泌乳曲线的数学描述

泌乳曲线可用一般方程Ｙ＝Ａ１（ｔ）２（ｔ）来进行数学表述，方程中Ａ为一个正纯数，（ｔ）是单调增函数，１＝１为其渐近线，２是一个单调减函数，它具有单位起始值，２＝０为其渐近线。可供１．选择的函数有：１—ｂ。ｅ－ｂ１ｔ（Ｍｉｔｓｃｈｅｒｌｉｃｈ）、１／［１＋ｂ。／（ｂ１＋ｔ）］（Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｒ）、１／［１＋ｂ０／（ｂ１＋ｔｂ２）］（一般动态饱和）、１／（１＋ｂ。ｅ－ｂｔ）（罗辑斯谛）、ｂ。ｅｘｐ［（—Ｉｎｂ。）（１—ｅ－ｂ１ｔ）］（Ｇｏｍｐｅｒｔｚ）和［１＋ｔａｎｈ（ｂ。＋ｂ１ｔ］／２（双曲正切）；可供２选用的函数有：ｅ－ｅｔ（指数）和１／（１＋ｃｔ）（倒直线）。于是可得到１２种模型，且Ｙ＝Ａｔｂｅ－ｅｔ（Ｗｏｏｄ模型）适合于２３头试验牛整个泌乳期内的数据。Ｍｉｔｓｃｈｅｒｌｉｃｈ×数式、Ｍｉｃｈａｅｌｉｓ－Ｍｅｎｔｅｎ×指数式、罗辑斯谛×指数式、罗辑斯谛×倒直线式及Ｗｏｏｄ模型都很适配。有了这些模型，达到产奶高峰的时间、最大产奶量、整个泌乳期的总产奶量以及在衰减期中点的相对衰减等的表达式都得到了。Ｍｉｔｓｃｈｅｒｌｉｃｈ×指数式模型一般比Ｗｏｏｄ模型适配得更好，与Ｗｏｏｄ模型不同的是，它对所?     

门源草原毛虫幼虫和茧的抽样技术研究

根据Ｉｗａｏ的抽样数模型，确定出门源草原毛虫（Ｇｙｎａｅｐｈｏｒａｍｅｎｙｕａｎｅｎｓｉｓ）的最适抽样数。当防治指标标为３０头／ｍ￣２时，序贯抽样的累积幼虫量界限公式为：Ｔ＿０（Ｎ）＝３０ｎ±２９．７１当ｔ＝１．６４，或Ｔ＿０（Ｎ）＝３０ｎ±３５．５１，当ｔ＝１．９６。在高寒草甸中，棋盘式抽样方法是随机取样幼虫和茧的最佳方式。     

大鹅观草的染色体组组成

以大鹅观草（ＲｏｅｇｎｅｒｉａｇｒａｎｄｉｓＫｅｎｇｅｔ．Ｓ．Ｌ．Ｃｈｅｎ）与竖立鹅观草（Ｒ．ｃｉｌｉａｒｉｓｖａｒ．ｊａｐｏｎｅｎｓｉｓ（ｈｏｎｄａ）Ｂ．Ｒ．Ｌｕ，Ｙｅｎｅｔ．ｙａｎｇ２ｎ＝２８，ＳＳＹＹ）犬草（Ｅｌｙｍｕｓｃａｎｉｎｕｓ（Ｌ．）Ｌ，２ｎ＝２８，ＳＳＨＨ）拟鹅观草（Ｐｓｅｕｄｏｒｏｅｇｎｅｒｉａｓｐｉｃａｔａ（Ｐｕｒｓｈ）Ａ．ｌｏｖｅ，２ｎ＝２８，ＳＳＳＳ）三个种进行杂交，对亲本     

生物素缺乏可能是肉鸡股骨头坏死的病因

生物素缺乏可能是肉鸡股骨头坏死的病因吴延功杜元钊摘译１９９５年１１月１５～１６日在希腊由５２名专家参加的禽病会上，专家们对给肉鸡饲养带来较大危害的股骨头坏死病（Ｆｅｍｏｒａｌｈｅａｄｎｅｃｒｏｓｉｓ；Ｅｐｉ－ｐｈｙｓｉｏｌｙｓｉｓ）的病因进行了研讨。...     

