The locomotion of dairy cows in passageways with different light intensities

Guidelines for the housing of dairy cows do not address the provision of su pplementary lighting in passageways,, oother than for inspection of the ani mals. Two experiments were conducted to investigate whether lighting passag eways 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 t he passageway was,as dark, the cow,s took shorter but more rapid steps - wh ich probably increased their stability. In the second experiment, cows walk ed down a cubicle passageway to receive a food reward with the light intens ity ill 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 mea sured from video recordings). Once again, the cows increased their stepping rate in the dark and this resulted ill art increased walking rate, perhaps because they wished to return more rapidly to other members of their group and found the darkness aversive. Iii addition, the arcs of travel of the m etacarpophalangeal joint and of the fore- and hindfeet angles to the floor were reduced in the dark, probably increasing the cows' stability, and Mere greatest at 119 lux. The slowest walking rate was observed at 39 lux. Henc e, the optimum illumination for daily 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.