Changes in the soft-tissue thickness of the claw sole in Holstein heifers around calving
Changes in the soft-tissue thickness of the claw sole in Holstein heifers around calving
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DOI：
10.3168/jds.2020-19161
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发表时间：
2021-03-16
影响因子：
3.5
通讯作者：
Capion, N.
中科院分区：
文献类型：
--
作者：
Bach, K.;Nielsen, S. S.;Capion, N.
蹄角破裂病变是奶牛跛行的常见原因。人们普遍认为，它们的发展是由于来自远端趾骨的过度压力对脚底产生角的组织造成的。远节指骨由悬吊器支撑，其中大部分由结缔组织组成。据推测，由于产犊前后激素变化导致结缔组织松弛增加，可能导致远端指骨支撑力下降，导致骨下沉和角产生组织压力增加。在这项纵向研究中，我们的第一个目标是确定是否有关的爪唯一的软组织的厚度（指垫和真皮的组合深度;软组织厚度，STT）在负重后爪的活小母牛产犊前后（产犊前约3周至产犊后2周）的变化。我们的第二个目标是评估招募的小母牛的身体状况评分（BCS）和我们获得的STT估计值之间的关系。我们测量STT（定义为远端趾骨和唯一的角之间的距离）的顶点和后部的唯一的34个荷斯坦奶牛的后爪4次超过3至4周左右产犊。我们确定STT的超声测量通过唯一的角负重爪。部位1的总体平均STT为3.3 mm [最小值-最大值（最小值-最大值）：1.8 - 5.2 mm]，部位2的平均值为3.7 mm（最小值-最大值：2.2 - 5.8）。总体平均STT在产犊前第一次检查时最厚[部位1：3.4 mm（最小值-最大值：1.9至4.7）;部位2：4.1 mm（最小值-最大值：2.7 - 5.8）]，产犊后第二次检查时，部位1最薄（3.2 mm，最小值-最大值：1.8 - 5.2）和产犊后第一次检查时的部位2（3.5 mm，最小值-最大值：2.2 - 5.0）。在研究期间，我们观察到部位1的STT平均减少-0.2 mm（最小值-最大值：0.8至-0.9 mm），但我们并未在所有动物中观察到这种减少。在研究中心2，我们发现从产犊前10天到产犊后5天，STT平均降低-0.6 mm（最小值-最大值：0.8至-1.3 mm），相当于降低约15%（最小值-最大值：0至31%）。我们认为，这种减少是由于旋转的远端趾骨向后方的一部分，唯一的角在周左右产犊。在同一时期，小母牛BCS下降0.25和0.5之间的BCS规模的增量，但我们没有发现BCS和STT之间的相关性。然而，在研究期间，小母牛经历了许多与管理，喂养和时间预算相关的变化，远端趾骨的旋转和STT的减少不仅可以解释为产犊，还可以解释为在过渡期间影响小母牛及其爪子的其他因素。
Claw horn disruption lesions are a common cause of lameness in dairy cattle. It is commonly agreed that they develop due to excessive pressure from the distal phalanx on the horn-producing tissue in the sole. The distal phalanx is supported by the suspensory apparatus, a large proportion of which is made up of connective tissue. It has been hypothesized that increased laxity of the connective tissue due to hormonal changes around calving may lead to decreased support of the distal phalanx, resulting in a sinking of the bone and increased pressure on the horn-producing tissue. In this longitudinal study, our first objective was to determine whether the thickness of the soft tissue related to the claw sole (the combined depth of the digital cushion and corium; soft-tissue thickness, STT) in the weight-bearing hind claws of live heifers changed around calving (the period from approximately 3 wk before calving to 2 wk after calving). Our second objective was to evaluate the relationship between the body condition score (BCS) of recruited heifers and the STT estimates we obtained. We measured STT (defined as the distance between the distal phalanx and the sole horn) in the apex and the posterior part of the sole of the hind claws of 34 Holstein heifers 4 times over 3 to 4 wk around calving. We determined STT by ultra-sonographic measurements through the sole horn on weight-bearing claws. The overall mean STT at site 1 was 3.3 mm [minimum-maximum (min-max): 1.8 to 5.2 mm], and the mean at site 2 was 3.7 mm (min-max: 2.2 to 5.8). The overall mean STT was thickest in the first examination before calving [site 1: 3.4 mm (min-max: 1.9 to 4.7); site 2: 4.1 mm (min-max: 2.7 to 5.8)] and thinnest at site 1 in the second examination after calving (3.2 mm, min-max: 1.8 to 5.2) and at site 2 at the first examination after calving (3.5 mm, min-max: 2.2 to 5.0). We observed an average reduction in STT of -0.2 mm (min-max: 0.8 to -0.9 mm) at site 1 during the study period, but we did not observe this reduction in all animals. At site 2, we found an average reduction in STT of -0.6 mm (min-max: 0.8 to -1.3 mm) from 10 d before calving to 5 d after calving, corresponding to a decrease of approximately 15% (min-max: 0 to 31%). We suggest that this reduction was caused by a rotation of the distal phalanx toward the posterior part of the sole horn in the weeks around calving. During the same period, heifer BCS decreased between 0.25 and 0.5 increments in the BCS scale, but we found no correlation between BCS and STT. However, the heifers experienced many changes related to management, feeding, and time budget during the study period, and the rotation of the distal phalanx and reduction of the STT might be explained not only by calving but also by other factors that affect heifers and their claws during the transition period.