Differential response of dairy cows to supplementary light during increasing or decreasing daylength

Abstract

Two experiments were conducted to compare the response oflactating cows to supplementary light in their lying area during increasing and decreasing natural daylength. During decreasing daylength, supplementary light in the lying area increased the time cows spent lying down and considerably reduced calculated food intake, milk production, live weight and body condition, so that lights were installed in the feeding area for the last half of the experiment, which partially restored intake and live weight. Plasma cortisol concentrations and milk somatic cell counts were increased by supplementary light in decreasing daylength before, but not after, lights were installed in the feeding passage, suggesting that cows may have been stressed by the difficulties encountered during feeding in the dark. During increasing daylength supplementary light did not affect lying time, had less effect on food intake and no effect on milk production or live weight. There was a small reduction in plasma corticosteroid by the end of the experiment with supplementary light. It is concluded that providing supplementary light only in the lying area of dairy cows will have adverse effects on their production and welfare in decreasing, but not increasing daylength

Effect of rumen fill on intake of fresh perennial ryegrass in young and mature dairy cows grazing or zero-grazing fresh perennial ryegrass

“…It has also been observed that the reduction of the daylight in autumn caused a compression of grazing time to within daylights hours (Phillips and Leaver, 1985). In the present experiment, artificial light of the barn was off during the night between 2030 and 0630 h, but it has been observed that artificial light during the night had limited impact of the daily pattern of chewing behavior of dairy cows (Tanida et al, 1984), at least when day length is increasing (Phillips et al, 1998). It is possible that the absence of vision during the night deterred the animals from grazing outside but other external factors, such as temperature or solar radiation, can significantly alter chewing behavior at grazing compared to indoor feeding (Prasanpanich et al, 2003).…”

Effects of evening feeding and extended photoperiod on growth, feed efficiency, live animal carcass traits and plasma prolactin of beef heifers housed outdoors during two Manitoba winters

“…2 in morning-fed EP heifers on day 163. Phillips et al (1998) suggested that the response of cattle to photoperiod may depend more on changes in photoperiod than photoperiod per se. Subsequent to the first month of our experiments, while the duration of photoperiod was longer for the EP than NP treatment, the duration of photoperiod was rising approximately 2.5-fold more rapidly in NP than EP treatments (Fig.…”