BRIEF COMMUNICATION Automatic oestrus detection from milking data - a preliminary investigation

Efficient oestrus detection is important economically, particularly with seasonal-calving herds employing artificial insemination, as every missed oestrus effectively costs 21 days milk production for that cow in that season which is about 8% of the total. Traditionally, oestrus detection relies mainly on visual observation of animal behaviour a cow in oestrus will stand and allow herself to be mounted by herdmates. Such events are readily noted when they take place amongst assembled cows, such as at milking times, but may be missed entirely in herds of free-grazing animals which are only brought in for milking twice a day, as is usual in New Zealand style systems. A common low-cost aid to oestrus detection is the use of “tail-paint” (Macmillan and Curnow, 1977), and although this can be very effective when properly executed the regular visual inspection and repainting is labour-intensive.