ABSTRACT
The poultry industry has advanced remarkably over the past 50 years. In particular, poultry meat production has been the most successful than any in the animal industry. Production standards of broilers and layers have continually improved over this period, with contemporary male broilers currently reaching a live weight of 2.5 kg at 33-35 days of age, and white egg layers capable of producing 330 eggs in 52 weeks of lay. Over this period, the body weight of broilers at 42 days has increased by 25-50 g per year and the feed conversion ratio to 2 kg body weight has improved 2-3 points annually. As shown by Havenstein et al. (2003), genetic selection brought about by breeding companies is responsible for 85-90% of the improvements in broiler growth, and advances in nutritional management have provided only 10-15% of the changes. When these researchers compared the performance of the 1957 broiler strain to the 2001 broiler strain, which were fed their representative diets, the birds from the 2001 genetic strain were 4.96 times heavier than those from the 1957 strain and averaged 8% more breast meat yield. The necessity to achieve and sustain these improvements in genetic potential was the driving force behind recent advances in poultry nutrition, and there had been continuous refinement in the nutrition and feeding practices of commercial poultry.
