MODELLING GROWTH CURVES IN COBB 500 STRAIN OF BROILER CHICKENS USING DIFFERENT ALGORITHMS

Abstract

This study was carried out to predict the body weight of Cobb 500 strain of broiler chicken reared with or without access to pasture using five mathematical models. The study was conducted at the Teaching and Research Farm of the Department of Animal Science, Faculty of Agriculture, Nasarawa State University, Keffi. A total of 200 randomly selected day-old chicks were used for the experiment. The birds were assigned to 2 groups in a completely randomized design: Group 1 birds had no access to pasture while Group 2 had access to pasture from week 4 to week 8 of the experiment. Each treatment group contained 25 birds and were replicated four times. Data on body weight of Cobb 500 broiler chickens were taken. The data on body weight were equally predicted using Logistic 3P, Logistic 4P, Logistic 5P, Gompertz 3P and Gompertz 4P model of JMP (SAS) statistical software. The results showed that Logistic 5P predicted body weight better than Logistic 3P, Logistic 4P, Gompertz 3P and Gompertz 4P models in birds with and without access to pasture with a corresponding coefficient of determination (R2 ) values of 96.9 and 96.5%, respectively. The current findings indicate that Logistic 5P is the best growth model in birds fed and those not fed pasture; thus, appears promising in broiler chicken production.