Lorino T, Daudin J-J, Robin S, Sanaa M
Laboratoire d'Epidemiologie et de Santé Animale, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France.
Prev Vet Med. 2005 May 10;68(2-4):91-102. doi: 10.1016/j.prevetmed.2004.11.013. Epub 2005 Jan 26.
A prospective study was carried out on 92 randomly selected beef herds in the Midi-Pyrenees region in France. The objective was to determine factors associated with time to neonatal gastroenteritis. By taking into account the "intra-herd" correlation in failure time (in the semiparametric Cox model), we identified 12 management risk factors associated with hazard of diarrhoea. Some previously have been identified, but "new" risk factors were feeding of corn silage and the incidence of diarrhoea in the last season. We used the two main approaches which are often reviewed: marginal and frailty Cox models. Our results show that these two models give different parameter estimates, so the choice of the model remains crucial.
在法国南部-比利牛斯地区对92个随机选取的肉牛群进行了一项前瞻性研究。目的是确定与新生儿肠胃炎发病时间相关的因素。通过在失效时间（在半参数Cox模型中）考虑“畜群内”相关性，我们确定了12个与腹泻风险相关的管理风险因素。其中一些因素先前已被识别，但“新”的风险因素是玉米青贮饲料的投喂以及上一季腹泻的发生率。我们使用了经常被审视的两种主要方法：边际Cox模型和脆弱Cox模型。我们的结果表明，这两种模型给出了不同的参数估计，因此模型的选择仍然至关重要。
