Effects of chopping length of corn and sorghum silages on chewing time and passage rates of digesta in wethers
1997
Ohshita, T. (Tohoku National Agricultural Experiment Station, Morioka (Japan)) | Kyuma, T. | Kondo, T.
Twelve wether (average weight 62.3kg) were used in an experiment with this 2 x 2 factorial design to determine effects of chopping length on digestibilities, chewing time and passage rates of digesta. Whole-plant corn (G 4589) and sorghum (Suzuho) were harvested at the yellow-ripe stage and hard-dough stage of maturity. The forages were cut at theoretical chopping lengths; (1) 9 mm (short) and (2) 20 mm (long), before ensiling, respectively. There was no effect of chopping length on silage quality for both crops,and all silages showed good fermentative qualities. Dry matter intake of sorghum silage was significantly lower (p0.01) than that of corn silage. There was a significant difference in eating time between 9 mm and 20 mm for both crops. For wether fed corn silages, there was no significant difference in ruminating time between 9 mm and 20 mm. In contrast, there was a significant difference (p0.05) between chopping length in ruminating time for sorghum silage. Ruminal fluid and particulate passage rates of digesta for sorghum silage were significantly slower (P0.01) than for corn silage. For corn silage, no significant differences were observed between 20 mm and 9 mm in rates of passage of fluid and particles. Ruminal particulate passage rates for 20 mm sorghum silage were significantly slower (p0.05) than for 9 mm sorghum silage. These results suggested that chopping length of sorghum silage affected dry matter intake and rates of passage from the rumen, and considering chewing time. It was closely related with particle size reduction by mastication
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