Laying the foundation for turkey success

In 2017, a team led by Dr. Christine Baes at the University of Guelph joined forces with Hybrid Turkeys to apply genomic selection for improved health, welfare, efficiency, and production in Canadian turkeys. This five-year project finished in 2021 and made significant contributions to advancing turkey research. 

In particular, a large proportion of research focused on the development of novel phenotypes related to health, welfare, carcass, and meat quality traits. In collaboration with Hybrid Turkeys, a commercial abattoir, and the U of G research team, over 44 weeks of data collection were performed by the team on >12,000 birds. This resulted in one of the largest datasets available worldwide for investigating the relationship between genomic variation, meat quantity, meat quality, and novel health/welfare-related traits in turkeys (see sidebar). 

The novel phenotyping pipeline in abattoir conditions was retained by Hybrid Turkeys to continue data collection to measure selected carcass and meat quality traits for future breeding program (i.e., colour, image analysis to estimate carcass components). 

Due to a lack of knowledge available on traits related to health and welfare, meat quantity, and meat quality in turkey production, several studies were performed to provide necessary direction and context. An innovative methodology to assess hypothalamic-pituitary-adrenal (HPA) axis activity via feather corticosterone was investigated as this would be a practical, non-invasive phenotype related to stress levels to collect at the abattoir. 

Methodological and biological validation was performed to provide context to this novel measurement. The influence of external factors (e.g., temperature stress, season, post-mortem muscle activity) on carcass and meat quality traits was assessed and deemed possible but with relatively small effect sizes. 

Regarding future health/welfare traits, a large survey among turkey producers benchmarked current housing and management practices within Canadian turkey farming and provided their perspective on bird health/welfare issues. Important issues such as footpad dermatitis and injurious pecking were investigated further, and risk factors identified. 

As only 30 per cent of the variation could be explained by management, this highlights the potential to address these issues in part through breeding approaches and lays the foundation for future research.  

All in all, the project facilitated the expansion of a database of genomic information for turkeys with over 87,000 birds genotyped. For all the collected traits, heritability, and genetic and phenotypic correlations between traits were evaluated as well as further genetic analyses like identifying regions of the genome associated with specific traits. 

For many of these traits, the estimates from this project were the first available for turkeys. Novel statistical approaches were developed which were shown to outperform traditional methods and have since been implemented to the breeding program. 

Industry impact
The project resulted in one of the largest datasets available worldwide for investigating the relationship between genomic variation, meat quantity, meat quality, and novel health and welfare-related traits in turkeys. This provided some of the first heritability estimates of traits related to carcass and meat quality as well as health and welfare traits that can contribute to sustainable turkey breeding. 

Hybrid Turkeys has expanded genotyping as part of their standard practice and single-step genomic selection developed within the project has been implemented, resulting in 30 per cent gains in accuracy for economically important traits. This has led to a realized economic gain of approximately $19 million to the turkey industry.

Ultimately, the theoretical and applied improvements to the genetic selection of turkeys developed through this project provide an integrated approach to incorporating health, welfare, efficiency, and production traits in the breeding of commercial turkey, thus contributing to more sustainable food production in Canada. 

This work manifests the benefits of deep integration of research results from multiple disciplines, providing tangible benefits to turkeys and turkey farmers in Canada and around the world, as well as training of more than 20 highly qualified personnel.

Future directions
The research project team is continuing to collaborate with Hybrid Turkeys to integrate study results. 

However, the collaboration between U of G and Hybrid Turkeys will not be stopping there. 

The past project resulted in one of the largest datasets available worldwide for investigating the relationship between genomic variation, meat quantity, meat quality, and novel welfare-related traits. 

However, it identified clear needs with regards to decreasing mortality and improving livability, which inspired the current project. 

A new project has been funded to apply genomic selection for body composition traits in turkeys using data from computed tomography (CT) technology. 

Computed tomography is an imaging procedure that uses combinations of many X-ray measurements taken from different angles, which are then used to construct cross-sectional images (slices) of specific areas of an object. 

Using measurements derived from CT images is expected to increase the rate of genetic gain for breast meat yield by providing a detailed view of muscle volume. This technology can also be used to improve livability by identifying animals susceptible to health problems. 

In particular, an increased frequency of circulatory disorders such as ascites, aortic rupture, spontaneous cardiomyopathy (round heart), and cardiomyopathy causing sudden death, each accompanied by poor meat quality, lower muscle production and/or high mortality, have been identified in parent stock birds. 

The use of CT technology allows animals with a predisposition for these disorders to be identified early. 

For example, animals with bulges along the length of the aorta are more likely to suffer from aortic rupture. 

The ability to clearly identify animals with anatomical abnormalities and associate genomic regions with them for use in a selection program offers an incredibly important opportunity for genetic improvement. 

Preliminary analyses have shown high correlations between muscle volume obtained via CT scan and body weight. Internal simulations have shown that a combination of genomic information, optimal modelling, and improved phenotyping can increase genetic gain for breast meat yield by up to 38 per cent. 

The objective of this ongoing project is to implement a genomic selection program using traits derived from CT technology for genetic improvement of turkey parent stock, enabling continuous genetic improvement in both production and livability traits, including those affecting health and welfare. 

Introducing liveability traits derived from CT technology is expected to substantially decrease mortality, equating to economic gains for Canadian turkey producers and healthier birds. 

Key traits
Traits considered throughout this project included:

• Health and welfare traits: Walking ability, feather corticosterone, fault bar traits, pendulous crop.
• Meat quantity:  Carcass portion weights and yield.
• Meat quality: Colour measurements, pH measurement, drip loss, cooking loss, shear force, white striping.
• Production and fertility: Body weight, feed conversion ratio, broodiness traits, egg numbers, fertile eggs, hatch of set eggs, hatch of fertile eggs.