郏县红牛的分子育种研究与高效选育

本文围绕郏县红牛肉用性状的高效选育,分析了郏县红牛种质资源特性与现状,综述了郏县红牛分子育种研究进展与成就,在此基础上,提出了郏县红牛高效选育的实施和措施。首先必须坚持进行郏县红牛的本品种选育,其次是利用已取得的在分子育种方面的研究成果,开展高效选育。在选育和扩群的基础上提出了郏县红牛遗传利用的原则和方法。     

Simulated efficiency of range beef production. III. Culling strategies and nontraditional management systems

A modified version of the Texas A&M Beef Cattle Production Model was used to simulate life-cycle biological and economic efficiency of various culling strategies and non-traditional management systems in a northern plains, range environment. Biological efficiency was defined as the ratio of TDN input (kg) to product output (kg), and economic efficiency was defined as the ratio of cost ($) to product output (100 kg), where products were live weight at weaning (LWW), empty body weight at slaughter (EBW) and fat-free weight at slaughter (FFW). Several economic scenarios were simulated. Culling cows at younger ages increased biological efficiency, but not necessarily economic efficiency. The simulated optimal age at culling was 8 yr, the same age at which simulated feed intake and milk production began to decline. Finishing young cows in the feedlot had little effect on biological efficiency and generally increased economic efficiency, although specific results depended on feed prices and relative values of cull cows vs fed animals. A simulated sex-controlled system in which only heifer calves were produced, while extremely biologically efficient for production of lean, resulted in relatively little output and was not economically efficient in most cases. Sex control combined with feeding of 2-yr-old cows was economically efficient, but not markedly more efficient than a conventional system. Results suggest that sex-controlled systems may be more appropriate where emphasis is on lean product and heifers can be bred at very early ages. General results indicate that producers should pay attention to relative values of cull cows and fed animals in choosing culling strategies and management systems.     

西藏日喀则市黄牛改良现状与对策

为提高西藏黄牛生产性能,使其成为当地的优良品种,利用优秀奶牛冻精使用胚胎移植的方法,或引进优质的种公牛对西藏黄牛进行改良.结果表明,改良后的黄牛经济效益显著,相当于两头以上当地母牛的产奶量,每头改良母牛增加收入1 755元,而且提前一年半投产.     

西镇牛种质特性研究 三、西镇牛毛色遗传分析

本文从群体遗传学角度对西镇牛的毛色进行了系统分析,确定其毛色遗传由8个位点的等位基因支配,毛色以红黄为主,混有晕毛、有色皮斑、胁及四肢内淡化、黑色背线及黑缟纹等杂色,黑色及白斑在群体中分布频率极低。估测的各位点基因型频率误差小、可靠性高,其毛色分布规律可以做为西镇牛品种特征的遗传标记。同时确认西镇牛毛色形成与中原黄牛和南方黄牛密切相关。     

欧洲不同良种肉牛杂交利用青海黄牛后代生长发育试验研究

为了研究青海省肉牛杂交改良效果,筛选适应高寒地区肉牛最佳杂交组合,从而为今后开展肉牛杂交工作提供有力的依据,通过6年的试验研究,测定分析了蓝本、皮本、利本、夏本、德本F1牛和青海黄牛的初生,3月龄,6月龄,12月龄,18月龄体重及体尺指标及杂交后代对青海高原高寒气候的适应性观察。结果显示:五个杂交组合F1代不同年龄的生长速度和体尺指标均明显优于青海黄牛(P<0.01)说明良种肉牛改良效果显著,在不同杂交组合后代的比较中,蓝本F1牛生长发育最快,各阶段体重及体尺指标显著高于青海黄牛,比皮本、利本、夏本、德本F1牛也有明显提高。     

The role of genetic engineering in livestock production

In this paper we discuss the use of genetic engineering in livestock production. We examine the main two different aspects of genetic engineering: cloning and transgenesis. After commenting what has been expected from both techniques in livestock production in the last 25 years, the practical difficulties for implementing cloning and transgenesis are examined. Apart from technical difficulties, problems derived from the detection of genetically superior animals and evaluation of the clones and the transgenic animals make these techniques less interesting than they appear to be. Most of the observed variability of the economically interesting traits is not genetic, genetic evaluation needs a large number of animals and cloning success will represent a serious loss of genetic variability and the loss of the flexibility needed for markets in constant evolution. There is a risk in transgenic animals of production of new intermediate biochemical products that may be toxic, allergenic or carcinogenic. The benefits produced by transgenic animals hitherto hardly justify this risk. The expectations that genetic engineering produced 25 years ago should be re-examined, considering the risks and the high investment required.     

