Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada.
Department of Animal Biosciences, University of Guelph, Guelph, Ontario, Canada.
Poult Sci. 2022 Aug;101(8):101917. doi: 10.1016/j.psj.2022.101917. Epub 2022 Apr 10.
Current commercial strains of broiler breeders display reproductive dysregulation when fed to satiety, but they can achieve optimal hatching egg production under feed restriction. However, chronic feed restriction in broiler breeders is a welfare concern due to physiological and behavioral signs of hunger, lack of satiety, and frustrated feeding motivation. The purpose of this study was to assess the welfare and productivity of slower-growing broiler breeders during lay. A total of 336 broiler breeders from 5 strains of slower-growing broiler breeders (3 female strains: 100 hens per strain, and 2 male strains: 12 and 24 roosters per strain) were kept in 12 identical pens throughout lay, 4 pens per combination of roosters and hens: A hens with Y roosters, B hens with Y roosters, and C hens with X roosters. According to guidelines, strain B and C hens and X roosters were slower growing strains and strain A hens and Y roosters were intermediate growing strains. Egg production was recorded daily, and settable eggs laid at 30, 40, and 50 wk of age were incubated to hatch. Growth rate, feed and water intake, and welfare indicators (feeding motivation, behavior, and physical assessment: feather coverage, foot and leg health, and keel bone status) were recorded during lay. Additionally, a subsample of 5 hens per pen was dissected for anatomical analyses. Laying rate started and peaked earlier in B hens than in A hens and remained above 70% in both strains, yielding high cumulative egg production (>165 eggs/hen) until 53 wk of age. Until 50 wk of age, fertility and hatched of fertile was high in slower growing broiler breeders, on average, above 95 and 80%, respectively. Compared to A hens, B and C hens had better feather coverage, lower feeding motivation, and lower daily water and feed intake. Results of this study suggest that slower growing broiler breeders show reduced signs of poor welfare and improved productivity during lay although susceptibility to obesity-related problems on laying rate may be strain-specific.
当前，商业肉鸡种鸡在自由采食时会出现繁殖失调，但在限饲下可以达到最佳种蛋生产水平。然而，由于种鸡存在饥饿、缺乏饱腹感和受挫的摄食动机等生理和行为迹象，慢性限饲会对其福利产生影响。本研究旨在评估生长速度较慢的种鸡在产蛋期的福利和生产性能。总共 336 只来自 5 个生长速度较慢的肉鸡品种的种鸡（3 个母鸡品种：每个品种 100 只母鸡，2 个公鸡品种：每个品种 12 只和 24 只公鸡）在整个产蛋期被饲养在 12 个相同的鸡舍中，4 个鸡舍为一组，每组包含公鸡和母鸡：A 组为母鸡和 Y 型公鸡，B 组为母鸡和 Y 型公鸡，C 组为母鸡和 X 型公鸡。根据指导原则，B 组和 C 组的母鸡和 X 型公鸡为生长速度较慢的品种，A 组的母鸡和 Y 型公鸡为生长速度中等的品种。每日记录产蛋量，在 30、40 和 50 周龄时将可孵化的种蛋进行孵化。在产蛋期间记录生长速度、饲料和水的摄入量以及福利指标（摄食动机、行为和身体评估：羽毛覆盖率、脚和腿部健康以及龙骨状况）。此外，每个鸡舍抽取 5 只母鸡进行解剖分析。B 组母鸡的产蛋率开始和高峰时间均早于 A 组母鸡，并且在两个品种中均保持在 70%以上，直到 53 周龄时累积产蛋量仍很高（>165 枚/只母鸡）。直到 50 周龄，较慢生长的肉鸡种鸡的受精率和孵化率均较高，平均分别高于 95%和 80%。与 A 组母鸡相比，B 组和 C 组母鸡的羽毛覆盖率更好，摄食动机更低，每日水和饲料摄入量也更低。本研究结果表明，生长速度较慢的肉鸡种鸡在产蛋期表现出较低的不良福利迹象，生产性能得到提高，尽管肥胖相关问题对产蛋率的影响可能因品种而异。
