Six ruminal-cannulated nonlactating Holstein Friesian cows (mean body weight:660 ± 42.9 kg) were used to investigate the effect of soybean meal (SBM) supplementation on voluntary rice straw (RS) intake, feed particle size reduction, and passage kinetics in the rumen. They were allocated to two dietary treatments: RS alone or RS supplemented with SBM. Voluntary dry matter intake of RS and total tract fiber digestibility was increased by SBM supplementation (p < 0.05). Supplementation with SBM decreased rumination time per dietary dry matter (DM) and neutral detergent fiber (NDFom) intake (p < 0.01). Particle size distribution in the rumen and total ruminal NDFom digesta weights were not affected by SBM supplementation. However, the disappearance rates of total digesta and large and small particles from the rumen were increased by SBM supplementation (p < 0.01). Moreover, SBM supplementation increased the rate of size reduction in ruminal particles (p < 0.05). In situ disappearance of DM and NDFom of RS in the rumen was greater in SBM-supplemented cows than in nonsupplemented cows (p < 0.05). This study clearly showed that increased ruminal RS particle size reduction, passage, and fermentation due to SBM supplementation accelerated the RS particle clearance from the rumen and resulted in increased voluntary RS intake of dairy cows.

中文翻译：

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添加豆粕对饲喂稻草的奶牛瘤胃饲料粒度减小和通过的影响

六头瘤胃插管的非泌乳荷斯坦黑白花奶牛（平均体重：660 ± 42.9 kg）用于研究补充豆粕（SBM）对自愿稻草（RS）采食量、饲料粒度减小和通过动力学的影响瘤胃。他们被分配到两种饮食治疗：单独的 RS 或补充 SBM 的 RS。补充 SBM 增加了 RS 的自愿干物质摄入量和总纤维消化率 ( p  < 0.05)。补充 SBM 可减少每份膳食干物质 (DM) 和中性洗涤纤维 (NDFom) 摄入量的反刍时间 ( p < 0.01)。瘤胃中的粒度分布和瘤胃 NDFom 食糜总重量不受 SBM 补充的影响。然而，补充豆粕增加了瘤胃中总食糜和大小颗粒的消失率 ( p  < 0.01)。此外，SBM 补充剂增加了瘤胃颗粒的尺寸减小率 ( p  < 0.05)。与未补充 SBM 的奶牛相比，补充 SBM 的奶牛瘤胃中 DM 和 RS 的 NDFom 的原位消失 ( p  < 0.05)。该研究清楚地表明，由于补充 SBM 导致瘤胃 RS 颗粒尺寸减小、通过和发酵增加，加速了 RS 颗粒从瘤胃清除，并导致奶牛自愿 RS 摄入量增加。