Greenough P R, Vermunt J J, McKinnon J J, Fathy F A, Berg P A, Cohen R D
Can Vet J. 1990 Mar;31(3):202-8.
The purpose of this study was to observe and quantitate changes in the claws of two groups of feedlot cattle (calves and backgrounded yearlings) fed diets that varied in energy (73.5 or 78.5% TDN) and crude protein (11, 13, 15, 16, 17, or 19%) content. At slaughter, the thickness of sole horn and the prevalence of toe and heel hemorrhages were greater in calves than in yearlings (p<0.02). Feeding the high-energy ration increased the prevalence of toe and heel hemorrhages in calves (p<0.02) and heel hemorrhages in yearlings (p<0.02). In yearlings, rotation of the distal phalanx and ridging of the dorsal wall of the claw were the most prominent pathological features. Osteopathy of the apex of the distal phalanx occurred more frequently in calves than in yearlings (p<0.01). This study suggests that intensive feeding of beef cattle before they reach 14 months of age has a deleterious effect on digital health.
本研究的目的是观察和量化两组育肥牛（犊牛和育成一岁牛）爪子的变化，这两组牛饲喂的日粮在能量（总可消化养分含量分别为73.5%或78.5%）和粗蛋白含量（11%、13%、15%、16%、17%或19%）上有所不同。屠宰时，犊牛的蹄底角质厚度以及蹄尖和蹄跟出血的发生率高于一岁牛（p<0.02）。给犊牛饲喂高能日粮会增加其蹄尖和蹄跟出血的发生率（p<0.02），给一岁牛饲喂高能日粮会增加其蹄跟出血的发生率（p<0.02）。在一岁牛中，远端指骨旋转和蹄壁背侧隆起是最突出的病理特征。犊牛远端指骨顶端的骨病发生率高于一岁牛（p<0.01）。本研究表明，肉牛在14月龄前进行高强度育肥对蹄部健康有有害影响。
