Hay and silage as vitamin sources in organic sheep production

摘要

The contribution of the essential vitamins A and E from organic forage-based rations was investigated, and how this affects the vitamin status of sheep. Two experiments were carried out during pregnancy and lactation in a herd consisting of 56 crossbred ewes. In the first study (I) hay and silage were compared. In the second study (II) two lambing times were compared and all the ewes had silage. Apart from forage, the rations contained barley, peas, rapeseed cake and minerals. There was no vitamin supplementation. Feed intake was registered and the vitamin content of feed and blood plasma was analysed. Experiment I: Silage-fed ewes had higher levels of blood alfa-tocopherol in mid pregnancy (0.50 mg I~(-1)) compared to hay-fed ewes (0.29 mg I~(-1)).The intake of beta-carotene in the hay group was significantly lower than in the silage group. This was also reflected in blood vitamin A levels, which were higher in the silage group from the middle of pregnancy. Experiment II: Early lambing ewes had higher blood levels of alfa-tocopherol during pregnancy compared with late lambers (in late pregnancy 0.91 and 0.58 mg I~(-1), respectively). One month after lambing, the late lambers were on pasture and had higher blood alfa-tocopherol levels (1.78 mg I~(-1)) than the early group (0.81 mg I~(-1)).