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By Hans Bijleveld
What is the connection between poultry breeding and drawing blood samples from birds? Red blood cells have the hereditary (genetic) information of an animal stored in its DNA, just like it is in the cells of all other body parts. The new technique, called genomic selection, can read the genetic information and thereby learn a lot about the characteristics and quality of the animals. This information can then be used to select parents for the next generation of the breeding programme.The goal of breeding chickens and turkeys is to mate the best animals of a generation to produce the next generation. But which ones are the best animals? The animals that perform best for the traits that the breeding company (actually its customers) finds important and likes to see most. These traits can change over time, because customers ask for an animal with different qualities. For years egg layers were selected for egg numbers, early maturity, peak production and persistency of lay and egg quality and colour. At the same time, selection attention was paid to the egg weight curve, feed conversion, body weight, hatchability and culls. All these traits were considered, more or less, strongly depending on how they fit in the breeding goal.
Emphasis on trait changes
Today robustness (especially for Europe), behaviour and feathering get more emphasis in the breeding goal while other traits get less. Not much progress can be made any more for early maturity and peak production. However persistency of lay and egg quality during the late stages of production have become much more important, according to Frans van Sambeek, director of primary breeding for ISA, the egg laying division of Hendrix Genetics. “To collect data about these traits, we have kept crossbred progeny from breeding males up to 80 weeks” he says. “Since 2009 progeny from the pure blood line is kept until 100 weeks. When you keep hens to 80 weeks then the males are older than 105 weeks. If selection is started at that late age then the selection interval is even longer. ISA also evaluates dry matter of eggs, which is a trait especially important to the egg product industry. A lower percentage dry matter indicates more water in the egg and that has to be removed to manufacture egg powder.
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| Blood samples offer a wide range of information on the birds’ individual traits, enabling quick and precise selection. |
To establish how good an animal is, we have to measure and collect all kinds of data. Certain traits, like growth, can be measured on the animals themselves, but for many other traits, like potential egg production on males, that is not possible. In such cases the geneticist evaluates parents, half siblings and progeny. Based on all this collected data an animal is assigned a breeding value, which is an estimate of how good an animal is.
ISA uses an enormous database, because every pure blood line contains thousands of animals. In today’s poultry breeding we use statistics, calculation models and computer programmes to analyse the success of the poultry breeding company.”
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Source: World Poultry, Vol. 27, No. 4, 2011