Weaning weight and post-weaning gain genetic parameters and genetic trends in a Blanco Orejinegro–Romosinuano–Angus–Zebu multibreed cattle population in Colombia

Genetic parameters and genetic trends for weaning weight adjusted to 240 d of age (WW240), and weight gain from weaning to 24 mo of age (GW730) were estimated in a Colombian beef cattle population composed of Blanco Orejinegro, Romosinuano, Angus, and Zebu straightbred and crossbred animals. Calves were born and weaned in a single farm, and moved to 14 farms postweaning. Data were analyzed using a multiple trait mixed model procedures. Estimates of variance components and genetic parameters were obtained by Restricted Maximum Likelihood. The 2-trait model included the fixed effects of contemporary group (herd–year–season–sex), age of dam (WW240 only), breed direct genetic effects (as a function of breed fractions of calves), breed maternal genetic effects (as a function of breed fractions of dams; WW240 only), individual heterosis (as a function of calf heterozygosity), and maternal heterosis (as a function of dam heterozygosity; WW240 only). Random effects for WW240 were calf direct genetic, dam maternal genetic, permanent environmental maternal, and residual. Random effects for GW730 were calf direct genetic and residual. All relationships among animals were accounted for. Program AIREML was used to perform computations. Estimates of heritabilities for additive direct genetic effects were 0.20 ± 0.003 for WW240, and 0.32 ± 0.004 for GW730. Maternal heritability was 0.14 ± 0.002 for WW240. Estimates of heritability suggest that selection for preweaning and postweaning growth in this population is feasible. Low direct and maternal preweaning heritabilities suggest that nutrition and management should be improved to allow fuller expressions of calf direct growth and cow maternal ability. The genetic correlation between direct additive and maternal additive effects for WW240 was − 0.42 ± 0.009, indicating an antagonistic relationship between these effects. The correlation between additive direct genetic effects for WW240 and GW730 was almost zero (− 0.04 ± 0.009), suggesting that genes affecting growth preweaning may differ from those influencing growth postweaning. Trends were negative for direct WW240 and GW730 weighted yearly means of calves, sires, and dams from 1995 to 2006. Maternal WW240 showed near zero trends during these years. Trends for calf direct WW240 and GW730 followed sire trends closely, suggesting that more emphasis was placed on choosing sires than on dam replacements.     

Simulated efficiency of range beef production. I. Growth and milk production

A revised version of the Texas A&M University Beef Cattle Production Model was used to simulate the effects of growth, milk production and management system on biological and economic efficiency of beef production in a northern plains, range environment. Animals varying in genetic potential for birth weight (BWA), yearling weight (YW), mature weight (WMA) and milk production (PMA) were simulated under both a weanling system of management (weaned calves custom-fed in the feedlot) and a yearling system (calves wintered on the ranch, then custom-fed after their second summer). The yearling system of management was biologically less efficient, but economically more efficient than the weanling system due primarily to heavier slaughter weights of fed animals. The advantage of the yearling system was most apparent for smaller genotypes. Herd efficiency improved with decreased BWA and increased YW, but changed little when WMA was varied while other growth traits were held constant. Increased PMA was favored for production of live weight at weaning and for production of slaughter product when feedlot costs were high. Increased PMA was not favored when feed costs for the cow herd were high. Economic weights generated from the simulation indicated the importance of selection for rapid early growth followed by selection for lighter birth weight. While larger genotypes were generally favored in this study, optimal cow size depended on economic conditions. Larger types were more biologically efficient and more economically efficient using standard costs, but medium- and small-size cattle were more efficient when feedlot costs were high. Small cattle were least efficient when feed costs for the cow herd were high.     

