Plasma vitamin D3 response in cattle and sheep exposed to ultraviolet radiation
Hidiroglou, M.; Williams, C.J.; Proulx, J.G.
International Journal for Vitamin and Nutrition Research. Internationale Zeitschrift für Vitamin- und Ernahrungsforschung. Journal International de Vitaminologie et de Nutrition 55(1): 41-46
1985
ISSN/ISBN: 0300-9831 PMID: 2987148 Document Number: 244104
For 5 weeks 10 Shorthorn X Hereford cows kept indoors during winter in northern Ontario and fed freely on grass silage were exposed to ultraviolet radiation (UVR) from 1700 to 2100 h daily. Groups of 4 yearling wether sheep were kept indoors for 6 weeks and had no UVR treatment or were exposed to UVR for 1 or 2 h daily. Exposure to UVR was associated with a significant increase in plasma cholecalciferol in cows. Plasma cholecalciferol increased also in sheep exposed to UVR. There was no difference in plasma cholecalciferol concentration between groups exposed to UVR for different times.