The effects of two light programs on sleep in dairy cattle

Abstract: Sleep is a vital part of life. Even so a lot of the mechanics regarding sleep is unknown. The dairy cattle of today live a stressful life, as their high milk yields forces them to eat large amounts of feed and spend a great portion of the day ruminating. Do they have time to get enough sleep? Which factors affecting the need of sleep in dairy cattle are largely un-known. In this study the effects of light are investigated. A crossover design with five pregnant, lactating cows divided into two groups were subjected to a 36 h period of either complete light or complete darkness (except for a 4 h long lit period per 24 h) with two weeks between each treatment. With glue-on electrodes on the cows heads the sleeping times and sleep stages could be recorded by means of an ambulatory EEG device. Standing and lying times were recorded by an activity meter fastened on one of the hind legs. The study showed that light seems to have little effect on the sleep in dairy cattle. Other results might have been found if the study had been going on for a longer period of time. The total time spent sleeping and drowsing were slightly higher during the day when com-pared to the night during the completely lit treatment and more time was also spent drows-ing during the day than during the night. These results are in line with previous findings on the subject. There were also no differences in the standing and lying times.