Productivity and health of camels (Camelus dromedarius) in Somalia: associations with trypanosomosis and brucellosis.

In Somalia, one of the world's largest dromedary populations of about 5.3 million animals are kept by nomadic pastoralists under traditional management. Interest in the development potential of camel herds in the semi-arid areas of central Somalia initiated an investigation to determine the productivity of herds, their major diseases and likely associations among these parameters. Using a systems approach, data were collected for herd production parameters, environmental factors, management and production systems, and health variables. One thousand and thirty nine camels in 33 herds were studied in the central regions of Somalia. Trypanosoma evansi prevalence ranged from 1.7% in blood-smears to 56.4% using enzyme-linked immunosorbent micro-assay (microELISA). Seroprevalence for brucellosis was determined as 1.9% by the standard agglutination test (SAT) and 0.3% by the complement fixation test (CFT). Using multiple regression, 15% of the total variation of the general fertility rate was explained by the results of the microhaematocrit centrifugation technique (MHCT) and the microELISA for T. evansi, CFT results for brucellosis, herdsize, and young stock death rate. Among herd production variables, herd size differed significantly for different management units. Young stock death rates, as well as general fertility rates varied in the ecological subzones with a marked effect in the zones labeled "Inland". Various other associations were noted among demographic, husbandry and disease variables. The importance of trypanosomosis and brucellosis to the productivity of herds and measures to control their limiting effects on production were discussed.