动物的性别控制

动物的性别控制是指通过对精子或胚胎的性别鉴定以达到调控子代性别的目的,人为调控动物的性别是人类长期以来的愿望,随着胚胎冷冻、胚胎切割、体细胞克隆技术的日渐成熟,动物的性别控制显得更为重要。     

鸡胚性别鉴定研究进展

家禽性别控制研究包括性别决定、性别分化、性别鉴定、性别诱导和性别控制等方面。性别决定与分化本质的发现是家禽性别研究的重要基础，对鸡胚性别的早期鉴定是对性腺基因研究的重要内容。     

家禽性别控制的研究进展

家禽性别决定的研究表明：目前对家禽性别决定机制尚未完全清楚，除性染色体理论外，尚有常染色体／性染色体平衡理论，而性别最终是由基因决定的。近年来在探索Ｗ染色体上ＤＮＡ特异序列方面虽取得了一些进展，但还没有发现类似Ｙ染色体上的ＳＲＹ片段。在人工诱导性腺分化控制家禽性别实验中，发现以免疫学方法和芳香化酶抑制剂处理效果较明显，尤其是芳香化酶抑制剂作用较稳定，但用于生产还有一定距离。家禽性别决定的有效控制最终取决于对家禽性别决定、性别分化本质的深入研究和了解     

性别控制技术的研究与应用进展

性别控制指通过人为干预使动物的繁育按照人们所希望的性别繁殖后代的技术.随着畜牧业生产智能化的迅速发展,高效准确的性别调控技术成为提高畜禽生产经济效益的重要研究方向.本文主要综述了性别分化调控、性别反转和X、Y精子分离技术,以期促进畜牧业养殖性别控制技术的发展和应用.     

家畜性别决定的机制及其控制的研究进展

家畜性别决定的分子机理以及通过实施精子分离和早期胚胎性别鉴定来进行性别控制的进展。     

哺乳动物性别控制研究进展

目前哺乳动物的性别控制方法主要是通过两种途径:早期胚胎的性别鉴定和精子的性别分离。其他的性别控制方法有:控制体内交配及受精时间、控制阴道酸碱度、无性繁殖技术(如卵核移植、雌核发育、卵母细胞融合及人工诱发雄核发育)和根据免疫学建立起来的技术等。本文就哺乳动物性别控制的研究方法做一综述,并提出了一些关于性别控制的设想。     

配子水平上对家畜性别控制的研究进展

实现对家畜性别的控制是生物学中重要的研究课题，依据畜牧业生产中不同的需要来决定不同家畜的性别在人类健康及畜牧业生产上有巨大的应用价值，实现对动物性别的控制一直是人类期望达到的目标之一。本文从配子角度出发对家畜性别决定原理机制、性别控制的生物学依据及各种性别控制方法作了简述，并着重对不同方法的理论基础、特点、实践应用价值以及这些方法存在的问题进行了综述。     

家畜性别控制的研究进展

对家畜性别决定机理、受精前的性别控制技术、受精后的胚胎性别鉴定技术以及今后性别控制技术的前景和趋势等方面进行了分析讨论,旨在为科研工作者和畜牧生产者提供参考.     

哺乳动物性别控制和鉴定技术的研究进展

文章对哺乳动物性别决定机理、受精前的性别控制技术、受精后的胚胎性别鉴定技术以及今后性别控制技术的前景和趋势等方面进行了综述。     

家畜早期胚胎性别鉴定的研究进展

家畜早期胚胎的性别鉴定是家畜胚胎移植的重要内容,对实现动物性别的人为控制具有重要意义。近年来随着性别鉴定技术的不断发展,出现了许多鉴定方法。本文对性别决定基因、动物性别决定机理、早期胚胎性别鉴定的方法等作简要综述。     

Environmental endocrine disruptors in farm animal reproduction: research and reality

In this review, possible comparative advantages of studying endocrine disruption in farm animals vs laboratory rodents are discussed. First, using farm animals, the generality of findings in laboratory rodents are challenged. Farm animals may in certain aspects be better models for humans than laboratory rodents, and sometimes there might be methodological advantages in using farm animals. Second, there are several in vitro studies based on cell-culture systems from sows and cows where the effects of chemicals on sex steroid secretion can be measured and maturation and fertilization of oocytes may be assessed. These in vitro systems are powerful tools for dissecting the mechanisms of action for endocrine-disrupting chemicals. Third, in a set of recent in vivo studies using sheep, goats and pigs, in which very different exposure regimens to endocrine-disrupting chemicals have been used, a full panel of reproductive parameters pertinent to farm animals were assessed. Clinically, it is suggested that endocrine disruption in farm animals should be considered when impaired reproduction could be linked to change in source of feed or pasture. Finally, epigenetic and toxicogenomic approaches can be particularly rewarding in elucidating endocrine disruption in future farm animal studies.     

