira interrogans, with a low cholesterol concentration (P < 0.05) in the fourth month of pregnancy (OR = 0.61), and a decrease in body condition from month three to four (OR = 0.32). BAS is associated with negative energy balances, protective effects of high cholesterol plasma concentrations in the first trimester of gestation and incidences of Neospora caninum, Leptospira interrogans, and a conjunction of the two. It is important to provide epidemiological surveillance tools that help anticipate herd reproductive losses through management measures, infectious disease control and proper nutritional management.