Martz F A, Belyea R L
J Dairy Sci. 1986 Jul;69(7):1996-2008. doi: 10.3168/jds.S0022-0302(86)80626-9.
Diminution of forage particles includes mastication, chewing, and digestion. In rumen of cattle and sheep fed all forage diets, particle size can range from 200 to over 1200 microns. Particle size reduction to about less than 1200 microns must occur before passage. Dietary particle size may influence rumen particle size, but mastication and rumination minimizes differences among diets. Ruminants expend considerable effort to move digesta. Density, cell wall percentage, osmotic pressure, and pH may affect propulsion. Dense particles may sink to the bottom and resist escape. Cell wall may reduce digestion and passage. Osmotic pressure or pH may affect digestive efficiency and rhythm of intestinal tract muscles. Chewing, exercise, physiological functions, and body size may also affect the reduction of forage particle size. More effort is necessary to chew high than low fiber diets. Young cattle (less than 225 kg) lack rumination capability and body size to process forage particles efficiently. Exercised sheep (26,400 kg-m/d) ate less forage and ruminated less than controls. Other body functions, such as lactation, appear to influence chewing patterns and rumination. These relationships are poorly understood at best and need additional intensive examination.
饲草颗粒的减小包括咀嚼、细嚼和消化。在全部以饲草为食的牛羊瘤胃中，颗粒大小范围可从200微米至超过1200微米。在通过之前，颗粒大小必须减小至约小于1200微米。日粮颗粒大小可能会影响瘤胃颗粒大小，但咀嚼和反刍可使不同日粮之间的差异最小化。反刍动物花费大量精力来移动消化物。密度、细胞壁百分比、渗透压和pH值可能会影响推进。致密颗粒可能会沉到底部并阻碍排出。细胞壁可能会降低消化和通过速度。渗透压或pH值可能会影响消化效率和肠道肌肉的节律。咀嚼、运动、生理功能和体型也可能会影响饲草颗粒大小的减小。咀嚼高纤维日粮比低纤维日粮需要付出更多努力。年轻牛（体重小于225千克）缺乏反刍能力和有效处理饲草颗粒的体型。运动的绵羊（26,400千克-米/天）比对照组采食的饲草更少且反刍更少。其他身体功能，如泌乳，似乎会影响咀嚼模式和反刍。这些关系充其量也只是了解甚少，需要进一步深入研究。
