Response of silage intake and milk production to replacement of barley by barley fibre derived from integrated starch-ethanol process

Authors

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

DOI: https://doi.org/10.23986/afsci.72339

Abstract

A duplicated 4 x 4 Latin Square experiment was conducted to determine the effects of a gradually increased level of barley fibre in the diet on ad libitum grass silage intake and milk production. Barley fibre is a fibrous ethanol-starch by-product (120 g crude protein, 550 g neutral detergent fibre (NDF) and 120 g starch/kg dry matter (DM)). The four supplements, given at the rate of 6.5 kg/d on DM basis, were barley (B) and barley of which 333 g/kg (BF), 667 g/kg (FB) and 1000 g/kg (F) were replaced by barley fibre. In addition the cows were given 1 kg of rapeseed meal and 0.25 kg of mineral mixture. As the proportion of barley fibre in the diet increased there was a linear (P<0.001) increase in silage DM intake. The cows ate less concentrate at the higher levels of barley fibre inclusion, so that there was a tendency for higher total DM intake only when the intermediate levels of barley fibre (diets BF and FB) were given (quadratic effect; P<0.1). Milk yield and fat corrected milk yield were not significantly affected by the level of barley fibre. However, as the proportion of barley fibre in the diet was increased, milk protein content decreased (linear effect; P<0.01), there was a trend towards lower milk fat content (linear and quadratic effect; P<0.1) and milk protein yield decreased (P<0.05). At the same time the digestibility of organic matter(OM) decreased from 0.742 to 0.661 (P <0.001). Digestibilities of ether extract and nitrogen were not affected by the diet but digestibilities of cell wall components decreased with the level of barley fibre. Calculations of energy balance suggested that the metabolizable energy of barley was either utilized less efficiently for milk production or, more likely, cows given barley partitioned more energy to body fat stores than those given barley fibre.