Forage mixtures for dairy cows: the effect on dry-matter intake and milk production of incorporating either fermented or urea-treated whole-crop wheat, brewers' grains, fodder beet or maize silage into diets based on grass silage

Abstract

Abstract One hundred and two multiparous Holstein/Friesian dairy coivs were used to examine the effect on food intake and milk production of replacing 330 g/kg dry matter (DM) of first-cut perennial ryegrass silage (GS) with either fermented (FW) or urea (40 g/kg DM) treated (UW) whole-crop wheat, brewers' grains (BG), fodder beet (FB) or maize silage (MS). A forage mixture containing GS and 750 g/kg DM of maize silage (MSH) was also offered. Dietary crude protein (CP) concentrations were equalized by offering all cows 6 kg DM per day of an appropriate concentrate supplement. DM intake and milk yield of cows offered GS (15·3, 23·0 kg/day) were increased (F < 0·01) by the inclusion of BG (16·3, 26·7 kg/day), FB (17·6, 25·9 kg/day), MS (16·6, 26·4 kg/day) and MSH (18·5, 27·6 kg/day). BG, FB and MS all produced similar increases in milk yield. Although the inclusion of FW and UW increased (F < 0·05) DM intake, milk yield was not significantly affected. The differences between the highest and lowest milk fat concentration, produced by FB (42·9 g/kg) and BG (40·1 g/kg) respectively, and the highest and lowest milk protein concentration produced by FB (32·1 g/kg) and GS (29·9 g/kg) respectively, were statistically significant (F < 0·001). Milk fat and protein yields of cows offered GS (0·97, 0·71 kg/day) were increased (F < 0·01) by BG (1·07, 0·82 kg/day), FB (1·11, 0·83 kg/day), MS (1·11, 0·83 kg/day) and MSH (1·12, 0·88 kg/day). Intermediate values were recorded for FW (1·01, 0·72 kg/day) or UW (1·00, 0·73 kg/day). Results show that farmers should consider replacing a major part of the grass silage component with an alternative forage or forage substitute.