Welfare regulations and their effects on breeding and genetics in laying hens

摘要

There are two main issues that will challenge breeders as a result of increasingly demanding and restrictive welfare standards. First is the response of existing varieties to the new environments to which they will be exposed as a result of the changing welfare rules. Secondly is how breeders will respond, in terms of altered selection criteria, to current and anticipated changes to cage and other environments. Commercial layers sold today are the progeny of pedigree stocks selected anywhere from four to six years ago. And the selection programs for many of them were designed much longer ago than that. If we go back to the 1960 percent many of the genetic selection programmes were based on floor managed flocks, with trap-nests used to measure eggproduction and to facilitate collection of egg weight and quality data. Two factors combined to change this situation very quickly. First, the high labour requirement for trap-nesting and the inherent inaccuracies associated with it, virtually forced breeders to undertake the high capital cost of installing single bird cages to record egg production and identify eggs. But the shift of the commercial industry to the cage environment also encouraged this move, on the grounds that the closer the selectionenvironment to the commercial one, the more appropriate the selection procedure became.