Genetic components in contemporary Faroe Islands Cattle as revealed by microsatellite analysis

The gene pool of indigenous Faroe Islands Cattle is strongly affected by crossing with Norwegian Red. In this study, the genetic structure in 191 animals representing five North European cattle breeds (Faroe Islands, Icelandic, Blacksided Troender, Western Fjord and Norwegian Red) and the genetic admixture in the contemporary Faroe Islands Cattle at the population and individual level were evaluated using 20 polymorphic microsatellite loci. Only 6.7% of the total genetic variation could be attributed to the differences amongst the breeds. The factorial correspondence analysis based on all allele frequencies could hardly reveal a divergence between Faroe Islands Cattle and Norwegian Red. In addition, a Neighbor‐Net tree constructed to examine the allocation of individuals of Faroe Islands Cattle and Norwegian Red provided a detailed interrelationship network for all the 72 animals. An estimation of the population admixture proportion showed a strong genetic contribution by Norwegian Red (47.3%) in the contemporary Faroe Islands Cattle. On the other hand, individual admixture analysis demonstrated that only seven of the individual Faroe Islands Cattle analysed, which also showed more traditional colour patterns, could be assigned to the Faroe Islands Cattle cluster, probably representing the breed's remaining purebred animals. Strategies for preserving the original native genes in Faroe Islands Cattle should be considered in order to prevent the breed from becoming extinct and to strengthen the breed's capability in future breeding programmes.     

肉牛微量元素舔砖对肉牛微量元素水平和抗氧化能力的影响

为了研究肉牛微量元素舔砖对肉牛血清中微量元素水平和抗氧化性能的影响,选取河西肉牛20头,随机分为2组,试验组添加肉牛微量元素舔砖,对照组仅饲喂基础日粮。分别在试验初和试验结束时静脉采血,测定肉牛血清中的微量元素水平和抗氧化指标变化。结果表明,肉牛微量元素舔砖可显著提高肉牛血清中Cu、Zn、Se水平,并能显著提高血清中T-SOD、GSH-Px、T-AOC水平,降低血清中MDA水平。提示肉牛微量元素舔砖具有显著提高肉牛血清微量元素水平和增强机体抗氧化能力的功效。     

草原红牛及其杂交群体中微卫星DNA多态性研究

选用草原红牛及其与利木赞牛的杂交后代66头作为试验牛群体,提取血液及肝脏基因组DNA,设计8对微卫星引物进行PCR扩增,从分子水平上对草原红牛及其杂交群体8个位点的遗传多态性进行微卫星分析。结果表明,在草原红牛中,ETH225、IDVGA2、IDVGA46和IDVGA44等位基因数分别为5、4、3和4,多态信息含量(PIC)分别为0．5420、0．6736、0．5218和0．5750,这4个位点均为高度多态。而另4个位点BM2113、BM1824、IDVGA55和TGLA44等位基因数分别,2、2、2和5,多态信息含量分别为0．3698、0．3604、0．3538和0．4708,属于中度多态性位点。在杂交牛群体中,BM2113、ETH225、IDVGA2、IDVGA46、ID- VGA44、BM1824、IDVGA55和TGLA44这8个位点的等位基因数分别为4、5、4、4、5、4、4和6,多态信息含量(PIC)分别为0．6432、0．5943、0．6593、0．5794、0．7259、0．6121、0．6120和0．6204,杂合度为0．7034,均属于高度多态性位点。这些微卫星位点作为遗传标记应用于草原红牛遗传育种研究之中是可行的。     

牛肉品质的评定指标及影响牛肉品质的因素

随着人民生活水平的提高，牛肉消费量在快速增长，与此同时消费者对牛肉品质的要求也越来越高，如何评价牛肉品质越来越受到重视。作者对牛肉品质评定的感观指标、内在指标以及影响牛肉品质的因素作一综述。     

陕西四个黄牛群体遗传变异的Shannon信息量分析

应用群体遗传变异的相对Shannon信息量指标体系，对陕西四个黄牛群体的遗传变异进行研究，结果表明：四个群体的遗传变异主要由杂合体的连续存在所致，平利牛的总遗传变异最大，陕西北部黄牛群体总遗传变异最小。     

Optimal genetic contribution selection in Danish Holstein depends on pedigree quality

