Need for Comparative Slaughter Experiments in Poultry Research

The comparative slaughter technique is a protocol used to estimate changes in the body composition of birds during an experiment. The protocol is based on the assumption that the body composition of the experimental group of birds (EG) at the beginning of an experiment can be predicted accurately and precisely from the carcass compositions of comparable birds from the same population that are slaughtered at the beginning of the experimental period. The present study examines the need for the initial slaughter group (ISG) of birds. By reexamining data from three previously published experiments that used broiler chicks and one that used adult cockerels, it is demonstrated that the same inferences can be obtained by an appropriate analysis of covariance using only the data from the EG birds. Elimination of the ISG results in a considerable reduction in the resources required for experimentation and means that the inferences are based on data obtained only from birds subjected to the various treatments.