ESTIMATION OF BODY WEIGHT FROM MORPHOMETRIC TRAITS IN THREE CHICKEN STRAINS USING LINEAR AND QUADRATIC MODELS.

Abstract

The experiment was conducted to compare the growth rate of three chicken strains using linear and quadratic models at different ages. A total of 300 day-old chicks, 100 chicks each of three strains – Arbor Acre broilers, Noiler hybrid and Yoruba ecotype cockerels were used for the study which lasted for 16 weeks. Linear measurements of body length, keel length, shank length, wing length, breast width, body depth and drumstick were regressed against body weight using linear and quadratic models at 2-8 and 10-16 weeks of age, respectively. Accuracy of body weight prediction based on the coefficient of determination (R2 %) for the cockerel ranged from very low to moderate at 2-8 weeks. The range of values was 0.10 - 46.90 % (linear) and 24.40- 48.20 % (quadratic). R2(%) values were generally low at age 10-16 weeks for both functions.Regression of linear traits against body weight of Arbor Acre strains also had low to moderate estimates at 2-8 weeks – 3.50 - 32.70 % (linear) and 10.10 - 34.80 % (quadratic). However, the R2(%) values for week 10-16 estimates were very high and ranged from 71.10 % - 92.60 % (linear) and 71.20 -93.70 % (quadratic). For the Noiler hybrid strain, moderate R2(%) values were observed at weeks 2-8having a range of 21.80 - 37.40 % (linear) and 26.80- 39.10 % (quadratic). Estimates were generally low at weeks 10-16 for this strain. The result of this study showed that the best accuracy of prediction was obtained with quadratic function with body depth, breast width, body length, shank length and drumstick as best regressors.