The Growth Pattern of Brazilian Canela-Preta Chickens with Different Plumages Reared in Two Rearing Systems

ABSTRACT Growth pattern is essential for economically efficient poultry production. In this study, we aimed to describe the growth curve of chickens of the Canela-Preta breed reared in two different rearing systems, considering their different plumage colors. Initially, 204 one-day-old male and female chicks were randomly distributed in confinement and semi-confinement (102 animals in each system) without separation by gender. The animals were individually identified by wing and foot plastic brands and were weighted every seven days. The body weight and age records were used to estimate the growth curves of the following factors using the Richards model: plumage color, gender, and rearing system. The likelihood ratio test was used to verify the equality of parameters and identify nonlinear models to compare the growth patterns of the evaluated groups. The growth pattern of Canela-Preta chickens changed as a function of gender, plumage color, and rearing system. Females with black plumage, black and gold hens, and males with black and white plumage showed greater sensitivity to changes in rearing systems. Within-breed selection strategies for specific colors can improve the use of growth pattern differences, improving production efficiency. Semi-confinement is suitable for rearing Canela-Preta chickens with any plumage color, as these animals meet the free-range poultry niche market requirements.

摘要
生长模式是实现经济效益优化的家禽生产的关键基础。本研究旨在描述两种不同饲养模式下饲养的Canela-Preta品种肉鸡的生长曲线，并考量其不同羽色带来的差异。本研究初始选取204只1日龄公母雏鸡，未按性别分组，随机分配至全舍饲与半舍饲两种饲养模式，每组各102只试验动物。试验鸡仅通过翅部与脚部塑料脚环完成个体标识，并每7天进行一次体重测量。本研究以体重与日龄记录为基础，采用理查兹模型（Richards model）估算不同羽色、性别及饲养模式对应的生长曲线；通过似然比检验验证参数齐性，并筛选适配的非线性模型，以对比各组试验鸡的生长模式差异。研究结果显示，Canela-Preta品种肉鸡的生长模式随性别、羽色及饲养模式的不同而呈现显著差异。其中，黑羽色母鸡、黑金羽色母鸡以及黑白羽色公鸡对饲养模式的改变表现出更高的敏感性。针对特定羽色的品种内选育策略，可通过合理利用生长模式差异提升生产效率。半舍饲模式适用于所有羽色的Canela-Preta品种肉鸡饲养，因其符合家禽散养细分市场的需求。