Training and Certification of Farm Animal Care in Teaching and Research Institutions

Fane animal worker training and certification programs are currently not available. Programs are needed for training and certification of farm animal workers in teaching and research facilities at universities and companies and on commercial farms. Consumers support farm animal welfare assurances. Although the focus of this paper is the development of programs for teaching and research institutions, commodity-based assurance programs and laboratory animal worker training programs provide models for future programs that could provide assurance of acceptable farm animal care. The Federation of Animal Science Societies (FASS) training tapes on the use of farm animals in teaching and research are a first step toward the development of a full menu of training products for farm animal care. The FASS Guide for the Care and Use of Agricultural Animals in Agricultural Research and Teaching (Ag Guide) should provide a template for science-based training materials for people who work with farm animals.     

A survey to determine public opinion about the ethics and governance of farm animal welfare

OBJECTIVE: To determine the attitude of the public toward farm animal welfare and identify beliefs regarding how decisions about farm animal welfare should be made. DESIGN: Telephone survey. STUDY POPULATION: A random sample of 1,019 US households. PROCEDURES: US households were contacted by telephone and asked to take part in a survey consisting of 48 items. RESULTS: A majority (437/773 [56.4%]) of respondents believed decisions about farm animal welfare should be made by experts rather than being based on the views of the public. Such advocates of expert decision making were less likely to believe the government should regulate farm animal welfare. Most (420/773 [54.3%]) respondents believed decisions about farm animal welfare should be based on scientific measures of animal well-being, as opposed to moral and ethical considerations. Those individuals who believed farm animal welfare decisions should be made by experts and be based on scientific measures were the least concerned about farm animal welfare issues. People who believed animal welfare decisions should be made by experts and be based on scientific measures were most responsive to information about use of gestation crates for sows. CONCLUSIONS AND CLINICAL RELEVANCE: These results should help increase recognition that changing public opinion is not simply a matter of convincing the public to support positions established by veterinarians and animal scientists. People's views about the role of the democratic process in regulating technologic change are important determinants of whether people accept the changes in animal agriculture that have occurred during the past century.     

湖羊初生重性状影响因素分析及遗传力估计

【目的】研究旨在分析场、出生季节、出生月份、出生类型和性别对湖羊初生重性状的影响,并估计该性状的遗传力。【方法】运用SAS 9.2软件对2021年新疆地区3个规模化湖羊养殖企业共计4 570只母羊所产的8 352只羔羊初生重作非遗传因素分析,使用DMU软件对湖羊初生重性状进行方差组分估计,并使用两种单性状动物模型估计该性状的遗传力,根据赤池信息准则(Akaike’s information criterion, AIC)确定最佳固定效应组合和动物模型。【结果】场、出生季节、出生月份、出生类型和性别对湖羊的初生重均有极显著影响(P<0.01)。场1和场2羔羊初生重无显著差异(P>0.05),且均极显著大于场3羔羊的初生重(P<0.01);冬季出生的羔羊的初生重整体较大,其中以1月出生的羔羊初生重最大;出生类型越丰富,其羔羊初生重越小,各出生类型间羔羊初生重均呈现出极显著差异(P<0.01);根据单性状动物模型(考虑母体效应)的计算得出,湖羊初生重性状的直接、母体、总体遗传力分别为0.251、0.668、0.211,属于中等遗传力。【结论】在对羊场首年的生产数据分析...     

Results of a national survey of US veterinary college faculty regarding attitudes toward farm animal welfare

OBJECTIVE: To examine attitudes toward farm animal welfare among veterinary college faculty. DESIGN: E-mail survey. STUDY POPULATION: 157 US veterinary college faculty with large animal or food animal emphasis. PROCEDURE: Veterinarians from 27 US veterinary colleges were contacted via e-mail and asked to complete a 7-page survey relating to farm animal welfare issues. Thirty-one percent of those contacted responded. RESULTS: 71% of respondents self-characterized their attitude toward farm animal welfare as "we can use animals for the greater human good but have an obligation to provide for the majority of the animals' physiologic and behavioral needs." An additional 19% of respondents were more concerned about animal welfare than was indicated by that statement, and 10% were less concerned about farm animal welfare than was indicated by that statement. Significant relationships among demographic variables and attitude scores were observed, including more concerned attitudes among females, those with more liberal political views, and those who cited lower religiosity. No relationship between attitude and age was observed. CONCLUSIONS AND CLINICAL RELEVANCE: Veterinary college faculty have the opportunity to impact many stakeholders within the animal agriculture industries (eg, future veterinarians and policy makers looking for a veterinary science perspective). Results indicated that a considerable level of concern toward farm animal welfare is present in this population. Although the process of change may not be rapid, it is likely that the influence of these respondents will factor heavily into enhancing farm animal welfare.     

