Broiler growth rates increased by over 400% from 1957 to 2005 从1957年到2005年,肉鸡生长速度增加了超过400%

The following text and images are quoted from a poultry science journal [1]: M.J. Zuidhof, B.L. Schneider, V.L. Carney, D.R. Korver, F.E. Robinson, Growth, efficiency, and yield of commercial broilers from 1957, 1978, and 2005. Poultry Science, Volume 93, Issue 12, 2014, Pages 2970-2982


The effect of commercial selection on the growth, efficiency, and yield of broilers was studied using 2 University of Alberta Meat Control strains unselected since 1957 and 1978, and a commercial Ross 308 strain (2005). Mixed-sex chicks (n = 180 per strain) were placed into 4 replicate pens per strain, and grown on a current nutritional program to 56 d of age. Weekly front and side profile photographs of 8 birds per strain were collected. Growth rate, feed intake, and measures of feed efficiency including feed conversion ratio, residual feed intake, and residual maintenance energy requirements were characterized. A nonlinear mixed Gompertz growth model was used to predict BW and BW variation, useful for subsequent stochastic growth simulation. Dissections were conducted on 8 birds per strain semiweekly from 21 to 56 d of age to characterize allometric growth of pectoralis muscles, leg meat, abdominal fat pad, liver, gut, and heart. A novel nonlinear analysis of covariance was used to test the hypothesis that allometric growth patterns have changed as a result of commercial selection pressure. From 1957 to 2005, broiler growth increased by over 400%, with a concurrent 50% reduction in feed conversion ratio, corresponding to a compound annual rate of increase in 42 d live BW of 3.30%. Forty-two-day Feed Conversion Ratio FCR decreased by 2.55% each year over the same 48-yr period. Pectoralis major growth potential increased, whereas abdominal fat decreased due to genetic selection pressure over the same time period. From 1957 to 2005, pectoralis minor yield at 42 d of age was 30% higher in males and 37% higher in females; pectoralis major yield increased by 79% in males and 85% in females. Over almost 50 yr of commercial quantitative genetic selection pressure, intended beneficial changes have been achieved. Unintended changes such as enhanced sexual dimorphism are likely inconsequential, though musculoskeletal, immune function, and parent stock management challenges may require additional attention in future selection programs.”


From 1957 to 2005, broiler growth rates increased by over 400%, with a concurrent 50% reduction in Feed Conversion Ratio FCR. The claim that broiler 42-d live BW was increasing at a compounded rate of 3.1% [2] has held up to scrutiny. The current study confirms that the rate of increase in 42-d live BW from 1957 to 2005 was 3.30% per year, compounded for 48 yr. Similarly, FCR to 42 d of age has decreased by 2.55% per year, also in a compounding manner. The net result was that over a period of almost 50 yr, the broiler industry has been able to reduce the amount of feed required to produce chicken meat by one-half, and breast meat by 67%. Because feed accounts for approximately two-thirds of the cost of producing chicken, the resulting savings to consumers is substantial.


To counter a surprisingly widespread popular misunderstanding of the underlying mechanisms behind rapid broiler growth, it is important to note the basis for this transformative change in productivity. Modern chickens grow quickly because they have tremendous genetic potential to grow. Traditional selection methods—breeding efficient and robust birds with high growth rates—have been a particularly successful strategy in poultry because of high reproductive rates and short generation times. There have been lessons along the way. Unintended consequences to selection have proven challenging for the broiler industry, and will likely continue to emerge in spite of a high level of diligence manifested through comprehensive balanced selection programs. Many unintended changes such as increasing sexual dimorphism are not likely to become problematic, but musculoskeletal biomechanics, changes in immune response, and implications of huge growth potential for the welfare of breeding stock will undoubtedly challenge primary meat-type poultry breeders for the foreseeable future.

broiler growth rate

本研究探讨了商业筛选对肉鸡生长、效率和产量的影响,使用了自1957年和1978年以来未经选择的2种亚伯达大学肉品控制品系以及一种商业Ross 308品系(2005)。每个品系的混合性别雏鸡(每个品系n = 180)被放置在4个重复笼子中,并按照当前营养计划生长到56天。收集每个品系8只鸡的每周正面和侧面照片。对生长率、饲料摄入量和饲料效率的指标,包括饲料转化率、剩余饲料摄入量和剩余维护能量需求进行了表征。使用非线性混合Gompertz生长模型来预测体重和体重变异,有利于随后进行随机生长模拟。从21天到56天龄期间,对每个品系的8只鸡进行了解剖,以表征胸肌、腿肉、腹部脂肪垫、肝脏、肠道和心脏的异速生长。使用新颖的非线性协方差分析来测试假设,即由于商业选择压力的影响,异速生长模式已经发生变化。从1957年到2005年,肉鸡生长率增加了超过400%,同时饲料转化率降低了50%,相应的42天活体重增长复合年增长率为3.30%。与此同时,42天的饲料转化率在同一48年期间每年减少2.55%。由于遗传选择压力,肌肉中胸肌的生长潜力增加,而腹部脂肪减少。从1957年到2005年,雄性42天时的胸小肌产量比雌性高30%,雌性高37%;胸大肌产量在雄性和雌性中分别增加了79%和85%。在几乎50年的商业数量遗传选择压力下,实现了预期的有益变化。增强的两性异形等意外变化可能无关紧要,但肌肉骨骼、免疫功能和种鸡管理方面的挑战可能需要在未来的选择计划中额外关注。





  1. M.J. Zuidhof, B.L. Schneider, V.L. Carney, D.R. Korver, F.E. Robinson,
    Growth, efficiency, and yield of commercial broilers from 1957, 1978, and 2005. Poultry Science, Volume 93, Issue 12, 2014, Pages 2970-2982
  2. N. Barton. Breeding meat type poultry for the future targets for selection, limits to performance and market requirements for chicken. Proc. 9th European Poultry Conference, World’s Poultry Science Association, UK Branch, Andover, Hants, UK (1994), pp. 33-38