羊的同期发情技术

论述了羊的同期发情技术原理、供受体同期发情处理方法、供受体发情时间以及发情检测方法,提出了羊的同期发情技术的应用范畴.     

奶牛杂交群体及其遗传评估的模拟研究

为验证在奶牛杂交群体中将品种组成和杂合度作为协变量的遗传评估理论,为奶牛杂交模式选择和杂交群体遗传评估等实际问题提供理论依据,结合我国奶业现状,本研究模拟了在低产荷斯坦牛群引入法系蒙贝利亚牛、德系西门塔尔牛进行杂交,采用随机交配和三品种轮回杂交模式、群体世代重叠17年的繁育过程.群体杂合度在第7年后趋于平衡,轮回杂交模式的群体杂合度高于随机交配.经过杂交,原中低产荷斯坦牛群体在产奶性能、生长性能方面都有进展,轮回杂交提高幅度相对略高.此外,利用品种效应和杂合度效应剖分杂种优势,采用单性状和多性状动物模型对模拟群体进行遗传评估,效果基本一致,都可以很好地用于杂交群体的遗传评估.结果表明,对荷斯坦牛中低产群体进行杂交,可实现生产性能和效益的提高,回归模型可用于多元群体的遗传评估.     

Multiple amino acid substitutions are involved in the adaptation of H9N2 avian influenza virus to mice

To explore adaptation of avian influenza virus to mice we previously performed serial lung-to-lung passages of the influenza A/Chicken/Jiangsu/7/2002 (H9N2) strain, resulting in the isolation of a variant influenza strain lethal for mice. We now report that virulence correlates with improved growth characteristics on mammalian cells and extended tissue tropism in vivo. Sequencing of the complete genomes of the wild-type and mouse-adapted viruses revealed 25 amino acid substitutions. Some were found to reiterate known substitutions in human and swine H9N2 influenza isolates. Functions affected include nuclear localization signals and sites of protein and RNA interaction, while others are known determinants of pathogenicity and host specificity such as the viral polymerase PB2 E627K substitution. These observations suggest that enhanced growth characteristics and modified cell tropism may contribute to increased virulence in mice. We conclude that multiple amino acid substitutions are likely to be involved in the adaptation of H9N2 avian influenza virus to mice.     

草原生态保护红线划定的基本思路与政策建议

草原保护事关我国生态及经济协调、可持续发展大局。划定草原生态保护红线是构筑我国生态安全屏障的基础,是加强我国民族团结和边疆稳定的前提,是确保我国畜牧业产业安全的保证,是实现牧区可持续发展的重要保障。草原生态保护红线与耕地保护红线一样,具有不可撼动的国家战略意义和重大历史意义。本文在分析我国草原保护现状及存在问题的基础上,提出了草原生态保护红线的内涵和意义,阐述了划定生态红线的基本思路,给出了实现草原可持续发展、划定草原生态保护红线的具体政策建议。     

阿鲁科尔沁旗紫花苜蓿需水规律与灌溉定额

为了给阿鲁科尔沁旗紫花苜蓿(Medicago sativa)灌溉提供科学依据,利用1984-2013年30年气象数据,采用联合国粮农组织推荐的彭曼-蒙特斯公式法,研究了阿鲁科尔沁旗紫花苜蓿需水规律和灌溉定额。结果表明,阿鲁科尔沁旗紫花苜蓿第1茬、第2茬、第3茬、第4茬、生长季、非生长季和全年需水量分别为221、187、169、179、755、70和825mm,需水强度分别为4.3、4.7、4.1、2.5、3.7、0.4和2.3 mm·d~(-1),灌溉需水量分别为194、118、66、131、508、56和564mm,灌溉定额分别为228、139、78、154、598、66和664 mm。     

家禽败血型大肠杆菌病的防治

禽大肠杆菌病是由致病性埃希氏大肠杆菌引起的传染病，主要表现为肠炎、脐带炎、全眼球炎、气囊炎、卵黄性腹膜炎、大肠杆菌性肉芽肿、关节炎和败血症。由于致病性大肠杆菌血清型众多，各地血清型分布差异大，给防治工作带来很大的难度，对养禽业造成严重的危害。据统计，我国每年因大肠杆菌病死亡鸡３１７０多万羽，经济损失３亿多元。２０００年８月以来，我区大面积发生以神经症状及下痢为主要特征的败血型大肠杆菌病，我们进行了大量的防治研究工作，现报道如下：１流行情况２０００年８月中旬以来，在南宁市、南宁地区、玉林市、桂林市…     

MAGNETIC RESONANCE IMAGING OF THE CANINE OPTIC NERVE

We describe the magnetic resonance (MR) imaging aspects of normal canine optic nerve, the diameter of the optic nerve as measured on MR images, and optimal MR sequences for the evaluation of the optic nerve using a 0.2 T MR unit. Three millimeter contiguous slides of the normal canine orbital region were acquired in transverse and dorsal oblique planes using a variety of tissue weighting sequences. It was apparent that detailed anatomic assessment of the optic nerve can be performed with low‐field MR imaging, but none of the sequences provided unequivocal superior image quality of the optic nerve. The mean diameter of the optic nerve sheath complex was 3.7 mm and of the optic nerve 1.7 mm. The intraorbital and intracanalicular parts of the optic nerve are consistently visible and differentiation between the optic nerve and optic nerve sheath complex is possible using low‐field MR systems.