Efeito da produção de leite na duração do período de serviço de vacas leiteiras mestiças

Abstract

Reproductive efficiency is a key factor in the economic sustainability of dairy production systems, with the days-open period serving as an important indicator of cow reproductive performance. This study aimed to evaluate the effect of milk production on the duration of the days-open period in crossbred dairy cows at the Glória Experimental Farm of the Federal University of Uberlândia. It was a retrospective observational study based on the analysis of production and reproduction records of crossbred cows (Holstein × Gir) from the institution's dairy cattle sector database. The variables evaluated were peak milk production (L/day), average milk production during the first five months of lactation (L/day), and the days-open period (days). Cows were categorized into groups above or below the herd average for each production variable, and data were subjected to analysis of variance (ANOVA) using MINITAB® software, with a significance level of 5% (P ≤ 0.05). No significant effect of peak milk production on the days-open period was observed (112.30 ± 65.30 days for cows below the average versus 130.50 ± 93.50 days for cows above the average; P = 0.40). Similarly, average milk production during the first five months of lactation did not influence the duration of the days-open period (111.30 ± 98.50 days for cows below the average versus 130.80 ± 92.50 days for cows above the average; P = 0.37). It is concluded that milk production did not significantly influence the length of the service period; it is likely that factors related to nutritional, sanitary, and reproductive management exerted a greater influence on the herd's reproductive performance.