Effects of physical treatment of barley and rapeseed meal in dairy cows given grass silage-based diets

Authors

• Pekka Huhtanen Agricultural Research Centre of Finland, Institute of Animal Production, FIN-31600 Jokioinen, Finland
• Terttu Heikkilä Agricultural Research Centre of Finland, Institute of Animal Production, FIN-31600 Jokioinen, Finland

DOI: https://doi.org/10.23986/afsci.72752

Abstract

Twenty-four Ayrshire cows were used to study the effects of physical treatment of barley, rapeseed meal (RSM) supplementation and heat-moisture treatment of RSM on silage intake and milk production. Experimental design was a cyclic change-over with six dietary treatments. The treatments in a 2 x 3 factorial arrangement consisted of either untreated (UB) or heat-moisture treated barley (TB), given without protein supplementation (control) or with untreated or heat-moisture treated RSM. Grass silage was given ad libitum and the concentrates at a rate of 10 kg/d. For the RSM diets, 2 kg/d of the basal concentrate was replaced with either untreated or treated RSM. Treatment of barley decreased silage intake, the effect being greater when the supplement did not contain RSM. There was no effect on milk yield, but due to the lower milk fat content, energy corrected milk yield was lower in cows given TB than in those given UB. Feeding the TB diets was also associated with lower milk urea content, and with increased milk protein content but not protein yield. Faster initial rate of gas production in vitro suggested that the treatment of barley increased the rate of fermentation. Compared with the control diets, RSM supplementation significantly increased silage intake, milk yield, milk protein content and yields of all milk constituents. Heat-moisture treatment of RSM did not produce any further production response.