Sydney School of Veterinary Science, The University of Sydney, Camden, New South Wales 2570, Australia.
Sydney School of Veterinary Science, The University of Sydney, Camden, New South Wales 2570, Australia.
J Dairy Sci. 2024 Nov;107(11):9752-9761. doi: 10.3168/jds.2023-24544. Epub 2024 Jun 28.
The primary objective of this study was to evaluate the association between preweaning diarrhea and measures of survival, health, and production. The measures of interest included survival (mortality before first calving and time to removal from the herd), health (retained fetal membranes, metritis, mastitis, and SCC), and production (305-d mature-equivalent milk yield and time to first calving). A secondary objective was to investigate if these associations varied according to the age of the calf when the case of diarrhea occurred. Herd records from a farm located in Southern Australia were used to conduct a retrospective cohort study where subjects (calves) with diarrhea were enrolled at the time of their first case along with 2 subjects without diarrhea, matched for age (±3 d) and date of birth (±15 d), amounting to 9,833 calves in the dataset. Survival analysis was conducted to determine whether preweaning diarrhea was associated with death in the short term (first 20 d after enrollment), medium term (21-100 d after enrollment) and long term (101 d after enrollment to first calving). Crude incidence rate ratios, Kaplan-Meier curves, and hazard ratios (HR, Cox regression) were derived for each event-based outcome (e.g., death, calving, mastitis). Multivariable linear models were used for continuous outcomes. Calves with preweaning diarrhea had greater mortality rates in the short term (HR = 2.48, 95% CI: 1.87-3.29) and medium term (HR = 1.89, 95% CI: 1.41-2.55), but not in the long term (HR = 0.98, 95% CI: 0.79-1.22). A small negative association between preweaning diarrhea and time to first calving was found, with calves with diarrhea calving 4 d later than calves without diarrhea (HR = 0.95, 95% CI: 0.91-1.00). Rates of postcalving removal from the herd (death or culling) were higher in calves with a history of preweaning diarrhea (HR = 1.13, 95% CI: 1.01 to 1.26), as were peak lactation log SCC (+0.08, 95% CI: 0.02 to 0.14). Further research is needed to replicate these novel findings, as they are based on exploratory analyses and could be spurious findings. No substantial associations were observed for the other measures of interest. Our study findings support existing research demonstrating the importance of preweaning diarrhea as a substantial cause of calf mortality and raise new hypotheses about other potential impacts during lactation.
本研究的主要目的是评估哺乳期腹泻与生存、健康和生产相关指标之间的关联。本研究的主要观察指标包括：（1）生存（首次产犊前的死亡率和从牛群中移除的时间）；（2）健康（胎衣不下、子宫炎、乳腺炎和 SCC）；（3）生产（305 天成熟当量奶产量和首次产犊时间）。次要目标是调查在犊牛发生腹泻的年龄不同时，这些关联是否会发生变化。本研究使用位于澳大利亚南部的一个农场的畜群记录进行了回顾性队列研究，在首次发生腹泻时，将腹泻病例（犊牛）与 2 名无腹泻的病例（年龄相差±3 天，出生日期相差±15 天）相匹配，纳入了 9833 头犊牛作为研究对象。采用生存分析来确定哺乳期腹泻是否与短期（入组后 20 天内）、中期（入组后 21-100 天）和长期（入组后 101 天至首次产犊）的死亡有关。基于每个事件的结局（如死亡、产犊、乳腺炎）计算了粗发病率比值、Kaplan-Meier 曲线和风险比（HR，Cox 回归）。对于连续结局，采用多变量线性模型。哺乳期腹泻的犊牛短期（HR = 2.48，95%CI：1.87-3.29）和中期（HR = 1.89，95%CI：1.41-2.55）死亡率较高，但长期（HR = 0.98，95%CI：0.79-1.22）死亡率较低。哺乳期腹泻与首次产犊时间之间存在轻微的负相关，腹泻犊牛比无腹泻犊牛晚 4 天产犊（HR = 0.95，95%CI：0.91-1.00）。有哺乳期腹泻病史的犊牛产后从牛群中移除的比例（死亡或淘汰）较高（HR = 1.13，95%CI：1.01-1.26），泌乳高峰期乳 SCC 峰值也较高（+0.08，95%CI：0.02-0.14）。需要进一步的研究来复制这些新的发现，因为它们是基于探索性分析得出的，可能存在虚假发现。其他感兴趣的观察指标没有观察到实质性的关联。本研究结果支持现有的研究，证明哺乳期腹泻是犊牛死亡的重要原因，并提出了哺乳期其他潜在影响的新假设。
