Leading genetics firm Aviagen recently invited customers from around the world for an update on company research and broiler breeder progress. Jake Davies provides an overview.
When the first broilers were created, they were simple crosses of two breeds and largely selected on the basis of good visual traits, such as a tall bird with a wide breast.
But as the performance of birds has improved, ever more sophisticated measurement is needed to keep up.
Breeding firm Aviagen takes into account hundreds of traits, from headline economic areas such as FCR or liveweight gain, to welfare indicators such as seven-day mortality or leg strength. And the means of measurement is constantly becoming more sophisticated.
“We are always looking for new developments,” says Alfons Koerhuis, chief technical officer at Aviagen. “To support high levels of production we need the health and welfare of the bird to be good. We need good skeleton quality and good metabolic function.”
And, as fewer antibiotic treatments become available, resistance to disease is becoming ever more important.
Measuring and selecting for these traits is an ongoing balancing act, says Dr Koerhuis. The breeding programme is based on global markets, and welfare is an important consideration alongside performance.
Leg strength is one example where focus has been applied for a long time. “We have been removing birds with leg defects from our breeding programme since the 1970s,” says Dr Koerhuis.
It has resulted in birds having better leg condition today, despite significant gains in growth rate and overall weight.
Traits, once they have been identified as important, must be kept in breeder programmes. In the 1980s the firm began to incorporate all family data into selection, rather than just individual birds.
The 1990s saw the measuring of oxygen levels in blood to analyse lung and heart function, as well as resistance to ascites. Around this time Aviagen also began using x-ray machines to measure tibial dyschondroplasia. Statistical modelling of entire flocks and selection using genetic information are yet more recent developments.
Birds were traditionally selected in “optimal” environments, using clean and highly biosecure units, says Dr Koerhuis. This was for two reasons; first to find the true potential of a breed, and second to identify any health problems that might arise from this optimal growth.
The turn of the millennium saw a slight change to this policy. Aviagen ceased using any antibiotics or coccidiostats in these pedigree breeding programmes, and introduced the siblings of the birds to high-challenge environments, where litter is older and nutrition is poorer. “In this environment we select for robustness, gut and digestive function, immune function, uniformity, liveability and growth. And again it is an antibiotic-free environment,” says Dr Koerhuis.
Another development has been selecting based on group FCR, rather than that of individual birds, and using radio tags to identify individual bird’s eating habits.
“There is a lot of genetic variation between eating habits. Some birds are snackers and others eat larger, but fewer, meals. The interesting thing is that these birds can still have the same FCR.”
So primary production is a key consideration for geneticists, but equally important is driving the performance of parent stock. Aviagen R&D director Magnus Swalander says it adds another dimension to the balanced breeding programme.
At breeder level, the firm monitors traits such as hatchability (especially of stored eggs), production beyond 40 weeks and even seven-day liveability or albumen quality.
Technology plays an important role at this level, too. Acoustic resonators borrowed from the egg industry can detect micro cracks in egg surfaces. Transponders monitor water consumption so that lower consumers can be actively selected, potentially improving litter quality.
Like broilers, there is a move to breeding programmes that incorporate larger numbers of birds. “This leads to larger selection and higher genetic progress,” says Mr Swalander.