The impact of fetching at night on milking parlour visitation for pasture-based dairy cattle

In most pasture-based automatic milking systems (AMS), three-way grazing (3WG) is utilised and cows that remain in a given paddock are fetched or encouraged to the milking facility (each paddock is cleared once per day). Fetching is ideally undertaken within 15 h of the opening of each pasture allocation, where one of these fetches would occur late at night to minimise the risk of cows having extended milking intervals (MI) which negatively impact on udder health. Farmers are understandably reluctant to fetch late at night or in the early hours of the morning (when they would typically be asleep), and the response of cows to being fetched at this time is unknown. Night fetching was undertaken on a farm managing up to 226 Holstein Friesian cows under a 3WG system. The objectives were to determine the impact of fetch timing on milking parlour visitation, cow behaviour and cow production on a pasture-based AMS to identify if automation of fetching at night would be viable for the future. Cows were fetched at two times of the night from a specific allocation ensuring that they couldn't spend more than 15 h or less than 5 h in that allocation. The herd performance was monitored over four-weeks consisting of a one-week preparation period followed by a three-week treatment period where cows in the target allocation were fetched at either 23:00 or 01:00 in a randomised block design. During the treatment period cows were fetched at the designated time of night from pasture onto the laneway, after which, cows were free to stay there (for up to 3 h) or to continue walking towards the milking facility without further encouragement. Fetching at 23:00 was associated with a lower (P < 0.001) milking interval and slightly more (P = 0.009) time spent in the pre-milking waiting area than cows fetched at 01:00. During the study the cows responded positively to being fetched at night by voluntarily trafficking along the laneway to the dairy, revealing potential for automation of this process in the future.