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31.
统计分析了2001年引进的新美系杜洛克种猪及繁殖后代在6月龄、12月龄、24月龄和36月龄四个阶段的体尺、体重数据,结合品种特征、体型外貌总结研究出杜洛克种猪的百分制评分及等级标准。  相似文献   
32.
1. The effects of changes in technical efficiency on the increase of broiler production are presented for the period 1994–2013 based on the panel data from seven farms located in southern and central Poland. A total of 766 cycles were analysed.

2. The Cobb–Douglas production function was used to assess the changes of output elasticities as well as technical changes in broiler production, for 5-year sub-periods separately.

3. Technical indices of broiler production significantly improved between years 1994–2013: feed conversion ratio decreased from 2.50 kg/kg to 1.78 kg/kg, mortality rate from 8.8% to 4.0% and daily weight gain increased from 37.1 g/d to 58.7 g/d, respectively.

4. Before accession to the EU, there was a substantial increase of fixed capital connected with modernisation of buildings and equipment. In the period 1994–2013, inputs of fixed capital per kilogram of livestock increased by 72% and at the same time the input of labour decreased by 56%.

5. Technical changes in years 1994–1998 contributed to a rapid production increase at a rate of 4.6% annually and only by up to 0.7% annually during 2009–2013. The slowdown of production rate increase after 2009 was partially caused by decreasing the stocking density.  相似文献   