奶牛饲养头日的计算方法

设（年初头数＋年末头数）÷２×３６５为理论饲养头日，ａ、ｂ分别为补充率和更新率，ｃ_２、ｄ_１分别为下半年补充比和上半年更新比，实际饲养头日（Ｇ）与理论饲养头日（Ｎ）的差距［Ｓ＝（Ｇ－Ｎ）÷Ｎ］可按以下公式计算：当ａ＝ｂ、ｃ_２＝ｄ_１时，Ｓ＝０．５_ａ－２ｃ_２＝０．５ｂ－ｂｄ_１；当ａ≠ｂ、ｃ_２≠ｄ_１时，Ｓ＝［０．５（ａ＋ｂ）－ａｃｗ－ａｃ_２－ｂｄ_１］÷（２－ａ－ｂ）。实际饲养头日可按以下公式计算：Ｇ＝Ｎ±ＳＮ。     

黑线仓鼠的染色体组型研究

本文报道了我国北方一种主要的农田害鼠，黑线仓鼠（ＣｒｉｃｅｔｕｌｕｓｂａｒａｂｅｎｓｉｓｆｕｍａｃａｓＴｈｏｍａｓ）的染色体核型，染色体标本采用骨髓细胞材料，按秋水仙素──低渗──空气干燥法制成。黑线仓鼠二倍体细胞的染色体数为２ｎ＝２４，常染色体臂数Ｍ＝２０，Ｘ染色体为中部着丝粒染色体，Ｙ染色体为较小的端部着丝粒染色体     

绿头野鸭繁殖性能随代次变化规律的研究

四年中对三个代次Ｐｉ（ｉ＝１，２，３）绿头野鸭不同利用年限Ｐｊ（ｊ＝１，２，３）繁殖性能进行了比较研究，结果表明：不同代次间，随代次递增相同利用年限的产蛋量递增；相同代次间，第二利用年限明显优于第一和第三利用年限。５０％以上产蛋率持续时间亦有相同变化规律，年均产蛋率与产蛋年持续时间有关，产蛋年持续时间与气候条件有关，代次与利用年限对这两个指标没有明显规律性变化。     

喜马排蜂和大蜜蜂的比较形态学研究

喜马排蜂（ＡｐｉｓｌａｂｏｒｉｏｓａＳｍｉｔｈ）的分类地位仍然有争议。本研究应用现代蜜蜂分类学的形态测定分析方法，对采自云南省同域分布的喜马排蜂和大蜜蜂（ＡｐｉｓｄｏｒｓａｔａＦａｂｒ．）进行比较形态学研究。两者绝大多数形态特征差异显著（ｔ－ｔｅｓｔ；Ｐ≤０．０１），统计学上证明它们是两个独立种。     

人工感染中间龙介虫导致产蛋鸡产蛋下降与粪便水分含量增加的研究

螺旋体中龙介虫（Ｓｅｒｐｕｌｉｎａ）属的压氧性肠螺旋体定值于各种动物的大肠部位,其中有三种被认为是猪的病原体;一利为强溶血性猪痢疾螺旋体（Ｓ　ｈｙｏｄｙｓｅｎ－ｔｅｒｉａｅ）引起猪痢疾（Ｓｔａｎｔｏｎ, １９９２）,而弱溶血性Ｓ ｐｉ－ｌｏｓｉｃｏｌｉ和Ｓ． ｉｎｔｅｒｍｅｄｉａ分别引起猪肠螺旋体病（Ｔｒｏｔｔ等,１９９６）和一种尚未明确的定植感染即“螺旋体结肠炎”（Ｈａｍｐｓｏｎ和Ｔｒｏｔｔ,１９９５;Ｓｔａｎｔｏｎ等１９９７）。 最近几年,相继在荷兰（Ｄａｖｅ１ａａｒ等,１９９６;Ｄｗａｔｓ等,…     

桑种质资源（Morus.L）染色体Giemasa—C带型研究

采用ＢＳＧ法对新一之濑和育２号优质种质资源的Ｇｉｅｍｓａ－Ｃ带的诱导及带型分析表明，新一之濑的带型公式为２ｎ＝２８＝２ＣＩＴ＋１Ｔ＾＋＋１ＣＩＴ＋Ｔ＾－＋１ＩＴ＋３ＣＴ＾＋Ｔ＋２ＣＩ＋２Ｃ＋Ｉ，育２号为２ｎ＝２８＝２ＣＩＴ＋１ＣＴ＋１Ｔ＋２ＣＩＴ＋１Ｔ＋４ＣＴ＾＋－＋ｉ＋２ｃｉ＋２ｃ＋Ｉ，２品种特征以着丝粒带（Ｃ）为主，其次为端带和中间带，２个桑品种未发现无带现象。断一之濑第４、８、１０、１４带纹     

