湖北白猪Ⅳ系毛色纯合方法的研究

在湖北白猪Ⅳ系世代选育过程中，采用毛色测交、后裔调查和系谱鉴定法，以准确判定个体的毛色基因型；通过严格的选择与淘汰，逐代减少毛色杂合子和基因型未知的个体，使群体中非白毛基因频率迅速下降，并达到了毛色纯合之目的。在品系世代选育初期，宜采用测交和后裔调查法来判定个体的毛色基因型，后期可选用系谱鉴定法，以减少饲喂测交猪的生产成本。     

家畜育种值估计方法及其发展

家畜育种的目的和任务就是选择优秀的公畜和母畜留作种用,通过它们之间的合理交配产生优良的后代,如此经过世代选择,从而提高家畜的生产水平。从遗传学角度来讲,只有通过基因型选择才能得到最大的选择效果,即按家畜的育种值进行选择。但是,育种值不能直接进行度量,只有通过表型予以估计。因此,家畜育种值的估计就成为家畜育种中主要的和经常性的工作。     

不同群体规模下闭锁群体遗传漂变的模拟

为了研究在施行随机留种、随机交配、世代不重叠、群体间个体无迁移、整个保种过程中基因不发生突变的原位保种群体中遗传漂变的变化情况,试验采用计算机模拟方法针对不同群体规模下闭锁群体基因频率、基因型频率在50个世代中的变化进行研究。结果表明:群体规模越大,基因频率、基因型频率在世代间波动的幅度越小,因此世代间随机遗传漂变基因被固定或丢失的概率越小。     

湘村黑猪毛色遗传的探讨

在杂交合成和横交固定的基础上,湘村黑猪2世代(F2)种猪进行了毛色测交,解决了毛色表型选择进展缓慢的难题,提高了毛色选择效率。世代间棕黄杂毛出现的频率由1世代的20.32%降至5世代的1.56%,黑毛基因型基本纯合,黑毛成为湘村黑猪的品种特征。     

选择在家畜育种中的应用

所谓选择，就是挑选出基因型优秀的公、母畜留作种用。也即把符合育种要求的个体选留下来，对于不符合育种要求的个体予以淘汰或充作其它用途。通过选择，可以定向地改变家畜群体遗传结构，使群体中优良基因频率不断升高，不良基因频率逐渐降低，从而达到改良家畜品种、培育新品种的目的。１选择机理选择分自然选择和人工选择两种。任何一个家畜群体、任何一个性状，个体之间的差异总是存在的。个体之间的变异性为选择提供了可能性。个体的变异受遗传物质和环境条件两因素的影响，如果我们的选择是作用于遗传物质的差异，那么选择出来的性状…     

绵羊PLIN基因多态性检测

试验利用PCR和DNA测序技术对3个绵羊群体中90个个体进行PLIN基因多态性检测。结果表明,PLIN基因在试验群体中存在TT型、CC型和TC型3种基因型,群体中TT基因型频率4%,CT基因型频率为60%,CC基因型频率为36%,C、T等位基因频率分别为66%、34%。     

微卫星DNA标记在山羊品种资源保存利用中的应用研究进展

山羊品种的进化是人为的通过许多世代形成的。当地的气候、环境、突变、迁移、选择以及遗传漂变在山羊品种的进化中都起着一定的作用。突变是遗传变异的源泉，为品种的进化提供了原材料，突变直接导致新等位基因的出现，改变群体已有的基因频率，引起群体遗传结构的改变。迁移是不同群体间由于个体转移引起的基因流动过程，由于山羊不同群体之间的差异主要体现在基因频率的不同，而迁移的作用就是通过不同频率的群体间基因流动引起群体基因频率的改变，迁移引起群体基因频率的变化取决于迁移率和两群体间基因频率差异的大小。     

