Productive and reproductive performance of Holstein cows in Agreste, Pernambuco, from 2007 to 2017

The aim of this study was to assess the productive and reproductive performance of Holstein cows grown in the Agreste region of Pernambuco. Dairy records were collected from three farms located in the Agreste region of the state of Pernambuco each month between 2007 and 2017. According to the National Institute of Meteorology the average annual temperature during the collection period was 24.21 oC, mean annual rainfall was 551.7 mm and mean annual relative humidity was 75.92%. A total of 42,677 data points concerning milk production, milk components and somatic cell score (SCS), as well as other zootechnical information regarding reproductive management, are analyzed herein. In order to assess cow productive performance, lactation curve estimates were performed according to calving order by applying the Wood model, while milk production, milk components and SCS were analyzed according to calving order and farm, season, calving year and the interaction between calving order and season. Regarding reproductive evaluations, farm effects on indices such as age at first calving (IPP), calving interval (IP) and service period (PS) were evaluated. Data were processed using analysis of variance SAS PROC GLM commands, while PROC NLIN commands were used to estimate the curves. Significant (p < 0.05) farm, calving order, season, calving year and interaction effects on production values, milk composition and SCS were noted. Higher amounts of certain milk components (lactose, total solids and non-fat solids) were observed in primiparous cows. Multiparous cows were the most productive in relation to the amount of milk produced milk (34.15 kg/milk/day) and, consequently, presented the highest SCS (4.48). The Wood model showed a good fit of lactation curve characterized by an ascending phase until peaking and a descending phase following the peak. Regarding the assessed reproductive indices, a significant effect (p < 0.05) of farm was observed on IP and PS. The parameters calving order, farm, season, year of calving, interaction between calving order and season, as well as the effect of farm on reproductive indices (IP and PS) are the most important factors in the evaluation of production and milk quality of cows raised in semiarid environments.