The aim of this study was to assess the importance of pedigree depth when performing optimal contribution selection as implemented in the software program EVA. This was done by applying optimal genetic contribution in the breeding program of the major Danish Dairy breed Danish Holstein. In the analyses earlier breeding decisions were considered by including all AI waiting- and young bulls and contract matings. Twenty potential sires, 2169 potential dams, 1421 AI-bulls and 754 contract matings plus pedigree animals were included. Results showed that the outcome was very dependent on quality of pedigree, also for information going more than 25 years (5–7 generations) back. The analyses showed that EVA works satisfactorily as a management tool for planning of breeding schemes with respect to contributions of sires of sons at population level in maximising the genetic gain, while controlling the increase in future inbreeding. The more weight put on the average additive genetic relationship in next generation relative to genetic merit, the lower the average merit of the matings, and the lower average additive genetic relationship among the chosen matings and the present breeding animals. Furthermore more weight on average additive genetic relationship gives a more diverse use of sires of sons. Given the potential sires and dams the average additive genetic relationship among the selected matings and the present breeding animals can be reduced from 0.1621 to 0.1495 at the cost of 0.7 genetic S.D. units at the total merit index. This reduction was obtained when selection was only on reduction of average relationship compared to selection only on genetic merit. Optimal genetic contribution selection is a promising tool for managing breeding schemes for populations facing inbreeding problems, such as Danish Holstein and other dairy breeds. However sufficient pedigree information is a necessity.     

Validation of commercial DNA tests for quantitative beef quality traits

Associations between 3 commercially available genetic marker panels (GeneSTAR Quality Grade, GeneSTAR Tenderness, and Igenity Tender-GENE) and quantitative beef traits were validated by the US National Beef Cattle Evaluation Consortium. Validation was interpreted to be the independent confirmation of the associations between genetic tests and phenotypes, as claimed by the commercial genotyping companies. Validation of the quality grade test (GeneSTAR Quality Grade) was carried out on 400 Charolais x Angus crossbred cattle, and validation of the tenderness tests (GeneSTAR Tenderness and Igenity Tender-GENE) was carried out on over 1,000 Bos taurus and Bos indicus cattle. The GeneSTAR Quality Grade marker panel is composed of 2 markers (TG5, a SNP upstream from the start of the first exon of thyroglobulin, and QG2, an anonymous SNP) and is being marketed as a test associated with marbling and quality grade. In this validation study, the genotype results from this test were not associated with marbling score; however, the association of substituting favorable alleles of the marker panel with increased quality grade (percentage of cattle grading Choice or Prime) approached significance (P < or = 0.06), mainly due to the effect of 1 of the 2 markers. The GeneSTAR Tenderness and Igenity TenderGENE marker panels are being marketed as tests associated with meat tenderness, as assessed by Warner-Bratzler shear force. These marker panels share 2 common mu-calpain SNP, but each has a different calpastatin SNP. In both panels, there were highly significant (P < 0.001) associations of the calpastatin marker and the mu-calpain haplotype with tenderness. The genotypic effects of the 2 tenderness panels were similar to each other, with a 1 kg difference in Warner-Bratzler shear force being observed between the most and least tender genotypes. Unbiased and independent validation studies are important to help build confidence in marker technology and also as a potential source of data required to enable the integration of marker data into genetic evaluations. As DNA tests associated with more beef production traits enter the marketplace, it will become increasingly important, and likely more difficult, to find independent populations with suitable phenotypes for validation studies.     

Multi-state Beef Reproduction Task Force provides science-based recommendations for the application of reproductive technologies

Since its formation, the Beef Reproduction Task Force (BRTF) has worked to enhance productivity and profitability of US beef herds by integrating research and extension efforts with the intent of more effectively transferring the use of reproductive technologies to the field. A key early step was to coordinate efforts in identifying effective breeding management protocols for beef cattle and to clarify their associated acronyms. A short list of recommended protocols and their acronyms for synchronization of estrus and ovulation in beef cattle was developed based on results from peer-reviewed, published research and a comprehensive review of data collected from the field. The list of recommended protocols was developed by the BRTF in cooperation with veterinarians and cattle AI industries. These protocols and their acronyms are presented uniformly in all of the major AI sire directories and are available online at http://www.beefrepro.info. Protocol updates are made annually to incorporate the most recent research findings related to estrous cycle control in beef cattle. The Estrus Synchronization Planner, a software program developed in cooperation with the Iowa Beef Center, now reflects these same recommendations. Beginning in 2002, the BRTF hosted and presented 11 educational workshops to more than 1,900 attendees in key cow-calf states. These Applied Reproductive Strategies in Beef Cattle workshops targeted beef producers, AI industry personnel, veterinarians, allied industry representatives, and academicians. A national media sponsor provided online coverage of the last 3 workshops at http://www.appliedreprostrategies.com. A postmeeting evaluation, developed to assess application of information from 2 recent workshops, was returned by 55% of those contacted (n = 150). Attendees averaged 16 (± 13.4 SD) yr of AI experience, and 80% of respondents represented more than 100 cows. Respondents were asked to estimate the value of AI-sired calves compared with natural-service-sired calves to their operation on a per-animal-marketed basis, and 17 and 31% responded $50 to $100 per animal and more than $100 per animal, respectively. As a result of what was learned at these conferences, 78% of respondents were better able to troubleshoot management-related issues, 60% made alterations to a protocol they had been using, and 35% of the respondents indicated they changed to a different estrus synchronization protocol.     

