Prediction of live broiler weight based on body measurements

Abstract

Two strains of broiler type chickens (WL and VC) that varied in body conformation were used to determine the relationship of egg weight, body weight and shank length at various ages to live weight at broiler age (BW7). Response for fast growth was observed in the VC strain. Larger skeleton as a response was observed in the WL strain. Differences between strains become very prominent as the birds advanced in age. Measurements of body weight at 5 weeks plus sex effect used as estimators of final weight (BW7) gave the highest values of R2 (0.910 and 0.818 in WL and VC strains, respectively). Measurements of body weight at 3 weeks (BW3) showed a significant positive linear relationship, but had a small effect on final weight.

The results indicate that selection response for heavy birds at 54 days of age by measuring their shank length at an age younger than 5 weeks is not recommended for these two strains.

Within a strain, the r2 or R2 increase values were always higher for body weight as a predictor of final weight than shank length at the same age and sex. Thus, body weight is the simplest and most accurate parameter to be used as a critierion for growth selection from 5 weeks of age onward.

The effect of egg weight on final weight (BW7) was not significant for the two strains.