Selective breeding: a short history
The principal of selective animal breeding is based on choosing animals to become parents of the next generation based on their suitability for a defined purpose/goal, often referred to as the breeding goal.
It has been practiced continuously at an informal level since the domestication of livestock and companion animals. Historically selection was based on fairly simple measures such as visual assessments and measurements of size or weight, but despite the simplicity of the approach, dramatic changes have been achieved.
A good example of the potential impact of the process can be seen in the extensive diversity in appearance and size of the breeds of dogs that are now available world-wide, all of which are descended from distant but common ancestors.
As developments have been made over time in improving measurement techniques and methods for estimating an animal's genetic potential, the power and effectiveness of animal breeding as a tool has also increased. Over the last half century it has helped achieve dramatic improvements in the productivity of livestock species as well as improvements in the health and welfare of livestock and other animals.
Results of selective breeding
- Modern dairy cows produce on average, more than twice the daily milk yield of cows milked in the 1950s
- Modern broiler chickens reach market weight in a third of the time of birds available in the 1950s whilst also consuming only a third of the total feed originally required to produce 1kg of breast meat
- Since 1950 the efficiency of egg production efficiency has increased by over a third
- Modern pigs grow more than 50% faster than pre-1940s pigs and this improved growth rate is achieved whilst also using 50% less feed per kg of lean meat.
The future of selective breeding
As the biological revolution continues, more and more knowledge is being gained on the genetics of different animal and parasite species, along with a better understanding of the effect of genetic differences on characteristics of those animals and parasites. This information, coupled with new developments in our ability to measure different characteristics, provide unprecedented opportunities for innovation in animal breeding, not only in terms of accelerating the rate of genetic progress but also to widen the traditional breeding goals and to select on characteristics and traits that previously could not be considered, such as resistance to a variety of diseases and reductions in green house gas (GHG) emissions per unit of production.
Cranfield University study: GHG emissions
For example, results from a study conducted by the KTN in collaboration with Cranfield University suggest that the genetic improvement production efficiency achieved over the last 20 years has resulted in reductions in GHG per unit product of around 1% per year in most livestock species. The results also show that this annual rate of reduction is likely to be sustained with continued selection, and the benefits could potentially be increased substantially through greater use of high merit animals in commercial populations and by incorporating more relevant measures in the breeding goals, such as feed efficiency for ruminant species.
Opportunities for innovation
Animal breeding has the potential to make very important contributions towards elevating many of the challenges facing UK society and businesses society.
- Food security - through improved production efficacy and ability to utilise low quality feed
- Food safety - through improvements in an animal's resistance to disease challenges
- Animal health & welfare - through reductions in incidences of suffering due to disease challenge
- Climate Change - through improvements in production efficiency and direct selection