Vitaminen in rantsoenen voor biologisch melkvee = Fat soluble vitamins in rations for organic dairy cows en goat

On five organic dairy cow farms during the period spring 2004/2005 feedstuffs and blood samples were taken 3 times to analyse beta carotene, vitamin D and vitamin E (tocopherols). On 3 organic dairy goat farms feeds and blood samples were taken only in spring 2005. Within types of feeds there are large differences in vitamin content. Vitamin shortages are not to be expected during the grazing season. During the housing period shortages of vitamin D and E might occur in dry cow and in fresh calved cows. In cow, coming into heat sometimes was a problem. On one of the goat farms animal health was not optimal. Rations with a variety of good quality grass silage, artificial dried grass or whole plant silage do not need extra supplementation of vitamins. For supplementation of rations with natural vitamin E plants rich in vegetable oil can be used, supplementation of diets with vitamin D could be found in sun cured products.