Alemu Yeshwas F, Jemberu Wudu T, Mekuriaw Zeleke, Abdi Reta Duguma
School of Animal Science and Veterinary Medicine, Bahir Dar University, Bahir Dar, Ethiopia.
International Livestock Research Institute, Addis Ababa, Ethiopia.
Front Vet Sci. 2022 May 23;9:859401. doi: 10.3389/fvets.2022.859401. eCollection 2022.
The Ethiopian government has initiatives for expanding the commercial and smallholder market-oriented urban and peri-urban dairy production systems to meet the demands for dairy products. However, there have been only limited on-farm studies on the health performance of commercial dairy breeds. The aim of this longitudinal study was to quantify the incidence and identify predictors of calf morbidity and mortality from birth to 6 months of age in urban and peri-urban dairy farms of Northwest Ethiopia. A total of 439 calves aged below 6 months from 174 dairy farms were included in the study. We collected data on 35 potential risk factors to determine their effect on calf morbidity and mortality in the area. Kaplan-Meier survival analysis was used to summarize survival probability. The Cox proportional hazard regression model with shared frailty to account for unmeasured herd-specific heterogeneity was also used to identify and quantify factors associated with time to morbidity and mortality. Among 439 calves enrolled for 6 months of follow-up period, a total of 141 morbidities and 54 mortality events were recorded. This gives an overall morbidity and mortality incidence rates of 64 per 100-calf 6-months at risk (risk rate of 47.3%) and 19 per 100-calf 6-months at risk (risk rate of 17.9%), respectively. Diarrhea was the most frequent calf health problem with a risk rate of 25.2%. It was the cause of death for 33.3% of all the 54 calf deaths. Next to diarrhea, pneumonia ranked second with risk rate of 8.6% and was responsible for death of 12.9% of all the 54 calf deaths. Among 35 potential risk factors, calf age, vigor status at birth, calf breed, colostrum ingestion, and herd size were significant ( < 0.05) predictors of calf morbidity and mortality. The Cox-shared frailty model revealed that the herd frailty component had no significant effect on hazard estimates of the covariates of all-cause morbidity and mortality. This implies that the dairy herds participated in the study were homogeneous in the distribution of unmeasured random effects. In conclusion, the magnitude of calf morbidity and mortality was higher and above economically tolerable level in this study. This could impede the success of Ethiopia's dairy development initiative in general, and the livelihood of smallholder dairy producers in particular. Therefore, educating farmers aimed at mitigating the identified risk factors can reduce calf morbidity and mortality in the study areas.
埃塞俄比亚政府已采取举措，扩大以商业和小农户为导向的城市及城郊乳制品生产系统，以满足乳制品需求。然而，关于商业奶牛品种健康表现的农场实地研究却很有限。这项纵向研究的目的是量化埃塞俄比亚西北部城市及城郊奶牛场犊牛从出生到6月龄的发病率，并确定犊牛发病和死亡的预测因素。该研究共纳入了来自174个奶牛场的439头6月龄以下的犊牛。我们收集了35个潜在风险因素的数据，以确定它们对该地区犊牛发病和死亡的影响。采用Kaplan-Meier生存分析来总结生存概率。还使用具有共享脆弱性的Cox比例风险回归模型，以考虑未测量的特定畜群异质性，来识别和量化与发病和死亡时间相关的因素。在纳入随访6个月的439头犊牛中，共记录了141起发病事件和54起死亡事件。这使得每100头犊牛6个月的总体发病率和死亡率分别为64（风险率47.3%）和19（风险率17.9%）。腹泻是最常见的犊牛健康问题，风险率为25.2%。它是54头犊牛死亡中33.3%的死因。仅次于腹泻的是肺炎，风险率为8.6%，是54头犊牛死亡中12.9%的死因。在35个潜在风险因素中，犊牛年龄、出生时的活力状况、犊牛品种、初乳摄入和畜群规模是犊牛发病和死亡的显著（<0.05）预测因素。Cox共享脆弱性模型显示，畜群脆弱性成分对全因发病和死亡协变量的风险估计没有显著影响。这意味着参与研究的奶牛群在未测量随机效应的分布上是同质的。总之，在本研究中，犊牛发病和死亡的程度较高，超出了经济上可承受的水平。这总体上可能会阻碍埃塞俄比亚乳制品发展计划的成功，尤其是小农户乳制品生产者的生计。因此，针对减轻已识别风险因素对农民进行培训，可以降低研究地区犊牛的发病率和死亡率。
