157 effects of metabolic conditions of dairy cows during transition period and early lactation in winter and summer on health and fertility

The aim of this study was to investigate and determine which metabolic predictors measured during the transition period, have a better association with health and fertility parameters in dairy cows in winter (W) and summer (S).The experiment was conducted with 235 multiparous Holstein dairy cows. The animals were divided, retrospectively into the experimental groups [High Production (AP), ≥45.9 to 65 kg of milk during peak lactation; Medium production (MP), between 30 and 45.8 kg of milk during peak lactation]. Blood samples and evaluations occurred during the transition period and during the timed fixed artificial insemination (TAI). Data were analysed for the main effects of group, day, and their interaction using the PROC MIXED procedure of SAS software (SAS 9.3, SAS Institute, Inc., Cary, NC, USA). Creatine kinase (CK) plasmatic concentrations increased during peak lactation in all groups, but the difference was not significant. Variations in superoxide dismutase (SOD) concentrations were observed in HP cows in both seasons (HPW and HPS). These cows had higher levels of superoxide dismutase (SOD) when compared of MP cows (MPW and MPS), with significant changes since 7 days before calving and remained higher until 104 days of lactation. The differences were observed in lipid profile, particularly in NEFA concentration. For this variable, there were group (P   0.05). There was a statistical tendency to all groups in the summer season for earlier calving (P = 0.1), less calf weight (P = 0.07), and retained placenta (P = 0.09) and metritis incidence (P = 0.08). These parameters were strongly correlated with metritis disease incidence and the significant parameters: Earlier calving (P = 0.03), dystocia (P = 0.05), and retained placenta (P = 0.009). The NEFA (0.4 mmol L–1) and BHBA concentrations (0.7 mmol L–1) were highly correlated with the occurrence of uterine diseases. We observed high levels of AST (around 128 U/L) pre calving in ketotic and in cows with displacement of abomasum. According to these results, we concluded that milk production was not a risk factor for fertility in the first three services. Also, metabolic changes in the transition period were determinant in milk yield and health diseases. Research was supported by FAPESP, CNPq, CAPES, Fazenda Colorado, and Ourofino animal health.