AUTOMATED ESTRUS DETECTION IN GROUP-HOUSED SOWS BY RECORDING VISITS TO THE BOAR

When group-housing sows automation of oestrus detection can help the stockperson in monitoring sows' reproductive status. Detecting oestrus automatically can be based on visits of sows to a boar. In recently weaned sows data were collected on both the frequency and duration of visits of sows to (1) a detection area in front of a boar pen, (2) a ticket-window in the front partition of the boar pen within the detection area or (3) a freely accessible ticket-window. Formulae combining duration and frequency of visits, derived from other sows in a previous study, were tested on the data collected in this study. The results were in good agreement with those found in the previous study. New formulae were derived to minimize the number of checkups that have to be made on sows not (yet) in oestrus. A reduction of more than 90% in the number of checkups was achieved, accepting 5% of the sows not being detected during oestrus (5% false negative). The results of detection methods based on visits to each of the ticket-windows could not be compared statistically with those obtained using the detection area, but they did not differ very much.