Dataset_Late embryonic losses

The dataset contains information obtained in an observational study run in a commercial dairy herd from Argentina to test the hypothesis that infections with Bovine Viral Diarrhea Virus (BVDV), Infectious Bovine Rhinotracheitis virus (IBRV), and Neospora caninum (N. caninum) are associated with the risk for Late Embryonic Loss (LEL) in grazing dairy cows. The objectives were to evaluate the association of BVDV, IBRV, and N. caninum with the risk for LEL. Additional objectives were to evaluate blood progesterone concentration at the time of LEL occurrence and to detect BVDV, IBRV and N. caninum in aspirated conceptuses from LEL cows. A prospective cohort study involving 92 cows (46 with LEL and 46 non-LEL) was run. The LEL was defined as a cow having an embryo with no heartbeat or with detached membranes or floating structures, including embryo remnants detected by ultrasonography (US) at 28-42 days post-AI, whereas a non-LEL was defined as cows with embryo heartbeats detectable by US at 28-42 d post-IA. Two blood samples were obtained from every cow, the first one, on the day of LEL detection by US (in LEL cows and paired non-LEL cows), and the second one, 28 d later. Serological diagnosis to BVDV, IBRV, and N. caninum infection was performed on all samples, and progesterone concentration was measured on the first sampling. Presence of BVDV, IBRV and N. caninum in aspirated conceptuses from LEL cows was evaluated by PCR. The associations of risk factors (serological titers, seroconversion, and progesterone) with LEL odds were assessed with logistic regression models. The risk for LEL was associated with the seroprevalence to BVDV in the second sampling (P=0.03), but not with seroprevalence to BVDV, IBRV, N. caninum in the first sampling, either IBRV or N. caninum in the second sampling. Also, the risk for LEL tended to be associated with seroconversion to BVDV (P=0.09). Conversely, the risk for LEL was not associated with seroconversion to IBRV or N. caninum. Progesterone concentration in blood was not associated with the risk for LEL and was similar in LEL and non-LEL cows (P=0.54). Finally, BVDV was only detected in conceptuses from seropositive LEL cows that seroconverted to BVDV. In conclusion, BVDV infection is a risk factor for LEL in dairy cows. Conversely, IBRV, N. caninum, and luteolysis seem not to play any role in LEL development.