caa a22 4500 386320187 CHVBK 20180307111623.0 cr unu---uuuuu 161130e198806 xx s 000 0 eng 10.1017/S0003356100018936 doi S0003356100018936 pii (NATIONALLICENCE)cambridge-10.1017/S0003356100018936 Milk production in early lactation dairy cows given grass silage ad libitum: Influence of concentrate energy source, crude protein content and level of concentrate allowance [Elektronische Daten] There is increasing interest in how the raw material make-up of concentrates can influence the milk performance of dairy cows. Thus, over two consecutive winters, 54 dairy cows were used to investigate the effects on dry matter (DM) intake, milk yield and its composition of feeding concentrates of diverse energy source (LNDF — 131 g neutral-detergent fibre per kg DM, 492 g starch plus sugars per kg DM; HNDF — 244 g neutral-detergent fibre per kg DM, 293 g starch plus sugar per kg DM) at two formulated crude protein (CP) levels (157 v. 187 g/kg DM) and three levels of concentrate allowance (9, 11, 13 kg DM). The concentrates were formulated to be of equivalent metabolizable energy concentration (MJ/kg DM) and were offered with silage ad libitum for a 10-week period (weeks 4 to 13 of lactation). Silage intakes were variable but not significantly influenced by concentrate energy source or formulated CP level, except in the 1st year where animals consuming the high CP concentrate ate more silage. Silage DM intake decreased as concentrate allowance was increased with the substitution rate (kg silage DM per kg concentrate DM) increasing as concentrate allowance was increased. Increasing the concentrate allowance effected the expected increases in milk yield. Concentrate energy source did not influence milk yield but the higher CP levels effected a 2-kg increase in milk yield. Feeding of LNDF concentrates depressed milk fat concentration and its yield, the depression being accentuated with each increase in concentrate allowance. The depression in milk fat concentration was negatively correlated with the forage: concentrate ratio of the diet consumed. Furthermore, dietary NDF proportion was shown to account for greater than half of the variation in milk fat concentration. In contrast to the observations made for milk fat, feeding the LNDF concentrates effected an increase in milk protein concentration but only at the lower CP level of the concentrate. Copyright © British Society of Animal Science 1988 Sloan B. K. Department of Agriculture, The University, Newcastle Upon Tyne NE1 7RU Rowlinson P. Department of Agriculture, The University, Newcastle Upon Tyne NE1 7RU Armstrong D. G. Department of Agricultural Biochemistry and Nutrition, The University, Newcastle Upon Tyne NE1 7RU Animal Production Cambridge University Press 46/3(1988-06), 317-331 0003-3561 46:3<317 1988 46 ASC https://doi.org/10.1017/S0003356100018936 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0003356100018936 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Sloan B. K. Department of Agriculture, The University, Newcastle Upon Tyne NE1 7RU NATIONALLICENCE 700 1- Rowlinson P. Department of Agriculture, The University, Newcastle Upon Tyne NE1 7RU NATIONALLICENCE 700 1- Armstrong D. G. Department of Agricultural Biochemistry and Nutrition, The University, Newcastle Upon Tyne NE1 7RU NATIONALLICENCE 773 0- Animal Production Cambridge University Press 46/3(1988-06), 317-331 0003-3561 46:3<317 1988 46 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge