The following requirements are necessary for the dDrei status:
- the dairy company guarantees that the natural concentration of vitamin D3 in the milk is at least 1.5 µg/100 ml milk.
- the dairy company guarantees that the milk is at least quality class “S” (superior standard).
- the farm has sufficient farmland (grassland and arable land) in relation to the number of cows. Basic rule: half a football field for each cow.
- the animals are kept exclusively in free-roaming systems in which the animals are able to freely go to their feeding, drinking and sleeping places at any time of the day or night.
- The animals must be able to roam freely in the sun or light must be installed in the barn that can emit all colors of the sunlight spectrum so that the animals can build up vitamin D and improve their self-immunization.
- the health and welfare of the animals must be regularly checked by the competent veterinary office.
- The statutory animal welfare conditions must be observed.
- Dairy farms that feed high-quality grass and herb mixes that contain the important amino acid tryptophan, e.g. alfalfa or clover (“green protein”) are particularly preferred.
- Only regional basic fodder is to be used.