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1.
The thyroid glands of 31 chickens at the age of 17 to 24 months were investigated. Different methods of anatomical preparation, casts of vessels and scanning electron microscopy were used. The thyroid gland of birds is a paired organ. It is located on the ventral surface of the base of the neck within the thoracic inlet. The left thyroid gland is placed more cranially than the right one. Each thyroid gland is closely connected to the common carotid artery on the medial side, from which it is supplied and to the jugular vein on the lateral side. It is a reddish-brown organ and of lenticular profile. The gland measures on average 10 mm in length, 6 mm in width and 2 mm in thickness, and is covered by a thin connective tissue capsule which holds adipose cells. It seems that each thyroid follicle is surrounded by a net of capillaries. The investigation by scanning electron microscopy proved that the follicles are oval with a pyramidal top on each end. The cuboidal epithelium cells leave impressions in the colloid. Epithelium cells carry microvilli on the follicle side surface. Described seasonal changes of the thyroid gland in size and activity were able to be confirmed by the examination of the organ in July and December. In winter the follicular cells were higher and the follicles had a greater volume. 相似文献
2.
Katherine A Houpt Steven Zicker 《Veterinary Clinics of North America: Small Animal Practice》2003,33(2):405-16, vii-viii
The effects of dietary deficiency, including both malnutrition and deficiency of specific vitamins, on behavior is discussed with special emphasis on the growing kitten and puppy. The effect of caloric restriction on behavior is reviewed so that owners can be advised what to expect when their dog is placed on a reducing diet. The evidence for influence of dietary protein and tryptophan on canine aggression is presented. The effect of special diets on canine cognitive dysfunction is reviewed. 相似文献
3.
Fairweather I 《Veterinary parasitology》2011,176(1):1-8
A survey of literature on experimental infections with the liver fluke, Fasciola hepatica published between 2005 and 2009 has revealed a general lack of information on where fluke material (i.e. metacercariae) was sourced from. Even less information was given on the drug status of the fluke isolate used, which is a particular concern for those studies that involved anthelmintics. In these two respects, information on the liver fluke lags far behind that for nematodes, where such information is given almost as a matter of course. Of additional concern is that, at times, information about the source and drug history of fluke isolates was incorrect. The overall aim of the review is to demonstrate why it is important to provide as much information as possible on what fluke material is being used. It also attempts to correct some of the errors in the literature and gather together what information is available about the provenance of those isolates that have been used in recent experimental studies. 相似文献
4.
Fravalo P Chanet JP Mas M Huchet E Queguiner S Salvat G 《Berliner und Münchener tier?rztliche Wochenschrift》2001,114(9-10):393-396
The direct immunofluorescent detection of pathogens on pork skin is evaluated. Calibrate contamination of pork skin with Salmonella Typhimurium (ST) and Listeria monocytogenes (Lm) is developed in 2 h at 4 degrees C. Then a specific indirect immunofluorescent staining protocol is optimized in order to obtain specific and intensive signals able to be detected by electronic cameras (deported microscopy). Despite the individual staining of ST and Lm is possible on pork skin and is specific and bright, the deported microscopy failed to detect these particles. After respectively 3 and 6 h, we obtain micro-colonies of ST and Lm. Due to the limited power of the video camera used, only the microscope permits the detection on the skin. However, our work gives standard conditions to mime the pathogens contamination and staining directly on a biological matrix such as pork skin. This work is a first step in the development of direct and rapid detection of pathogens on biological matrix. 相似文献
5.
In 1978, Canada was the first country to regulate animal embryo transfer in a manner similar to regulations for artificial insemination. Research has shown that the risk of disease transmission by bovine embryos is minimal therefore regulations are evolving to recognize this potential. The Canadian Embryo Transfer Association plays a key role in regulatory decisions. Importing embryos is based on risk assessment and on the impact of potentially introduced disease agents. Export strategy is based on negotiation of valid conditions, on effective certification of embryos and on full involvement at the international level. 相似文献
6.
Anthony P. RUSSELL 《Integrative zoology》2009,4(3):309-315
The current challenges (increasing levels of integration in the biological sciences) facing the teaching of zoology and the structure of the zoology curriculum are explored herein. General context is provided and a more focused scrutiny of the situation in North America is presented. The changing emphases in more broadly‐based biological sciences programs in North America are outlined, and their influence on the role of zoology as part of fundamental biological training is considered. The longer term impact of such changes in emphasis on the teaching of zoology is discussed, and the central role that zoology can play in dealing with both science content and science education is advanced. Based upon a focal workshop on the future of the zoology curriculum in Canada, a perspective on the challenges facing curriculum evolution is provided. Extensive curriculum redesign is called for to ensure that zoology provides a broad‐scale integrative approach to the understanding of biodiversity in evolutionary, ecological and functional contexts. Barriers to, and drivers of change are identified and the need for collaborative approaches to curricular evolution is emphasized. 相似文献
7.
