牛双肌性状及其形成的分子机制

早在 1 80 7年就在牛中发现了双肌现象。由于双肌牛具有瘦肉率高、肉质好的特点 ,因而一直受到人们的青睐。双肌现象在牛中较为普遍[1] ,迄今为止 ,已经在包括比利时蓝白花、皮埃蒙特在内的 1 4种牛以及羊、鼠中发现了双肌现象。本文仅对牛的双肌性状及其形成的分子机制作一综述。1　双肌牛的性状1 1　形态学性状　双肌牛的外部特征是臀部、大腿、上臂、胸及起支撑作用的中前端肌肉群异常发达。双肌牛皮下脂肪发育不良 ,皮肤较薄。与普通牛相比 ,双肌牛有较多的脂肪沉积于肌间和脂肪窝 ,且脂肪的沉积从内到外呈逐渐减少的趋势。双肌牛胴体…     

牛的双肌(double-muscular)性状研究进展

本文综述了牛双肌性状的遗传特性、基因定位、多形性及双肌牛的生理、繁殖、胴体特性；并对双肌牛在牛肉生产中的利用方式及在我国肉牛生产中的应用前景等进行也阐述。     

牛双肌基因PCR-SSCP分析

双肌(肌肉生长抑制素)基因是一种肌肉生长的负调控因子,试验应用PCR-SSCP和测序的方法对我国秦川牛、南阳牛双肌基因的第3外显子进行了多态性分析.结果表明:第3外显子938位G→A的单核苷酸突变造成了南阳牛第3外显子扩增片段呈多态性;秦川牛中未发现突变.     

双肌牛的特征及其遗传研究

双肌牛具有屠宰率高，瘦肉率高，优质高价肉比例大，肉质较嫩等优点，倍受消费者欢迎，本文概述了双肌牛的特征，双肌性状的遗传机制，旨在为提高家畜产肉量以及为瘦肉型动物育种工作提供新的科学依据。     

肉用动物双肌性状的研究现状

综述肉用动物双肌性状的形态,生理生化,组织学,遗传机制及其对相关性状影响等方面的研究,牛双肌基因位于第２号常染色体上,是由ｍｙｏｓｔａｔｉｎ基因在第３外显子处核苷酸突变造成的,为不完全显性遗传,羊ｃａｌｉｐｙｇｅ突变基因定位于第１８号染色体上,以非孟德尔方式遗传,被称做极性超显性。双肌动物的瘦肉率,瘦肉量,肉骨比显著高于普通动物,而其脂脂率较低,繁殖性能较差并对应激更敏感。双肌基因在生产中主要通过     

双肌性状形成的分子机理及其研究进展

肌肉生成是一个复杂的正负调控过程,双肌品种以其特有的饲料报酬高、瘦肉率高’、生长快在近几年来逐步受到育种专家的重视。研究表明,肌肉生长抑制素(mysatatin,MSTN)缺失或突变会导致肌肉过度生长或肥大,即双肌现象;双肌性状受常染色体上一对等位基因控制,存在主基因效应。现从肌肉生长机理入手,分别从不同家畜双肌现象阐明该性状的分子机理及其应用前景。     

牛的生产性状QTL和主基因的研究进展

随着加入WTO,我国肉牛业面临严峻的考验。本土专用肉牛良种资源匮乏造成产肉量低、肉品质差等问题,因而选择合适的标记进行标记辅助选择势在必行。作者较全面总结了国内外在基因水平上对牛进行全基因组扫描定位的QTL和与生长、肉质、繁殖、抗病力有关的主效基因的研究成果,探讨今后我国本土良种的遗传资源利用和提高遗传进展的育种工作应该注意的问题。     

肉用动物双肌性状的研究现状

综述肉用动物双肌性状的形态、生理生化、组织学、遗传机制及其对相关性状影响等方面的研究。牛双肌基因位于第２号常染色体上,是由ｍｙｏｓｔａｔｉｎ基因在第３外显子处核苷酸突变造成的,为不完全显性遗传;羊ｃａｌｉｐｙｇｅ突变基因定位于第１８号染色体上,以非孟德尔方式遗传,被称做极性超显性。双肌动物的瘦肉率、瘦肉量、肉骨比显著高于普通动物,而其脂肪率较低、繁殖性能较差并对应激更敏感。双肌基因在生产中主要通过将双肌动物作为终端杂交父本来应用。     

中国荷斯坦牛生产性状候选基因研究进展

遗传因素在影响奶牛生产性能方面起到非常重要的作用,目前主要利用RAPD、PCR-SSCP、PCR-RFLP等分子生物学技术鉴定影响奶牛生产性状的候选基因,并取得初步成果。本文就近几年来在奶牛生产性状相关候选基因上的研究进展作一综述。     

牛繁殖性状候选基因研究进展

繁殖性状是牛（Bos taurus）重要的经济性状,与生产成本、经济效益密切相关。繁殖相关的主要性状包含精液品质、卵泡发生、排卵、胚胎发育、产犊难易、产犊间隔等,其表现通常受到基因的严格调控。对繁殖性状的重要基因功能深入挖掘和筛选对于牛的改良和选育、提高生产性能、节约生产成本至关重要。文章介绍了国内外关于牛繁殖性状基因的研究进展,如促黄体素受体（luteinizing hormone receptor,LHR）及牛精子鞭毛2（sperm flagella 2,SPEF2）与精液品质相关,促性腺激素释放激素（gonadotropin-releasing hormone,GnRH）、促卵泡素（follicle-stimulating hormone,FSH）、促黄体激素（luteinizing hormone,LH）及抗缪勒氏管激素（anti-Müllerian hormone,AMH）、骨形态发生蛋白15（bone morphogenetic protein 15,BMP15）、生长分化因子9（growth differentiation factor 9,GDF9）与卵泡发生、排卵相关,JY-1、尾型同源框2（caudal type homeobox 2,CDX2）及冠毛素2（pappalysin 2,PAPP-A2）与早期胚胎发育及产犊难易相关,唾液酸结合Ig样凝集素5（sialic acid binding Ig like lectin 5,SIGLEC5）、CXC基序趋化因子受体1（C-X-C motif chemokine receptor 1,CXCR1）及叉头转录因子O1（forkhead box O1,FoxO1）与产犊间隔相关,作者通过综述以上重要繁殖性状相关基因的研究,介绍了这些繁殖性状重要基因对牛生产性能的影响,以期为牛繁殖性状相关调控基因的研究提供参考依据。     

湘西黄牛与湘南黄牛主要种质特性的比较研究

[目的]为评价、保护和利用好湘西黄牛和湘南黄牛重要的遗传资源提供科学依据.[方法]按照DB43/T638-2011规定的方法对湘西黄牛和湘南黄牛的体型外貌、体重体尺、繁殖性能、生长发育性状、胴体性状、肌肉品质和役用性能等主要种质特性进行了研究和评价.[结果]湘西黄牛较湘南黄牛体型大,生长发育快,役力大;肌内脂肪高和肌肉...     

胆碱在奶牛生产中的应用研究进展

针对胆碱的结构、性质、来源、品质鉴定方法、过瘤胃保护技术、生物学功能及其在奶牛生产中的应用作一综述。     

Principles and application of internal fixation in cattle

The principles of bone healing and vascular and periosteal responses are considered in relation to different methods of fracture fixation and complications. Advantages and disadvantages of the available internal fixation devices are reviewed for the fractures that most commonly occur in the different age groups.     

SNPs标记技术及其在牛遗传育种中的应用

本文综述了SNPs的基本概念原理和特点,重点讲述其在牛遗传育种中的应用现状和前景,以推动国内该领域研究的发展。     

二、奶牛的品种特征

1、世界奶牛品种 世界奶牛品种主要有:荷斯坦牛(主要是黑白花牛,也有红白花牛)、娟姗牛(毛色为淡黄色或黄褐色)、更赛牛(毛色为黄褐色或褐黄色,带有白斑,腹下、四肢下部、尾稍多为白色)、爱尔夏牛(毛色为白色与桃红或深红相间,头部额至鼻梁、腹下、四肢下部及尾稍多为白色)。 2、我国奶牛品种     

Growth- and breed-related changes of marbling characteristics in cattle

The objective of this study was to investigate the growth- and breed-related changes of marbling characteristics in cattle. Four cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus, as a typical beef cattle; Galloway, as a smaller, environmentally resistant beef cattle; Holstein-Friesian, as a dairy-type cattle; and double-muscled Belgian Blue, as an extreme type for muscle growth, were used. These 4 breeds were expected to have differences in muscle development and i.m. fat deposition. Between 5 and 15 bulls of each breed were slaughtered at 2, 4, 6, 12, or 24 mo of age. Marbling characteristics were determined and classified in LM and semitendinosus muscle by computerized image analysis. Among breeds, differences appeared in the quantity, structure, and distribution of the marbling flecks in both muscles. The deposition of fat in the double-muscled Belgian Blue bulls remained substantially inferior to that of the other breeds, up to the age of 24 mo. Marbling in German Angus bulls particularly showed larger (P < 0.05) marbling fleck areas. Galloway cattle had the greatest (P < 0.05) number and the most regular (P < 0.05) distribution of the marbling flecks in young animals. Furthermore, for marbling characteristics in Holstein-Friesian animals, a great number and slightly finer structure were observed compared with the other breeds investigated. Postnatal growth-related changes of marbling in LM were characterized by as much as a 40-fold increase in the number of marbling flecks from 2 to 24 mo of age but also by up to a 4-fold enlargement in the area of the marbling flecks. The structure of marbling flecks was determined by 2 development trends. On the one hand, the marbling flecks became larger (P < 0.05), and the structure became coarser, which was reflected by an increasing (P < 0.01) proportion of long marbling flecks as well as an increasing (P < 0.01) maximum skeleton line length. On the other hand, continually new small, round marbling flecks appeared. This caused a decrease (P < 0.01) in the proportion of the 3 largest marbling fleck areas. The distribution of the marbling flecks became more regular (P < 0.05) with increasing proportion and number of marbling flecks. The results suggest that hyperplasia of adipocytes plays an important role in marbling during growth of muscle in cattle.     

Studies on the suitability of alpha-hybrid interferon application in cattle

Twelve cattle with body wts ranging from 100 to 250 kg were treated using various doses and routes for four days with an E. coli derived alpha-hybrid interferon. The lowest parenteral doses (10⁴ units per kg body wt) and the orally administered interferon did not lead to any disturbances, whereas the higher dosages led to marked changes in body temperature, pulse and respiration rates. Animals with the highest dose (10⁸ units per kg body wt) became extremely distressed. The blood picture showed distinct changes, with very low leukocyte counts during treatment, which took weeks to recover. It is suggested that the dosages that did not lead to clinical symptoms are best suited for prophylactic or therapeutic purposes.     

牛用益生素的研究与应用

随着大量使用抗生素而表现出来的动物抗病力减弱,药物残留问题严重使动物肉蛋奶产品质量下降,而且使病菌带有抗药性;尤其是1981年英国发生使用“三合一”针剂大量注射抗生素、激素和羊下水引发“疯牛病”事件以来,世界各国,尤其欧美、日本等发达国家纷纷采取官方强硬措施,对饲用抗生素的种类、使用方法、剂量和配伍等方面严加限制。同时,大力开展研究药用饲料添加剂代用品的可能性,积极鼓励和倡导绿色安全饲料添加剂的研究和推广,受到世人的瞩目。     

Clinical application of computed tomography in cattle

Computed tomography involves the use of x-rays to produce cross-sectional images of body regions. It provides non-overlapping, two-dimensional images of all desired planes as well as three-dimensional reconstruction of regions of interest. There are few reports on the clinical use of computed tomography in farm animals. Its use in cattle is limited by high cost, the application of off-label drugs and the need for general anaesthesia. In cattle computed tomography is indicated primarily for diseases of the head, e.g. dental diseases and otitis media, and neurological disorders. Less often it is used for diseases of the vertebrae and limbs. In valuable cattle, the results of computed tomography can be an important part of preoperative planning or be used to avoid unnecessary surgery when the prognosis is poor.