Desempenho reprodutivo de vacas leiteiras em rebanhos da região sudoeste do Paraná

Abstract

Reproductive efficiency is one of the main factors influencing the productivity and profitability of dairy production systems. In this context, the objective of this study was to evaluate thereproductive efficiency of dairy cows in the Southwestern region of Paraná, Brazil. Data from 405 gynecological evaluations performed on dairy cows from 18 dairy farms between October 2021 and February 2025 were collected, organized in electronic spreadsheets, and subjected to statistical analysis using SAS software. Analysis of variance (ANOVA) and Tukey's test at a 5% significance level were applied. The results showed that cows with up to 45 days in milk (DIM) had a lower conception rate (20.00%; p < 0.05) compared to females with 46 to 90 DIM (72.71%), while cows with more than 90 DIM presented a conception rate similar to that of the 46 to 90 DIM group (69.45%). Regarding the number of services, a higher conception percentage was observed in animals submitted to a single service (32.03%), with lower percentages in the subsequent groups: up to two services (22.78%), up to three services (16.96%), and more than three services (28.23%). It was concluded that days in milk influence reproductive efficiency, and cows inseminated after the voluntary waiting period show better conception rates. Furthermore, a lower number of services is associated with greater reproductive efficiency in the evaluated herds.