An epidemiological study of ascites in broiler birds in the periurban areas of Nairobi, Kenya
Inability to achieve self-sufficiency in food production, especially protein, in Kenya has necessitated the need to improve agricultural productivity. As a result, poultry production is being used to meet this food requirements although its potential has not been fully exploited due to various constraints such as poor husbandry and disease control. This study was done with the main objective of ascertaining whether as.-c-ites condition is a problem in broiler industries in the peri-urban areas of Nairobi. In this study, prevalence of ascites and potential risk factors associated with its occurrence were examined. The economic impact of ascites in broiler production was also assessed. The area of study covered the peri-urban districts of Nairobi, namely Machakos, Kajiado and Kiambu districts, which were further categorized according to agro-ecological zones ECZII, EZCIII and EZCIV. Data was gathered from 57 Kenchic Contract farms located in the study area and visited between January and March 1995. Considered also, was a sub-sample of 49 Kenchic Contract farms which were actively followed to slaughter at the kenchic abattoir located at Tigoni in Kiambu District, from January to April 1995. other data were obtained from kenchic abattoir records for 1992, 1993 and 1994. These data were computerised and analysed. The farm survey achieved 100% response rate. Ascites was reported singly or in combination with other diseases in 47% of the farms in ECZII, 50% of the farms in ECZIII and 62% of the farms in ECZIV. Overall, the leading causes of broiler poultry condemnations at Tigoni abattoir from January to April 1995 were cadavers (51.5%), ascites (26.1%) and others (22.4%). However, from the 1992 to 1994 abattoir data, ascites was the major cause of broiler poultry condemnations in the three ecological zones. xv There existed significant (P=0.0071) annual variations in mean ascites prevalences in 1992, 1993 and 1994, with the lowest (0.52%) annual prevalence in 1994. However there was no significant (P=0.5351) variations in zone-specific mean ascites prevalence. Risk factors associated with prevalence of ascites from this study were age at slaughter, mortality during rearing, month of placing day old chicks, total feed consumed by a broiler during rearing period, brooding time, presence of other diseases, temperature range and inadequate ventilation. There was evidence of substantial monetary loss attributed to ascites. For instance in 1994, the total market loss was estimated at Ksh 1,677,100.00, while that for the three month study period in 1995 was estimated at Ksh 120,494.67. From this study, it could be concluded that the prevalence of broiler ascites in Kenya is low and that it is not associated with altitude as in temperate countries. Also changes in farm management aspects and company policies such as feeding regime and age at slaughter have effect on ascites prevalence. The results demonstrate that ascites is a major problem in commercial broiler production at farm and abattoir level especially when monetary losses and opportunity costs are considered.