Effect of barley or rape seed cake as supplement to silage for high-yielding organic dairy cows

An experiment was carried out to investigate the effects of barley or rape seed cake as supplement to silage given ad libitum on milk production and health of dairy cows. A total of 103 cows were divided into two groups on two farms. Before the experiment, the cows had an average milk yield of 26.9 kg ECM and they were in milk for an average of 99 days. Their average parity was 2.3 and their weight 596 kg. The cows in each group received either solely barley or an isoenergetic mixture of rape cake seed and barley as supplement. The supplement feed was fed frequently by automatic feeding. A mixture of clover grass silage and whole crop silage was fed ad libitum. The daily milk yields were not significantly different in the barley and rape seed cake treatment (22.8 vs 24.1 kg). The milk fat content was not significant different either (4.51% vs 4.35%). However, the protein content tended to be higher in the barley treatment (3.51% vs 3.45%). But the energy corrected milk yield (ECM) was not significantly different in the barley and rape seed cake treatments either (24.2 vs 24.9 kg ECM). No differences in health as indicated by clinical illness treated by the vet and somatic cell count (SCC) was seen. It was concluded that barley and a mixture of isoenergic rape seed cake and barley had similar feeding value when used as supplement with a high proportion of easily digestible clover grass silage allocated ad libitum and frequently allocation of supplementary feed.