Quantifying economic and farm system trade-offs for automating milking in batches to improve labor productivity in pasture-based dairy systems.

Automating milking systems with voluntary cow traffic can be challenging to manage in large pasture-based dairy herds (e.g., > 300 cows), due to logistical complexity relating to grazing. This challenge could be overcome by combining automating milking with milking in batches (ABM) which has the potential to improve labor productivity. However, the economic viability and systems implications of ABM in pasture-based systems are unknown. The purpose of this study was to develop a model and quantify the trade-offs between the number of automated milking units required (i.e., likely economic feasibility), the hours of operation, and a range of farm factors such as herd size (in 150 cow increments), milking interval, the number of milking groups (batches) and the milk yield of the herd. The model was used to investigate a range of scenarios to illustrate the interactions between factors. Subsequently, the revenue differential required to pay for the additional capital of automated relative to conventional milking was determined using a net present value of zero at 25 years, assuming a discount rate of 8%. The results indicate that dividing the herd into multiple groups could be an effective strategy for reducing the number of automated milking units needed relative to a direct substitution for conventional milking units. Milking interval had a nonlinear effect on the number of milking units required and the feasibility of achieving different working day lengths, with a 24 h milking interval requiring the fewest milking units. ABM is unlikely to be economic for herds of 150 to 450 cows. For herd sizes of ≥ 600 cows it appears critical that the automated milking equipment is able to operate unsupervised to achieve sufficient labor savings and automated herding technology would also be required. The combined cost of these 2 technologies could undermine the viability of ABM. The attractiveness of individual scenarios will vary between farmers, but this analysis can facilitate conversations between farmers or their advisors about how milking in batches could be automated and its potential viability.