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Conference abstract2014

Effect of Low Light Intensity on Stress Indicators in Dairy Cows

Ferneborg, Sabine; Eriksson, J.; Olsson, P.; Agenäs, Sigrid; Ternman, Emma


One of the most important senses for cows is vision, which accounts for approximately 50% of all sensory information (Phillips 2002). It has been shown that cows’ vision differs from that of humans (Phillips and Weiguo 1990), but how cows perceive different light intensities is not yet known (Phillips et al 2000). There is a concern that lighting at night might interfere with cows’ diurnal rhythm and the benefits of certain long day photoperiods. Red light has been suggested to affect cows less than white light and red lights are therefore marketed as night lighting for cows. Using red lights should in theory make it possible for stockmen to observe their animals without disturbing them (Dahl 2005). However, it has also been found that cows are more active when exposed to red light compared to light of other colours (Dabrowska I 1981; Riol et al 1989; Phillips and Lomas 2001). The aim of this study was to investigate the effect of four low light intensities and additional red light on behavioural and physiological stress indicators in dairy cows. The change-over trial included four groups of cows and four different light intensity treatments, in total 12 dry cows of the breeds Swedish Red (n=10) and Swedish Holstein (n=2). Each group of three cows was in the study for four consecutive days, exposed to one light intensity treatment per day. The light intensities used in the study were 0±0, 5±1, 20±1 and 50±2 lux, with and without the addition of 0.2±0.1 lux red light. The light sources used were a combination of fluorescent, halogen and LED. The cows were encouraged to walk through an obstacle course at all four light intensities. The cows passed through the course once in full light (221±19 lux) before each light intensity was set. The cows then passed through the same test course twice. After this, the obstacle course was rebuilt for the following two rounds, generating two new (and unfamiliar) courses. Additional red light was applied in random order for each set of obstacle courses. In total, the cows passed through the course five times per day, of which two were in additional red light. The obstacle course measured 14 m and was constructed from white rails and cavaletti blocks. When navigating through the obstacle course, the cow walked toward the single pens where the remaining two cows in the group were held and a bucket with concentrate that was used to actively encourage the cow to move. In addition, one person went behind the cow and encouraged her to move if standing still for more than approximately 15 seconds. Heart rate was measured before and after the obstacle course using a blood pressure tail cuff. Direct observations were used to record number of steps and time to pass through the obstacle course. At 0 lux, infrared light and video cameras were used in order to see the cows. The number of steps taken by cows in the obstacle course was significantly higher at 0±0 lux (16 steps) than at 5, 20 and 50 lux (14 steps per treatment, p<0.001). In the presence of red light the cows took fewer steps through the obstacle course than in the absence of red light (14 and 15 respectively, p<0.01), and the cows spent a longer time in the obstacle course at 0 lux than at 20 and 50 lux (87.4, 51.6 and 57.6 sec respectively, p<0.005). The presence of red light did not affect the time spent in the obstacle course. Heart rate did not differ between any of the treatments, and was unaffected by the presence of red light. Our conclusion is that cows walk slower and with shorter steps at 0 lux compared with 0.2 lux and higher light intensities. However, in this study the cows did not show any signs of physiological stress at low light intensities or darkness and thus it could be argued that no additional light is needed at all during night-time. We also conclude that red light may be perceived by cows as light and affect their behaviour, since the cows in this study tended to respond to red light. The recommended use of red light in cow housing should therefore be questioned.

Published in

Animal Production in Australia
2014, Volume: 30, pages: 152-152 Title: Proceedings of the 30th Biennial Conference of the Australian Society of Animal Production
Publisher: Australian Society of Animal Production


Joint ISNH / ISRP International Conference 2014 : Harnessing the Ecology and Physiology of Herbivores