Animal medical genetics: a perspective on the epidemiology and control of inherited disorders

This perspective considers genetic disorders of domestic animal populations, in particular their epidemiology and control. Inherited disorders of animals share the same basic molecular biology as those of human beings, but they differ in their epidemiology due largely to the breed structure of the various species, human control of breeding and a greater influence of the founder effect, particularly due to extensive use of a limited number of sires, and inbreeding. Control of genetic disorders in animals is also more practical through extensive screening for disease, or heterozygous animals within defined breed populations, followed by exclusion of affected or carrier animals from breeding. This is assisted by the fact that, within a breed, many inherited monogenic disorders are associated with a single mutation. However some of the more important disorders may be inherited in a non-Mendelian manner, being influenced by multiple genes as well as environmental factors. These aspects are discussed and contrasted with similar aspects in human medical genetics.     

罗曼褐父母代产蛋前期产蛋规律的分析

对1249只健康的23周龄的罗曼褐父母代种母鸡的产蛋情况进行观察,试验期67 d(至32周龄),目的在于了解产蛋前期,蛋用种鸡产蛋性能的变化规律。试验结果表明,随鸡群日龄的增大蛋壳颜色逐渐变浅,产蛋率和种蛋合格率逐渐上升,鸡群的死淘率在开始人工授精的前2周最高,双黄蛋率随产蛋率的上升而逐渐减小,双黄蛋平均重随产蛋率上升逐渐增大,到产蛋率达最高峰时开始变小,软壳蛋率和破蛋率随鸡群日龄的增大而逐渐减小,总蛋重及种蛋平均重随鸡群日龄的增大而逐渐增大。     

A comparison of Friesian, Aberdeen Angus × Friesian and Belgian Blue × Friesian steers finished at pasture or indoors

Cross-breeding of dairy cows with beef bulls is common in Ireland with the Aberdeen Angus and Belgian Blue beef breeds both widely used. These breeds differ in maturity and consequently in their suitability for production systems differing in intensity and slaughter age. The objective of this study was to compare spring-born Holstein–Friesian (FR), Aberdeen Angus × Holstein–Friesian (AA) and Belgian Blue  × Holstein–Friesian (BB) steers slaughtered off pasture at the end of their second grazing season or slaughtered at the end of the second winter following indoor finishing. Fifty-four (18 per breed type) steers were managed together to 16 months of age. They were then blocked on weight within breed type and assigned to a 3 (breed types) × 2 (finishing strategies) factorial experiment. The two finishing strategies were (i) concentrate supplementation (mean 3.65 kg/day) at pasture for 105 days to slaughter, and (ii) pasture only for 105 days followed by indoor finishing on grass silage plus concentrates for 141 days to slaughter. Mean slaughter and carcass weights per day of age for FR, AA and BB were 852, 802 and 834 (S.E. 13.1) g, and 427, 412 and 452 (S.E. 7.3) g, respectively. Corresponding kill-out proportions, carcass conformation and carcass fat classes were 501, 514 and 542 (S.E. 2.4) g/kg, 1.90, 2.15 and 2.89 (S.E. 0.073), and 3.09, 3.27 and 2.59 (S.E. 0.122), respectively. The response to concentrates at pasture was 101 g live weight and 83 g carcass weight per kg dry matter. It is concluded that there were few differences between FR and AA in carcass growth and composition but BB had heavier carcasses of better conformation with higher proportions of lean meat and high-value lean joints than both FR and AA. Acceptable live weight and carcass weight gains were obtained on pasture plus concentrates but BB and FR carcasses were not acceptably finished off pasture. Both FR and AA produced acceptable carcasses following indoor finishing and BB carcasses, while below the target fat class, were acceptably finished based on internal fat and dissected carcass fat proportions.     

矮脚黄鸡与国内地方品种鸡配套生产的应用研究

选用浙江省宁波市振宁牧业有限公司育种中心携带有dw基因的纯系矮脚黄鸡K系公鸡为父本。以浙江省宁海县梅林镇当地鸡群选育而成的D系黄羽正常脚母鸡作为母本，先进行两系杂交，后分别用国内4个地方的不同品种L系、G系、H系、X系为第二父本。同KD母鸡进行三系配套杂交。通过对商品代的质量性状和数量性状的观察和测定，筛选出符合当地的配套模式。     

Farmer’s views and values to focus on cattle conservation policies: the case of eight European countries

Our aim was to identify elements useful in designing policies and programmes for conservation of farm animal genetic resources, taking as case study a group of European local cattle breeds. We first investigated the implications of differences among countries in the policies and programmes to be developed. Secondly, we analysed key elements common to countries, which may affect local breed viability. We used the herd size trend expected by the farmer in the near future as an indicator of breed viability. Fifteen breeds, for a total of 355 farms, were surveyed. To take into account the multiple factors influencing breeds’ demographic trends, the questionnaire included economical, technical and social aspects. Among the major differences across countries was the perception of the farmer on the value attributed to the local breed by society. Concerning the elements common to countries and their association to breed viability, the greater the collaboration among farmers and the stakeholders’ appreciation as perceived by the farmer, the greater the viability of the farm. An opposite trend was observed for the age of the farmer. Older farmers generally planned to soon cease farming or decrease herd size, whereas young farmers planned to increase the size of their herds. Implications of including these elements in conservation polices are discussed.     

