Genetics: Selecting for Sustainability

Over the years, selection for improved efficiency has been extremely successful. The cost of producing a pound of live chicken declined from US $2.32 in 1934 to US$1.08 in 1960 down to US$0.45 in 2004 in today’s money. Within a flock, improvements in veterinary medicine, environmental control, nutrition, etc., have undoubtedly had dramatic impacts on bottom line performance; however, Havenstein (2003) stated that his results “indicate that genetic selection brought about by commercial breeding companies has brought about 85 to 90 per cent of the change that has occurred in broiler growth rate over the past 45 years. Nutrition has provided 10 to 15 per cent of the change.”

The challenge for this century will be to continue these improvements, so that as an industry we make high quality animal protein available to all, but to do this in a way that is “sustainable”.

What is Sustainability?
There are many definitions of sustainability but many of these definitions are unclear or open to interpretation. Often the definition “to meet the needs of the present without compromising the ability of future generations to meet their own needs” is used. As commonsense as this may sound it provides no metrics for us to measure ourselves against. The International Reporting Initiative uses a framework for reporting “sustainability” using three “pillars” of: economic, environment and social. Sustainability to a breeding company must encompass these three pillars.

The social and ethical issues associated with animal production have become increasingly important. Accumulations of leg health issues, poor immune responses, high feed intake or high outputs of waste product are today not considered suitable for a long-term sustainable breeding program. As an industry we also face issues the social issues of human health (pathogen freedom and the nutritional factors in the meat we produce) and the availability of animal protein for nutrition on a global scale.

Environmental Thinking
Environmental traits will be increasingly considered in breeding goals for the future, but these interlink with social issues across many parts of the globe. As wild populations of fish and animals shrink and human population becomes increasingly urbanized, the provision of low cost animal protein will be increasingly desired by consumers world-wide. Poultry with its scalability, high throughput and excellent FCR is an opportunity for people in both established and emerging markets.

Land is becoming more expensive if not scarce. Peri-urban land previously used for agriculture is being utilized for urban expansion and industry. This will increase the distance our food supplies have to travel to reach us, with its knock on effects of greenhouse gas emissions, congestion and so forth.

Published data indicates that of all the meat producing livestock species, commercially raised broilers have the lowest green house gas (GHG) emissions per kg of meat produced. Genetic selection of broilers over the last 20 years has shown a reduction of GHG emission of around 25 per cent, with this reduction predicted by the authors to continue for the next 20 years or so.

Commercial geneticists feel that this is a very conservative estimate given the enhanced technologies available today and in the near future. Selection targets for efficiency, especially in FCR and meat yield have primarily driven this reduction, at the same time as reducing the wholesale price of high quality, healthy animal protein to the customer.

Breeding Strategy
The breeding industry is required to produce products that are acceptable and desired by the end user. Therefore feedback and consultation with direct customers, end users, consumers, scientists and lobby groups has always been a key feature in developing breeding goals. Due to the structure and nature of the breeding business, there are approximately five years from a breeding decision being made in the pedigrees, before the first effects of these changes can be experienced in the broiler generation. Genetic change is not sudden and is often not greatly noticeable until some years of advancement accrue much like compound interest. It is therefore crucial to the future success of the animal breeders to effectively predict consumer issues in the future and to identify emerging issues from the field. Within Aviagen a major part of our global success has been the emphasis that has been placed on balance, not just in terms of performance traits, but also by ensuring that we focus on the support traits for our birds, with this strategy now broadening to capture environmental and emerging ethical concerns.

Performance Efficiencies
Aviagen has long been a leader in the use of advanced technology to improve the feed efficiency of broiler chickens. For over 30 years we have used highly controlled individual test pens to enhance FCR in our birds. This technique has almost halved the amount of feed required to generate a unit of poultry meat since the 1970’s. Individual pens, while cost effective and of high welfare standards, do not address the behavioural aspects of feed efficiency. In 2005, Aviagen started selecting pedigree chickens using performance testing stations in its breeding program.

