Effects of Thigh and Rear Udder Hygiene on Daily Milk Yield and Somatic Cell Score

To investigate the importance of dairy cow hygiene for management, the objective of this research was to determine the relationship between hygiene scores and daily milk yield as well as somatic cell score(SCS), and also the relationship between thigh and rear udder hygiene scores.The hygiene scores of thigh and rear udder were collected from 472 lactating cows in 3 Holstein dairy farms in Henan province, and dairy herd improvement(DHI) data for July, 2014 was also collected.After correcting the influence of fixed effects including lactating stage and dairy-parity, the effects of thigh and rear udder hygiene scores on daily milk yield and SCS were analyzed using SAS 9.1 with general linear model(GLM) procedure.The results showed that thigh and rear udder hygiene scores had no significant effect on average daily milk yield and SCS(P>0.05).For average daily milk yield, the regression coefficients of thigh and rear udder hygiene scores were-0.14 and-0.02, respectively.This meaned if thigh and rear udder hygiene scores increased 1 score, average daily milk yield of each cow would decrease 0.14 and 0.02 kg, respectively.For SCS, when thigh hygiene score ≥ 4, the proportion of cows with SCS ≥ 5 increased extremely significantly(P<0.01);when rear udder hygiene score ≥ 3, the proportion of cow with SCS ≥ 5 tended to increase(P=0.0546).Significant test for correlation and correlation coefficient estimation results showed that, there was a extremely significantly positive correlation discovered between thigh and rear udder hygiene scores(P<0.01).Therefore, hygiene scores was not only a management indicator, also could help understand udder health condition, which was beneficial for management.     

如何提高大修柴油机的清洁度

如何提高大修柴油机的清洁度（１５１８０１）黑龙江省兴隆林业局李振友，赵颖，兰安锋根据《森林铁路内燃机车检修规则》的规定，机车在运行２０万ｋｍ后要进行大修．大修时，也必须对１２１３５Ｚ柴油机进行全面解体，并对配件进行清洗、修复及总组装，使其恢复基本技术...     

脱粒机使用调整

(1)脱粒不干净。主要原因:谷物太潮湿,喂入量过大或喂入不匀,滚筒转速过低,纹杆和凹板之间的间隙过大。排除的方法:等谷物晒干再脱粒,减少喂入量或均匀喂入,适当提高滚筒转速。如果胶带在带轮上打滑,应调整动力机带轮与脱粒机带轮的配合,将胶带张紧,调整纹杆与凹板之间的间隙,对磨损严重的零件进行更换。(2)籽粒破碎过多。主要原因:谷物过干或过湿,喂入不均匀,滚筒转速过高;纹杆和凹板之间间隙过小。排除的方     

广联珠江4LZ-2.0型全喂入联合收割机的研制

研制了广联珠江4LZ-2.0全喂入联合收割机,该机采用履带式行走机构,清选脱粒机构采用双筛加风扇及二次清选机构,并设置复脱机构.同时,从基本结构、工作原理和性能参数方面介绍了该收割机关键部件设计制造.试验结果表明,该机破碎率和总损失率低,清洁度高,接地压力小,满足南方下水田收割的作业要求.     

内燃机清洗工艺及清洁度控制

内燃机零部件的清洁度直接影响内燃机的可靠性,在制造工艺中,清洗工艺占有比较重要的地位,本文介绍内燃机零部件清洁度的重要性、清洗工艺及清洗设备的概况。     

森林与空气负离子

近年来,空气离子特别是空气负离子的保健作用受到人们的普遍关注.空气离子浓度也是衡量空气清洁度的重要指标之一.森林地区空气负离子浓度明显高于其它地区,成为重要的森林旅游资源.文中就空气负离子的来源、时空变化、森林与空气负离子的关系、空气负离子的保健及治疗功能,以及以空气负离子浓度为指标的空气清洁度的评价标准等一些问题进行了综述.     

拖拉机清洁度的重要性及控制措施

拖拉机清洁度的控制水平,其直接影响因素是液压系统,而液压元件的使用寿命和可靠性将直接影响拖拉机整机的可靠性。阐述了拖拉机清洁度的重要性,介绍了清洁度的常用测量方法,并提出了清洁度的控制措施,以期提高液压元件的可靠性,继而提高拖拉机的可靠性。      

城市绿地对空气负离子水平的影响研究

对扬州市不同绿地类型中空气负离子水平研究表明:城郊林和公园绿地空气负离子浓度是城区其它类型绿地的2倍,城区绿地中空气负离子水平又表现为公园>校园>广场>小区>街心游园。绿地中空气负离子浓度和空气清洁度值大部分为对照空旷地的1~3倍,广场绿地和城郊雪松林中空气清洁度达到对照区的3~4倍,且林内比林缘空气负离子浓度有显著提高。不同植被组成的绿地中空气负离子水平为高大乔木最优,灌草次之,空旷地最差。