Dark pathways : cows’ walking behavior in dim light environments

Sammanfattning: Swedish dairy cows should have access to dim light at night according to the animal welfare act, but there are no further recommendations stated for dim light management regarding light intensity, light color, or light distribution. This study aimed to examine the effects of five dim light intensities, in red and white light color, and in even and uneven light distribution on cows’ walking behavior in an obstacle course. The study was performed during four weeks and a change-over design was applied. Twelve cows were assigned to walk through an obstacle course in 14 light treatments including two control treatments. Five different light intensities, in red and white light, and in evenly and unevenly distributed light were tested. Time taken for the cows to pass through, and number of steps during the obstacle course were recorded. Speed, stepping rate, and step length was calculated. In addition, behavioral observations of the cows walking through the obstacle course were performed. Results showed that cows walked slower and took fewer steps per second in red, unevenly distributed light in medium intensity compared with control light (p<0.05) and red, evenly distributed light in low intensity (p<0.005). Cows’ walking behavior did not differ in the darkest light treatment compared to the other light treatments (p>0.1). Light treatment did not affect the observed behaviors (P>0.3). In conclusion, the results indicate that cows can navigate in dark environments without supplementary light and in red light environments. Red, unevenly distributed light in medium intensity interfered with cows’ walking behavior in the obstacle course. Further research is desirable to investigate dim light effects on cows’ walking behavior in a loose housing system.