RISK FACTORS FOR LOW PREGNANCY RATE IN DAIRY CATTLE: A RETROSPECTIVE STUDY IN THE NORTH WEST OF SPAIN

摘要

Risk factors for low pregnancy rate to first artificial insemination (PR/FAI) were studied using 2859 lactations from 203 farms sited in the province of Lugo (Galicia, North West of Spain). Data were obtained from previous records collected by different veterinarians or by the farmers themselves. Potential risk factors considered in the study were: farm size and location, parity, pregnancy length, calving season, calving difficulty, twin calves and potential postpartum diseases (hipocalcaemia, retained placenta, metritis, or ketosis disease). The mean PR/FAI was 49.8 percent. Multiple logistic regression analysis indicated that intervals parturition to first Al shorter than 51 days (OR= 2.47, p<0.01), dystocia (OR= 1.79, p<0.01), autumn calvings (OR= 1.43, p<0.01), cows belonging to farms located in the central area of the province vs those in the coastal area (OR= 1.46, p<0.01) or cows with parity equal to 5 (OR= 1.38, p<0.05) were risk factors for low PR/FAI. Postpartum pathologies such as metritis (OR= 1.75, p<0.01) hypo-calcaemia (OR= 1.66, p<0.05) and retained placenta (OR= 1.46, p<0.01) were also associated to a higher risk for low PR/FAI.