Efeito da duração do período seco na produção de leite e eficiência reprodutiva na lactação subsequente de vacas leiteiras mestiças

Abstract

The dry period in dairy cows can impact reproductive efficiency and milk production in the subsequent lactation. Furthermore, it is also important for the health of the animal and its calf. This study aimed to evaluate the relationship between the duration of the dry period and milk production, as well as reproductive performance in the subsequent lactation of crossbred dairy cows. Data were collected from the dairy herd of the Glória Experimental Farm at the Federal University of Uberlândia (UFU) from September 25, 2023, to November 17, 2025. All data were obtained from data stored in the herd management system (COWMED®). The following data were analyzed: drying-off date, calving date, peak milk production, average cumulative milk production up to 150 days in milk (DIM), number of AI/conception, and date of fertile insemination. Based on these data, the interval between drying off and calving (dry period [DP]) and the interval between calving and conception (service period) were calculated. For the analysis, the duration of the DP was categorized as: less than 44 days; between 45 and 69 days; 70 to 120 days; and greater than 120 days. Statistical analyses were performed using analysis of variance in the MINITAB program, including the effect of the DP category in the model. A statistically significant difference was considered when P ≤ 0.05. Data from 70 animals were recorded regarding milk production; no effect of DP duration was detected in any of the variables evaluated. Data from 50 animals related to reproductive performance were recorded, and again, no effect of DP duration was detected in any of the variables evaluated. It is concluded that when evaluating the duration of the dry period in isolation, it was not possible to detect an effect of the duration of the dry period on the productive and reproductive performance of the crossbred herd.