The normal time budgets of dairy cows are influenced by oestrus, with cows spending less time resting and eating but more time walking. Previous studies have shown that cows spend approximately 21% less time feeding where the day of oestrus is assumed to be the day of successful artificial insemination. The objective of the present study was to determine whether the number of steps, lying time, lying bouts, dry matter intake (DMI), feeding duration and the number of visits to feed were affected by behavioural and silent oestrus in lactating dairy cows. Thirty Holstein Friesian cows were housed in a free-stall barn with 34 cubicles and were continuously monitored by four video cameras. Milk samples were collected on Monday, Wednesday and Friday afternoon and analysed for progesterone concentration by enzyme immunoassay. Steps, lying time and lying bouts were measured using IceQubes (IceRobotics Ltd., Edinburgh, UK). Daily feed intakes and feeding duration were recorded by a Roughage Intake Control (RIC) system (Insentec B. V., Marknesse, Netherlands).
Of the 40 behavioural oestrus events, standing behaviour was observed in 50% of events. On the day of behavioural oestrus the number of steps were increased significantly (P < 0.001) compared to three days before (3DB) and three days after (3DA) oestrus, whilst the percentage of lying time, lying bouts, DMI, feeding duration and the number of visits to feed were reduced (P < 0.001) compared to 3DB and 3DA oestrus. On the predicted day of silent oestrus, only duration of feeding was reduced (P < 0.03) compared to one day before and one day after oestrus.
In conclusion, although the number of steps were increased, lying time, lying bouts, DM intake and feeding duration were reduced by behavioural oestrus, and only feeding duration was significantly lower during silent oestrus.