Effects of barley grain compared to commercial concentrate or rapeseed meal supplementation on performance of growing dairy bulls offered grass silage-based diet

Abstract

The objectives of the study with dairy bulls offered grass silage-based diet were to determine the effects on animal performance of (1) concentrate type (barley vs. commercial concentrate) and (2) supplementation of rapeseed meal (RSM) in barley-based concentrate, with data being compared from preweaning to slaughter. The experiment comprised a total of 37 Finnish Ayrshire and 23 Holstein-Friesian bulls. Experimental concentrate treatments were 1) rolled barley (B), 2) rolled barley + rapeseed meal (BRSM) and 3) commercial concentrate (CC). During the preweaning (from 0.5 to 2.5 months) there were no differences in intake, gain or feed conversion. During the postweaning (from 2.5 to 6.0 months) the energy intake and gain of the B bulls were 12-13% lower than those of the BRSM bulls (p < 0.05) and 16% lower than those of the CC bulls (p < 0.01). However, there were no treatment differences in the energy intake or gain of the bulls during the finishing period (from 6.0 to 18.0 months of age) or on average during the experiment. Furthermore, carcass traits of the bulls did not differ between treatments. It is concluded that production traits were unaffected by concentrate type or RSM supplementation when data is compared from preweaning to slaughter. © Agricultural and Food Science.