The influence of the width of the saddle tree on the forces and the pressure distribution under the saddle

As there is no statistical evidence that saddle fit influences the load exerted on a horse's back, this study was performed to assess the hypothesis that the width of the tree significantly alters the pressure distribution on the back beneath the saddle. Nineteen sound horses were ridden at walk and trot on a treadmill with three saddles differing only in tree width. Kinetic data were recorded by a sensor mat. A minimum of 14 motion cycles were used in each trial. The saddles were classified into four groups depending on fit. For each horse, the saddle with the lowest overall force (LOF) was determined. Saddles were classified as "too-narrow" if they were one size (2 cm) narrower than the LOF saddle, and "too-wide" if they were one size (2 cm) wider than the LOF saddle. Saddles two sizes wider than LOF saddles were classified as "very-wide". In the group of narrow saddles, the pressure in the caudal third (walk 0.63 N/cm(2)+/-0.10; trot 1.08 N/cm(2)+/-0.26) was significantly higher compared to the LOF saddles (walk 0.50 N/cm(2)+/-0.09; trot 0.86 N/cm(2)+/-0.28). In the middle transversal third, the pressure of the wide saddles (walk 0.73 N/cm(2)+/-0.06; trot 1.52 N/cm(2)+/-0.19) and very-wide saddles (walk 0.77 N/cm(2)+/-0.06; trot 1.57 N/cm(2)+/-0.19) was significantly higher compared to LOF saddles (walk 0.65 N/cm(2)+/-0.10/ 0.63 N/cm(2)+/-0.11; trot 1.33 N/cm(2)+/-0.22/1.27 N/cm(2)+/-0.20). This study demonstrates that the load under poorly fitting saddles is distributed over a smaller area than under properly fitting saddles, leading to potentially harmful pressures peaks.     

Monitoring of the mare during the perinatal period at the clinic and in the stable

Complications in late gestation are challenging problems for the equine clinician and are causes of considerable distress to owners. Health problems in a pregnant mare in each stage of gestation can adversely affect the pregnancy. It is important to obtain a thorough history and perform a detailed and systematic examination of the pregnant mare so that the mare may be classified as normal or high-risk. However, even after a thorough examination, practitioners may face problems with the interpretation and assessment of risk. Normal mares should foal in the stable or pasture. Mares classified as having a high-risk pregnancy need to be monitored precisely for signs of oncoming foaling with attendance of trained personnel when labour begins. A valuable method for monitoring of the high-risk mare is assessing fetoplacental well-being. Fetoplacental well-being is most accurately assessed with ultrasonography as well as several available hormone profiles. We are proposing our scoring system of the mare's health, which may be useful in the assessment of risk during pregnancy and help clinicians to decide whether sending the mare to the clinic is reasonable or unnecessary.     

中国饲料工业协会第五届理事会顾问、会长、常务副会长、副会长、秘书长、副秘书长、常务理事、理事名单

顾问刘中一张德邻宋瑞祥聂振邦张子仪戎易王维四会长白美清国务院原副秘书长、第四届理事会会长常务副会长(8人,以姓氏笔划为序)刘永好新希望集团董事长、第四届理事会副会长刘汉元通威股份有限公司董事长、第四届理事会副会长陈丹广东恒兴集团股份有限公司董事长、第四届理事会副会长张延喜农业部原副部长、第四届理事会副会长吴明夏湖南正虹科技发展股份有限公司董事长、第四届理事会副会长陶一山唐人神集团股份有限公司董事长、第四届理事会副会长温鹏程广东温氏食品集团有限公司董事长、第四届理事会副会长谭竹洲原化学工业部副部长、第…     

鸡胆囊交感节后神经元的定位研究

为了找出支配鸡胆囊交感节后神经元的分布规律,选用体重1.5 kg～2.5 kg的成年母鸡6只,将CT-HRP溶液注入胆囊壁,动物存活3 d～4 d后,经左心室灌流固定,取内脏神经节、肾上腺神经节以及双侧胸、腰和荐段交感干神经节,制成50 μm的连续冰冻切片,TMB法呈色反应,置明视野显微镜下观片统计.结果发现,支配鸡胆囊的交感传出神经元胞体位于内脏神经节(占41.1%)、肾上腺神经节(占40.5%)和T2～T7交感干神经节(占18.4%),在交感干神经节中标记细胞的峰值位于T5、T6交感干神经节.所有的标记细胞以位于右侧的占优势.     

