caa a22 4500 386320918 CHVBK 20180307111626.0 cr unu---uuuuu 161130e198808 xx s 000 0 eng 10.1017/S000335610003703X doi S000335610003703X pii (NATIONALLICENCE)cambridge-10.1017/S000335610003703X A study on consistency of differences between cows in rumen outflow rate of fibrous particles and other substrates and consequences for digestibility and intake of roughages [Elektronische Daten] In 22 cows given complete diets of 500 g straw and 500 g concentrates per kg fresh weight the outflow rate of small fibrous particles was determined on two occasions to investigate the consistency of this measurement and its association with apparent digestibility. The correlation between the outflow rates on the two occasions were r = +0·90 and the correlation with apparent digestibility was r = −0·80. In a second experiment, the outflow rates of long and small particles were determined together with rumen retention time. There was no difference between outflow rate of long and small particles but rumen retention times were greater with the long particles. The correlation between the two estimates of outflow rate was r = +0·84. The outflow rate of fish meal was found to be 0·070 while that of short fibrous particles was 0·031 per h. The average liquid outflow rate was 0·146 per h. The three cows with the highest outflow rate and the three with the lowest outflow rate from experiment 2 were selected for experiment 3. While voluntary food intakes of the two groups were similar, the differences in outflow rates between the cows persisted both with ad libitum and restricted intakes of both a high and a low roughage diet. The differences were reflected in significant differences between the two groups in apparent digestibility of the diets. The practical implications for breeding and selection are discussed. Copyright © British Society of Animal Science 1988 Ørskov E. R. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Ojwang I. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Reid G. W. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB Animal Production Cambridge University Press 47/1(1988-08), 45-51 0003-3561 47:1<45 1988 47 ASC https://doi.org/10.1017/S000335610003703X text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S000335610003703X text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Ørskov E. R. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Ojwang I. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 700 1- Reid G. W. Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB NATIONALLICENCE 773 0- Animal Production Cambridge University Press 47/1(1988-08), 45-51 0003-3561 47:1<45 1988 47 ASC CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge