牛经济类型划分的意义和方法

以肉用指数（Ｂｅｅｆ ｐｕｒｐｏｓｅ ｉｎｄｅｘ，简写为ＢＰＩ），即平均成年活重与体高的比值，作为划分肉用牛与役用牛（品种）的量值指标。经对国内外７４个肉牛和役牛品种（类型）资料计算，平均ＢＰＩ值，公牛４．５６ｋｇ／ｃｍ，母牛３．３２ｋｇ／ｃｍ。以此作为划分役牛、肉牛的基本界限，与传统抽象描述法划分结果吻合良好，符合比率由９２．６％（国外肉用品种公牛平均值）到９７．９％（国内黄牛品种母牛平均值）。     

来自饲料厂和养殖场生产第一线的若干问答(三十三)

1．怎样根据牛类型进行育肥？（浙江读者 周爱华） 答：①牛品种。牛品种按生产性能可分为肉用牛、役用牛、乳用牛、肉乳兼用、肉役兼用、肉乳役多用等。由于品种不同，在育肥期采用的技术也有差异，如肉用牛的增重速度高于役用牛，因此，在制定饲料配方和日采食量等方面不能完全一样。     

论牛的肉用、役用经济类型划分的意义和方法(BPI指数)

关于以一个量值指标来划分现今典型的肉用型牛和役用型牛品种，还未见有报导，本文提出肉用指数（Beef purpose index，简写BPI），即平均成年活重与体高的比值，作为划分肉用牛与役用牛（品种）的量值指标，经对国内外74个肉牛和役牛品种（类型）资料计算，平均BPI值，公牛：4．56kg/cm，母牛3．32kg/cm，以此作为划分役牛，肉牛的基本界限，与传统抽象描述法划分结果吻合良好，符合比率由92．6％，（国外肉用品种公牛平均值）到97．9％（国内黄牛品种母牛平均值）。     

肉牛育肥技术问答

(一)怎样根据牛类型进行育肥?答:1.牛品种和育肥技术。牛按生产性能可分为肉用牛、役用牛、乳用牛、肉乳兼用、肉役兼用等品种。采用育肥技术、制定饲料配方和日采食量时应有所区别。     

牛经济类型划分的意义和方法

以肉用指数(Beef purpose index,简写为BPI),即平均成年活重与体高的比值,作为划分肉用牛与役用牛(品种)的量值指标.经对国内外74个肉牛和役牛品种(类型)资料计算,平均BPI值,公牛4.56 kg/cm,母牛3.32 kg/cm.以此作为划分役牛、肉牛的基本界限,与传统抽象描述法划分结果吻合良好,符合比率由92.6%(国外肉用品种公牛平均值)到97.9%(国内黄牛品种母牛平均值).     

论我国黄牛的育种方向、方法

我国黄牛数量多,分布广,有很多优点,但经济性能较低。随着农业机械化的进展,各地黄牛将由役用转变为肉用、乳用或兼用。一、黄牛的育种方向(一) 地方良种及非地方良种黄牛是否需要育成高产品种? 1.秦川牛、南阳牛、鲁西牛、晋南牛及延边牛等地方良种具有,体格大、肉质好、适应性强等优点。宜采用本品种选育,培育成肉用或乳肉兼用牛。2.非地方良种黄牛与进口的肉用或     

南阳牛育肥进展综述

南阳牛是全国著名的役肉兼用品种，体格高大，肌肉发达，皮板致密，役用性强，肉用性能好，毛色以黄色最多、红色、草白色次之。一般南阳牛体重标准如下表。南阳牛的繁殖率为６７％－８８％，犊牛初生重２１ｋｇ－３３ｋｇ。经过育肥，日增重０．６ｋｇ－０．９ｋｇ，每增...     

门源县牛品种改良工作现状与发展对策

随着畜牧业经济的发展，各农户养牛正从役用向乳肉兼用、肉用及乳用牛方向发展，要实现这个目标，就要改良牛的品种。但门源县牛品种改良工作起步较晚，力度不大，这就要求我们要大力加强牛品改良工作的力度，更好更快地改良本地牛，以提高牛个体生产性能，使牛的总体质量不断提高，使肉、乳的质和量得到大幅提升，从而增加农民收入。     

中国肉牛分子育种研究进展

1．中国黄牛肉用选育的背景 由于社会经济的不断发展和人民生活水平的不断提高及市场的变化，中国黄牛的选育方向也经历了一系列历史性的变化，即“役用-以役用为主-役肉兼用-肉役兼用-肉用”的选育过程。20世纪70年代以前，中国牛业以役用为主，大部分研究主要是集中在牛的营养代谢试验、役用性能、生长发育、生理生化指标测定、冻精制作及种质特性等基础研究工作。20世纪70年代以后，中国黄牛作为农业的动力已退居次要地位，随着中国良种黄牛委员会的成立，     

浅析影响肉牛育肥效益的因素

肉牛肥育效益受很多因素的影响,既有先天性因素,又有后天性因素.主要有以下几个方面. 1 品种和类型的影响 肉用品种的牛比乳用牛、乳肉兼用牛和役用牛能较快地结束生长期,能早期进行育肥,提前出栏,节约饲料,并能获得较高屠宰率和胴体出肉率,肉的质量也好.     

