Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada; Campbell Centre for the Study of Animal Welfare, University of Guelph, Guelph, Ontario, Canada.
Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada.
Poult Sci. 2021 Mar;100(3):100955. doi: 10.1016/j.psj.2020.12.052. Epub 2020 Dec 23.
To meet the growing consumer demand for chicken meat, the poultry industry has selected broiler chickens for increasing efficiency and breast yield. While this high productivity means affordable and consistent product, it has come at a cost to broiler welfare. There has been increasing advocacy and consumer pressure on primary breeders, producers, processors, and retailers to improve the welfare of the billions of chickens processed annually. Several small-scale studies have reported better welfare outcomes for slower-growing strains compared to fast-growing, conventional strains. However, these studies often housed birds with range access or used strains with vastly different growth rates. Additionally, there may be traits other than growth, such as body conformation, that influence welfare. As the global poultry industries consider the implications of using slower growing strains, there was a need for a comprehensive, multidisciplinary examination of broiler chickens with a wide range of genotypes differing in growth rate and other phenotypic traits. To meet this need, our team designed a study to benchmark data on conventional and slower-growing strains of broiler chickens reared in standardized laboratory conditions. Over a 2-year period, we studied 7,528 broilers from 16 different genetic strains. In this paper, we compare the growth, efficiency, and mortality of broilers to one of two target weights (TW): 2.1 kg (TW1) and 3.2 kg (TW2). We categorized strains by their growth rate to TW2 as conventional (CONV), fastest-slow strains (FAST), moderate-slow strains (MOD), and slowest-slow strains (SLOW). When incubated, hatched, housed, managed, and fed the same, the categories of strains differed in body weights, growth rates, feed intake, and feed efficiency. At 48 d of age, strains in the CONV category were 835 to 1,264 g heavier than strains in the other categories. By TW2, differences in body weights and feed intake resulted in a 22 to 43-point difference in feed conversion ratios. Categories of strains did not differ in their overall mortality rates.
为了满足消费者对鸡肉的需求不断增长，家禽业已经选择了肉鸡，以提高效率和增加胸部产量。虽然这种高生产力意味着产品价格实惠且稳定，但这是以牺牲肉鸡福利为代价的。人们越来越呼吁主要的饲养者、生产者、加工者和零售商提高每年加工的数十亿只鸡的福利。一些小规模的研究报告称，与快速生长的传统品种相比，生长速度较慢的品种的福利结果更好。然而，这些研究通常是在有活动范围的情况下饲养鸟类，或者使用生长速度差异很大的品种。此外，除了生长速度之外，可能还有其他影响福利的特征，例如身体形态。随着全球家禽业考虑使用生长速度较慢的品种的影响，需要对生长速度和其他表型特征差异很大的各种基因型的肉鸡进行全面的、多学科的研究。为了满足这一需求，我们的团队设计了一项研究，以基准测试在标准化实验室条件下饲养的传统品种和生长速度较慢的肉鸡的各种数据。在两年的时间里，我们研究了来自 16 个不同遗传品种的 7528 只肉鸡。在本文中，我们将肉鸡的生长、效率和死亡率与两个目标体重（TW）之一进行比较：2.1 公斤（TW1）和 3.2 公斤（TW2）。我们根据肉鸡达到 TW2 的生长速度将品种分为常规品种（CONV）、最快-慢品种（FAST）、中速-慢品种（MOD）和最慢-慢品种（SLOW）。当在孵化、孵化、饲养、管理和喂养方面都相同的情况下，品种的分类在体重、生长速度、饲料摄入量和饲料效率方面存在差异。在 48 日龄时，CONV 类别的品种比其他类别的品种重 835 至 1264 克。到 TW2 时，体重和饲料摄入量的差异导致饲料转化率相差 22 到 43 个点。品种分类在总死亡率方面没有差异。
