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Vet Parasitol. 2022 Sep;309:109760. doi: 10.1016/j.vetpar.2022.109760. Epub 2022 Jul 3.
To identify any universal impact of strongyle parasite burden on the growth rate of young cattle.
A meta-analysis and meta-regression of the relationship between differences in strongyle parasite burden between cohorts and average daily weight gain was conducted. Publications were identified from a search of databases applying PRISMA 2020 principles. Eligible studies had at least two groups of growing cattle on the same farm that were identical in composition, management and diet except for parasite exposure and were subject to body weight gain or average daily gain and faecal egg count measurements across the common growing period. The reference group had the lowest growth-period faecal egg count. A meta-regression estimated the impact of strongyle parasitism. The dependent variable was the log of the ratio of average daily gain between comparison groups and the reference group with the predictor variable as the common logarithm of the difference in average faecal egg count (plus 1) between the comparison and the reference groups.
26 publications containing 85 groups and 59 comparison ratios were analysed. Papers included representatives from dairy and beef industries and from pasture and feedlot production systems and from all cattle-producing continents. The comparison group average daily growth rate was 0.89 (95%CI 0.81-0.97) that of the reference group. Meta-regression identified a 0.131 linear reduction in average daily weight gain ratio for every log increase in the difference between comparison and reference group faecal egg count. Direction of effect was consistent across all subset analyses (continent, class of stock and production system). Whilst small faecal egg count differences between the comparison and reference groups often provided similar rates of daily weight gain, the trend was negative with most comparison groups having lower daily weight gains than their reference group.
Strongyle parasitism of growing cattle as measured by faecal egg count is associated with reduced growth across all production systems, geographies and classes of cattle.
确定强寄生虫负担对小牛生长率的普遍影响。
对队列之间的强寄生虫负担差异与平均日增重之间的关系进行荟萃分析和荟萃回归。通过应用 PRISMA 2020 原则搜索数据库来确定出版物。合格的研究至少有两组在同一农场的生长牛，除寄生虫暴露外，在组成、管理和饮食方面完全相同，并在整个生长期间进行体重增加或平均日增重和粪便卵计数测量。参考组在生长期间的粪便卵计数最低。荟萃回归估计了强寄生的影响。因变量是比较组与参考组之间平均日增重的对数比，预测变量是比较组与参考组之间平均粪便卵计数（加 1）差异的常用对数。
分析了 26 篇包含 85 组和 59 个比较比的出版物。这些论文的作者来自奶牛和肉牛行业，以及来自牧场和饲养场生产系统，来自所有生产牛的大洲。比较组的平均日增长率为 0.89（95%CI 0.81-0.97），是参考组的 0.89。荟萃回归发现，比较组和参考组粪便卵计数差异每增加一个对数，平均日增重比就会线性减少 0.131。所有亚组分析（大洲、牲畜类别和生产系统）的效果方向一致。虽然比较组和参考组之间的粪便卵计数差异通常提供相似的日增重率，但这种趋势是负面的，大多数比较组的日增重低于参考组。
通过粪便卵计数测量，生长牛的强寄生现象与所有生产系统、地理位置和牛的种类的生长减少有关。
