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1. Three behavioural tests involving social competition were used to determine rank orders in groups of 8 male chicks aged between 4 and 18 days posthatching. 2. The group structure was found to consist of one or two dominant animals which consistently held a position at the top of the rank order, with a more flexible order beneath this. 3. Compared to the top-ranking birds, the middle- and lower-ranking birds showed more variability in their ranking positions across the behavioural tests and the testing periods. 4. Treatment of the lowest ranking individual in each group with testosterone led to this individual's rise in the rank order, most often to the top rank. 相似文献
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Cows were vaccinated once or twice intracisternally in order to protect calves against salmonella infections. The amount of antibodies measured in the colostrum of re-vaccinated and not re-vaccinated cows indicated that a sensitive immunological memory has been provoked by this vaccination technique. This immunological memory showed a distinct synchronism with the state of pregnancy in order to provide a maximum amount of antibodies in the colostrum. 相似文献
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Narindra H. Roopnarine Sunil K. Gupta Lizette du Plessis Tom A. Aire 《Anatomia, histologia, embryologia》2020,49(6):814-819
It remains a major concern that sperm structure has continued to be poorly investigated and reported in avian species. To our knowledge, sperm structure in the order Pelecaniforme has not been reported. Although McFarlane (1963; Proceedings of the XIII International Ornithological Congress; Ithaca, NY; American Ornithologists’ Union) reported the study of spermatozoa in two genera and two species of the family Ardeidae, he did not provide an account, or the names of the species examined. The present report on the sperm structure of the cattle egret, Bubulcus ibis, is, thus, the first in the order Pelecaniformes (this bird has been placed variably under the order Ciconiiformes, or the order Pelecaniformes). Five sexually mature and reproductively active male cattle egrets were obtained from the wild, humanely euthanized, the reproductive organs dissected out, and tissues from the ducti deferentia were prepared for transmission electron microscopy. The sperm structure of this bird is generally similar to that described for most non-passerine birds. However, the acrosome is a short, conical or bullet-shaped, blunt-ending organelle that lacks a perforatorium. The base of the acrosome is flat and makes contact with the nucleus along, a correspondingly flat plane. The nucleus, thus, ends anteriorly in a flat plane devoid of a concavity or a rostrum, and an endonuclear canal. The acrosomal and nuclear features of this bird are, therefore, main deviations from the situation in the non-passerine clade of birds. 相似文献
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潘伟洪 《广东畜牧兽医科技》1999,(3)
本文设计计算机程序对同型交配 进行了100 多万代 的计算机模 拟运算,发现 杂合降低非 常缓慢;高世代二阶差分接近于 0 ,说 明了基 因型频 率可用一 次多项 式表示; 低世代的 高阶差 分不为 0( 六阶) 。可见基因频率与世代的关系在高世代和低世代有所不同。 相似文献
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Hermann JR Fry AM Siev D Slate D Lewis C Gatewood DM 《Canadian journal of veterinary research》2011,75(4):278-284
Rabies is an incurable zoonotic disease caused by rabies virus, a member of the rhabdovirus family. It is transmitted through the bite of an infected animal. Control methods, including oral rabies vaccination (ORV) programs, have led to a reduction in the spread and prevalence of the disease in wildlife. This study evaluated the stability of RABORAL, a recombinant vaccinia virus vaccine that is used in oral rabies vaccination programs. The vaccine was studied in various field microenvironments in order to describe its viability and facilitate effective baiting strategies. Field microenvironments influenced the stability of this vaccine in this study. This study emphasizes the importance of understanding how vaccines perform under varying field conditions in order to plan effective baiting strategies. 相似文献
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奶牛细菌性乳腺炎一直是困扰奶牛养殖业的一大难题,给奶牛养殖行业造成巨大经济损失,直接危害奶牛健康。为有效治疗奶牛细菌性乳腺炎,研究人员需要通过动物模型来进行相关研究,以期找到优良的治疗方法。随着动物模型多年的探索与使用,小鼠细菌性乳腺炎模型因具有省时、省力以及性价比高的优点获得了研究人员的广泛认可,被大量用于相关研究中。就此对小鼠细菌性乳腺炎模型的建立、特点以及应用进行综述,旨在为细菌性乳腺炎相关研究提供参考。 相似文献
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Elise Norberg Jørgen Ødegård Per Madsen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(4):181-186
In recent decades, electrical conductivity (EC) has been introduced as an indicator of mastitis, and genetic selection based on this trait may be possible. In this study, genetic parameters for test-day EC and test-day somatic cell score (SCS) were compared. Data were collected from a Danish experimental herd, including daily records of EC and SCS from 265 first lactation cows. Different genetic models were tested, and a random regression animal model with a 4th order Legendre polynomial for the permanent environmental effect for both traits, a 1st order Legendre polynomial for the additive genetic effect of EC and a 2nd order Legendre polynomial for the additive genetic effect of SCS, gave the best fit. The patterns of the curves were similar for both permanent environmental and additive genetic variance for the two traits. Heritability estimates ranged from 0.05 to 0.12, and from 0.01 to 0.09, for EC and SCS, respectively. The estimate of genetic correlation between the traits was high, and ranged from 0.86 to 0.98. Based on these results, EC could be a potential indicator trait in a breeding programme where selection for increased mastitis resistance is included. 相似文献