全基因组选择信号检测方法在家畜研究中的应用进展

长期的自然和人为选择使家畜品种经济性状得到了显著改善,其相关的基因组区域也发生了特定遗传变异。随着时间的推移部分基因多态性已经下降或消失,而在群体中保留包含单一单倍型的多个基因。这种基因组上特定区域基因多态性频率的变异被称为选择信号。识别选择信号可以提供家畜驯化机制并进一步揭示表型相关的基因变异。目前,高密度SNP芯片及大规模重测序技术已成功应用于家畜选择信号鉴定研究。全基因组选择信号检测方法有等位基因频率检测法、连锁不平衡检测法和群体分化分析法。作者综述了全基因组范围内选择信号检测方法及其在家畜研究中的应用进展,为从事家畜育种及生物进化研究人员提供参考。     

大通牦牛培育中种公牦牛的选择及群体世代改良进展

结合牦牛生产实践,运用现代家畜育种理论和方法,提出在培育牦牛新品种过程中,应重视种公牛的选择,提高选择技艺,在群体中不断创造变异,迅速扩大优良基因和基因型配套体系的策略和具体方法;同时总结了近十余年来牦牛育种核心群的群体世代改良进展,为牦牛新品种的培育积累基础资料.     

东北寒区肉羊新品种群FecB基因鉴定与基因频率分析

本试验旨在对两个东北寒区肉羊新品种群体进行FecB基因鉴定和基因多态性分析。通过提取两个群体个体外周血基因组DNA样品,基因组PCR直接测序和HRM法检验,结果发现两个群体中均含有FecB基因,但无论从基因型频率还是等位基因频率均存在明显差异。首先肉毛兼用型群体只含有少量B+基因型个体,B等位基因频率只有3%左右,且处于Hardy-Weinberg平衡状态。多胎型群体中FecB基因含量则显著提高,BB和B+基因型频率依次上升至7%和25%左右,且处于Hardy-Weinberg不平衡状态,说明FecB基因在该群体中受到较为强烈的选择压力。如需利用两个群体进行兼具产肉性能和高繁殖性能肉羊新品种(系)培育,较为理想的策略是在进一步提升两个群体优良特性的前提下,开展两个群体间杂交。     

转基因动物在动物营养研究中的应用

本文综述了转基因动物在动物营养中的应用。包括两个主要部分，一是用转基因动物做模型，研究外源基因对动物生长和代谢的调控作用，说明外源基因对动物生长速度、饲料利用率及其胴体的组成均有影响。与此同时，还可以导入新的代谢体系中的主要基因，使动物本身获得对某些必需物质的合成能力，从而达到提高生产性能的目的。另一部分是日粮的营养成分对动物某些基因表达的调控作用，从基因表达水平说明营养成分对动物某些物质的合成、代谢的调控作用。这两个方面都为在分子水平上研究动物营养学提供了有效的手段和方法。     

THE DURATION OF THE RESPONSE OF CATTLE TO INOCULATION WITH ATYPICAL MYCOBACTERIA

SUMMARY Each of 4 strains of atypical mycobacteria was inoculated into 2 cattle and the responses of the cattle were studied over the following 52 weeks. Each strain was injected subcutaneously into one animal and into a mesenteric lymph node of another. Within 7 days palpable lesions were produced at the sites of subcutaneous inoculation in response to all the strains. After intervals varying from 3 to 26 weeks, lesions due to 3 of the strains were no longer palpable. The lesion produced in response to the fourth strain, a non-agglutinable serotype of Mycobacterium intracellulare, was still palpable at necropsy, 52 weeks post-inoculation (PI). Of the 8 cattle inoculated with mycobacteria, the latter was the only animal that had a lesion with features consistent with a mycobacterial infection and from which mycobacteria were isolated. The inoculated cattle and 4 uninoculated control cattle were turberculin tested on 8 occasions during the post-inoculation period. Bovine purified protein derivative (PPD), avian PPD and PPD tuberculins prepared from each of the atypical mycobacteria were used. In inoculated cattle, sensitivity to both avian and bovine PPD was short lived, significant levels not persisting in any animal beyond 16 weeks PI. From the results of intradermal tests on the control cattle, a 95% confidence interval for their response to any of the 6 tuberculins used, was found to be ±1.36mm. On this basis all inoculated cattle developed sensitivity to the homologous tuberculin. The animal with mycobacterial granuloma at the subcutaneous inoculation site at necropsy had never developed significant levels of sensitivity to bovine PPD, had not shown significant levels of avian sensitivity after week 16 PI nor had it shown homologous sensitivity after week 22 PI. In all animals the level of sensitivity to bovine PPD decreased between successive tests. This fact could be used to clarify the status of a reactor if non-specific bovine sensitivity was suspected. Alternatively, the comparative intradermal tuberculin test using both bovine and avian PPD may be employed.     

