Effects of Stage of Growth and Duration of Rumen Incubation Time on Intestinal Digestibility of Rumen-Undegradable Nitrogen of Grass by Mobile-Bag Method in Cows
作者:
Aila Vanhatalo,
Pawel Dakowski,
Pekka Huhtanen,
期刊:
Acta Agriculturae Scandinavica, Section A — Animal Science
(Taylor Available online 1996)
卷期:
Volume 46,
issue 1
页码: 1-10
ISSN:0906-4702
年代: 1996
DOI:10.1080/09064709609410918
出版商: Taylor & Francis Group
关键词: forage;nylon bags;post-ruminal digestibility;protein evaluation
数据来源: Taylor
摘要:
The ruminal and intestinal degradability of the nitrogen constituents of timothy grass cut at five different stages of growth was studied in three non-lactating cows. The grass samples were incubated in nylon bags in the rumen for 0, 6, 12, 24, 48, 72 and 96 h. The subsequent digestion of rumen-undegradable N in the intestine was measured by the mobile-bag method. The N content of grass declined, and the fibre content and the proportion of N bound in acid detergent fibre increased with increasing maturity. The values for rumen degradability of grass N corrected for microbial contamination were generally high and they decreased with increasing maturity. The intestinal N digestibility of rumen-undegradable N of grass ranged from 49% to 78%, being affected by growth stage and the duration of preceding rumen incubation time. These values may, however, be confounded by non-feed N. Pre-incubation of forage samples in the rumen indicated that at least 48 h of rumen incubation is needed for predicting intestinal N digestibility from the indigestible N fraction determined with the mobile-bag method.
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