These stations allow birds to be group housed and demonstrate the behavioural aspects of feed intake and efficiency. This technology will allow Aviagen to make faster improvements in FCR, with improvement rates around 2.5 per cent per annum. This improvement rate is close to the predicted increases in world chicken meat output. This being the case, the industry will be close to truly sustainable with inputs reducing at around the same rate as growth.

Improving meat yields also play a part in ensuring long-term sustainability. Using traditional conformation scoring along with ultrasound technology and information on the actual yield of siblings, we are able to increase yields at over 0.30 per cent per annum.

Global Focus
For many years Aviagen believed it was appropriate to grow our pedigree birds to their maximum potential under close to ideal conditions, in order to expose any underlying physiological issues. This allows selection only from families that are capable to rapid growth with no negative related issues. We still believe that this is appropriate, however we understand that around the world there are people unwilling or unable to achieve the levels of nutrition, biosecurity and management that we recommended. Almost 10 years ago we set up sibling testing, where brothers and sisters of pedigree birds are exposed to management and feeding practices in line with the bottom quartile of the industry. This exposes our chickens to lower input type scenarios, again potentially improving the sustainability, and ability of our stock to thrive under such conditions. Increasingly robust chickens, in the face of disease challenge or management misstep, have no negative implications for those with the finances or management skills to follow high input advice.

Physiological Function
Twenty years of continued focus on welfare traits such as leg strength and cardio-vascular function, using traditional inspection methods, medical technologies, such as X-Rays, ECG and oximetry, as well as genetic technologies that better understand the relationship between traits, has reduced these issues to very low incidences on effectively run commercial production facilities. While effective measurement of the reduction of these concerns is difficult, large datasets like those available from the Canadian Meat Inspection Service, indicate dramatic improvements in both the underlying genetic susceptibility of modern broilers to these issues, and an increased awareness as to the management requirements of these improved individuals.

Biodiversity
All of the large commercial companies keep large populations within each “line” to maintain variation and control inbreeding. There has also been a move for many of the breeding companies to acquire more varied stock types to give more depth to their programs and provide greater choice to consumers. In some, primarily developed countries, there is increasing interest in non-standard farmed chickens, due to a perception of higher “quality”, in systems such as free-range, organic, slow-growing and so on. The demand stems from a small but significant percentage of consumers, to which producers are responding. All of these strategies tend to reduce “sustainability” through usage of greater amounts of feed and increased GHG production.

They also increase cost and care should be taken that lower income consumers are not legislated out of eating chicken, as this remains one of the healthiest animal proteins available.

Future Potential
With the publication of the full chicken genome, the inclusion of genomic technologies into commercial poultry breeding programs has moved a step closer to reality. All the current primary breeding groups are investing heavily into these areas. Our increased knowledge of the genetic factors in our birds will be used to select more efficiently and effectively for traits of importance.

The traits that will benefit the most from these technologies are likely to be the ones for sustainability, environmental impact and robustness, as these are traits often difficult or destructive to measure in a traditional breeding structure.

There is good evidence to suggest that the concerted efforts by Aviagen, and other breeding companies have reduced the levels of physiological issues associated with modern fast growing types of broilers. At the same time improvements in absolute performance have greatly reduced the carbon footprint of the industry and will continue to do so. Undoubtedly there will be emerging issues of welfare, sustainability and consumer ethics that will come to the forefront over time. Genetic lag will be an issue in these circumstances, with the time taken from a breeding decision made to the first impact appearing in the field, potentially being construed as lack of willingness or understanding by the breeding companies. It is important to understand that while selection for sustainability and welfare traits will continue, with additional power coming through genomics, that this is a slow and gradual process. Daily management, nutrition, and biosecurity, etc., can have more dramatic and immediate impacts on individual flocks in the field than genetics alone can offer.