Development, validation, and demonstration of the herringbone parlor model

The objective of this study was to develop, validate, and demonstrate the herringbone parlor model (HPM). The HPM was built using empirical data collected from a sample of commercial Irish dairy farms (n = 16). The HPM is a mechanistic model that accurately simulates the milking process time and milking efficiency of herringbone swing-over parlors, where 1 operator is present at milking, accounting for variances in parlor infrastructure, management practices, and automation specification. The HPM was validated by comparing simulated outputs against empirical recordings from a commercial dairy farm across 2 typical periods during the lactation cycle. Mean absolute percentage error (MAPE) values of 9.6% and 8.4% for cows per hour (cows/h) and milking process time per cow (MPT, s/cow) were observed through the HPM validation process, respectively. The average MAPE for row times was 7.9%. HPM was then demonstrated across 3 parlor sizes (1 × 16, 1 × 20, and 1 × 24 clusters) with automatic cluster removers (ACR) and rapid exit. We found that smaller parlors experienced the largest benefits from the use of automations. For example, for a 1 × 16 parlor, we found the addition of ACR or rapid exit increased milking efficiency (cows/h) by 11% and 6%, respectively. Combined, they increased milking efficiency by 14%. In contrast, for a 1 × 24 parlor, adding ACRs increased milking efficiency (cows/h) by 7%, whereas rapid exit increased cows/h by 2%. Combined, ACR and rapid exit increased milking efficiency by only 8%. A sensitivity analysis examined the effect of an increased ACR threshold (from 0.2 to 0.8 kg/min) on the milking efficiency for the 3 different parlor sizes. Increasing the ACR threshold had a low impact on milking efficiency, with cows/h values increasing by 9%, 1%, and 7% for 1 × 16, 1 × 20, and 1 × 24 cluster parlors, respectively, when compared with values achieved at the lower threshold (0.2 kg/min). However, when an increased ACR threshold (0.8 kg/min) was used together with a rapid exit system, substantial gains in efficiency were generated. Using the increased ACR threshold together with the rapid exit system increased milking efficiency (cows/h) by 26% for a 1 × 16 cluster parlor when compared with a 1 × 16 cluster parlor with no automations. Similarly, for a 1 × 24 cluster parlor, using an ACR threshold of 0.8 kg/min with the rapid exit system increased milking efficiency (cows/h) by 16% when compared with a 1 × 24 cluster parlor with no automations. Further, we found that the use of ACR increased the operator idle time across all parlor sizes. Using ACR with a threshold of 0.2 kg/min increased the operator idle time of 1 × 16, 1 × 20, and 1 × 24 cluster parlors by 38, 45, and 50 min, respectively, when compared with parlors without ACR. This study highlights that the ability of automations to enhance milking efficiency and reduce labor requirements at milking varies across parlor size, emphasizing the need for strategic decision making in parlor configuration and operation.