Department of Animal Sciences and Agricultural Education, California State University Fresno, Fresno, CA 93740.
Pitman Family Farms, Sanger, CA 93657.
Poult Sci. 2020 Feb;99(2):698-701. doi: 10.1016/j.psj.2019.09.004. Epub 2019 Nov 22.
In no antibiotics ever (NAE) broilers, enteric diseases pose a threat to intestinal health and generally welfare, which can be exacerbated because of stocking density. Through knowledge of litter condition and management, disease can be minimized, and broiler welfare can be improved. To evaluate how stocking density influences NAE broilers raised in conventional housing, we evaluated production traits for broilers raised at two stocking densities within a single commercial house. Over the course of 4 flocks, 78,960 Cobb 500 broilers were raised in an industry-style tunnel ventilated house. The house was divided into four equally sized pens, each representing one of two stocking densities. An industry standard stocking density (SSD; 0.23 m per bird) and low stocking density (LSD; 0.27 m per bird) were each assigned to two pens per flock and were alternated for each subsequent flock raised. Litter moisture content, body weight, mortality, and feed conversion (FCR) were evaluated and averaged over all four flocks for both stocking densities. Data were analyzed in JMP with an ANOVA, and means were separated by Tukey's honestly significant difference. As expected, the litter moisture content was significantly larger in the more densely packed SSD pens at weeks 2, 3, 4, and 6, totaling 0.242 moisture content on average at week 6 vs. 0.217 in LSD pens at the same flock age (P = 0.035). Weekly body weight and final flock FCR were not significantly impacted by stocking density. No association was observed in mortality between the broilers raised in SSD and LSD. The results from this study indicate that the two densities examined were comparable in their growth and efficiency. Additional management pressure would exist to handle the increase in litter moisture in flocks placed at SSD in a production setting; although, raised in the same barn at the same time, the impact of SSD vs. LSD was minimal in this study.
在无抗生素（NAE）肉鸡中，肠道疾病对肠道健康和一般福利构成威胁，由于饲养密度的增加，这种威胁可能会加剧。通过了解垫料状况和管理，疾病可以最小化，肉鸡福利可以得到改善。为了评估饲养密度如何影响常规饲养环境中的 NAE 肉鸡，我们在单个商业鸡舍内评估了两种饲养密度下肉鸡的生产特性。在 4 个鸡群中，78960 只科宝 500 肉鸡在一个工业隧道通风鸡舍中饲养。该鸡舍被分成四个大小相等的围栏，每个围栏代表一个饲养密度。一个工业标准饲养密度（SSD；每只鸡 0.23 米）和低饲养密度（LSD；每只鸡 0.27 米）分别分配给每批鸡群中的两个围栏，并在随后饲养的每批鸡群中交替使用。评估了垫料水分含量、体重、死亡率和饲料转化率（FCR），并对两种饲养密度下的所有 4 个鸡群进行了平均。数据在 JMP 中使用 ANOVA 进行分析，均值通过 Tukey 的诚实显著差异法进行分离。如预期的那样，在第 2、3、4 和 6 周，SSD 围栏中垫料的水分含量明显更大，在同一鸡群年龄下，SSD 围栏的垫料平均水分含量为 0.242，而 LSD 围栏的垫料水分含量为 0.217（P=0.035）。饲养密度对每周体重和最终鸡群 FCR 没有显著影响。在 SSD 和 LSD 饲养的肉鸡死亡率之间没有观察到关联。本研究的结果表明，在所检查的两种密度下，肉鸡的生长和效率相当。在生产环境中，将鸡群置于 SSD 时，处理垫料水分增加会带来额外的管理压力；尽管在同一时间在同一个鸡舍中饲养，但在本研究中，SSD 与 LSD 的影响微不足道。