Survey of quality defects in market beef and dairy cows and bulls sold through livestock auction markets in the Western United States: I. Incidence rates

A survey was conducted to quantify incidence of Beef Quality Assurance (BQA)-related defects in market beef and dairy cows and bulls selling at auction during 2 seasons in 2008. Twenty-three BQA-related traits were evaluated by 9 trained personnel during sales at 10 livestock auction markets in Idaho (n = 5; beef and dairy), California, (n = 4; dairy only), and Utah (n = 1; beef and dairy). Overall, 18,949 unique lots (8,213 beef cows, 1,036 beef bulls, 9,177 dairy cows, and 523 dairy bulls,) consisting of 23,479 animals (9,299 beef cows, 1,091 beef bulls, 12,429 dairy cows, and 660 dairy bulls) were evaluated during 125 sales (64 spring, 61 fall) for dairy and 79 sales (40 spring, 39 fall) for beef. The majority of market beef cows and bulls (60.9 and 71.3%, respectively) were predominantly black-hided, and the Holstein hide pattern was observed in 95.4 and 93.6% of market dairy cows and bulls, respectively. Market cattle weighed 548 ± 103.6 kg (beef cows), 751 ± 176.1 kg (beef bulls), 658 ± 129.7 kg (dairy cows), and 731 ± 150.8 kg (dairy bulls). Most beef cows (79.6%) weighed 455 to 726 kg, and most beef bulls (73.8%) weighed 545 to 954 kg, respectively. Among market beef cattle, 16.0% of cows and 14.5% of bulls weighed less than 455 and 545 kg, respectively, and 63.7% of dairy cows and 81.5% of dairy bulls weighed 545 to 817 kg or 545 to 954 kg, respectively. However, 19.5% of dairy cows and 13.1% of dairy bulls weighed less than 545 kg. Mean BCS for beef cattle (9-point scale) was 4.7 ± 1.2 (cows) and 5.3 ± 0.9 (bulls), and for dairy cattle (5-point scale) was 2.6 ± 0.8 (cows) and 2.9 ± 0.6 (bulls). Some 16.5% of beef cows and 4.1% of beef bulls had a BCS of 1 to 3, whereas 34.8% of dairy cows and 10.4% of dairy bulls had a BCS of 2 or less. Emaciation (beef BCS = 1, dairy BCS = 1.0) or near-emaciation (beef BCS = 2, dairy BCS = 1.5) was observed in 13.3% of dairy cows and 3.9% of beef cows. Among beef cattle, 15.1% of cows and 15.4% of bulls were considered lame. In contrast, 44.7% of dairy cows and 26.1% of dairy bulls were lame. Ocular neoplasia (cancer eye) was observed in only 0.6% of beef cows, 0.3% of beef bulls, 0.3% of dairy cows, and 0.0% of dairy bulls. However, among animals with ocular neoplasia, it was cancerous in 34.4% of beef bulls, 48.0% of dairy cows, and 73.3% of beef cows. In conclusion, numerous quality defects are present in market beef and dairy cattle selling at auction in the Western United States, which could influence their value at auction.     

Growth- and breed-related changes of muscle bundle structure in cattle

The objective of this study was to investigate the changes in muscle fiber bundles of cattle of different breeds during growth. Different numbers of muscle fibers are surrounded by connective tissue to form bundles macroscopically visible as meat fibers or meat grain, a common meat quality trait. To determine the influence of breed and age on morphological characteristics of muscle fiber bundles, 4 cattle breeds with different growth impetus and muscularity were reared and slaughtered under experimental conditions. German Angus, a typical beef cattle; Galloway, a smaller beef type; Holstein Friesian, a dairy type; and double-muscled Belgian Blue, an extreme type for muscle growth, were used. Between 5 and 15 bulls of each breed were slaughtered at 2, 4, 6, 12, or 24 mo of age, and slices of semitendinosus muscle were removed. Muscle structure characteristics were determined by computerized image analysis. During growth, the muscle cross-sectional area enlarged (P < 0.001) about 5-fold in double-muscled Belgian Blue bulls and about 4-fold in the other breeds. This was a result of the enlargement (P < 0.001) of primary bundles and muscle fibers. The bundle size was similar (P > or = 0.15) in bulls of German Angus and Galloway in all age groups and was doubled (P < 0.001) in double-muscled Belgian Blue animals from 4 mo of age on. The Holstein Friesian bulls had the smallest (P < 0.001) muscle fiber bundles at 24 mo of age. The number of muscle fibers per bundle and the number of bundles per muscle remained nearly constant (P > 0.05) during growth. This supports the existing view that the structure of the muscle is already fixed in prenatal life. The double-muscled Belgian Blue bulls showed a more than 2.5-fold greater (P < 0.001) number of muscle fibers per primary bundle compared with the other breeds investigated. The larger muscle fiber bundles led to a smaller amount of connective tissue per muscle area in double-muscled cattle. The coarser grain of meat in double-muscled Belgian Blue bulls and in older animals was not related to greater shear force values.     

