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Abstract：
A farm-level stochastic simulation model was modified to estimate the cost per case of 3 foot disorders (digital dermatitis, sole ulcer, and white line disease) by parity group and incidence timing. Disorder expenditures considered within the model included therapeutics, outside labor, and on-farm labor. Disorder losses considered within the model included discarded milk, reduced milk production, extended days open, an increased risk of culling, an increased risk of death (natural or euthanized), and disease recurrence. All estimates of expenditures and losses were defined using data from previously published research in stochastic distributions. Stochastic simulation was used to account for variation within the farm model; 1,000 iterations were run. Sensitivity of foot disorder costs to selected market prices (milk price, feed price, replacement heifer price, and slaughter price) and herd-specific performance variables (pregnancy rate) were analyzed. Using our model assumptions, the cost per disorder case over all combinations of parity group and incidence timing, regardless of incidence likelihood, was lowest for digital dermatitis ($64 ± 24; mean ± standard deviation), followed by white line disease ($152 ± 26) and sole ulcer ($178 ± 29). Disorder costs were greater in multiparous versus primiparous cows and were always highest at the beginning of lactation. The greatest contributing cost categories were decreased milk production, an increased risk of culling, and disease recurrence. The contribution of cost categories to the total cost of disorder varied by disorder type, parity group, and incidence timing. For all disorders, the cost per case increased as milk price or replacement heifer price increased and decreased as feed price, pregnancy rate, or slaughter price increased. Understanding how foot disorder costs change according to cow-specific conditions (i.e., disorder type, parity group, and days in milk at incidence) and herd-specific conditions (i.e., market prices and performance variables) can help improve on-farm decisions about treatment and prevention of foot disorders.
摘要：
对农场级随机模拟模型进行了修改，以估计3例足部疾病（数字皮炎，鞋底溃疡，和白线病）按胎次组和发病时间划分。模型中考虑的无序支出包括治疗学，外部劳动，和农场劳动。模型中考虑的无序损失包括废弃的牛奶，牛奶产量减少，延长开放天数，剔除的风险增加，死亡风险增加（自然或安乐死），和疾病复发。所有支出和损失的估计都是使用先前发表的随机分布研究的数据定义的。使用随机模拟来解释农场模型内的变化；运行了1,000次迭代。足部失调成本对选定市场价格的敏感性(牛奶价格，饲料价格，替换小母牛价格,和屠宰价格)和群体特异性表现变量(妊娠率)进行了分析。使用我们的模型假设，每个疾病病例的成本，在所有的组合的平价组和发病时间，不管发生的可能性，数字皮炎最低（$64±24；平均值±标准偏差），其次是白线病(152±26美元)和单发溃疡(178±29美元)。经产母牛与初产母牛的疾病成本更高，并且在泌乳开始时总是最高的。最大的成本类别是牛奶产量下降，剔除的风险增加，和疾病复发。成本类别对无序总成本的贡献因无序类型而异，奇偶校验组，和发病时间。对于所有疾病，每箱成本随着牛奶价格或替代小母牛价格的增加而增加，随着饲料价格的减少而减少，怀孕率,或屠宰价格上涨。了解足部疾病的成本如何根据奶牛的具体情况而变化(即，紊乱类型,奇偶校验组，和发病时牛奶中的天数)和群体具体情况(即，市场价格和性能变量）可以帮助改善有关治疗和预防足部疾病的农场决策。