Board-invited review: the ethical and behavioral bases for farm animal welfare legislation

Concerns about farm animal welfare vary among individuals and societies. As people increasingly consider the values underlying current farm animal production methods, farm animal welfare policy debates have escalated. Recent food animal protection policies enacted in the European Union have fueled highly contentious discussions about the need for similar legislative activity in the United States. Policymakers and scientists in the United States are apprehensive about the scientific assessment, validation, and monitoring of animal welfare, as well as the unforeseen consequences of moving too hastily toward legislating farm animal welfare. The potential impact of such legislation on producers, food prices, animals, and concerned citizens must also be considered. Balancing the interests of all stakeholders has therefore presented a considerable challenge that has stymied US policymaking. In this review, we examine the roles of ethics and science in policy decisions, discuss how scientific knowledge relative to animal behavior has been incorporated into animal welfare policy, and identify opportunities for additional refinement of animal welfare science that may facilitate ethical and policy decisions about animal care.     

Safeguarding herds from the animal hygiene point of view

One of the most important concepts for the protection of herd health is the implementation of structural and organisational measures to prevent infective agents and other adverse compounds from entering the farm. Safeguarding health, well-being and production efficiency is part of the overall management concept of hygiene in animal production systems. This paper presents an overview of the most important rules and recommendations to protect livestock production facilities from the intrusion of infectious pathogens, beginning with the right choice of the site for the farm and the animal housing ("safe distances" to neighbouring farm animal houses), solid fencing and control and disinfecting places at the entrance gate. The traffic of vehicles and people transporting animals, feedstuff, equipment and slurry or manure to and from the facility should be reduced to a minimum. Fallen animals should be stored in separate and safe containers until removed by specialised companies. Regular control of rodents, insects and wild birds is crucial to avoid the transfer of infectious agents from farm to farm and between herds within a farm. Equally important factors are the health status of personnel to avoid transmission of zoonotic diseases, the application of the all-in-all-out system and a strict cleaning and disinfecting regime. The internal and external organisational measures for preventing the spread of infections in animal production will gain increasing importance in the future because the farm animal producer bears the responsibility for the production of safe and healthy food at the primary segment of the food chain. Increasing restrictions on the use of veterinary drugs for food delivering animals will increase the importance of prophylaxis, prevention and protection of production units as the keys for safeguarding health, well-being and efficiency of farm animals. Only the application of strict hygiene principles in animal production will make it possible to meet the consumer demand for safe and high quality food of animal origin.     

Characterizing the Role of Animal Exposures in Cryptosporidiosis and Shiga Toxin‐producing Escherichia coli Infections: South Dakota, 2012

Cryptosporidium spp. and Shiga toxin‐producing Escherichia coli strains (STEC) are important causes of human illness. Incidence rates of these illnesses are high in South Dakota compared to the USA as a whole. Direct animal contact has been identified as a possible route of exposure for these illnesses. Ruminant animals may carry STEC subclinically, while young ruminants are common sources of zoonotic strains of Cryptosporidium. South Dakota patients with either STEC or cryptosporidiosis during 2012 were interviewed regarding seven categories of animal exposure: (i) petting zoo/fair attendance, (ii) animal event/rodeo attendance, (iii) feed/pet store visits, (iv) farm visits, (v) employment or residence at a farm, (vi) residence with pets and (vii) visiting other households with pets. Of the 50 STEC cases, 78.0% reported animal exposure prior to illness onset, with 23.3% having lived or worked on a farm. Farm visitors in particular had high degrees of animal contact and infrequently practiced personal protective measures. Of the 115 cryptosporidiosis cases, 87.8% reported animal exposures, with 45.6% having lived or worked on a farm and 29.0% having visited a farm prior to illness. Cases with farm exposures reported a high degree of direct animal contact and inconsistent use of personal protective measures. Cryptosporidiosis patients were significantly more likely than STEC patients to have lived or worked on a farm prior to their illness and were older on average. Patients with these illnesses had high rates of animal contact prior to illness. Animal contact on farms emerged as an important exposure route. Educational messages about personal protective measures should be directed at these individuals.     

Satisfaction of farm animal behavioral needs in behaviorally restricted systems: Reducing stressors and environmental enrichment

In modern intensive husbandry, systems often restrict farm animal behavior. Behavioral needs will be generated by external stimuli such as stressors deriving from environmental factors or the method of animal care, or some internal factor in farm animals. This means that behavioral restriction would induce maladaptation to stressors or chronic stress. Such a risk of behavioral restriction degrades an animal's physical and mental health and leads to economic loss at a farm. Methods to reduce the risk of behavioral restrictions are to ameliorate the source of a stressor through adequate animal management or to carry out environmental enrichment. This review is intended to describe the relation between animal management and behavioral needs from the perspective of animal motivation.