EpiVets, 565 Mahoe St, Te Awamutu 3800 New Zealand; Massey University, School of Veterinary Science, Private Bag 11 222, Palmerston North 4474, New Zealand.
Massey University, School of Veterinary Science, Private Bag 11 222, Palmerston North 4474, New Zealand.
Prev Vet Med. 2023 Nov;220:106047. doi: 10.1016/j.prevetmed.2023.106047. Epub 2023 Oct 17.
To understand the current impact of lameness on a system, it is important to define lameness prevalence across a range of dairy farms in that system. Prevalence estimates from dairy systems where cows are permanently managed at pasture are uncommon, although the limited data suggest that they have a lower lameness prevalence than housed cattle. One hundred and 20 farms from eight of the major dairying regions of New Zealand were randomly enrolled into a cross-sectional lameness prevalence study. On each of the farms, trained observers lameness scored cattle on two occasions, between October-December (spring, coinciding with peak lactation for most farms) and between January-March (summer, late lactation for most farms). At each visit, all lactating animals were scored using a four-point 0-3 scoring system, and included animals that had previously been identified as lame by the farmer. Animals with a lameness score (LS) ≥2 were defined as lame. Mixed logistic regression models assessed the interaction between region and season and island and season, respectively, and differences between the lameness prevalence within farm across the two seasons reported descriptively. A total of 116,317 locomotion scores over two events were conducted across the 120 farms. At the spring scoring event, 2128/60,007 (3.5 %) cows had a LS ≥2 and 1868/56,310 (3.3 %) cows had a LS ≥ 2 at the summer scoring event. At the farm level, across both scoring events, median lameness prevalence was 2.8 (interquartile range 1.5 - 4.5) %, with a range of 0.0-17.0 %. The median farm-level prevalence of LS = 3 was 0.5 % with a range of 0-4.6 %. The effect of timing of scoring was modified by region (p < 0.001), and island (p = 0.006) and at the individual farm level, differences between spring and summer farm level lameness prevalence were generally small (interquartile range: -1.8 to 1.0 %) but potentially large on individual farms (range from -12.3 % to 7.6 %). The median farm-level lameness prevalence estimate of 2.8 % across a random representative sample of New Zealand dairy farms give confidence that the overall prevalence of cattle lameness on New Zealand dairy farms is low. This adds to the growing evidence that pasture is a good management system with respect to hoof health. The evidence of strong seasonality of lameness was lacking. Instead of using lameness scoring to identify farms with large lameness problems, lameness scoring should be encouraged to farmers as a tool to improve the identification of lame animals.
要了解跛行对系统的当前影响，重要的是要在该系统的一系列奶牛场中定义跛行的流行率。在永久性牧场管理奶牛的奶牛系统中，跛行流行率的估计值并不常见，尽管有限的数据表明，它们的跛行流行率低于圈养牛。从新西兰 8 个主要奶牛养殖区中随机选择了 120 个农场参与了一项跛行流行率的横断面研究。在每个农场，经过培训的观察员在两次评估中对奶牛的跛行进行评分，一次是在 10 月至 12 月（春季，大多数农场处于泌乳高峰期），另一次是在 1 月至 3 月（夏季，大多数农场处于泌乳后期）。在每次访问中，所有泌乳动物都使用 0-3 的 4 分制进行评分，包括之前被农民确定为跛行的动物。跛行评分（LS）≥2 的动物被定义为跛行。混合逻辑回归模型评估了区域与季节之间的相互作用，以及岛屿与季节之间的相互作用，并描述性地报告了两个季节内农场间跛行流行率的差异。在 120 个农场中进行了总共 116,317 次两次活动的运动评分。在春季评分事件中，2128/60,007（3.5%）头奶牛的 LS≥2，1868/56,310（3.3%）头奶牛的 LS≥2在夏季评分事件中。在农场层面，在两次评分事件中，跛行的中位数流行率为 2.8%（四分位距 1.5-4.5%），范围为 0.0-17.0%。中位数农场层面 LS=3 的流行率为 0.5%，范围为 0-4.6%。评分时间的影响受到区域（p<0.001）和岛屿（p=0.006）的修饰，在个体农场层面，春季和夏季农场层面跛行流行率的差异通常较小（四分位距：-1.8%至 1.0%），但在个别农场可能较大（范围从-12.3%至 7.6%）。在新西兰奶牛场的随机代表性样本中，2.8%的农场级跛行流行率中位数估计值使人们有信心认为新西兰奶牛场的整体跛行流行率较低。这增加了越来越多的证据，即牧场是一种有利于蹄健康的良好管理系统。缺乏跛行明显季节性的证据。与其使用跛行评分来识别存在严重跛行问题的农场，不如鼓励农民将跛行评分作为一种工具来提高对跛行动物的识别。
