At the recent 25th Alltech International Animal Health and Nutrition Symposium, Dr. Neil O’Sullivan of Hy-Line International stressed that selective breeding has improved efficiency and contributed directly to sustainable production systems. Each group of pedigree matings can theoretically produce 32 billion eggs through five successive generations (pedigree; ggp; gp; parent; commercial).
Currently selection is based on an index which incorporates both sire and dam evaluation and the application of biological markers. Important production traits include age and sexual maturity, peak production, egg mass, persistency of production during the first and post-molt cycles. Addition traits considered include livability, disease resistance and temperament.
Selection for flock wellbeing includes feather cover, social behavior and interaction and especially with respect to floor housing, the ability to find and use nest boxes. It is noted that selection over the past 35 years has focused on caged-housed flocks and accordingly many of the behaviors which reduce floor laying have in fact been eliminated in favor of characteristics which benefit caged flocks.
Quality traits are an important consideration in selection and include shell, strength, shell color, freedom from cracks, integrity of shells, egg size, albumen height, yolk and albumen weights and yield of solids. The presence of blood spots and protein particles are also considered in selection programs.
With the increase in cost of feed ingredients, feed intake and related body size and partitioning of energy between maintenance and production are regarded as important with respect to profitability. Environmental considerations have introduced a focus on moisture content of excreta. Although not important from the point of view of commercial egg production, breeders must include reproductive efficiency in the various lines which constitute the commercial hybrid. These include fertility, ability of males to mate, hatchability and sperm viability.
During the past 30 years, live hen feed conversion efficiency has improved from 2.5 to close to 1.8. The gap between potential production of white and brown feathered hybrids has narrowed. Social adaptability and stress response are important in brown feathered flocks held under floor management systems.
Annual progress in a white feathered line (presumably W-36) is estimated to be:
- Livability has been improved by +0.17%;
- Feed conversion ratio has been lowered by -0.014g;
- Egg production has been increased by 2.1 eggs through 60 weeks.
This progress has been achieved by intense selection for objective traits. Results of breeding programs are measured by primary breeders, in structured field trials and in a few remaining random sample tests including the North Carolina State University test conducted by Dr. Ken Anderson.