Harnessing the genetic toolbox for the benefit of the racing Thoroughbred

The understanding and application of genetics have grown extremely quickly since it has become possible to sequence the whole genome of an organism. The human genome sequence was completed in 2001 and that of the horse in 2007. The significance of this is that it makes it more feasible to explain how both genetically simple and complex traits are transmitted from one generation to the next and, therefore, to make informed breeding decisions, modify how horses are managed and trained to minimise the risk of disease and injury, and improve methods of prevention, diagnosis and treatment of many conditions. The science of genetics/genomics will continue to grow internationally, limited only by the funds available. The application of the science to man, horses and other species raises very complex moral and commercial issues. Thoroughbred breeders are perceived by some as resistant to change, but their apparent intransigence is often based on a genuine concern for the integrity of the breed. By taking control of the application of the advances in genetics, the Thoroughbred industry potentially has the opportunity to improve both the health and performance of Thoroughbreds. If, however, the science is applied in an uncoordinated manner, driven by commercial interests with no underlying concern for the horses themselves, there is a very real risk that breeders, the Thoroughbred breed and individual horses will all suffer as a consequence.     

商品猪胴体性能对分割销售后效益的影响

试验以深圳某集团销售外三元商品猪为研究对象,分析了商品猪不同胴体性能对分割销售效益的影响.结果表明,销售完成率与胴体背膘厚呈正相关,不同背膘厚的销售完成率差异极显著(P<0.01);销售完成率与胴体重呈正相关,不同胴体重的销售完成率差异显著(P<0.05);销售毛利率与胴体背膘厚呈正相关,不同背膘厚的销售毛利率差异极显...     

陕北白绒山羊繁育中心羊场绒山羊日粮的评价

试验选择陕北白绒山羊繁育中心羊场的成年健康母羊（怀孕前期）16只,育成母羊13只,育成公羊13只,空腹称重。测定每只羊1d的采食量,计算其摄入的营养成分含量,并与原苏联绒用山羊饲养标准比较,进行饲养水平评价。结果显示,与饲养标准比较,陕北白绒山羊繁育中心羊场的育成母羊代谢能高2．68MJ,粗蛋白低59．29g,钙低3．00g,磷低1．52g;育成公羊代谢能高3．47MJ,粗蛋白低81．92g,钙低4．42g,磷低2．62g;成年母羊代谢能高2．51MJ,粗蛋白低91．33g,钙低3．09g,磷低1．93g。结合羊的体况综合评价饲养水平基本合理,但尚需要按饲养标准增加粗蛋白、钙、磷等营养物质的供给量。     

Evidence for the non-involvement of the uterus in the lifespan of the corpus luteum in the cyclic dog

Progesterone levels in peripheral blood of dogs were analysed during the cycle in which hysterectomy (n = 5) or sham surgery (n = 3) was performed as well as during the cycle of dogs (n = 5) hysterectomized at least one year prior to this study; the data were compared with the findings in control dogs (n = 3). The averages of the duration of the luteal period observed in the three experimental groups were not significantly different from those of control dogs. Immediately after surgery, the progesterone level decreased from 25 to 50% of the presurgical level, but returned to presurgical level in about four days. Prolactin levels were elevated for about 30 h after surgery. Nevertheless, the averages of the mean prolactin levels for each animal during the luteal period of the experimental groups were not significantly different from those of control dogs. It is concluded that in the dog, the uterus is not involved in the lifespan of the cyclic corpus luteum.     

犊牛腹泻与肠道菌群的变化

本文检测腹泻犊牛的直肠内8种主要正常菌群的变化,并与健康犊牛进行对比。结果发现,犊牛腹泻时,大肠杆菌、双岐杆菌和乳杆菌变化较大,而其它菌群变化较小。腹泻或将腹泻时,大肠杆菌数增加,双岐杆菌和乳杆菌数下降。腹泻康复或即将康复时,大肠杆菌减少,双岐杆菌、乳杆菌数增加。