Maloo S H, Rowlands G J, Thorpe W, Gettinby G, Perry B D
Kenya Agricultural Research Institute, P.O. Box 10275, Bamburi (Mombasa), Kenya.
Prev Vet Med. 2001 Nov 2;52(1):17-29. doi: 10.1016/s0167-5877(01)00235-5.
A longitudinal study was carried out in the coastal lowlands coconut-cassava agro-ecological zone of Kaloleni Division, Coast Province, Kenya between June 1990 and December 1991 to estimate disease incidence and cause-specific case-fatality risk in an average of 120 cattle in 26 small-holder dairy herds kept in two grazing-management systems. East Coast fever (ECF) was the predominant disease diagnosed; the mean monthly incidence rate was 2.5 and 6.9% in animals < or = 18 months of age under stall-fed and herded-grazing systems, respectively. In cattle > 18 months of age, the monthly incidence rate was < 1%. The 6-month ECF incidence rate was 20+/-8% (S.E.) in the stall-feeding system compared with 39+/-7% in the herded-grazing systems. There was a gradual increase in antibody prevalence with age to over 90% in cattle over 18 months of age in herded-grazing systems, whilst less than a third of cattle in the stall-feeding systems were sero-positive at any age. Overall accumulated mortality to 18 months of age was estimated to be 56%. Annual mortality in cattle > 18 months averaged 9%. Cattle managed in the herded-grazing system had a 60% higher mortality, although not significantly so, than those fed in stalls. Deaths due to ECF accounted for over two-thirds of the deaths. ECF was then the major disease constraint to small-holder dairy production in the coconut zone of coastal Kenya. Clinical cases occur the whole year round (especially in young stock)--despite apparent tick control, and in both herded-grazing and stall-feeding system.
1990年6月至1991年12月期间，在肯尼亚海岸省卡洛莱尼分区沿海低地椰子 - 木薯农业生态区开展了一项纵向研究，以评估采用两种放牧管理系统的26个小农户奶牛群中平均120头牛的疾病发病率和特定病因的病死率风险。诊断出的主要疾病是东海岸热（ECF）；在舍饲和放牧系统中，18个月及以下的动物平均每月发病率分别为2.5%和6.9%。18个月以上的牛，每月发病率低于1%。舍饲系统中6个月的东海岸热发病率为20±8%（标准误），而放牧系统中为39±7%。在放牧系统中，18个月以上的牛抗体阳性率随年龄逐渐增加至90%以上，而舍饲系统中任何年龄的牛血清阳性率均不到三分之一。估计到18个月龄时的总累积死亡率为56%。18个月以上牛的年死亡率平均为9%。放牧系统管理的牛死亡率比舍饲牛高60%，尽管差异不显著。东海岸热导致的死亡占死亡总数的三分之二以上。因此，东海岸热是肯尼亚沿海椰子种植区小农户奶牛生产的主要疾病限制因素。尽管进行了明显的蜱虫控制，且在放牧和舍饲系统中全年都有临床病例发生（尤其是幼畜）。
