Organic dairy production based on rapeseed, rapeseed cake or cereals as supplement to silage ad libitum

Summary

This experiment presents the effect of 100% organic feed rations grown at an equal area per cow on milk production performance and metabolic responses. A total of 174 Danish Holstein cows were included in two experiments on two commercial organic dairy farms during the winter 2000/2001. Three types of supplementary feed were examined: 5 kg cereals, 3 kg rapeseed/cereal pellet or 1 kg rapeseed cake fed with a mixture of clover grass silage, whole crop silage and grass pellets ad libitum. The supplement of rapeseed/cereal pellet compared with cereals tended to decrease both milk fat and protein content, whereas fat and protein yield were unaffected. Milk yield was increased by supplement of rapeseed/cereal pellet compared with cereals in experiment 1, but unaffected in experiment 2. Consequently, energy corrected milk yield tended to be increased in experiment 1 but decreased in experiment 2. The supplement of rapeseed cake compared with cereals changed neither milk composition nor yield. The risk of subclinical ketosis based on metabolic parameters and other metabolic disorders was not affected by the different feedings.