L. Rönnegård R. Al-Sarraj & D. von Rosen 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2009,126(2):110-116
In variance component quantitative trait loci (QTL) analysis, a mixed model is used to detect the most likely chromosome position of a QTL. The putative QTL is included as a random effect and a method is needed to estimate the QTL variance. The standard estimation method used is an iterative method based on the restricted maximum likelihood (REML). In this paper, we present a novel non-iterative variance component estimation method. This method is based on Henderson's method 3, but relaxes the condition of unbiasedness. Two similar estimators were compared, which were developed from two different partitions of the sum of squares in Henderson's method 3. The approach was compared with REML on data from a European wild boar × domestic pig intercross. A meat quality trait was studied on chromosome 6 where a functional gene was known to be located. Both partitions resulted in estimated QTL variances close to the REML estimates. From the non-iterative estimates, we could also compute good approximations of the likelihood ratio curve on the studied chromosome. 相似文献
8.
Animal welfare is part of the Mission Statement of the Faculty of Veterinary Science at the University of Sydney and is taught throughout the undergraduate curriculum. Two units of study have a particular focus on animal welfare: Professional Practice in years 1, 2, and 3 and Animal Behaviour and Animal Welfare Science in year 3. There is an emphasis on the refinement and development of alternatives to the use of animals in teaching. With a conscientious objection policy in place, these elements of our approach demonstrate the increasing importance of ethical teaching in the faculty. Undergraduate students have recently founded a vibrant special interest group called Veterinary Students for Animal Welfare. The faculty is advised on matters relating to animal welfare by its Animal Welfare Advisory Committee, chaired by the Sub-Dean for Animal Welfare. With the development of a Faculty Animal Welfare Policy, the faculty is progressing to a more proactive and public profile on animal welfare issues. 相似文献
9.
MV Root Kustritz 《Reproduction in domestic animals = Zuchthygiene》2012,47(Z4):214-222
Surgical sterilization of dogs and cats is a well-accepted measure for population control in some countries, but is considered unethical as an elective surgery in other countries. This is a review of what is known regarding positive and negative effects of gonadectomy surgery on individual animals and on societal management of unowned dog and cat populations. 相似文献
10.
如今动物园给野生动物注射药物时,依靠吹管和气枪来发射,但有时相当的不便。本实用新型涉及了一种用于远程注射器的发射装置,包括发射本体,所述发射本体包括托架、管体、端盖;所述托架上设置有支架,所述管体置于托架上,所述端盖位于支架的后侧,所述端盖的前侧设置有从后至前口径依次缩小的固定部,所述端盖的固定部向前穿过支架,管体的后端与对应口径的固定部连接;所述管体与托架在靠近前端的位置通过连接件连接。旨在为日后的应用做出贡献。 相似文献
11.
《科技视界》2014,(30)
The paper is organized in three parts. The first part is about the history and development periods of business incubation; the second one is on its three generations defined by scholars; and the third one is on its present situation including various forms of incubators. In the conclusion, a brief reflection is made on its significance in economy and on the value it provides for society. 相似文献
12.
13.
The currently recommended intake of vitamin E for dairy cows is based on the prevention of nutritional myopathy, a calf disease. However, it is likely that the vitamin E requirement of the modern dairy cow is very different from that of a calf. This review of the literature investigates the effect of vitamin E supplementation on the health and fertility of the dairy cow. Supplementation of high levels of vitamin E (at least 1000 iu per day) during the dry period and early lactation can reduce the incidence of mastitis, possibly because of an increase in immune system activity and function, but there appears to be little benefit of supplementation on infectious diseases other than mastitis. The evidence for a response in the reproductive system is more equivocal. In herds with a history of selenium deficiency and a high incidence of retained fetal membranes, supplementation, in conjunction with selenium, can reduce retention, but the evidence for an effect of supplementation on other reproductive diseases, such as cystic ovarian disease and metritis, is based on a very limited number of cases. The literature suggests that the current recommendations for vitamin E are inadequate. In particular, it suggests that the current linking of requirement to dry matter intake is incorrect, because vitamin E requirement is probably at its highest when intake is at its lowest However, the majority of the data on which this conclusion is based, come from North America where cows will encounter significantly different levels of oxidative stress from cows in the EU. 相似文献
14.