中国家养动物多样性概况

中国家养动物物种、品种和群体数量资源丰富,包括近缘野生种在内的家养动物物种有54个,品种1943个。它们在动物农业可持续发展中发挥重要作用。随着对家养动物认识的不断深入和人们需求的多样化,不断有新的资源被发现、引入、培育出来。与此同时,由于经济利益的驱动,许多具有优良特性的地方品种遗传资源,其数量不断下降,处于濒危、甚至灭绝的境地,这种趋势应引起足够重视。为保持动物农业的可持续发展,对家养动物多样性进行深入研究和有效保护是极为必要的。     

同仁县畜牧业生产现状及发展对策

阐述了同仁县畜牧业生产现状及畜牧业发展生产中存在的诸多问题,面对存在问题,有针对性的提出了畜牧业发展的对策与建议及应采取的具体措施。从而实现同仁县畜牧业由粗放经营向集约经营的转变,实现畜牧业向高产、高效、优质的方向发展。     

Resistance to various antibiotics of Salmonella and Escherichia coli isolated from registrable farm feeds

Resistance to 20 antibiotics of 128 Salmonella and 97 Escherichia coli isolates from various registrable farm feeds was determined. A high frequency of comparatively low levels of resistance was found in both the Salmonella and E. coli isolates. This, together with an elevated frequency of multiple resistance, indicates that problems related to an effective transfer in bacterial populations of resistance to certain antibiotics are a distinct possibility. The addition of antibiotics, such as penicillin and tetracyclines, to animal feeds can create conditions for rapid selection amongst bacteria resistant to antibiotics. The numbers of resistant bacteria in the animal environment may be increased and may lead to the development of veterinary and human health problems from the possible transfer of antimicrobial resistance from animal pathogens to human pathogens or spreading in the human population of animal pathogens resistant to antibiotics. There is a need for caution in the use of antibiotics, particularly in animal feeds. Extended survey of, and epidemiological research on, farm feeds, manufacturing mills and animal production units are emphasized.     

Top down preselection using marker assisted estimates of breeding values in dairy cattle

Top down preselection of young bulls before entering progeny testing has been proposed as a practicable form of marker‐assisted selection (MAS), especially in dairy cattle populations with large male paternal half‐sib families. Linkage phase between the superior (Q) and the inferior (q) QTL alleles of heterozygous sires (Qq at the QTL) with informative markers is established within each paternal half‐sib family and may be used for selection among grand‐progeny. If, additionally to sires, bulldams are also genotyped and data from consecutive generations are used, then a marker‐assisted best linear unbiased prediction (MA‐BLUP) model can be employed to connect the information of all generations and families of a top down design, and to select across all families. A customized ‘augmented’ sire model (with sires and dams of sires as random effects) is introduced for this purpose. Adapted formulae for the mixed model equations are given and their equivalence to a corresponding animal model and to a certain variant of previously proposed reduced animal models is shown. The application of the augmented sire model in MA‐BLUP estimation from daughter‐yield deviations and effective daughter contributions is presented.     

