Effects of pre-milking waiting time and selection behavior in cows milked in an automated batch milking system

Abstract

The adoption of automated milking systems (AMS) has transformed the dairy industry by improving efficiency, animal welfare, and milk production. DeLaval's Batch Voluntary Milking System (Batch VMS) provides a structured alternative to traditional AMS for larger dairy herds. Unlike continuous voluntary milking, Batch VMS organizes cows into groups and schedules their milking at set intervals, enhancing herd management while reducing labor demands. As a hybrid approach, it offers a seamless transition from conventional milking methods to automation. Through a literature review and two research studies, this thesis explores how Batch VMS may affect cow health and performance. Chapter 1 contains the literature review. It introduces the changes in the AMS technologies in recent years and compares it to Batch VMS. Secondly, it discusses the effects of pre-milking waiting time on milking performance and cow health in terms of mastitis and lameness. And lastly, it discusses selection behavior in cows, comparing behaviors in conventional and automated milking systems. Chapter 2 explores the effects of pre-milking waiting time (WT) in an automated batch milking system (ABMS). Visit information was collected to calculate pre-milking WT, defined as the time elapsed between the entrance of the cow to the milking barn, as indicated by pedometers attached to each cow that were read by sensors located at the parlor, and the entrance of each individual cow to the robot milking box. WT were categorized into quartiles within each parity group as Q1 ≤ 9 min, Q2 = 10 to 24 min, Q3 = 25 to 46 min and Q4 ≥ 47 mins for primiparous and Q1 ≤ 11 min Q2 = 12 to 30 min, Q3 = 31 to 51 min and Q4 ≥ 52 mins for multiparous. To assess the association between lameness and WT, individual cow WT averages were calculated separately for primiparous and multiparous groups. Lameness was treated as a categorical variable, where 1 indicated a cow diagnosed with lameness and 0 indicated non-lame cow. The results show that the average waiting time for all milking events was 33.6 min (± SD = 28.5), 34.5 ± 28.9 for PP, and 30.7 ± 27.3 for MP. The means for each breed were 25.6 ± 15.2, 42.3 ± 16.8, and 42.3 ± 23.4, for HO, JE, and HJ, respectively. While significant differences in LSM were observed between breeds for most variables, there was little to no significant association between WT and the analyzed outcomes. An increase of 10 minutes in WT was associated with a 23.7% increase in the odds of lameness in multiparous cows (95% CI: 10.2–39.0; p < 0.001). However, no significant association was found in primiparous cows (OR: 1.09, 95% CI: 0.85–1.38, p = 0.462). Chapter 3 discusses selection behavior in an ABMS where cows select between 22 robots each time there are brought to the milking parlor. The objective of this study was to analyze the robotic milking station selection behavior of three breeds including Holstein, Jersey, and Holstein × Jersey crossbred cows in a multibreed dairy farm with a batch milking system with automatic milking units. The study used data from 1,762,461 milking events in 3705 HO (n=1355), JE (1876) and HJ (475) cows from May 2023 to September 2024 in a commercial organic grass-fed dairy in TX. Cows were moved to the milking center twice per day, where they could select their milking visits among 22 robot units (DeLaval, Sweden). For the analysis, robots were also classified by barn location [East (n=11); West] and arm configuration [left (n=11); right]. Milking visit information was collected to determine the frequency of specific robot usage per cow during the study period. Subsequently, the frequencies of selection for the top 1, 3, and 5 robotic milking stations, top barn location, and top arm configuration were calculated for each cow. Preference consistency scores (PCS) were calculated considering the frequency of access to each robotic milking station, barn side, and arm configuration in 30 days periods. Overall, multiparous and HO cows evidenced more consistent behaviors in milking station preference. Dairy cow selection behavior should be considered when analyzing the efficiency of milking procedures.