Endocrine and winter performance responses to supplemental light and evening feeding in heifers

The manipulation of photoperiod is useful to improve dairy cattle milk production and may be useful to improve beef cattle production efficiency. Studies were conducted to investigate the threshold intensity of supplemental light for inhibition of melatonin secretion and to examine the efficacy of s...

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Main Author: Lawson, Trevor J.
Language:en_US
Published: 2007
Online Access:http://hdl.handle.net/1993/1815
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spelling ndltd-LACETR-oai-collectionscanada.gc.ca-MWU.1993-18152014-03-29T03:41:43Z Endocrine and winter performance responses to supplemental light and evening feeding in heifers Lawson, Trevor J. The manipulation of photoperiod is useful to improve dairy cattle milk production and may be useful to improve beef cattle production efficiency. Studies were conducted to investigate the threshold intensity of supplemental light for inhibition of melatonin secretion and to examine the efficacy of supplemental light and evening feeding for improvement of production efficiency of beef cattle housed outdoors in the winter. The threshold intensity of supplemental light for inhibition of melatonin secretion was investigated in dairy heifers using a 5 x 5 Latin Square design with repeated measures. Light treatments were exposure to 0, 50, 100, 200 and 400 lx for 8 h following an 8 h control period at 400 lx. Two experiments (Exp. 1, 1998; Exp. 2, 1999) were conducted to investigate the effects of supplemental light and evening feeding on heifer growth and efficiency, carcass composition, plasma prolactin concentration, and hair shedding of outdoor housed beef heifers (n = 48) in winter. The experiments were conducted using a 2 x 2 Factorial Design and treatments were morning (09:00-10:00 h) or evening (20:00 h) feeding and natural or supplemental light (SL). (Abstract shortened by UMI.) 2007-05-18T19:59:36Z 2007-05-18T19:59:36Z 2000-07-01T00:00:00Z http://hdl.handle.net/1993/1815 en_US
collection NDLTD
language en_US
sources NDLTD
description The manipulation of photoperiod is useful to improve dairy cattle milk production and may be useful to improve beef cattle production efficiency. Studies were conducted to investigate the threshold intensity of supplemental light for inhibition of melatonin secretion and to examine the efficacy of supplemental light and evening feeding for improvement of production efficiency of beef cattle housed outdoors in the winter. The threshold intensity of supplemental light for inhibition of melatonin secretion was investigated in dairy heifers using a 5 x 5 Latin Square design with repeated measures. Light treatments were exposure to 0, 50, 100, 200 and 400 lx for 8 h following an 8 h control period at 400 lx. Two experiments (Exp. 1, 1998; Exp. 2, 1999) were conducted to investigate the effects of supplemental light and evening feeding on heifer growth and efficiency, carcass composition, plasma prolactin concentration, and hair shedding of outdoor housed beef heifers (n = 48) in winter. The experiments were conducted using a 2 x 2 Factorial Design and treatments were morning (09:00-10:00 h) or evening (20:00 h) feeding and natural or supplemental light (SL). (Abstract shortened by UMI.)
author Lawson, Trevor J.
spellingShingle Lawson, Trevor J.
Endocrine and winter performance responses to supplemental light and evening feeding in heifers
author_facet Lawson, Trevor J.
author_sort Lawson, Trevor J.
title Endocrine and winter performance responses to supplemental light and evening feeding in heifers
title_short Endocrine and winter performance responses to supplemental light and evening feeding in heifers
title_full Endocrine and winter performance responses to supplemental light and evening feeding in heifers
title_fullStr Endocrine and winter performance responses to supplemental light and evening feeding in heifers
title_full_unstemmed Endocrine and winter performance responses to supplemental light and evening feeding in heifers
title_sort endocrine and winter performance responses to supplemental light and evening feeding in heifers
publishDate 2007
url http://hdl.handle.net/1993/1815
work_keys_str_mv AT lawsontrevorj endocrineandwinterperformanceresponsestosupplementallightandeveningfeedinginheifers
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