Access to outside areas during March and April in Denmark has negligible effect on the vitamin D₃ status of organic dairy cows

Lone Hymoller, Louise Karoline Mikkelsen, Soren Krogh Jensen, Mette Olaf Nielsen and Ole Aaes

Acta Agriculturae Scandinavica, Section A - Animal Sciences 58 ( 1 ): 51 - 54 , 2008