Cobb places well over two million pedigree birds every year of which only about 1.1 per cent are selected for breeding purposes. This enormous number allows us to make predictable progress in many traits at the same time even if some, such as egg production and body weight, have a degree of negative correlation.

The Company has long been using a combination of observable welfare traits by highly skilled selectors who remove inferior birds together with technology to measure accurately certain welfare traits that are not easily observable. These include removing birds with tibial dyschondroplasia using a Lixiscope and verification of the oxygen-carrying capacity of each bird with a blood oximeter.

Cobb supports research worldwide to develop new technology and improve the breeding programme. A lot of this research is focused on animal welfare and disease resistance (kinematic variables linked to walking ability, innate immunity and genetic resistance to infection).

Evolution of poultry breeding

Cobb's geneticists believe it will still be possible to continue to increase efficiency and improve welfare outcomes, using the current technology. However, the increasing use of genomics will make this task easier and more accurate.

This science focuses on tracking multiple parts of genome within pedigree populations using SNPs (single nucleotide polymorphisms) to select for complex polygenic traits (unlike markers that were developed for single genes).

From 2006 to 2009, the first unique 60,000 SNP microarray chip was developed by Cobb to analyse the genomes of our pedigree birds. Thousands of informative SNP markers were identified as research tools in each Cobb pedigree line and placed on this chip.

The process has now begun to associate SNP’s markers with desirable traits in each pedigree line. This technology will allow us to select birds based on DNA (blood) testing and presence of the desired SNPs and not just their phenotypic expression which is influenced by the environment.

Genomic selection will not replace the current selection methods - but it will complement them to increase the accuracy in the selection process of all traits.

Broiler mortality versus body weight trends in the United States
(Agristats, 2010)

Of particular importance will be those traits with low heritability (fertility, certain leg disorders) or traits that are not easy to measure on pedigree populations such as disease resistance.

At the moment, disease resistance can only be selected by challenging the birds to a particular disease, which cannot be practised on the pedigree birds. While we can simulate disease challenge studies via the use of pedigree relatives, it is risky to select against a single disease/disorder as this change may increase the bird’s sensitivity to another disease.

Breeding companies have also a responsibility to maintain genetic diversity and control inbreeding within the chicken populations. Cobb maintains over 40 different pure lines, including very slow growing, hardy coloured lines.

In 2007, Cobb established a partnership with Sasso, a leading French company in the selection of traditional slow growing coloured breeds to develop jointly speciality products.

Having a broad spectrum of genetic lines will allow the Company to develop products that meet regional requirements either because of the specific environmental conditions or because the market demands differentiated products.

Rather than progressive trait improvement within the lines of already specialised existing products such as Cobb500, Cobb700, CobbAvian48, Cobb is developing new ones by line replacement for example with CobbSasso150 and CobbSasso175, or by selecting pedigree lines in specific environments (Cobb400Y in India).

Female mortality versus egg production in the United States

November 2012