Although previous studies have investigated the effects of
different vitamin dosages, the influence of ultraviolet (UV)
radiation from sunlight on the animals has not been considered.
This influence may explain inconsistencies in the results
regarding vitamin D3 supplementation, especially at lower
levels. The 25-hydroxy-vitamin D3 [25(OH)D3] concentrations
in sheep are affected as the result of the interaction between
intravenously administered 25(OH)D3 and sunlight
exposure