Tāwharau Ora - School of Veterinary Science, Massey University, Palmerston North, New Zealand.
N Z Vet J. 2023 Sep;71(5):236-243. doi: 10.1080/00480169.2023.2216658. Epub 2023 Jun 5.
To compare the retention by New Zealand dairy cows kept at pasture in a lame cow group, of three hoof block products commonly used in the remediation of lameness.
Sixty-seven farmer-presented Friesian and Friesian x Jersey dairy cows from a single herd in the Manawatū region (New Zealand) suffering from unilateral hind limb lameness attributable to a claw horn lesion (CHL) were randomly allocated to one of three treatments: foam block (FB), plastic shoe (PS) and a standard wooden block (WB). Blocks were applied to the contralateral healthy claw and checked daily by the farm staff (present/not present) and date of loss was recorded. Blocks were reassessed on Day 14 and Day 28 and then removed unless further elevation was indicated. Daily walking distances were calculated using a farm map and measurement software. Statistical analyses included a linear marginal model for distance walked until block loss and a Cox regression model for the relative hazard of a block being lost.
Random allocation meant that differences between products in proportion used on left or right hind foot or lateral or medial claw were small. Mean distance walked/cow/day on farm tracks whilst the block was present was 0.32 (min 0.12, max 0.45) km/day; no biologically important difference between products in the mean distance walked was identified. Compared to PS, cows in the WB group were five times more likely to lose the block (HR = 4.8 (95% CI = 1.8-12.4)), while cows in the FB group were 9.5 times more likely to lose the block (HR = 9.5 (95% CI = 3.6-24.4)).
In this study, PS were retained for much longer than either FB or WB. As cows were managed in a lame cow group for the study duration, walking distances were low and did not impact on the risk of block loss. More data are needed to define ideal block retention time.
In cows with CHL the choice of block could be based on the type of lesion present and the expected re-epithelisation times.
比较新西兰牧场跛行奶牛对三种常用蹄块产品的保留情况，这些产品常用于治疗跛行。
从新西兰马纳瓦图地区一个牛群中随机分配 67 头农民呈现的荷斯坦和荷斯坦泽西奶牛，这些奶牛患有单侧后肢跛行，归因于爪角病变（CHL）。这些奶牛被随机分配到以下三种处理方式之一：泡沫块（FB）、塑料鞋（PS）和标准木块（WB）。将块应用于对侧健康的爪子上，由农场工作人员每天检查（存在/不存在）并记录丢失日期。块在第 14 天和第 28 天重新评估，如果没有进一步升高，则将其移除。使用农场地图和测量软件计算每天的步行距离。统计分析包括用于块丢失的步行距离的线性边缘模型和块丢失的相对危险的 Cox 回归模型。
随机分配意味着产品在左右后脚或外侧或内侧爪子上的使用比例差异较小。在块存在时，在农场轨道上每天行走的平均距离/奶牛/天为 0.32（最小 0.12，最大 0.45）公里/天；在行走的平均距离方面，产品之间没有生物学上的重要差异。与 PS 相比，WB 组的牛更有可能丢失块（HR=4.8（95%CI=1.8-12.4）），而 FB 组的牛更有可能丢失块（HR=9.5（95%CI=3.6-24.4））。
在这项研究中，PS 的保留时间比 FB 或 WB 长得多。由于在研究期间，牛被管理在跛行牛群中，因此行走距离较低，不会影响块丢失的风险。需要更多的数据来确定理想的块保留时间。
对于患有 CHL 的奶牛，块的选择可以基于存在的病变类型和预期的再上皮化时间。
