Title: EFFECT OF EXTENDED PHOTOPERIOD IN WINTER ON GROWTH RATE OF FRIESIAN MALE CATTLE
Abstract: Four experiments were carried out to determine the effect of extended photoperiod on growth rate of Friesian male cattle in winter. In Experiment 1, bull calves exposed to 16 h light and 8 h darkness had a liveweight gain of 39 ? 2.8 kg compared to 42 ? 2.8 kg for calves exposed to 8 h light and 16 h darkness over an 84-day experimental period (p>0.05). In Experiment 2, bull calves exposed to natural daylight in winter for 84 days had a liveweight gain of 40 ? 2.1 kg compared to 44 ? 2.1 kg for calves exposed to natural light (p>0.05) which was extended by an extra 8 h with fluorescent lights switched on from 16.00 to 24.00 hours. In Experiment 3, 15-month-old steers were exposed in winter to (i) natural light, (ii) 16 h light and 8 h darkness or (iii) 8 h light and 16 h darkness. The liveweight gains (p > 0.01) over a 100-day experimental period were as follows: (i) 87 ? 3.4 kg, (ii) 94 ? 3.4 kg and (iii) 97 + 3.4 kg. In Experiment 4, finishing steers in winter were exposed to (i) natural daylength, (ii) natural day length + low-intensity artificial light from 16.00 to 24.00 h and (iii) natural daylength + high intensity artificial light from 16.00 to 24.00 h. The final carcass weights were not different (p > 0.05), being 304 ? 5.6, 301 + 5.6 and 305 + 5.4 kg for the three treatments respectively. It is concluded that extending the photoperiod in winter does not increase growth rate in male Friesian cattle at locations in Meath or Kildare, Ireland.
Publication Year: 2016
Publication Date: 2016-01-01
Language: en
Type: article
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Cited By Count: 16
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