By-products from integrated starch-ethanol production from barley in the diets of growing cattle

Authors

• Pekka Huhtanen Department of Animal Husbandry, University of Helsinki, SF-00710 Finland
• Matti Näsi Department of Animal Husbandry, University of Helsinki, SF-00710 Finland
• Hannele Khalili Department of Animal Husbandry, University of Helsinki, SF-00710 Finland

DOI: https://doi.org/10.23986/afsci.72365

Abstract

Two experiments were carried out to evaluate the nutritive value for growing cattle of by-products from a new process for integrated starch-ethanol production from barley. Experiment 1 was a 4 x 4 Latin Square, in which the effects of barley protein (375 g crude protein (CP)/kg dry matter (DM)) on digestibility and N retention were examined in four male cattle (initial live weight(LW) 147 kg). The control diet (C) consisted of hay and rolled barley (1 : 1). In isonitrogenous experimental diets, soybean meal (S), a mixture of soybean meal and barley protein (SB) or barley protein (B) was substituted for barley to increase the dietary CP content from 125 to 150 g/kg DM. Replacement of barley with protein supplements increased (P<0.01) the apparent digestibility of CP but had no effect on organic matter (OM) digestibility. Gradual replacement of soybean meal with barley protein decreased N retention linearly (P<0.05) from 32.0 to 28.9 g/d. Increasing the supply of CP by including barley protein in the diet had no effect on N retention. In experiment 2 the effects of barley fibre (566 g NDF/kg DM, 137 g CP/kg DM) as an energy supplement for growing cattle given grass silage ad libitum were examined. In a 3 x 2 factorial experiment the three energy supplements were barley (B), barley + barley fibre (1:1, BF) and barley fibre (F), each fed without and with 0.5 kg of rapeseed meal (RSM) per day. The supplements including RSM were fed at the rate of 45 g DM/kg LW0.75. The experiment involved 24 bulls (initial LW 165 kg) and the treatments were imposed for 224 days. The silage used was of high quality in terms of both digestibility and fermentation parameters. RSM had no effect on silage DM intake or LW gain. During the first 16 weeks of the study the cattle given RSM tended (P < 0.06) to grow faster than those fed without additional protein, but this advantage entirely disappeared during the last 16 weeks of the study. Replacing barley with barley fibre resulted in a non-significant (P>0.1) linear decrease in LW gain (from 1278 to 1214 g/d). Feed conversion rate in terms of feed units per kg LW gain improved linearly (P <0.05) with the level of barley fibre. Carcass characteristics were not significantly affected by the diet given.