蛋种鸡对本交笼产蛋窝内光环境的偏好性选择

    Preference of internal light environment of nest box by layer breeders in natural mating colony cages

    • 摘要: 产蛋窝是种鸡表达行为需求的必要福利设施,为明确本交笼养模式下种鸡对产蛋窝内部光环境相关设计参数的需求,探究种鸡对产蛋窝内部LED光环境的偏好性选择,该研究采用窝内蛋比例、产蛋行为与竞争行为作为评价产蛋窝使用效果的指标,选择LED白光(400~700 nm)、LED红光(585~690 nm)、LED蓝光(460~490 nm)3种光色作为诱导光源,每种光色设置2种不同的光照强度(5 lx、30 lx),对照组为无光源诱导组,对比7个试验组产蛋窝使用效果。结果表明,产蛋窝内设置30 lx的LED白光与蓝光时,窝内蛋比例显著高于其他试验组(P<0.05),在33周龄时,窝内蛋比例可达91.5%±3.4%、93.2%±4.5%。30 lx的LED白光与蓝光组鸡只的打斗行为与排挤行为频次显著高于其他试验组(P<0.05),30 lx的LED红光组鸡只啄羽行为频次显著高于其他试验组(P<0.05)。竞争行为频次随时间分布的趋势与产蛋数量随时间分布趋势一致,产蛋数量与竞争行为频次主要集中在开灯后的第2~5小时,开灯后第3和第4小时为产蛋高峰。鸡只更偏好于30 lx的LED白光与蓝光作为产蛋窝内诱导环境,在该刺激下鸡只的产蛋行为可较好地表达,产蛋窝利用率更高。

       

      Abstract: Abstract: Commercial enriched colony cages have become commonplace for the natural mating of layer breeders in China in recent years. It is now generally accepted that a nest box is essential to ensure the welfare requirements of laying hens in the internal environment of colony cages. Specifically, the LED light environment of a laying nest depends on various factors, including the position, color, substrate, enclosure, and light intensity in the nest box. Therefore, the utilization rate of a nest can be improved via the evaluation on the preference selection of layer breeders in the internal light environment of a nest box. Taking a commercial layer breeder farm in Handan, Hebei province, China, as a research object, this study aims to investigate the effects of 3 LED light colors (white 400~700 nm: WL, red 585~690 nm: RL, blue 460~490 nm: BL) and 2 light intensities (5 lx: L1, 30 lx: L2) in the nest box on the nest choice of hens using preference selection index method. The nests with no light were termed as the control group (DK). The experimental house was with 4 rows of 4-tier double-sided colony cages (304 cages in total) along the length of a house. Each cage was in the size of 4.80 × 1.20 × 0.71 m (L × W × H), holding 10 roosters and 90 laying hens. 28 identical cages were selected to evaluate at the fourth tier in the house. 7 treatments were divided into WL-L1, WL-L2, RL-L1, RL-L2, BL-L1, BL-L2, DK, to compare that in a randomized block design, where each row had a replicate for each treatment. The specific measurements were made on the number of eggs laid in the nest and on the floor, as well as the nesting and agonistic behavior in the nest. The results showed that there were significant effects of light color, light intensity and their interaction on the number of nest eggs, and the agonistic behavior of egg laying (P<0.05). 1) The proportion of nest eggs in the WL-L2 and BL-L2 treatment was much higher than that in other light treatments (P<0.05), whereas, in the RL groups, the number of nest eggs was much lower than that in the control group (P<0.05). At the end of 33 weeks, the proportion of nest eggs in the WL-L2 and BL-L2 groups were 91.5±3.4% and 93.2±4.5%, respectively. However, there was no significant difference in the egg production among all groups. 2) The WL-L2 and BL-L2 treatment significantly improved the percentage of hens in the nest, the number of sitting events, the frequencies of scratching and rotating, as well as the duration of hens without egg laying. Nevertheless, the number of nest visits, the ratio of nest visits/nest eggs, and the duration of exploring were much lower than that in other groups (P<0.05). 3) In the BL-L2 treatment, the frequencies of threats and aggressive pecks were higher than that in WL-L2, but not significant correlation, whereas, the frequencies of feather pecking reached the highest among all groups (P<0.05). In the WL-L2 and BL-L2 treatments, the frequencies of fights and displacements in the nest were much higher than that in other groups. 4) The percentages of eggs laid varied over time during each hour from the time lights came on, regardless of the treatment with the highest number laid between 06:30 and 08:30 (P<0.05). The highest rates of agonistic behavior occurred with the peak time of lay in the nest. In the WL-L2 and BL-L2 treatments, the distribution of laying times for nest eggs was much less evenly than that in other groups (P<0.05). Therefore, the change of internal light environment in a nest box can be used to enhance the nest utilization rate. A stronger preference for the layers can be the high intensity of LED white and blue light. There were different requirements for the light environment in different behavioral demands of layers. It is suggested to select the sub-area illumination according to the behavioral requirements of layer breeders in the natural mating colony cages.

       

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