Patterson P H, Siegel H S
Department of Poultry Science, The Pennsylvania State University, University Park 16802-3501, USA.
Poult Sci. 1998 Jan;77(1):32-40. doi: 10.1093/ps/77.1.32.
The effects of cage density on pullet live performance and blood indices of stress were evaluated in two commercial White Leghorn strains housed at 38, 32, 26, and 20 birds per cage from Day 1 to 6 wk of age, and 19, 16, 13, and 10 birds per cage from 6 to 18 wk. Cage densities of 26 and 13 birds per cage represent a U.S. standard of 142 and 284 cm2 per bird that is often applied in commercial pullet rearing. Cage density treatments include confounding cage, feeder, and drinker spaces per bird as might be encountered in commercial practice when growing more pullets per cage. Body weight was significantly reduced at greater bird densities in both strains; however, one strain was affected as early as 6 wk of age, whereas in the other strain, body weight was not reduced significantly until 18 wk. Feed intake was increased by more than 13% in both strains at the lowest density treatment (20 birds per cage) from Day 1 to 2 wk but reduced by more than 9% by higher cage densities during the remainder of the study. Feed conversion (FC) ratio was similarly improved (i.e., reduced) when more pullets were housed per cage, and increased when fewer birds were placed per cage compared to the standard. Despite a significant reduction in feed intake and a corresponding loss of body weight, cage density treatments had no significant affect on hemagglutinin titers to sheep red blood cell antigen, percentage heterophils (H), lymphocytes (L), or the H:L ratio. However, pullet age and strain differences were observed for all blood parameters. Overall, treatments allowing more cage, feeder, and drinker spaces per bird than the U.S. commercial standard provided no body weight advantage, and allowed for greater feed intake and poorer FC at several ages.
在两个商业化白来航鸡品系中评估了笼养密度对雏鸡生长性能和应激血液指标的影响。从1日龄至6周龄，每个笼子饲养38、32、26和20只鸡；从6周龄至18周龄，每个笼子饲养19、16、13和10只鸡。每个笼子饲养26只和13只鸡的笼养密度分别代表美国每只鸡142平方厘米和284平方厘米的标准，这一标准常用于商业化雏鸡饲养。笼养密度处理包括了商业化实践中每笼饲养更多雏鸡时可能出现的每只鸡笼舍、采食器和饮水器空间的混杂情况。在两个品系中，较高的鸡只密度均显著降低了体重；然而，一个品系早在6周龄时就受到影响，而另一个品系直到18周龄体重才显著降低。在最低密度处理（每笼20只鸡）下，从第1天到第2周，两个品系的采食量均增加了13%以上，但在研究的其余时间里，较高的笼养密度使采食量减少了9%以上。与标准相比，每笼饲养更多雏鸡时饲料转化率（FC）同样得到改善（即降低），每笼饲养较少鸡只时饲料转化率则升高。尽管采食量显著减少且体重相应下降，但笼养密度处理对绵羊红细胞抗原血凝素滴度、异嗜性粒细胞（H）百分比、淋巴细胞（L）百分比或H:L比值均无显著影响。然而，在所有血液参数方面均观察到雏鸡年龄和品系差异。总体而言，每只鸡的笼舍、采食器和饮水器空间比美国商业标准更大的处理方式并未带来体重优势，且在几个年龄段导致采食量增加和饲料转化率降低。
