The Locomotion of Dairy Cows in Passageways with Different Light Intensities
Abstract:Guidelines for the housing of dairy cows do not address the provision of supplementary lighting in passageways, other than for inspection of the animals. Two experiments were conducted to investigate whether lighting passageways to various intensities influenced the locomotion of dairy cows. The first experiment compared the locomotion of dairy cows in a dark or lighted passageway as they walked back to their accommodation from milking. When the passageway was dark, the cows took shorter but more rapid steps – which probably increased their stability. In the second experiment, cows walked down a cubicle passageway to receive a food reward, with the light intensity in the building varying from 0–250 lux. Step length and stepping rate were recorded, as well as the angles of the cows' leg joints (which were measured from video recordings). Once again, the cows increased their stepping rate in the dark, and this resulted in an increased walking rate, perhaps because they wished to return more rapidly to other members of their group and found the darkness aversive. In addition, the arcs of travel of the metacarpophalangeal joint and of the fore- and hindfeet angles to the floor were reduced in the dark, probably increasing the cows' stability, and were greatest at 119 lux. The slowest walking rate was observed at 39 lux. Hence, the optimum illumination for dairy cow locomotion may lie approximately between 39 and 119 lux, as measured by our technique.
We conclude that during locomotion in dark passageways cows have to modify their walking behaviour significantly, so that the provision of at least a low level of lighting is desirable at night.