Shakespeare A S
Department of Production Animal Studies, Faculty of Veterinary Sciences, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa.
J S Afr Vet Assoc. 2009 Dec;80(4):247-53. doi: 10.4102/jsava.v80i4.221.
The term 'thin soles' refers to the suboptimal thickness of the weight-bearing surface of claws in ruminants. These palmar/plantar surfaces of the claws support the weight of the animal and consist of the distal wall horn, the sole proper, the heel and the minute white line area. The sole should normally only bear weight on uneven or undulating surfaces. A decrease in the thickness of the weight-bearing claw surface will decrease the protective function of this structure and may alter the proportion of weight-bearing by each section with possible detrimental effects on hoof function. Horn tissue readily absorbs water and becomes softer which can lead to increased wear rates. Growth rates normally match wear rates but, unlike the latter, time is needed for the growth rate response to adapt to changes in wear rate. Concrete surfaces can be abrasive and dairy cows that spend their lactation cycle on these floors should be let out to pasture in the dry period so that their claws can recoup lost horn. Frictional coefficient is a measure of the'slipperiness' of hooves on various surfaces. Newly laid or fresh concrete is not only abrasive but the thin surface suspension of calcium hydroxide that forms has a very alkaline pH which causes keratin degradation and is mostly responsible for the excessive claw wear that occurs. Four case studies are used to illustrate the importance of the distal wall horn, the dangers of over-trimming and the effects of disease and concrete on horn growth and wear rates.
“薄蹄底”一词指反刍动物蹄爪负重面厚度欠佳的情况。这些蹄爪的掌/跖面支撑着动物的体重,由远端壁角质、蹄底本体、蹄跟和微小的白线区域组成。正常情况下,蹄底仅在不平整或起伏的地面上承重。负重蹄爪表面厚度的减小会降低该结构的保护功能,并可能改变各部分的负重比例,对蹄功能产生潜在的不利影响。角质组织容易吸水并变软,这会导致磨损率增加。生长速度通常与磨损速度相匹配,但与磨损速度不同的是,生长速度的反应需要时间来适应磨损速度的变化。混凝土表面具有磨蚀性,在泌乳期待在这些地面上的奶牛在干奶期应放到牧场,以便其蹄爪能够恢复失去的角质。摩擦系数是衡量蹄在各种表面上“滑度”的指标。新铺设的或新鲜的混凝土不仅具有磨蚀性,而且形成的氢氧化钙薄表面悬浮液具有很强的碱性pH值,会导致角蛋白降解,这是造成蹄爪过度磨损的主要原因。本文通过四个案例研究来说明远端壁角质的重要性、过度修剪的危害以及疾病和混凝土对角质生长和磨损速度的影响。