Preferences of Dairy Cattle for Supplemental Light-Emitting Diode Lighting in the Resting Area

SIMPLE SUMMARY: The effects of light exposure on dairy cattle milk production are well known, whereas aspects of light quality and potential benefits on dairy production and health are currently undetermined. We developed a supplemental lighting system (i.e., in addition to existing natural and artificial light in the facility) to provide light to cows while lying down. This study assessed dairy cow preferences for three colours of light-emitting diode lighting in the free-stall area. Cows did not prefer lying down under any of the light-emitting diode light options provided. Our results suggest that short-term use of supplemental light-emitting diode lighting in the stall area was not avoided by cows and lays the groundwork to study various aspects of light-emitting diode light, including the quality (wavelength), intensity, and duration of exposure. ABSTRACT: Light from the environment is important for vision and regulating various biological processes. Providing supplemental lighting in the stall area could allow for individually targeted or group-level control of light. This study aimed to determine whether dairy cattle had preferences for short-term exposure to white (full-spectrum) light-emitting diode (LED) light or no LED light, yellow-green or white LED light, and blue or white LED light in the stall area. In total, 14 lactating cows were housed in a free-stall pen with unrestricted access to 28 stalls. LED light was controlled separately for each side of the stall platform. Two combinations of light were tested per week, and each week consisted of three adaptation days and four treatment days. Lying behaviour and video data were recorded continuously using leg-mounted pedometers and cameras, respectively. Preference was assessed by the amount of time spent lying and the number of bouts under each light treatment. No differences occurred between treatments within each week for daily lying time and number of bouts. Similarly, no differences occurred between treatments within each time period. Further controlled studies of long-term exposure to different LED wavelengths and intensities are required to determine potential benefits on metabolic processes.