The project was carried out at “LA Esmeralda” farm of the Biblián city, Cañar province. The aim of this research was to establish if is possible to use the blood concentration of β-hydroxybutyrate (BHB) of dairy cows as a predictor of postpartum ovarian activity (cyclicity and anestrus). We used 40 cows in transition period, clinically healthy, with similar condition of handling and feeding. BHB measurement was performed at 7, 14, 21, 28 and 35 pospartum days (DPP). Ovarian activity was assessed by ultrasonography at 21, 28 and 35 DPP. Statistics assay was performed using Chi-squarer test, correlation coefficient of Kendall’s Tau_b and the ROC curve. The result showed that there is not dependence between the type of anestrus and BHB’s concentration, however the highest concentration of this metabolite were found in type III and IV anestrus. We concluded that the concentration of BHB has low predictive power of the reproductive status of the cows as well as the type of anestrus present in the animals up to 35 DPP.