Comparative study of mammary gland development and differentiation between beef and dairy heifers

Sixteen Hereford and 16 Holstein heifers were used to study the relationship of milk production potential to mammary development and differentiation. Heifers were slaughtered 150, 180, and 260 days of first gestation and at 49 days of first lactation. Prolactin binding capacity of mammary tissue was 2.5 fold higher in dairy than beef heifers at day 260 of gestation (27.2 vs 11.0 fmols/mg protein). In both breeds, maximal growth hormone binding in liver coincided with the beginning of the rapid phase of mammary growth at 180 days. Mammary tissue from dairy heifers released more casein and alpha-lactalbumin during in vitro incubations than tissue from beef heifers. No differences were observed between breeds with respect to incorporation of [¹⁴C]acetate into lipids. Mass of dairy mammary tissue at 49 days of lactation was 3.3 times greater (16.4 vs 4.9 kg) and produced 5.7 times more milk (20.3 vs 3.5 kg/day) than its beef counterpart. The total DNA content and the RNA/DNA ratio of lactating dairy mammary tissue was approximately twice that of lactating beef mammary tissue. The data suggested that the higher milk production observed in dairy cattle is a result of a greater number of secretory cells and greater activity per cell.     

Review of diagnostic laboratory submissions of adult cattle 'found dead' in England and Wales in 2004

A total of 253 submissions from adult cattle 'found dead' in England and Wales were referred to the Veterinary Laboratories Agency in 2004. Carcases accounted for 54 per cent of the submissions and were of more diagnostic value than other types of sample. Whether the animals were beef or dairy, their distance from the laboratory and the number of deaths in the incident affected the likelihood of samples being submitted. The probability of reaching a diagnosis was influenced by the type of sample, the level of testing and the interval from sampling to receipt in the laboratory. Systemic disease was the most frequent cause of death in both dairy and beef cattle with hypomagnesaemia being the most frequent diagnosis (52 per cent) in beef cattle. In dairy cattle, 34 per cent of the diagnoses were for sporadic events, including haemorrhage and torsions of the digestive and reproductive tracts.     

育成荷斯坦奶公牛与其他3个品种牛的肉品质比较研究

通过对育成荷斯坦奶公牛与西门塔尔牛、新疆褐牛及新疆土种牛肉品质部分指标的比较分析研究,旨在探讨荷斯坦奶公牛的肉品质。选择在相同营养模式下18月龄左右4个品种牛各3头进行屠宰,取右半边胴体的背最长肌作为肉品质试验样品,分别对牛肉的肉品质、常规营养成分及氨基酸含量进行测定和分析。结果表明,荷斯坦奶公牛肉色、失水率、系水力、熟肉率、大理石花纹等指标均优于新疆褐牛、新疆土种牛,次于西门塔尔牛;荷斯坦奶公牛嫩度优于新疆土种牛;粗蛋白质、粗灰分含量分别为20.14%、1.11%,且各品种间差异均不显著(P>0.05),干物质含量为26.30%,显著高于新疆褐牛和新疆土种牛(P<0.05),低于西门塔尔牛(P>0.05),粗脂肪含量为10.04%,显著高于其他品种牛(P<0.05);荷斯坦奶公牛含有人体需要的各种氨基酸,其中蛋氨酸、谷氨酸、甘氨酸、组氨酸、牛磺酸等含量丰富,氨基酸组成比例良好。     

Virological and serological evidence of bovine herpesvirus type 4 in cattle in Northern Ireland

Bovine herpesvirus type 4 (BHV-4), a member of the genus Rhadinovirus, subfamily Gammaherpesvirinae, within the family Herpesviridae, was isolated in fetal bovine lung cells from samples of vaginal discharge taken from a dairy herd in which approximately 50 per cent of the cattle developed metritis after calving. The identity of the isolate was confirmed by immunofluorescent staining with a BHV-4-specific monoclonal antibody and partial sequencing of a portion of the glycoprotein B gene. Serological testing failed to demonstrate a significant association between the exposure of the cattle to BHV-4 and the metritis, but several cattle seroconverted during the periparturient period, consistent with the recrudescence and shedding of virus associated with the stresses of parturition and the onset of lactation. Despite the previous failure to detect BHV-4 in Northern Ireland, a serological survey of 999 cattle in 49 dairy herds and 51 beef herds found widespread evidence of exposure: 29 of the dairy herds and 35 of the beef herds contained one or more seropositive cattle, and 33.3 per cent of the dairy cattle and 23.3 per cent of the beef cattle were positive.     

