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Influence of early quantitative food restriction on long bone growth at different environmental temperatures in broiler chickens 总被引:4,自引:0,他引:4
1. This investigation was carried out to study the influence of early quantitative food restriction (40% of ad libitum intake from 7 to 14 d of age) and environmental rearing temperature (thermoneutral, cold and hot) on long bone (tibia, femur and humerus) development in broiler chickens. 2. Tibia, femur and humerus were obtained at the ages of 14, 21, 28, 35 and 42 d, and the variables studied were: length and width (mm, expressed as absolute values), bone breaking strength (kgf) and bone weight/bone length index (BW/BL, mg/mm). 3. All bone variables increased with bird age. Food restriction reduced bone length and width but did not affect bone weight. High environmental rearing temperature reduced bone length and width at 42 d of age. Bone strength was not affected by environmental temperature but the calculated BW/BL index was reduced by heat exposure. 4. The findings suggest that food restriction and high environmental rearing temperature reduce long bone growth; bone breaking strength was affected by bird age but not by food restriction nor rearing ambient temperature. 相似文献
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推进蚕业适度规模经营,发展蚕业家庭农场是稳定蚕桑产业的有效途径,但推进蚕业适度规模经营尚缺乏技术保障。为此,我们开展了全年适应多批次养蚕的桑叶收获技术探索,通过1年的探索,对全年多批次养蚕的桑叶收获技术得出了初步的结果。 相似文献
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Summary Following an investigation concerning the well‐being of piglets in a farrowing house, the study was continued in a rearing house. The same parameters were used: mortality, morbidity, and external injuries. Two housing systems were involved: one with a fully slatted concrete floor and one with a solid concrete floor with straw bedding. The investigation was carried out three limes in each system, with approximately 550 piglets each time. Statistical analyses showed that mortality, morbidity, and frequency of external injuries were significantly higher in piglets reared in the slatted floor system than in the system with straw. The main diseases and causes of death were post‐weaning enteritis and bowel oedema. Especially in the first examination (in the second week of the rearing period) the level of injury was strongly influenced by the housing system in the farrowing house. Sex, breed, origin of the piglets, litter size, and parity of the sow had no influence on the incidence of disease, but the breed had an influence on the frequency of injuries. 相似文献
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紫花苜蓿田短星翅蝗发生规律及防治对策 总被引:3,自引:0,他引:3
短星翅蝗是紫花苜蓿田中的主要害虫,为摸清该虫的发生规律,于1999--2002年采取了笼内饲养与大田系统调查相结合的方法,对该虫进行了调查。该虫在滨州市紫花苜蓿田1年发生1代,以卵在土中越冬,蝗蝻雌虫6个龄期,雄虫5个龄期。介绍了该虫的为害特点、年生活史、生活习性、发生与环境的关系以及防治方法。 相似文献