Distribuição temporal de ordenhas e da produção de leite por ordenha de vacas leiteiras em sistemas de ordenha robotizada

Abstract

The objective of this study was to evaluate the temporal distribution of milkings and milk yield per milking throughout the day in a robotic milking system. Data were collected daily over a 180-day period using the DelPro™ software on a commercial dairy farm located in Lagoa da Prata, Minas Gerais, Brazil. Lactating cows were housed in two compost barn facilities, each equipped with two DeLaval robotic milking units operating under a guided cow traffic system (Milk First). Data were categorized according to parity, days in milk and production quartile. The 24-hour day was divided into four 6-hour intervals. Statistical analyses were performed using two-proportion comparison tests and multiple comparison tests to compare milking proportions and analysis of variance (ANOVA) to evaluate milk yield per milking, adopting a significance level of 5% (P < 0.05). The distribution of milkings throughout the day was not uniform, indicating periods of greater and lower robotic milking activity. Primiparous cows concentrated milkings between 12:00 and 17:59 (27.3%), whereas multiparous cows showed the highest concentration between 06:00 and 11:59 (27.6%). Primiparous cows exhibited a more heterogeneous milking distribution during the first 21 days of lactation (range of 34.3%), with reduced heterogeneity during the second stage of lactation (range of 9.6%). Overall, multiparous cows showed a more uniform distribution of milkings across the daily periods during the first two stages of lactation, with ranges of 7.1% and 6.7%, respectively. Primiparous cows showed a marked increase in milk yield per milking during the second stage of lactation compared with the first stage, a pattern also observed in multiparous cows, although to a lesser extent. Production quartile 1 showed a heterogeneous milking distribution, with milkings concentrated between 06:00–11:59 and 12:00–17:59 for both primiparous and multiparous cows. Overall, as milk production increased, the distribution of milkings became more homogeneous. In conclusion, the distribution of milkings was not uniform throughout the day, with periods of greater robotic milking activity influenced by parity, days in milk, and milk production. Although milk yield per milking was also affected by these factors, it was consistently higher during the morning period (06:00–11:59).