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The population of laying hens loses important genes: a case history

Published online by Cambridge University Press:  01 August 2011

P. Sørensen
Affiliation:
Danish Institute of Agricultural Science, Dept. of Breeding and Genetics, Research Centre Foulum, DK-8830, Tjele, Denmark
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Summary

The switch from keeping laying hens in a floor or free range system into a cage system led to a considerable change in the way that breeding and selection took place. In the past 40–50 years up to the present date, the increase in genetic improvement of the egg laying trait was substantial. However, cage-adapted populations of laying hens seem to have lost some of their abilities to an adequate performance when returned to the old floor\free range systems. The strong concentration of all parts of the poultry production has meant that less than 10 international breeding companies supply most hens for laying purposes in the world and they have very little interest in developing genetic material for the West-European region where there are marked consumer preferences for eggs produced in non-cage systems. A particular Danish line, of White Leghorn origin named “The Skalborg hen” seems to have survived during an era of cage production system and they seems to have a production potential at farm level.

El paso de la cría de gallinas en suelo o libres a la utilización del sistema de jaulas, ha llevado a un cambio importante en la cría y la selección. En los últimos 40–50 años el aumento en la mejora genética de los huevos ha sido sustancial. Estas poblaciones de gallinas ponedoras adaptadas al sistema de jaula parecen haber perdido algunas de sus habilidades de rendimiento cuando se las vuelve a colocar en el antiguo sistema libre. La alta concentración en la producción avícola ha llevado a que menos de 10 compañías internacionales provean la mayor parte de las gallinas ponedoras en el mundo. Estas compañías no están interesadas en desarrollar material genéticamente para Europa del oeste, donde las preferencias de consumo del mercado van hacia los huevos producidos con sistema tradicional sin jaula. Una línea danesa particular proveniente de la White Leghorn y llamada “The Skalborg Hen”, parece haber sobrevivido sin una época en jaulas y mantiene un potencial de producción a nivel del de granja.

Type
Research Articles
Copyright
Copyright © Food and Agriculture Organization of the United Nations 1997

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References

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