烟台市奶牛业现状调查与发展对策

烟台市奶牛业在改革开放以后，特别是在过去6～7年内有了较快发展，奶牛头数由1978年的不足500头发展到2001年的27000头，牛奶产量达87320t。人均年消费牛奶13．5kg。对烟台市三个奶牛场和三个奶农户抽样调查，5月中下旬奶牛日平均产奶量为24kg，年单产约在6000kg左右，与京、津、沪大型奶牛场的7000kg至9000kg有一定差距，杂交改良牛年单产依杂交改良代数和饲养管理水平不同，约在1500～4000kg。存在的主要问题是奶牛总存栏量少，育种体制不健全，饲料配合欠科学，个体户缺乏组织，产、加、销没有形成在市场经济条件下的利益共同体等。鉴此，应利用现代生物技术，加快现有品种改良，提高奶产业的产、加、销科学组织化程度，创立烟台品牌乳品加工企业等，使烟台市奶牛业向优质、高产、高效方向发展。     

中国不同牛种DGAT1基因遗传多样性及经济性状关联分析研究进展

乙酰辅酯A∶二酰甘油酰基转移酶(DGAT1)是甘油三脂合成过程中唯一的关键酶,对动物机体脂肪代谢、沉积起重要作用,已成为研究奶牛泌乳性状和肉牛主要经济性状的重要候选基因之一。近年来,随着相关研究的不断深入,研究者普遍认为DGAT1基因对奶牛的产奶量、乳脂率、乳蛋白率、乳糖率、乳脂肪酸及空怀天数、输精次数、初配年龄等繁殖性状均有显著影响,且与肉牛体脂也存在相关性。作者主要介绍了DGAT1基因的遗传多态性及其与经济性状关联分析在中国各地区不同品种奶牛、肉牛、水牛和牦牛上的研究进展,指出该基因对奶牛的产奶性能及肉牛的肉质性状、生长性状具有重要的调控作用。但由于环境条件、品种及选育背景等因素影响,DGAT1基因遗传多态性对不同地区不同牛群体的经济性状影响不尽相同。因此,要将DGAT1基因实际应用在品种选育工作中还需明确该基因对研究群体的具体遗传效应,并结合其他候选基因进行综合分析。     

牛DGAT2基因第6内含子MspI-RFLPs和TaqI-RFLPs及其与牛经济性状相关性研究

利用PCR-RFLPs方法分析牛DGAT2基因第5、6和7内含子内部的MspI和TaqI等11种酶切多态性,并在第6内含子检测到MspI-RFLPs和TaqI-RFLPs 2个多态位点。分析表明,该MspI-RFLPs普遍存在于鲁西牛、晋南牛、秦川牛、利木赞×鲁西牛、西门塔尔×延边牛、夏洛来×延边牛、安格斯×延边牛和三河牛、中国荷斯坦牛等9个试验群体中,TaqI-RFLPs只在鲁西牛、晋南牛和秦川牛3个地方品种和利木赞与鲁西牛的杂交群体中检测到,而且等位基因B(T碱基)在除鲁西牛外的群体中分布频率很低。统计分析表明,MspI-RFLPs与肉牛的体脂没有相关,但显著影响屠宰率,AA型个体的屠宰率显著高于AB和BB型(P<0.05)。DGAT2基因第6内含子MspI酶切多态性与三河牛群体平均乳脂率和平均干物质含量有极显著或显著的相关性(P<0.01和P<0.05),AA型个体的平均乳脂率和平均干物质含量均高于BB型个体的均值,但在荷斯坦牛群体中却没有得到相同的结果。研究分析了鲁西牛中TaqI-RFLPs的AA型与AB型个体之间屠宰性能的差异,结果表明这2种基因型与鲁西牛的屠宰性能没有显著的相关(P>0.05),有待在更大的鲁西牛群体中检验TaqI-RFLPs是否影响屠宰性状。     

国际肉牛育种的新动向-小型肉牛培育

本文在查阅大量文献资料的基础上,指出国际肉牛育种的新趋势是向小型肉牛方向发展。提出了肉牛大、中、小型划分的国际标准;列举出小型牛品种培育的四个方式途径;从六个方面详细论述了小型牛的优点或特点;最后根据我国肉牛业牛品种资源丰富,尤其是长江以南地区的当地牛品种是培育中国小型专门化肉牛的良好基础的现状,结合国际肉牛育种的趋势,指出中国肉用牛品种的培育方向为以中小型为主,培育出我国自己的小型肉牛品种。