Research opportunities in the field of animal genetic resources

Animal genetic resources are those animal species that are used, or may be used, for the production of food and agriculture, and the populations within each of them. The working unit of a database for farm animal genetic resources is the breed, a term taken in its widest possible sense to mean a population within the species, possessing a number of particular traits that permit the grouping of these animals under a common label and are associated to geographical areas and human groups. Research opportunities cover a wide range of thematic areas. The biggest gap in knowledge is animal breeding for local populations in harsh environments. There is also a lack of research in functional genetics and genomics of adaptation and disease resistance traits. By comparison, breed characterization, in particular molecular characterization, has been a more popular research subject. The same can be said for conservation, although some fundamental questions on genetic diversity and risk of its loss are still unanswered. Research is required to understand the socio-economic, infrastructural, technical and formal constraints that limit the operation of sustainable conservation programs in less developed countries. Information systems on animal genetic resources need input from research and data capture networks, in order to achieve a reasonable degree of completeness. Economic analysis and issues related to gene flow and access and benefit sharing should also profit from more research.     

八眉猪肥育和胴体性能及与部分品种的比较分析

[目的]为八眉猪的保护、选育和合理利用提供理论依据。[方法]以12头青海八眉猪为试验动物进行肥育试验，肥育结束后随机选择6头屠宰，测定其胴体和肉质性能，并与国内外其他品种进行比较。[结果]八眉猪肥育期平均日增重409．86g，低于杜洛克猪、荣昌猪和民猪；屠宰率70．19％，与国内外大部分品种相当；平均膘厚3．38cm，较二花脸猪和民猪薄；肌肉pH值6．43，与地方品种相当；肉色和肌肉大理石纹全部被评为3～4分（1～5分制），略低于民猪和内江猪；失水率18．86％，低于杜洛克猪；熟肉率66．12％，低于内江猪，高于民猪、二花脸猪和杜洛克猪；肌肉脂肪含量（7．16％）高于其他品种。[结论]应继续对青海八眉猪进行保种选育。     

四川九个黑山羊品种(群体)X染色体微卫星DNA多态性研究

以7个微卫星标记,PCR扩增,12%非变性聚丙烯酰胺凝胶电泳,sanguinetti银染法显色,对四川建昌、金堂、乐至、合江、江安、自贡、嘉陵、营山、白玉9个黑山羊品种(群体),进行X染色体微卫星DNA遗传多态性研究.结果表明:7个微卫星座位在9个黑山羊品种(群体)中均为高度多态座位,建昌、金堂、乐至、合江、江安、自贡、嘉陵、营山和白玉9个黑山羊的平均PIC、H和Ne分别为:0.764 4,0.796 6,5.114 5;0.725 8,0.762 8,4.466 0;0.743 8,0.776 9,4.724 2;0.758 0,0.791 0,5.006 6;0.736 5,0.774 7,4.508 4;0.746 3,0.781 9,4.694 4;0.768 3,0.799 3,5.194 8;0.764 2,0.795 6,5.033 3;0.721 1,0.760 0,4.286 7.嘉陵与营山黑山羊在D＝0.284处聚为一类;自贡与江安黑山羊在D＝0.294处聚为一类;金堂与乐至在D＝0.381处聚为一类,在D＝0.395处再与合江黑山羊聚为一类;白玉与建昌黑山羊在D＝0.456处聚为一类.最后4种聚为一大类.     

遗传距离聚类法和模型聚类法在地方鸡种群体遗传结构分析中的比较

利用16个微卫星标记,计算品种间DA遗传距离和基因流（Nm）,并基于DA遗传距离运用NJ算法和基于Structure程序构建2类聚类图,比较分析10个地方鸡品种群体间的遗传结构和亲缘关系。结果表明：基于DA遗传距离运用NJ算法构建的聚类图将10个地方鸡品种总体上分为2大类：轻体型的鸡种（包括茶花鸡、藏鸡、仙居鸡、固始鸡和白耳鸡）和重体型的鸡种（包括狼山鸡、大骨鸡、北京油鸡、鹿苑鸡和萧山鸡）;在轻体型的类别中,茶花鸡和藏鸡、仙居鸡和固始鸡聚为一类;在重体型的类别中,鹿苑鸡和萧山鸡聚为一类,狼山鸡、大骨鸡和北京油鸡则表现为独立分支,聚类结果与品种问基因流动相一致。Structure程序在预先未标识个体品种来源的条件下,准确推断出10个地方鸡种群体所属类别,构建的聚类图与遗传距离聚类结果基本一致。Structure程序还根据个体基因组分数,指出了10个地方鸡种群体中迁移个体和具有复杂遗传基础个体的分布,这是遗传距离聚类法所不能揭示的。     

Epidemiological survey,general blood biochemistry,and histological examination of slaughtered heavy horse breeds with hemorrhage in the adipose tissue in the crest of the neck

Fifty-four slaughtered horses were classified into groups having adipose tissue in the crest of the neck with or without hemorrhage (AH and NH groups, respectively). Blood biochemical tests (Alb, TP, T-bil, GOT, GPT, LDH, T-cho, and BUN) and an epidemiological survey (age, gender, weight, origin, breed, BCS, CNS, and hoof disease) were performed. T-bil tended to be high, while the other parameters were normal. Weight, BCS, and CNS were higher in the AH group (P<0.05). GOT was lower in the AH group (P<0.05). It was suspected that the horses in the AH group had lipomatosis. It was assumed that the adipose tissue of the horses in the AH group contained damaged capillaries, and inflammation was confirmed based on evidence of macrophages and lymphocytes.