The objective of this work was to evaluate the effect of some environmental factors on days open (DO) and days dry (DD), as well as to estimate genetic parameters for these traits in Holstein breed cows. A total of 6,485 records of DO and DD were used. The database were analyzed using a model that included the fixed effects of dairy group farmers, calving year, calving season, production level (PL), genetic group (GG), calving age class (CA) and the first […]