Effect of ensiling whole barley grain with pasture on silage quality and effluent production, and the performance of growing cattle

Abstract

Pasture was ensiled with increasing amounts of whole barley in stacks [0, 75 (SLB), 150 (SMB) kg/t fresh pasture] or in 200-L drum silos 10, 75 (DLB), 150 (DMB), 225 (DHB) kg/t fresh pasture]. All silages were well fermented with low pH values and low ammonia concentrations. The addition of barley significantly (P<0.05) increased the dry matter content of the resultant stack silages by 29% (SLB) and 54% (SMB) and significantly (P<0.05) increased residual water-soluble carbohydrate levels in the SMB silage compared with untreated stack silage. Incorporation of barley with pasture in 200-L silos significantly (P<0.001) increased the dry matter of the resultant silages and significantly (P<0.01) reduced effluent production by 55, 93, and 100% for DLB, DMB, and DHB compared with the untreated silo silage. Dry matter, nitrogen, and lactic acid concentrations in effluent did not differ significantly, although total losses of these components were significantly (P<0.01) higher in the untreated silage.| The stack silages were fed to beef steers (293 kg) and compared with silage diets containing equivalent levels of rolled barley mixed with untreated silage at feeding. Irrespective of method of feeding barley, animal performance improved compared with feeding a silage-only diet. At equivalent levels of barley inclusion, liveweight gains were higher and feed conversion ratios lower with the rolled barley diets. The results indicate that the addition of barley to low dry matter pasture during ensiling can reduce effluent production and the loss of soluble nutrients; however, it is likely that the grain will need to be processed to maximise subsequent animal production.