Smallholder dairy farming in the Chikwaka communal land, Zimbabwe: birth, death and demographic trends
Smallholder dairy farming in the Chikwaka communal land, Zimbabwe: birth, death and demographic trends
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DOI：
10.1016/s0167-5877(00)00191-4
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发表时间：
2001-01-29
影响因子：
2.6
通讯作者：
Hirst, WM
中科院分区：
文献类型：
--
作者：
French, NP;Tyrer, J;Hirst, WM
在津巴布韦奇克瓦卡公共土地对小农奶牛场的牛的死亡率、发病率和生产力进行了研究。我们估计了DDP牛死亡率的频率和决定因素，并探讨了人口统计学趋势。使用Cox比例风险模型（将农场作为随机效应），与死亡率相关的动物水平变量是年龄、性别和品种。小牛在出生后第一年的死亡率为35%。这几乎是成人死亡率的5倍（相对危险度（RR） 4.73, 95% CI 2.12, 10.6）。女性的死亡率低于男性（RR = 0.25, 95% CI 0.11, 0.56）。在调整了年龄的混杂效应后，泽西育种与较高的死亡率相关（RR = 2.89, 95% CI 1.16, 7.22），而红丹育种与较低的死亡率相关（RR = 0.27, 95% CI 0.11, 0.69）。非DDP:DDP牛比例较高的农场，其DDP牛的死亡率较高。莱斯利矩阵模型模拟了人口增长，并显示（在目前的死亡率和生育率水平下）人口将在大约10年内翻一番。(C) 2001 Elsevier Science B.V.版权所有
A study of mortality, morbidity and productivity of cattle on smallholder dairy farms was conducted in Chikwaka communal land, Zimbabwe. We estimated the frequency and determinants of mortality in DDP cattle and explored demographic trends. Using Cox proportional-hazards modelling (with the farm as a random effect), the animal-level variables associated with mortality were age, sex and breed. Calf mortality was 35% of calves within the first year of life. This was nearly five-times higher than adult mortality (relative risk (RR) 4.73, 95% CI 2.12, 10.6). Females had lower mortality than males (RR = 0.25, 95% CI 0.11, 0.56). After adjusting for the confounding effects of age, Jersey breeding was associated with higher mortality (RR = 2.89, 95% CI 1.16, 7.22) whereas Red Dane breeding was associated with lower mortality (RR = 0.27, 95% CI 0.11, 0.69). Farms with a higher ratio of non-DDP:DDP cattle had higher mortality in their DDP cattle. Leslie-matrix models simulated population growth and showed that (at the current levels of mortality and fertility) the population would double in approximately 10 years. (C) 2001 Elsevier Science B.V. All rights reserved.