Evolution of the Modern Broiler and Feed Efficiency

Abstract

Although the chicken was domesticated during the Neolithic period, the development of the modern broiler is a recent event that has occurred within the past 100 years. The chicken's adaptability has allowed it to be grown globally under a range of husbandry conditions. That is, the same genetic stock may be found in a range of environments, where it is noted for rapid growth to market weight and efficiency of feed use, which has increased dramatically, mainly through genetic selection. Under good husbandry and a high-energy diet, at 35 days of age a 1.40-kg broiler required 3.22 kg of feed in 1985. Twenty-five years later, we have a 2.44-kg broiler produced on 3.66 kg of feed. This review attempts to address the history of factors contributing to these changes, obstacles that have had to be overcome, and future limitations.

Improving the sustainability of global meat and milk production

“…Through selective breeding, precise nutritional strategies, changes in husbandry practices and improvements in animal health, marked improvements have been made in the efficiency of animal production. While considerable improvements have been achieved for all livestock species perhaps the most impressive changes have been achieved in poultry (9) . The impact of selective breeding was graphically illustrated by Zuidhof et al (10) who compared the growth characteristics of a broiler strain which had remained unselected from 1957 with a current day commercial strain.…”

The genetics of body weight and feed efficiency in broiler chickens

“…Those genetic changes, along with management and nutritional changes, as well as the application and efficiencies of vertical integration led to the development of the modern broiler industry and its ability to produce chicken meat at about the same absolute price today as it was being produced in the early 1950s (Havestein, 2003a). The modern broiler is a chicken that reaches market weight at an early age, has high carcass yield and is highly feed efficient (Siegel, 2014). Broiler breeding programs mainly select for growth rate, feed efficiency, and breast meat yield, ascites and skeletal abnormalities.…”

“…Moreover, the Ross 308 broiler line with the 2001 feed was estimated to have 1,815 gram body weight and feed conversion ratio of 1.47 at 32 days of age while the ACRBC line with the 1957 feed would not have 1,815 gram body weight and feed conversion ratio of 4.42 before 101 days of age . By focusing on economically most important traits, breeding companies succeeded to produce a broiler cross that reach market weight about 1 day earlier each generation (Siegel, 2014). Together with this change, a dramatic reduction in the feed conversion ratio has been recorded.…”

“…There are different forms of the modern broiler, each designed to address a specific market, and breeding programs are limited to a small number of groups operating globally. Generations are overlapping rather than discrete, and selection is multistage that is, selections are made at several points during the life of an individual, which may be removed from the population at any time (Siegel, 2014).…”

“…With the development of a high quality sequence assembly of the chicken genome, genomics can help to complement selection, particularly for traits that are expressed in one sex or later in life or for traits that are difficult to measure (Siegel, 2014).…”