Riber Anja B, Wurtz Kaitlin E
Department of Animal and Veterinary Sciences, Aarhus University, Blichers Allé 20, P.O. Box 50, DK-8830 Tjele, Denmark.
Livestock Behavior Research Unit, USDA-ARS, 270 S. Russel St., West Lafayette, IN 47907, USA.
Animals (Basel). 2024 Nov 19;14(22):3330. doi: 10.3390/ani14223330.
Selection for the more efficient production of broilers has resulted in rapid growth rates. The aim was to review the existing knowledge on the effect of growth rate on broiler welfare. Genotypes with faster growth rates consistently demonstrate poorer gait scores and increased prevalence of disorders affecting their legs than slower-growing genotypes. Reduced mobility places faster-growing broilers at an increased risk of developing contact dermatitis, as they spend increased durations sitting in contact with litter. Poor walking ability, heavy body weights, and conformational differences such as proportionally larger breast muscle in genotypes with faster growth can impact a bird's ability to walk and navigate the environment, making it difficult to access resources and express natural behaviors. Faster growth has also been associated with poor cardiovascular health, increased susceptibility to heat stress, increased prevalence of mortality, ascites, as well as multiple breast muscle myopathies. Feed restriction, a practice associated with hunger and frustration, may be used to control the growth of broiler breeders, with birds having higher growth potential typically experiencing higher restriction levels. Overall, there is strong evidence that fast growth rates negatively impact welfare, and that slower-growing genotypes show significantly improved welfare. Furthermore, some evidence suggests that even minor reductions in growth rate can lead to welfare improvements.
对生长速度更快的肉鸡进行选育导致了其生长速度迅速提高。目的是回顾关于生长速度对肉鸡福利影响的现有知识。与生长较慢的基因型相比，生长速度较快的基因型始终表现出较差的步态评分，以及影响腿部疾病的患病率增加。行动能力下降使生长较快的肉鸡患接触性皮炎的风险增加，因为它们与垫料接触的时间增加。行走能力差、体重过重以及生长较快的基因型中比例较大的胸肌等体型差异会影响禽类行走和在环境中活动的能力，使其难以获取资源并表现出自然行为。生长速度较快还与心血管健康不佳、对热应激的易感性增加、死亡率、腹水以及多种胸肌肌病的患病率增加有关。限饲，一种与饥饿和挫折相关的做法，可能用于控制肉种鸡的生长，生长潜力较高的禽类通常经历更高的限饲水平。总体而言，有充分证据表明快速生长速度对福利有负面影响，而生长较慢的基因型显示出福利有显著改善。此外，一些证据表明，即使生长速度略有降低也可导致福利改善。