Possibilities for a legal complaint by an association in animal protection law

Access to justice for qualified entities in the area of animal protection should not follow the procedures of the access to justice for qualified entities in nature protection. This access is limited to certain administrative procedures, where damages to nature and landscape are to be expected. This will not carry very far with animal protection, because the rights of animals can be injured in many ways. Considering this it seems appropriate, to give access to justice to any animal, as a creature equal to man. Whenever the rights of an animal are neglected by the administration or a citizen, they can be defended in court. As the animal cannot represent itself in court, a qualified entity in animal protection shall act on its behalf, being its lawyer. In the end this would give access to justice to qualified entities in the area of animal protection, but the right would not be restricted to certain administrative procedures. It would provide the animals with a lawyer to present their interests in court.     

Is the use of formulae a reliable way to predict the accuracy of genomic selection?

We studied four formulae used to predict the accuracy of genomic selection prior to genotyping. The objectives of our study were to investigate the impact of the parameters of each formula on the values of accuracy calculated using these formulae, and to check whether the accuracies reported in the literature are in agreement with the formulae. First, we computed the marginal distribution of accuracy (by integration) for each parameter of all four formulae: heritability h², reference population size T, number of markers M and number of effective segments in the genome M_e. Then, we collected 145 accuracies and corresponding parameters reported in 13 publications on genomic selection (mainly in dairy cattle), and performed analysis of variance to test the differences between observed and predicted accuracy with effects of formulae and parameters. The variation of accuracy for different values of each parameter indicated that two parameters, T and M_e, had a significant impact and that considerable differences existed between the formulae (mean accuracies differed by up to 0.20 point). The results of our meta‐analysis showed a big formula effect on the accuracies predicted using each formula, and also a significant effect of the value obtained for M_e calculated from N_e (effective population size). Each formula can therefore be demonstrated to be optimal depending on the assumption used for M_e. In conclusion, no rules can be applied to predict the reliability of genomic selection using these formulae.     

CRITTER: A database for managing research animals

We describe CRITTER, a computer database program for managing research animals. We designed it especially for institutions which operate health surveillance plans, such as specific pathogen-free schemes. Because CRITTER can be used to record any type of test result in any species of animal, it can be customized to suit each institution and its management protocol. In addition to maintaining a current inventory of each individual animal and its location, the program retains historical information on those that have been removed from the colony. Output summaries are generated by selecting from a menu of standard reports or by designing a custom query. Although CRITTER has been designed for individual research establishments, it could be modified for use in area health surveillance programs. CRITTER operates on IBM compatible computers using a menu-driven, runtime version of Paradox.     

QUANTITATIVE COMPUTED TOMOGRAPHY EVALUATION OF PULMONARY DISEASE

Objective assessment of pulmonary disease from computed tomography (CT) examinations is desirable but difficult. When such assessments can be made, it is important that they are related to some part of the pathophysiologic process present. Herein we propose that automated volume histogram analysis can yield data that allow differentiation of normal from abnormal lung, and that the magnitude of disease will have an association with objective CT indices. Data from pulmonary CT images from 34 foxes (six uninfected controls and 28 infected with Angiostrongylus vasorum , subdivided by age and infective dose) were available. Lung tissue was segmented from surrounding tissue using an automated segmentation method. A volume histogram showing voxel frequency for each CT number in the range −1024 to −250 HU was created from the entire image stack from each fox. Using these data, the inter-quartile range and the CT number at the 95th percentile were determined. The results showed that segmentation could be readily achieved but that areas of severely diseased lung were excluded. Based on two-way analysis of variance for both the inter-quartile range and the CT number at the 95th percentile, both quantities were significantly affected by the infection status of the animal and were related to worm burden ( P <0.001). The study shows that this form of analysis is readily achieved and provides quantitative data that can be used to assess disease severity, progression, and response to treatment.