caa a22 4500 386320527 CHVBK 20180307111625.0 cr unu---uuuuu 161130e198812 xx s 000 0 eng 10.1017/S0003356100003457 doi S0003356100003457 pii (NATIONALLICENCE)cambridge-10.1017/S0003356100003457 The effects of body condition at calving and dietary protein content on dry-matter intake and performance in lactating dairy cows given diets of low energy content [Elektronische Daten] Four groups of six cows were fed from 12 weeks before calving to achieve condition scores at calving of 3·15 (F) and 2·15 (T). For the first 20 weeks of lactation all cows were given 8 kg concentrate (13·93 MJ metabolizable energy (ME) per kg dry matter (DM), 200 g crude protein (CP) per kg DM) which contained either a high or a low dietary concentration of undegradable dietary protein (UDP) (70 g/kg DM, H, and 49 g/kg DM, L) and 3 kg sugar-beet pulp. Hay was also offered ad libitum. There was no significant effect of treatment on milk yields over the first 20 weeks of lactation (overall mean yield 27·3 (s.e. 3·65) kg/day) but cows in group FL tended to produce less (P > 005). Milk composition was similar for all groups (48·8 (s.e. 5·12) g fat per kg, 27·2 (s.e. 1·48) g protein per kg and 49·0 (s.e. 2·52) g lactose per kg). DM intakes for groups FH, FL, TH and TL were 18·1, 16·9, 17·5 and 18·2 (s.e.d. 0·58) kg/day, respectively (TL v. FL, P < 0·05; FH v. FL, P < 0·05). Mean condition scores for groups FH, FL, TH and TL respectively, were 3·T7, 3·13, 2·21 and 2·08 (s.e.d. 0·18) at calving; 2·25, 2·50, 2·21 and 1·83 (s.e.d. 0·27) in week 10; and 2·46, 2·83, 2·46 and 1·96 (s.e.d. 0·35) in week 20, of lactation. Groups FH, FL, TH and TL lost proportionately 0·09, 0·02, 0·01 and 0·04 (s.e.d. 0·035) of their calving live weights, respectively, over 20 weeks of lactation. It is concluded that increasing the supply of UDP to cows which are fat at calving results in a greater negative energy balance and a small though non-significant increase in mobilization of body fat reserves. At the dietary ME and protein concentrations used, the thin cows could not respond to increased UDP supply and their intake was limited by physical restriction. Copyright © British Society of Animal Science 1988 Jones G. P. Department of Agriculture and Horticulture, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough LE12 5RD Garnsworthy P. C. Department of Agriculture and Horticulture, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough LE12 5RD Animal Production Cambridge University Press 47/3(1988-12), 321-333 0003-3561 47:3<321 1988 47 ASC https://doi.org/10.1017/S0003356100003457 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S0003356100003457 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jones G. P. Department of Agriculture and Horticulture, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough LE12 5RD NATIONALLICENCE 700 1- Garnsworthy P. C. Department of Agriculture and Horticulture, University of Nottingham School of Agriculture, Sutton Bonington, Loughborough LE12 5RD NATIONALLICENCE 773 0- Animal Production Cambridge University Press 47/3(1988-12), 321-333 0003-3561 47:3<321 1988 47 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge