title: A longitudinal study of disease incidence and case-fatality risks on small-holder dairy farms in coastal Kenya.
abstract: 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.
authors.affiliation: Kenya Agricultural Research Institute, P.O. Box 10275, Bamburi (Mombasa), Kenya.
authors.forename: S H
authors.initials: SH
authors.lastname: Maloo
authors.forename: G J
authors.initials: GJ
authors.lastname: Rowlands
authors.forename: W
authors.initials: W
authors.lastname: Thorpe
authors.forename: G
authors.initials: G
authors.lastname: Gettinby
authors.forename: B D
authors.initials: BD
authors.lastname: Perry
mesh_terms: D000367:Age Factors; D000821:Animal Feed; D000822:Animal Husbandry; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000401:mortality*; D005260:Female; D015994:Incidence; D007630:Kenya / Q000453:epidemiology; D008137:Longitudinal Studies; D018570:Risk Assessment; D012698:Serologic Tests; D013801:Theileriasis / Q000401:mortality*; D017282:Tick-Borne Diseases / Q000401:mortality / Q000662:veterinary