Choice of sample sizes for carcass yield and chicken cuts

Abstract

SUMMARY: The objective of this study was to determine the appropriate number of replicates to identify significant differences in carcass and cut yields in broiler chickens. At 42 d of age, a total of 480 broiler chickens were selected, weighed, and processed to obtain the hot carcass yield. Subsequently, after cooling, the cold carcass yield was determined. The cold carcass was dismembered into boneless and skinless breast, tenders, legs, and whole wings, which were individually weighed to obtain the cuts yield. The collected data underwent normality analysis and subsequent determination of descriptive statistics, as well as analysis of variance, in both cases to determine mean values, standard deviation, and coefficient of variation (CV). The required number of replicates to detect differences between means for different magnitudes was determined. The CVs obtained were stable, with the highest CV observed for tenders’ yield (11.34%) and the lowest for the hot carcass (2.35%). To achieve significant differences in both, cold and hot carcass, a minimum of 8 replicates is needed for 5% differences in 97% of experiments. For breast fillet characteristics, 10 replicates are required to detect a 10% difference in 99% of experiments. Due to higher variation, tenders yield necessitates at least 10 replicates to detect a 20% difference in 90% of cases. For wing yield, 8 replicates suffice for 94% accuracy when differences exceed 15%. Lastly, 10 replicates enable detection of 7.5% differences in leg variables in 95% of experiments. Effective experimental planning, based on the statistical power of the test, is essential for determining the requisite number of replicates. Researchers must prioritize the specific carcass characteristic relevant to their study and design the number of replicates, accordingly, ensuring more reliable and realistic results.

Keywords

• statistics
• experimental power
• repetition