33.
34.
Feed intake and diet composition appear to affect the body temperature of pigs. Two trials were conducted to analyse the effect of feed intake level and dietary protein content on the intestinal temperature (IT) of pigs housed under thermo neutral conditions. Ten pigs (64.1 ± 1.3 kg initial body weight) fitted with an ileal cannula were used. A thermometer set to register the IT at 5‐min intervals was implanted into the ileum through the cannula. In both trials, the ambient temperature ranged from 19.1 to 21.6°C and the pigs were fed at 07:00 and 19:00 hr (same amount each time). In trial 1, the pigs were fed daily 1.2 or 1.8 kg of a wheat–soybean meal diet. The IT followed a similar pattern along a 24‐hr period regardless the feed intake level. The IT rapidly increased up to 0.61 and 0.74°C after the morning meal and up to 0.53 and 0.47°C after the evening meal in pigs fed 1.2 and 1.8 kg/d respectively. The postprandial IT was higher in pigs fed 1.8 kg after each meal (p < .05). In trial 2, pigs were fed daily 1.8 kg of a low (11%) or a high (22%) crude protein diet. The IT followed a similar pattern along the 24‐hr period regardless the dietary protein level. The postprandial IT did not differ between pigs fed the low protein or the high protein (p > .10). The IT rapidly increased up to 0.66 and 0.62°C after the morning meal in pigs fed the high‐ and low‐protein diet (p < .05), but there was no change after the evening meal (p > .10). In conclusion, the feed intake level affected the IT of pigs housed under TN conditions, but the dietary protein content had no effect.  相似文献   
35.
仓房自动堆包机是专门为粮食储藏和粮食加工企业研制的一款有限空间堆包设备。它不仅能在有限空间将粮包提升到目标高度、自动堆放,而且还能替代多人工作,设备操作简单、方便、灵活,可实现粮食储藏和食品加工企业有限仓房机械化作业。  相似文献   
36.
中国热带农业科学院环境与植物保护研究所是从事热带农业环境与植物保护领域研究的国家级公益类非营利性研究所。海口环境与植物保护研究实验室项目工程即将竣工,该所科研主体由儋州向海口转移工作已列入所2011年计划的第一项重点工作。从工作方案入手,重点从领导管理、群众参与、宣传引导、督导落实等方面提出建议确保转移工作平稳有序。  相似文献   
37.
利用酒精、镊子对黑木耳耳片进行组织分离,方法方便、快捷,分离成功率100%。  相似文献   
38.
试验旨在探究日粮中添加不同水平β-胡萝卜素(β-C)对牦牛皮下脂肪颜色及组织维生素A含量的影响。试验选取12头2~3岁牦牛为研究对象,随机分为4个组,每组3个重复。各处理组日粮分别在基础日粮中添加0(对照)、720(低剂量)、1 440(中剂量)、1 620 mg/d(高剂量)β-C,饲养90 d后,分别测定牦牛脂肪、肌肉色度、背膘厚度及不同组织中β-C和代谢产物维生素A的含量,结果表明:日粮中添加不同水平β-C,牦牛背部、胸部脂肪及半腱肌的黄度值(b*)显著高于对照组(P<0.05),亮度值(L*)和红度值(a*)没有显著变化(P>0.05);牦牛背膘厚度在中剂量组达到最大值;对照组牦牛血清中β-C及维生素A含量显著低于各试验组(P<0.05),且维生素A含量随β-C添加量的上升呈上升趋势(P<0.05);牦牛皮下脂肪、腹腔脂肪、心脏、肝脏、脾脏、肺脏、肾脏及空肠等组织器官中β-C含量在中剂量组均达到最大值,除肝脏中维生素A含量较高外,其他组织中维生素A含量在各处理组间差异不显著(P<0.05)。综上所述,日粮添加β-C影响牦牛皮下脂肪颜色,且在中剂量组牦牛皮下脂肪、心脏、肝脏、脾脏及空肠等组织器官中β-C含量达到最大值,故推荐其最佳摄入量为1 440 mg/d;在日粮中添加β-C影响牦牛肝脏和血清中维生素A含量,对其余组织器官中维生素A含量没有影响。  相似文献   
39.
A range of agricultural practices influence soil microbial communities, such as tillage and organic C inputs, however such effects are largely unknown at the initial stage of soil formation. Using an eight-year field experiment established on exposed parent material (PM) of a Mollisol, our objectives were to: (1) to determine the effects of field management and soil depth on soil microbial community structure; (2) to elucidate shifts in microbial community structure in relation to PM, compared to an arable Mollisol (MO) without organic amendment; and (3) to identify the controlling factors of such changes in microbial community structure. The treatments included two no-tilled soils supporting perennial crops, and four tilled soils under the same cropping system, with or without chemical fertilization and crop residue amendment. Principal component (PC) analysis of phospholipid fatty acid (PLFA) profiles demonstrated that microbial community structures were affected by tillage and/or organic and inorganic inputs via PC1 and by land use and/or soil depth via PC2. All the field treatments were separated by PM into two groups via PC1, the tilled and the no-tilled soils, with the tilled soils more developed towards MO. The tilled soils were separated with respect to MO via PC1 associated with the differences in mineral fertilization and the quality of organic amendments, with the soils without organic amendment being more similar to MO. The separations via PC1 were principally driven by bacteria and associated with soil pH and soil C, N and P. The separations via PC2 were driven by fungi, actinomycetes and Gram (−) bacteria, and associated with soil bulk density. The separations via both PC1 and PC2 were associated with soil aggregate stability and exchangeable K, indicating the effects of weathering and soil aggregation. The results suggest that in spite of the importance of mineral fertilization and organic amendments, tillage and land-use type play a significant role in determining the nature of the development of associated soil microbial community structures at the initial stages of soil formation.  相似文献   
40.
Large mounds amended with plant residues are a common cultivation method for sweetpotato (Ipomoea batatas) in the western parts of the Papua New Guinea highlands, with a suggested benefit of elevated root zone temperature (RZT) from decomposition. This study aimed to evaluate whether RZT affects the formation and growth of sweetpotato storage roots. Experiments evaluated the effects of a constant elevated RZT on the Beauregard cultivar and of a short‐term increase in RZT on the Beauregard and Northern Star cultivars. Plants were grown in 18‐L pots divided into a control compartment (constant RZT at 20°C) and a treated compartment (RZT at 30, 40 or 50°C). Constant elevated RZT was maintained until harvest, while short‐term increase in RZT occurred in weeks 2 and 3 only. Constant elevated RZT did not affect the total number of storage roots, but RZT of 30°C and above reduced the dry‐biomass of storage roots. The short‐term increase in RZT did not alter the total number or dry‐biomass of storage roots in Beauregard, while both of these attributes were reduced at RZT of 40°C or above in Northern Star. Elevated RZT inhibited dry‐biomass accumulation of storage root, with a more pronounced impact at constant elevated RZT. These results demonstrate that any benefits of the mound culture on sweetpotato yield production do not arise through the influence of temperature elevation.  相似文献   
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