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Gnudi G Volta A Manfredi S Ferri F Conversi R 《Journal of Feline Medicine and Surgery》2012,14(4):292-294
A radiographical study of a cat mummy from the Egyptian collection of the National Archeological Museum in Parma, Italy was carried out in order to evaluate the content and to describe how cats were wrapped and mummified. The mummy contained the complete skeleton of a 4-5-month-old cat. Radiology revealed the position of the cat's body; it was wrapped to occupy the smallest space possible. In order to better position the cat, the ribs of the thorax were compressed cranio-caudally and the fore limbs were then positioned very close to the thorax. The hind limbs were flexed close to the lumbar spine and the tibio-tarsal joints were subluxated to allow the repositioning of the tarsal, metatarsal and phalanx bones cranio-caudally near the tibiae. A coccygeal vertebra was fractured in order to reposition the tail as close as possible to the body. Atlanto-occipital subluxation and a fracture/hole was present in the occipital region of the skull: whether this was made for draining skull contents as a mummification process and/or to euthanase the cat remains open for discussion. 相似文献
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概述了一种新型氨基乙腈衍生物类驱虫药莫奈太尔的理化性质、作用机制、药代动力学、药效学等特点,以期为该药在兽医临床应用提供参考。 相似文献
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The risk of zoonotic disease transmission when handling livestock or animal products is substantial. In industrialized countries, the classical zoonotic diseases such as tuberculosis or brucellosis are no longer in the foreground. Latent zoonoses such as salmonellosis and campylobacteriosis can cause serious disease in humans and have become a major public health problem during the past years. Since animals infected with these pathogens show only mild transient disease or no clinical signs at all, new concepts in the entire production line ("stable to table") are necessary in order to avoid human infection. Two emerging viruses with zoonotic potential--avian influenza virus and Nipah virus--have been found in Asia in 1997 and 1999. Both diseases had a major impact on disease control and public health in the countries of origin. In order to cope threats from infectious diseases, in particular those of public health relevance, a combined effort among all institutions involved will be necessary. The proposed "European Center for Infectious Diseases" and the "Swiss center for zoonotic diseases" could be a potential approach in order to achieve this goal. 相似文献
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Römming H Deegen E Löscher W Moennig V Sallmann HP Schemann M 《DTW. Deutsche tier?rztliche Wochenschrift》2000,107(12):541-542
On June 29, 2000, the Council of the School of Veterinary Medicine Hannover (TiHo) passed a new fundamental order. Upon termination of the current terms of office of the rector and the chancellor in September and at the end of the year 2001, respectively, a school management will be established with a longer term of office and a new type of School Council. However, the new fundamental order must still be approved by the Lower Saxony Ministry of Science and Culture. This change has been made necessary by radical restructuring affecting all universities in Lower Saxony: the transformation to a state enterprise with the concomitant introduction of a global budget demands full-time management. This is a step of historical significance, for this change in the fundamental order puts an end to a tradition of 87 years at the School of Veterinary Medicine Hannover under a constitutional rectorate. The following essay describes the most important changes and explains their necessity. 相似文献
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The treatment of canine atopic dermatitis is multifaceted and consists of a combination of actions that include the use of allergen avoidance, anti-inflammatory agents, allergen-specific immunotherapy and antimicrobial drugs. The importance and order of these treatment steps vary from patient to patient. General recommendations for each of the therapeutic steps are highlighted in this paper. Specific details are covered in other papers of this issue. 相似文献
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鳞翅目昆虫属于完全变态昆虫,许多科的老熟幼虫都要吐丝结茧,为蛹期提供适当的蔽护场所,因此结茧和脱茧是鳞翅目结茧昆虫完成变态发育的重要过程。本文通过查阅资料,简述这些昆虫独特的茧及脱茧方式,以期更好地了解昆虫这一特殊的生理过程。 相似文献
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Denicourt M Gradel D Martineau GP 《The Canadian veterinary journal. La revue veterinaire canadienne》1987,28(6):346-354
Environment is of primary importance to animal health and development. Ventilation is a problem in establishing an adequate environment, particularly in swine housing. In order for veterinarians to deal with this problem, a fundamental understanding of the building is necessary. The present article describes a clinical approach to ventilation diagnosis problems in the piggery. 相似文献