Poor oestrous detection is considered by many the most important management problem in the UK dairy herds. Various detection aids are available to the farmer, but in spite of these the average oestrous detection rate in Britain is low, only about 40 - 60% (Poole and Mabey, 1986).

Cows in oestrus tend to be more active than non-oestrous cows and results from various workers indicate that activity is a good indicator of oestrus (Kiddy 1976, Lewis and Newman, 1984). Three experiments were conducted to investigate the relationship between the distance walked and oestrous state of cows.

Pedometers designed to measure human walking activity were used to measure the physical activity of the dairy cow. These were attached to the hind leg of the cow. In experiment 1 distance walked (miles/day) was recorded twice daily for 20 cows in a cubicle shed on the day of oestrus and 5 days pre - or post - oestrus. In experiment2 pedometers were evaluated in two environments for oestrous detection with 20 cows allocated to a cubicle shed or a straw yard. In a third experiment behavioural observations of 20 cows were recorded four times daily with pedometer readings.