不同肉牛育肥的牛肉产品生产对饲料粮消耗比较分析

在对繁殖母牛、哺乳犊牛和架子牛进行饲养试验及调查的基础上,结合所进行的架子牛育肥试验和犊牛直线育肥试验,参考肉牛饲养标准和已发表的肉牛育肥试验数据,并根据目前我国牛肉产品提供状况和肉用牛育肥的饲料资源情况,分别比较不同肉牛育肥牛肉产品生产所需要的粮食。结果表明,为获得等同重量的肉牛产品,直线育肥技术比后期集中育肥要消耗较少的粮食,而高档牛肉生产（高端肉产品生产）需要消耗更多的饲料粮。     

Effect of body fatness and selection for prolificacy on survival of rabbit does assessed using a cryopreserved control population

The aim of this experiment was to investigate the effect of body condition and selection for prolificacy on the reproductive life span of female rabbits. The body condition was obtained by ultrasound measurement of the perirenal thickness of 166 crossbred does at day 10 after parturition in 6 consecutive parities. Two genetic groups were included: the current generation of does crossbred between two lines, both selected within line for number of pups at weaning, and a control group consisting of animals from the same cross but from 12 generations earlier. This control population was obtained by use of cryopreservation techniques, and made a simultaneous comparison between animals of different generations possible. A proportional Cox model was used to obtain estimates of survival characteristics. Twelve generations of selection for litter size at weaning did not significantly affect reproductive life span. Animals in poor body condition were found to have a significantly (P < 0.05) higher risk of dying than animals in better condition. Also, animals with high body fat mobilisation had a higher risk of culling (P < 0.05) than animals with intermediate mobilisation. Animals with zero pups born alive were also found to have a high risk of culling (P < 0.001).     

Crossbreeding experiment with beef and dual-purpose sire breeds on Danish dairy cows III. Daily gain,feed conversion and carcass quality of intensively fed young bulls

Beef production characteristics of 254 intensively fed young bulls are described. The results are part of a beef × dairy crossbreeding experiment, where sires of eight European beef and dual-purpose breeds were used on cows of RDM (Danish Red Cattle) and SDM (Black Pied Danish Cattle).Daily gain and feed conversion were influenced by the sire breeds. Charolais, Blonde d'Aquitaine and Simmental crosses showed the highest daily gain, followed by Romagnola, Danish Red and White, Chianina, Limousin and Hereford crosses.Carcass composition and carcass conformation were strongly influenced by sire breed with Blonde d'Aquitaine and Limousin crosses producing the most valuable carcasses followed by Chianina, Charolais, Romagnola, Simmental, Danish Red and White and Hereford crosses in descending order.The analysis showed a sire breed × weight/age interaction in carcass composition traits, due to sire breed differences in maturity. That demonstrates the importance of serial slaughtering in breed comparison experiments. Hereford and Limousin produced the earliest maturing crosses and Danish Red and White and Blonde d'Aquitaine the latest maturing crosses.     

平凉红牛遗传资源及选育策略

本文综述了平凉红牛遗传资源的形成过程,保护与利用现状及存在的问题,提出了“先保再用”的保护利用策略,即：先申请认定为地方品种,列入国家地方品种保护目录,划定保护区先保护,固定前期选育成果;再系统规划开展平凉红牛遗传资源本品种选育和以此为育种素材的新品种选育,以期为“保护好平凉红牛地方品种,早日育成新品种”提供参考。