Introduction
Demand for animal protein is set to increase dramatically over the next few decades (FAO, 2002; Alexandratos and Bruinsma,2012). This represents a significant challenge in terms of increasing productivity against a backdrop of reducing resources including land and water. It will require the application of many different technologies including genetic improvement (Ludu and Plastow,2013). Whilst the largest cost of production is associated with feed, another significant element is the impact of disease. The cost of disease may be underestimated due to its multifactorial nature and the relative success, at least in the developed world. Bush et at., 2011 state that the role of genetics in improving animal health will become increasingly important as focus increases on tackling antimicrobial drug resistance.
Technological innovations have been drivers of social and economic change. They have played a pivotal role in enhancing the quality of life and the safety of animals and humans. In the last four decades there has been an unprecedented surge in the development of biotechnology in animal production and health, with gene-based biotechnologies becoming most prominent in the last decade. While the vast majority of these technologies has been developed and utilized in developed countries, they have the potential to alleviate poverty and hunger, reduce the threats of diseases and ensure environmental sustainability in developing countries. Some of the technologies have a long history of successful use, others have been used with varied success, and many more are at different stages of development and commercialization.
In selective breeding, the potential of individuals to transmit good genes to the next generation is estimated (i.e. their breeding value is calculated). With genomic selection it is possible to estimate an animal’s breeding value quite accurately without the need for own performance or performance of large number of offspring. Modern breeds of livestock differ markedly from their ancestors as a result of breeding strategies. For example, milk production per cow has increased among Holstein dairy cattle. Similarly, breeding programs have resulted in lean, fast-growing pigs (Notter.,1999). Chickens from modern breeds each produce more than 250 eggs per year, approximately double that produced in 1950, again mainly due to genetic selection. Currently countries that are following genomic selection are United States of America, Canada, New Zealand, Netherlands, Australia, Denmark, Sweden and Brazil. Benefits of genomic selections have well been demonstrated in developed countries that include reduced generation interval accuracies of above 70% have been reported for young genomic proven bulls, higher rates of genetic gains. Genomic systems in developed countries are characterized with large reference populations, collaboration among countries, well defined phenotypes but mostly within pure breeds