米脂县秦川母牛不孕的原因及防治

母牛不孕严重影响养牛业的发展，特别在偏远的农村，母牛不孕会给养殖户带来很大的经济损失。根据笔者对黄牛人工配种的实践，对米脂县秦川母牛不孕的原因及防治谈谈自己的看法。     

奶牛胚胎早期死亡的预防

怀孕母牛流产原因很多，如习惯性流产、损伤性流产等，但多数属胚胎早期死亡，死亡率可达20％。30％．胚胎早期死亡大致可分为两个时期．一是在配种后的8一12天之间．另一个足在配种后40天左右。这是冈为母牛正常发情周期为20-21天，如果母牛配种后经30天左右和40天以上出现再发情现象的，这就可以认为这些母牛具有胚胎早期死亡的可能性。     

北极狐在成都地区的适应性及繁殖性能试验研究

对北极狐在成都地区适应性及繁殖性进行了试验研究，结果表明，由河南安阳市引入北极狐在成都地区能够适应，群发情率９８％，群配种率９０％，产仔率９７％以上，胎平均产仔数１０．６６只。单胎产仔高达１６只。     

提高肉用种兔繁殖力的方法

肉用种兔繁殖力的好坏,直接关系到养殖户的经济效益。本文分析了影响肉兔繁殖力的因素;通过选择优良肉兔品种、加强饲养管理、适宜的配种时间和配种方法,可显著提高肉用种兔的繁殖力。     

瘦肉型猪新品种——金枫猪

金枫猪是用金山枫泾猪(太湖猪的一个种群)、长白猪、皮特兰猪等品种，经选育选配而成的新品种猪。母猪毛色纯黑、母性好、产崽多；商品猪毛色纯白、瘦肉率高、肉质优良、生长速度快。经饲养证明，金枫猪不仅适应规模猪场的集约化饲养，而且适合小型猪场的传统喂养和个体农户的散养。     

母奶牛繁殖障碍的原因及诊治(上)

一、母牛生殖器官疾病 1.慢性子宫炎. 病因:多由急性转变而来.大多由大肠杆菌、链球菌、葡萄球菌等引起.配种用具污染、分娩时消毒不严、助产不当、产后子宫复旧不全、胎衣停滞、牛布氏杆菌病等均可引发子宫内膜炎.     

奶牛繁殖中的几个问题

奶牛的发展很大程度上取决于牛的繁殖,繁殖力就是奶牛的生产力,如果奶牛不能有效的繁殖,也就失去了饲养价值,而被淘汰。奶牛因不孕症淘汰占母牛淘汰率的比例达32％,因此,搞好奶牛的繁殖对增加奶牛头数,产奶量的提高和获得好的经济效益至关重要。目前在石河子垦区,规模化大牛场,出现头胎母牛产后90—120天不发情,有些是久配不孕,还有些配种后2—3上个情期又返情等,     

Primary investigation on GISH-NOR in cotton

Six loci of nucleolar organizer region (NOR) were detected in genomic in situ hybridization (GISH) of cotton (Gossypium). NOR was the characteristic of 45S rDNA but could be generated by genomic DNA (gDNA) extracted from Gossypium species as probe. With twice FISH to the same mitotic cell of G herbaceum or G hirsutum, number, position and size for NORs generated from 45S rDNA and gDNA were identified largely similar or even the same. The NORs with gDNA as probe were therefore permanently defined as GISH-NORs. GISH-NORs from G hirsutum and Graimondii mitotic images were all terminal types. Four and two GISH-NORs from G herbaceum (var. africanum) were terminal and centromere types, respectively. Six GISH-NORs in G hirsutum were chromosome mapped with two in A- and four in D-subgenomes. There were also GISH-NORs in mitotic image of G raimondii with its own gDNA as probe. From mitotic image of G herbaceum with its own gDNA as probe, GISH-NOR could not be observed but non-wholerecovery of hybridized signals was distinguished. These non-whole-recovery of hybridized signals were detected on long arm terminals of most chromosomes and especially existed in nearly half long arm of a pair of chromosomes in Gherbaceum gDNA probed itself GISH image, which may be possibly induced by low copy genes within the regions rather than inter-subgenomic segment translocations. GISH-NORs in G hirsutum mitotic images were dominantly observed when gDNAs from D and A genome species were used as probes and block, respectively, but not when the reverse probe and block gDNA from the two diploid progenitor genomes were designed. There may be two speculations to this special phenomenon: rDNA concerted evolution; content of rDNA in genome D more than genome A.