caa a22 4500 388060301 CHVBK 20180307125118.0 cr unu---uuuuu 161130e199812 xx s 000 0 eng 10.1017/S1357729800032860 doi S1357729800032860 pii (NATIONALLICENCE)cambridge-10.1017/S1357729800032860 Productivity of grazing Angus steers of different structural size [Elektronische Daten] With the objective of studying the response patterns of two biotypes of different body (structural) size to stocking rate (SR) in terms of individual growth rate (ADG), meat production per ha (PROD) and backfat thickness (BFT) under grazing conditions, 64 steers of two biotypes of the Angus breed of different body size were used: small-sized (SB: frame score of 1·3 (s.d. 0·7)) and medium-sized (MB: 2·9 (s.d. 0·6)). Four levels of SR were applied (1·8, 2·3, 2·8 and 3·3 steers per ha). The experiment lasted 241 days (April to December). Animals were weighed every 14 days, forage availability (FA) was estimated on four occasions and BFT was recorded at the end of the experiment (between 12th and 13th ribs). There were no differences between biotypes in ADG. SB tended to be earlier maturing showing higher BFT (4·39 v. 3·97 mm; P = 0·22). ADG was affected by SR and was higher at lower SR (0·612, 0·529, 0·414 and 0·375 kg/day, for 1·8, 2·3, 2·8 and 3·3 steers per ha, respectively). Individual average daily gain of the MB was more variable across the seasons of the year. None of the variables showed effects of the biotype × SR interaction but differences in ADG between biotypes as a function of the SR were observed as a trend (P = 0·29). Despite the difference in frame score between biotypes it was not possible to associate it with consistent differences in the response variables. Individual productivity (potential) of MB was not reflected in a greater productivity per surface unit. The data from this experiment do not allow the choice of a particular biotype in order to optimize the productivity of the pastoral production systems. Copyright © British Society of Animal Science 1998 backfat nationallicence beef cattle nationallicence body size nationallicence growth rate nationallicence stocking rate nationallicence Romera A. J. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina Mezzadra C. A. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina Villarreal E. L. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina Brizuela M. A. Facultad de Ciencias Agrarias de Balcarce, UNMdP, Argentina Corva P. M. Facultad de Ciencias Agrarias de Balcarce, UNMdP, Argentina Animal Science Cambridge University Press 67/3(1998-12), 455-460 1357-7298 67:3<455 1998 67 ASC https://doi.org/10.1017/S1357729800032860 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1357729800032860 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Romera A. J. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina NATIONALLICENCE 700 1- Mezzadra C. A. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina NATIONALLICENCE 700 1- Villarreal E. L. Estación Experimental Agropecuaria Balcarce, Instituto National de Tecnologia Agropecuaria (INTA), Casilla de Correos 276, 7620 Balcarce, Argentina NATIONALLICENCE 700 1- Brizuela M. A. Facultad de Ciencias Agrarias de Balcarce, UNMdP, Argentina NATIONALLICENCE 700 1- Corva P. M. Facultad de Ciencias Agrarias de Balcarce, UNMdP, Argentina NATIONALLICENCE 773 0- Animal Science Cambridge University Press 67/3(1998-12), 455-460 1357-7298 67:3<455 1998 67 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge