Grass Hay as a Supplement for Grazing Cattle II. Ruminal Digesta Kinetics

Guillermo Villalobos, Terry J. Klopfenstein, Don C. Adams, Drew Shain, Thomas E. Long
1997 Journal of range management  
This study evaluated the effects of supplementing a diet of range hay (5.7% crude protein, 68% NDP) with grass hay from subirrigated meadows (16.5% crude protein, 53.5% NDP), or with a 70% soybean meal:30% wheat grain supplement (40% crude protein) on intake and ruminal digesta kinetics. Twelve ruminally fistulated steers were assigned to 3 treatments (4 steers/treatment) at 2 levels of intake. Treatments were: 1) control, range hay; 2) range hay supplemented with meadow hay (meadow hay was 20%
more » ... (meadow hay was 20% of intake); and 3) range hay supplemented with soybean meal:wheat supplement (supplement was 8% of intake). Intake levels were: 1) ad libitum and 2) equal intake (15% of body weight). Range hay was Yb-labeled, and meadow hay and soybean meabwheat supplements were Er-labeled to measure passage. Intake and digestibility of range hay was not affected by supplementation (P > 0.05). During ad libitum intake, total intake (range hay + supplement) was greater (P < 0.05) for supplement treatments than for the control. No supplement treatment X level of intake interactions were detected (P > 0.05). Total digestibiity (range hay + supplement) was greater (P < 0.01) for the soybean meabwheat treatment than for the control or meadow hay treatments. Total digestibility was similar (P > 0.05) for control and meadow hay treatments. Ruminal passage rate (% hour-'), total tract mean retention time, and intestinal transit time of range hay did not differ among treatments (P > O.OS), but ruminal passage rate, total tract mean retention time, and intestiml transit time were greater (P < 0.01) with ad libitmn than equal intake. We conclude that a meadow hay supplement produced similar effects on ruminal kinetics and intake of range hay as a soybean meahwheat supplement.
doi:10.2307/4003299 fatcat:pwvzvch6x5chpbxlgpx7grwvnq