Hymøller Lone, Jensen Søren K, Lindqvist Hanna, Johansson Birgitta, Nielsen Mette O, Nadeau Elisabet
Department of Animal Health, Welfare and Nutrition, Aarhus University, Blichers Allé 20, Box 50, DK-8830 Tjele, Denmark.
J Dairy Res. 2009 Aug;76(3):372-8. doi: 10.1017/S0022029909004130. Epub 2009 May 18.
Use of synthetic feed additives, including synthetic vitamin D3 (D3) in the feed for cows and other ruminants, is not consistent with the international principles of organic farming. If dairy farmers wish to produce in accordance with the organic principles, production animals would be left with only their endogenous production of D3 from summer sunlight as a source of D3. To examine the impact of supplemental synthetic D3 from the feed on the D3 status of dairy cattle in organic production in Nordic countries, 20 high-yielding dairy cows and 30 dairy steers were divided into two groups: one supplemented with synthetic D3 in the feed and one not supplemented with synthetic D3. Vitamin D3 status of the animals was assessed by measuring the concentration of the liver-derived 25-hydroxyvitamin D3 (25OHD3) in plasma. Results showed that 25OHD3 concentration in plasma from dairy cattle as well as from steers decreased during winter for both supplemented and unsupplemented groups. Unsupplemented cows and steers had approximately 2 ng 25OHD3 per ml plasma during winter, whereas supplemented animals had between 10 (cows) and 30 (steers) ng/ml. During summer and autumn there was no additive effect of supplementing with synthetic D3 since unsupplemented and supplemented animals had the same D3 status at this time of year. In all cows summer concentrations of 25OHD3 were 20-25 ng/ml and in all steers 40-50 ng/ml plasma. The decrease in vitamin D3 status during winter indicates that cows and steers are able to store D3 only to a limited extent. The results also show that cows or steers fed supplemental D3 according to Swedish recommendation throughout the year are not able to maintain their summer value of 25OHD3 during winter.
在奶牛和其他反刍动物的饲料中使用合成饲料添加剂，包括合成维生素D3（D3），不符合有机农业的国际原则。如果奶农希望按照有机原则进行生产，生产动物将只能依靠夏季阳光内源性产生的D3作为D3的来源。为了研究饲料中添加合成D3对北欧有机生产中奶牛维生素D3状态的影响，将20头高产奶牛和30头育肥牛分为两组：一组在饲料中添加合成D3，另一组不添加合成D3。通过测量血浆中肝脏来源的25-羟基维生素D3（25OHD3）的浓度来评估动物的维生素D3状态。结果显示，在冬季，添加组和未添加组的奶牛以及育肥牛血浆中的25OHD3浓度均下降。未添加组的奶牛和育肥牛在冬季血浆中约有2 ng/ml的25OHD3，而添加组动物的血浆浓度在10（奶牛）至30（育肥牛）ng/ml之间。在夏季和秋季，添加合成D3没有额外效果，因为未添加组和添加组的动物在一年中的这个时候维生素D3状态相同。所有奶牛夏季的25OHD3浓度为20 - 25 ng/ml，所有育肥牛血浆中的浓度为40 - 50 ng/ml。冬季维生素D3状态的下降表明奶牛和育肥牛只能有限地储存D3。结果还表明，全年按照瑞典建议饲喂补充D3的奶牛或育肥牛在冬季无法维持其夏季的25OHD3值。
