Comportamento diurno de vacas leiteiras em pastagem hibernal

Abstract

The objective was to evaluate the ingestive behavior of dairy cows in semi-intensive systems of winter pastures. Eighteen adult cows were used (6 of the Jersey breed and 12 of the Holstein breed), aged between three and eight years old, with an average body weight of 510 kg and in different stages of lactation. The experimental area had black oat (Avena strigosa Scherb) intercropped with ryegrass (Lolium multiflorum Lam.) as forages. Each animal was evaluated for eight hours. The design used was completely randomized, with the data being submitted to the Lilliefors normality test, with application of logarithmic transformation when necessary (log [X+1]). Data were submitted to analysis of variance (ANOVA) and regression, and the means were compared by Tukey's test with 5% significance. It was found that the activity most performed by the cows was grazing, with 265.44 ± 1.28 minutes during the observation period, followed by rumination and idleness with 163.50 ± 2.43 and 51.06 ± 2, 71 minutes, respectively. A longer grazing was observed in the morning (183.72 ± 3.72 minutes), corresponding to 69.21% of the grazing time, while in the afternoon the time spent on this activity was 81.72 ± 2.99 minutes. There was a greater amount of rumination in the afternoon (140.56 ± 2.79 minutes), corresponding to 85.97% of the time spent on this activity; in addition, the animals preferred to ruminate lying down for 129.94 ± 2.89 minutes in this activity, corresponding to 79.47% of the total used for rumination. Dairy cows in winter pastures concentrate their grazing activities in the morning and ruminating in the afternoon. Knowledge of the ingestive behavior of dairy cows is essential for the adoption of efficient management measures.