Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S 8H5, Canada; Regroupement FRQNT Op+Lait, Saint-Hyacinthe, QC, J2S 2M2, Canada.
Département de sciences cliniques, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, QC, J2S 8H5, Canada.
J Dairy Sci. 2020 Dec;103(12):11659-11675. doi: 10.3168/jds.2020-18191. Epub 2020 Oct 15.
Our first objective was to estimate the prevalence of foot lesions by type of milking system in dairy cows examined during regular hoof-trimming sessions between 2015 and 2018 in Québec dairy herds. A secondary objective was to describe the effect of day-to-day variation, cow, and herd characteristics on the prevalence of foot lesions. Data included 52,427 observations (on a cow during a specific trimming session) performed on 28,470 cows (≥2 yr old) from 355 herds. Only observations from trimming sessions in which ≥90% of the lactating herd was trimmed were considered. Lesions were recorded at the hoof level by 17 trained hoof trimmers between March 23, 2015, and July 10, 2018, using a computerized recording system. Hoof-level information was then matched with cow information and centralized at the Eastern Canada Dairy Herd Improvement. Foot lesions were classified into 6 categories: infectious, white line disease, heel erosion, ulcers, hemorrhages, and any type of foot lesions. Prevalence of each outcome was quantified using the marginal predicted mean probability estimated from a null generalized linear mixed model with a logit link, and accounted for clustering of observations by cow and by herd. Variance was partitioned to assess the variation in the probability of the outcomes attributable to each level of the data structure (day of exam, cow, and herd). Prevalence of a given foot lesion as function of milking system and of various explanatory variables (mean herd size, herd average daily production, breed of the cow, age of the cow at trimming, and year of the visit) was then estimated using a generalized linear mixed model. At least 1 foot lesion was observed in 29% of cows examined during regular trimming sessions in Québec from 2015 to 2018. Prevalence for any type of lesion was 27% for pipeline, 38% for robotic milking, and 41% for milking parlors. The highest prevalence of infectious lesions (mainly digital dermatitis) was observed in milking parlors and robotic systems, while the most prevalent lesions in pipeline were hemorrhages. Herd-level factors explained most of the disease probability for infectious diseases, heel erosion, and hemorrhages. Therefore, control of these diseases should be based on applying best herd-management practices. On the other hand, probabilities of white line disease and sole ulcers were mainly determined by cow-level characteristics.
我们的首要目标是估计 2015 年至 2018 年期间在魁北克奶牛场定期蹄修剪期间，通过挤奶系统类型检查的奶牛的脚部病变的流行率。次要目标是描述日常变化、奶牛和牛群特征对脚部病变流行率的影响。数据包括 355 个牛群中 28470 头（≥2 岁）奶牛的 52427 次观察（在特定修剪期间对一头奶牛进行的观察）。仅考虑至少有 90%泌乳牛群接受修剪的修剪期的观察结果。2015 年 3 月 23 日至 2018 年 7 月 10 日期间，17 名经过培训的蹄修剪师在计算机记录系统的帮助下，在蹄部水平上记录病变。然后将蹄部信息与奶牛信息相匹配，并在加拿大东部奶牛群改良中心进行汇总。将脚部病变分为 6 类：传染性、白线病、后跟侵蚀、溃疡、出血和任何类型的脚部病变。使用带有对数链接的空广义线性混合模型估算的边缘预测均值概率来量化每种结果的流行率，并考虑到通过奶牛和牛群的观察聚类。方差进行划分，以评估数据结构（检查日、奶牛和牛群）的各个水平归因于结果的概率变化。然后使用广义线性混合模型估计给定脚部病变与挤奶系统以及各种解释变量（平均牛群规模、牛群平均日产量、奶牛品种、修剪时的奶牛年龄和就诊年份）的关系。在 2015 年至 2018 年期间，魁北克定期修剪期间检查的奶牛中有 29%至少观察到 1 种脚部病变。任何类型病变的流行率分别为管道 27%、机器人挤奶 38%和挤奶厅 41%。在挤奶厅和机器人系统中观察到传染性病变（主要是趾间皮炎）的流行率最高，而在管道中最常见的病变是出血。在传染性疾病、后跟侵蚀和出血方面，牛群水平因素解释了大部分疾病概率。因此，这些疾病的控制应基于应用最佳的牛群管理实践。另一方面，白线病和鞋底溃疡的概率主要由奶牛水平特征决定。
