Prigge E C, Stuthers B A, Jacquemet N A
Div. of Anim. and Vet. Sci., West Virginia University, Morgantown 26506-6108.
J Anim Sci. 1990 Dec;68(12):4352-60. doi: 10.2527/1990.68124352x.
To assess the influence of forage diets on particle size of digesta in the rumen, three ruminally fistulated steers were fed alfalfa, orchardgrass or switchgrass hays in a 3 x 3 Latin square design. Mean sieve size of ruminal digesta for alfalfa, orchardgrass and switchgrass diets was 671, 652 and 466 microns, respectively. A second experiment examined the influence of ruminal particle size on digesta passage, digestibility and intake. Four ruminally fistulated Angus-Hereford steers were given ad libitum access to different proportions of alfalfa and switchgrass in a 4 x 4 Latin square design. Either a 100% alfalfa, 50% alfalfa:50% switchgrass, 25% alfalfa:75% switchgrass or 100% switchgrass diet was offered once daily. Mean sieve sizes of the ruminal digesta of these diets responded cubically (P less than .01; 1,066, 946, 1,003 and 925 microns, respectively). Mean ruminal turnover times were 24.3, 24.8, 24.7 and 29.8 h, respectively. Dry matter intake increased linearly (P less than .10) as the proportion of legume in the diet increased; no influence of diet on DM digestibility was observed. Passage rate of dosed nylon particles 1, 3 and 5 mm in length was influenced (P less than .01) by size; however, no difference in the passage rates of the nylon particles due to diet was evident. Particle size of ruminal digesta did not respond in a linear manner to the proportion of legume in the diet. A smaller ruminal particle size was not associated with a faster turnover of digesta.
为评估饲草日粮对瘤胃食糜颗粒大小的影响，选用三头安装了瘤胃瘘管的公牛，采用3×3拉丁方设计，分别饲喂苜蓿、果园草或柳枝稷干草。苜蓿、果园草和柳枝稷日粮的瘤胃食糜平均筛孔尺寸分别为671、652和466微米。第二个试验研究了瘤胃颗粒大小对食糜通过速率、消化率和采食量的影响。选用四头安装了瘤胃瘘管的安格斯-赫里福德公牛，采用4×4拉丁方设计，让它们自由采食不同比例的苜蓿和柳枝稷。每天提供一次100%苜蓿、50%苜蓿:50%柳枝稷、25%苜蓿:75%柳枝稷或100%柳枝稷日粮。这些日粮的瘤胃食糜平均筛孔尺寸呈三次方响应（P<0.01；分别为1066、946、1003和925微米）。瘤胃平均周转时间分别为24.3、24.8、24.7和29.8小时。随着日粮中豆科植物比例的增加，干物质采食量呈线性增加（P<0.10）；未观察到日粮对干物质消化率有影响。长度为1、3和5毫米的定量尼龙颗粒的通过速率受颗粒大小影响（P<0.01）；然而，日粮对尼龙颗粒通过速率没有明显差异。瘤胃食糜颗粒大小对日粮中豆科植物比例没有线性响应。较小的瘤胃颗粒大小与食糜更快的周转无关。
