Teagasc, Moorepark Dairy Production Research Centre, Fermoy, Co. Cork, Ireland.
Vet J. 2011 Feb;187(2):189-94. doi: 10.1016/j.tvjl.2009.11.018. Epub 2009 Dec 21.
The incidence of and risk factors associated with calving assistance and dystocia in pasture-based dairy herds were determined from analysis of 152,641 records of full-term calvings from Holstein-Friesian dams served by artificial insemination (AI) sires of seven breeds in herds of 20 calvings or more per year over 4 years. The overall incidence of calving assistance and dystocia was 31.1% and 6.8%, respectively. The incidence in primiparae and pluriparae was 40.0% and 28.2% for assistance, and 9.3% and 5.8% for dystocia, respectively. Association analyses were undertaken using generalised estimating equations using a logit link function. The likelihood of calving assistance or dystocia did not change over time but was greatest in autumn and in spring. The likelihood of calving assistance or dystocia was greater for males in primiparae and males sired by Charolais sires. The odds of calving assistance and dystocia were greater in twin calves (OR 2.0 and 2.4; P<0.001) and in dams that had dystocia at the previous calving (OR 1.65 and 2.9; P<0.001). The logit of the probability of calving assistance and dystocia increased linearly per unit increase in sire predicted transmitting ability for direct calving difficulty. The probability of assisted calving, but not dystocia, increased linearly in primiparae as animals calved at a younger age relative to the median age at first calving. Herd size and day of the week of calving were not associated with the odds of dystocia. Stakeholders must focus on identified modifiable risk factors to control the incidence of dystocia in dairy herds.
在过去 4 年中，对来自 7 个品种的人工授精（AI）公牛的荷斯坦-弗里森奶牛进行了 152641 例足月产犊记录的分析，以确定在牧场奶牛群中与助产和难产相关的发病因素和风险因素。助产和难产的总发病率分别为 31.1%和 6.8%。初产和经产的助产发病率分别为 40.0%和 28.2%，难产发病率分别为 9.3%和 5.8%。使用广义估计方程和对数链接函数进行关联分析。助产和难产的可能性没有随时间而变化，但在秋季和春季最大。在初产中，雄性和夏洛来公牛所生雄性的助产可能性更大。在双胞胎牛犊中（OR 2.0 和 2.4；P<0.001）和在上一次产犊时发生难产的母牛中（OR 1.65 和 2.9；P<0.001），助产和难产的可能性更大。助产和难产的对数概率随公牛直接分娩难度预测传递能力的单位增加而线性增加。在初产中，尽管助产的可能性呈线性增加，但难产的可能性并没有增加，因为与首次产犊的中位数年龄相比，动物的产犊年龄更年轻。群体规模和产犊日与难产的几率无关。利益相关者必须关注已确定的可改变的风险因素，以控制奶牛群中难产的发病率。
