“My, how you’ve grown…”
Broiler growth and performance has come a long way
Written by
Dr. Valerie Carney If Only I had a Nickel….
As a poultry scientist, I often think, “If only I had a nickel for every time I was asked about hormones in chicken.” It is quite satisfying to be able to respond that the poultry industry does not feed or inject hormones. At times the conversation ends with a look of distrust and a change of subject, but more often than not it is followed with the classic question: “Then…why are they so big?”
“It’s genetics,” I answer.
History of Poultry Genetics
The history of poultry domestication dates back to 1000 B.C., but poultry as an industry was slow to develop initially. During the 19th century, poultry breeding was largely a cultural phenomenon that focused primarily on feather and form with little interest in egg and meat production. As interest in poultry began to move towards its suitability as a food source, two significant events of the 20th century enabled the expansion of the poultry industry and fueled its progress: the rediscovery of Mendelian principles of heredity, and the invention of a reliable trap nest to record egg production.
Prior to the 1930’s, production birds were mass selected and bred as pure lines without pedigree records. Selection focused on increasing egg production and the poultry meat industry was generally a byproduct of the egg industry. Although advances were made in production traits, progress was slow. The use of pure lines did not capitalize on the effect of heterosis or hybrid vigor.
Between the 1930s and 1950s crosses of pure lines were used to improve fitness and reproduction. The use of pedigrees allowed for removal of unwanted traits and promotion of desirable traits to the next generation while maintaining genetic variation. Modern broilers are descendants of a Cornish and White Plymouth Rock cross that, by means of genetic selection, has resulted in the development of broilers with astounding production and breeding performance.
Poultry breeding in the 21st century requires knowledge of economics, science and consumer preferences. Market demand drives product development and thus breeding programs. The commercial broilers of today are a result of three or four way crosses. Although important economic traits are measured on pure lines, much of the progress in production traits takes advantage of the combining ability of these crosses.
The time line between pedigree selection and commercial broiler production is three to five years, and thus primary breeding companies are obligated to recognize field performance and market signals that help to predict requirements of future products. The basic principles of breeding have not changed. The primary breeders continue use to evaluate genetic potential through various performance measurements of an individual and its relatives. Birds that exhibit the best genetic potential to meet the product requirements are allowed to naturally mate to produce the next generation.
Adaptation of new technology and application of science combined with powerful statistical methods and computing power have allowed the poultry industry to make more informed decisions about the most suitable candidates for pedigree populations.
Drivers of Change
Over the last 50 years, there has been a significant change in the poultry industry. As consumer demands changed, the poultry industry responded by providing new products to meet these demands.
This responsiveness of the industry has had a significant effect on the steady increase in poultry consumption of the last few decades. In the 1960s poultry consumption in Canada was 9.5 kg per person. By 2004, per capita poultry consumption increased to 30.4 kg .1
Both the form in which poultry is consumed and the location of purchase has also changed significantly. Fifty years ago, almost all chicken was purchased as a whole bird to be cooked at home. Today, whole bird production has dropped below ten percent of total production, as ninety percent of broilers processed today are sold as pieces or further processed products. Various market sectors have evolved to include retail, fast food, full service restaurants and hotels/institutions.
These market changes have significantly impacted breeding program objectives. Consequently, efficient white meat yield has become the most economically important driver of selection programs.
Genetic Progress
The poultry industry is one of the most efficient sectors in all of agriculture. To meet changes in consumer preferences over the last 50 years, poultry production has experienced phenomenal improvements in growth and efficiency. Much of this progress can be attributed to the reproductive ability of poultry, the adoption of new and advancing technologies and industry structure.
But exactly how far has the industry come with respect to growth and efficiency in the past five decades? My colleagues Brenda Schneider and Martin Zuidhof and I decided to evaluate the change in poultry production and meat quality traits over the last 50 years in a recent study performed at the Poultry Research Centre at the University of Alberta.
