A compartmentalised model for the estimation of the cost of coccidiosis to the world's chicken production industry.

A compartmentalised model is presented for the estimation of the monetary losses suffered by the world's poultry industry resulting from coccidiosis of chickens and costs of its control. The model is designed so that the major elements of loss may be separately quantified for any chicken-producing entity, e.g., a farm, a poultry company, a country, etc. Examples are presented and the sources, reliability and geographical relevance of the data used for each parameter are provided. Loss elements for specific geographical areas should be recalculated at appropriate intervals to take into account local and international fluctuations in costs of chicks feed, labour, financial inflation and world currency exchange rates. Equations are given for relationships among numbers of chickens, liveweights, weights of carcasses, feed consumptions, feed conversion ratio (FCR), prices of feeds, prices of anticoccidial therapeutic and prophylactic drugs, values of chickens, chicken rearing costs; and effects of coccidiosis on mortality, weight gain and FCR. Using these equations, it is theoretically possible for an international team of representatives, each using reliable local data, to calculate simultaneously each relevant loss element for their respective countries. Addition of these elements could give, for the first time, an accurate global estimate of the losses due to chicken coccidiosis. The total cost of coccidiosis in chickens in the United Kingdom in 1995 is estimated to have been at least GB pound silver 38 588 795, of which 98.1% involved broilers (80.6% due to effects on mortality, weight gain and feed conversion, and 17.5% due to the cost of chemoprophylaxis and therapy). The costs of poor performance due to coccidiosis and its chemical control totalled 4.54% of the gross revenue from UK sales of live broilers. This model includes a new method for comparing the profitabilities of different treatments in commercial trials. providing actual costs rather than the arbitrary numerical scores of other methods. Although originally designed for the study of coccidiosis, the model is equally applicable to any disease. It should be of value to agricultural economists, the animal feed and poultry industries, animal health companies, and to research scientists (particularly for preparing grant applications).