Descriptive Statistics, Correlation and Regression Coefficient of Growth Traits in the Nigerian Heavy Local Chicken Ecotype
Keywords:Descriptive statistics, correlation, regression, growth traits and NHLCE.
Body weight is a very important characteristic in animal husbandry due to selection criteria and economic profit, and linear body measurement is used as an indirect method of estimating body weight. The aim of the study was to predict body weight from the linear body measurement and establish regression equations for the prediction of body weight and determine the growth trait that most predicts body weight for selection and improvement purposes. A total of 240 grower chicks were used for the study. The birds were generated from the existing 7th Generation of the Nigeria heavy local chicken ecotype (NHLCE) parent stock in the Department of Animal Science, University of Nigeria, Nsukka farm. Ten cocks and sixty hens were selected from the existing flock to establish 10 sire families. Each cock was randomly assigned to 6 hens to form a sire family at a mating ratio of 1:6. Each sire family was housed in a particular pen with a demarcation separating the cock from the hens. Artificial insemination was used as the mating method. Artificial insemination was done at an interval of two days. Fertile eggs produced were marked according to sire families. Fertile eggs were hatched with the aid of an electric automated incubator. The chicks were brooded for eight weeks. At the end of the brooding period, the grower-chicks were randomly chosen for the study and given similar treatments. Body weight and linear body measurements were taken bi-weekly. The results showed that at 20 weeks of age, the birds had an average body weight of 1627.78g and, an average body length, shank length, chest circumference, thigh circumference and thigh length of 24.14cm, 8.32cm, 37.19cm, 11.01cm and 14.50cm, respectively. The correlation coefficients between body weight and linear body measurements were significant (p<0.01), strong and positive. Chest circumference had highest coefficient of 0.91, followed by thigh length 0.86 and shank length 0.75, respectively, on the body weight. The regression result showed that chest circumference is the best predictor of body with highest value of R2 (0.72) and lowest standard error (1.49). It was therefore concluded that linear body measurements can be used to predict body weight and the best predictor of body weight is the chest circumference.