Effects of brown midrib 3 mutation in corn silage on productivity of dairycows fed two concentrations of dietary neutral detergent fiber: 2. Chewingactivities

Authors
Citation
M. Oba et Ms. Allen, Effects of brown midrib 3 mutation in corn silage on productivity of dairycows fed two concentrations of dietary neutral detergent fiber: 2. Chewingactivities, J DAIRY SCI, 83(6), 2000, pp. 1342-1349
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Food Science/Nutrition
Journal title
JOURNAL OF DAIRY SCIENCE
ISSN journal
0022-0302 → ACNP
Volume
83
Issue
6
Year of publication
2000
Pages
1342 - 1349
Database
ISI
SICI code
0022-0302(200006)83:6<1342:EOBM3M>2.0.ZU;2-0
Abstract
The effects of digestibility of corn silage neutral detergent fiber (NDF) a nd dietary NDF content on chewing activities were evaluated with eight mult iparous high producing dairy cows in a duplicated 4 x 4 Latin square design with 21-d periods. Experimental diets contained corn silage from a brown m idrib (bm3) hybrid or its isogenic normal control at two concentrations of dietary NDF (29 and 38%). The NDF digestibility estimated by 30-h in vitro fermentation was higher for bm3 corn silage by 9.4 units (55.9 vs. 46.5%). Feeding behavior of animals and ruminal pH were monitored continuously for 4 d in each period by a computerized data acquisition system. Ruminal diges ta were evacuated twice per period to determine the ruminal NDF pool and it s turnover rate. There was no effect of NDF digestibility on total chewing time either per day or per kilogram of NDF intake, or on ruminating time ei ther per day or per kilogram of NDF intake. Although bm3 treatments increas ed the turnover rate of NDF in the rumen, they increased dry matter intake and had no effect on ruminal NDF pool size. Total chewing time and ruminati ng time per day were related positively to NDF intake and ruminal NDF pool size, but were not related to ruminal turnover rate of NDF. These results p rovide no evidence that enhanced NDF digestibility decreases the physical e ffectiveness of NDF of corn silage.