Department of Production Animal Clinical Sciences, Faculty of Veterinary Medicine, Norwegian University of Life Sciences, P.O. Box 5003, Ås, 1432, Norway.
Animalia, P.O. Box 396, Økern, Oslo, 0513, Norway.
BMC Vet Res. 2024 Jun 18;20(1):261. doi: 10.1186/s12917-024-03941-z.
Digital dermatitis (DD) is a contagious bovine foot disease causing reduced animal welfare and negative economic consequences for the farmer. Treponema spp. are the most important causative agents. Studies indicate that trimming equipment can transfer DD-associated treponemes between cows. The aim of this observational study in 22 DD-positive Norwegian dairy herds was to investigate the risk of transferring Treponema spp. with trimming equipment and chutes after claw trimming, and after washing and disinfection. Swabs from the trimming equipment and chutes were collected from nine different locations, at five different time points. Bacterial DNA was extracted from 647 swabs and analysed by qPCR for Treponema spp. In addition, 172 swabs taken immediately after trimming, were analysed by a multiplex qPCR targeting T. phagedenis, T. pedis and T. medium/vincentii. Biopsy sampling from DD lesions was performed on cows in the same herds during trimming. Altogether 109 biopsies were analysed by FISH for confirmation of the DD diagnosis and identification of Treponema phylotypes (PTs).
High numbers of Treponema spp. were detected from all nine locations on the trimming equipment and chutes immediately after trimming, and T. phagedenis was detected on two or more locations in all but two herds, 1 and 19. There was a decline in the amount of Treponema spp. after washing and disinfection. The belly belt, the cuff, and the footrest on the chute had the highest proportion of positive samples after disinfection. The belly belt had the highest copy numbers of all nine locations (median = 7.9, max = 545.1). No Treponema spp. was detected on the hoof knives after disinfection. Treponema phagedenis, T. pedis, and Treponema phylotype 3 (T. refringens) were detected by FISH analysis of the biopsies. Treponema phagedenis was detected in biopsies from all herds except 1 and 19.
This study shows that DD-associated Treponema spp. were present on the trimming equipment and chutes after trimming cows in DD-positive herds. Washing and disinfection reduced the load of Treponema spp. However, large differences in Treponema spp. between different locations were documented. High copy numbers on the grinder and the chute after disinfection, indicates that sufficient cleaning and disinfection of these locations is difficult, and that passive transfer of DD-associated treponemes (viable or not) is possible.
数字性皮炎（DD）是一种传染性牛脚病，导致动物福利降低，并给农民带来负面的经济后果。螺旋体属是最重要的病原体。研究表明，修剪设备可以在牛之间传递与 DD 相关的密螺旋体。本研究观察了 22 个挪威奶牛场的 DD 阳性奶牛场，目的是调查在修剪后、清洗和消毒后，修剪设备和滑槽中密螺旋体转移的风险。从 9 个不同位置的修剪设备和滑槽中采集了 647 个拭子，通过 qPCR 分析密螺旋体属。此外，在修剪后立即采集的 172 个拭子通过针对 T. phagedenis、T. pedis 和 T. medium/vincentii 的多重 qPCR 进行分析。在同一牛群中，对修剪时的 DD 病变进行了活检取样。总共分析了 109 个活检样本，通过 FISH 确认 DD 诊断，并鉴定密螺旋体的 phylotype（PT）。
修剪后，所有 9 个修剪设备和滑槽上的所有位置立即检测到大量的密螺旋体属，除了 1 号和 19 号牛场外，所有牛场的两个或更多位置都检测到 T. phagedenis。清洗和消毒后，密螺旋体属的数量减少。消毒后，滑槽的腹带、袖口和脚踏板的阳性样本比例最高。腹带的九个位置中，其拷贝数最高（中位数=7.9，最大值=545.1）。消毒后，蹄刀上没有检测到密螺旋体属。通过对活检的 FISH 分析，检测到 T. phagedenis、T. pedis 和 T. phylotype 3（T. refringens）。除了 1 号和 19 号牛场外，所有牛场的活检均检测到 T. phagedenis。
本研究表明，在 DD 阳性牛群中修剪奶牛后，修剪设备和滑槽上存在与 DD 相关的密螺旋体属。清洗和消毒降低了密螺旋体属的负荷。然而，不同位置之间的密螺旋体属差异很大。消毒后在研磨机和滑槽上的高拷贝数表明，这些位置的彻底清洁和消毒很困难，并且与 DD 相关的密螺旋体（有活力或无活力）的被动转移是可能的。
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