弓形虫病(Toxoplasmosis)是由刚地弓形虫(Toxoplasma gondii,TOX)引起的一种重要人兽共患寄生虫病,该虫是一种可寄生于有核细胞的原虫。当前对弓形虫病的诊断和治疗虽已有一些方法,但均不够理想。本文就该病的免疫学诊断方法的研究进展加以概述,以研究SAG2为检测抗原,以制备弓形虫SAG2蛋白的单克隆抗体和免疫胶体金试纸条为核心,建立一种快速、特异、便捷的检测方法,为我国弓形虫病的诊断与防治、弓形虫与宿主关系、以及弓形虫的分子生物学等研究奠定良好基础。 相似文献
15.
代价问题是我国改革开放和现代化建设中日益凸显出来的现实问题。贯彻落实科学发展观,必须充分认识代价意识的地位和作用。事实上,只要有发展就有代价,代价意识不仅是科学发展观形成和发展的动力源泉,而且是科学发展观正确指导实践的基本理念。 相似文献
16.
Mansfeld R Sauter-Louis C Martin R 《Tier?rztliche Praxis. Ausgabe G, Grosstiere/Nutztiere》2012,40(4):239-250
In terms of milk production, the dry period (DP) is a non-productive time. In addition, the risk of mastitis increases when cows with daily milk yield >12.5kg are dried off, which is often the case when the DP is set to 55-60 days. References on the positive effects of a shortened DP on the metabolic health at the start of lactation and the subsequent reproductive performance were the motive of this review. Completely foregoing or shortening the DP produces a decrease in milk yield during the following lactation. This decrease is particularly pronounced for cows at the beginning of the second lactation. It is thought that this may be due in part to different involution and proliferation processes of the mammary glands in primiparous and multiparous animals. The majority of the scientific papers suggest that shortening the DP has a positive rather than a negative effect on udder health. The quality of the colostrum is also unaffected; but if there is no drying off, the colostrum will be diluted. When considered overall, the literature, with support from metabolic profile studies, appears to favour a reduced impact on energy metabolism in early lactation in circumstances when the DP is shortened or waived. Clear positive effects on parameters relevant to energy metabolism however only apply to multiparous animals, and other factors, such as milking frequency before and after calving, exert an influence. Positive effects of shortening the DP on the reproductive performance were shown in several studies. Time from calving to first ovulation as well as indicators for assessing the success of artificial insemination and reproductive performance showed better results in animals with no or shortened drying off periods. Again, this only applied to multiparous animals. Overall, there is no single clear answer to the question of an optimal length of the DP, but conversely it is abundantly clear that a dry period of 55-60 days is not necessary in all cases and does not make sense under certain circumstances. Based on the study findings from recent years, the determination of dry periods should be used as a farm-specific and needs-oriented applied management decision. 相似文献
17.
耕地保护制度是我国最基本、最严格的制度之一,是保障我国粮食安全,社会持续稳定发展的基础制度之一。通过文献资料法从政策、法律、经济、技术四个方面构建了实现重庆市耕地总量动态平衡的保障体系。严格执行耕地保护法规,制定切实可行的政策措施,加大耕地建设的财政投入,建立以3S技术为支撑的土地动态监测系统,以保障重庆市耕地总量动态平衡。 相似文献
18.
R S Singer W O Johnson J S Jeffrey R P Chin T E Carpenter E R Atwill D C Hirsh 《Journal of veterinary diagnostic investigation》2000,12(2):118-125
A general problem for microbiologists is determining the number of phenotypically similar colonies growing on an agar plate that must be analyzed in order to be confident of identifying all of the different strains present in the sample. If a specified number of colonies is picked from a plate on which the number of unique strains of bacteria is unknown, assigning a probability of correctly identifying all of the strains present on the plate is not a simple task. With Escherichia coli of avian cellulitis origin as a case study, a statistical model was designed that would delineate sample sizes for efficient and consistent identification of all the strains of phenotypically similar bacteria in a clinical sample. This model enables the microbiologist to calculate the probability that all of the strains contained within the sample are correctly identified and to generate probability-based sample sizes for colony identification. The probability of cellulitis lesions containing a single strain of E. coli was 95.4%. If one E. coli strain is observed out of three colonies randomly selected from a future agar plate, the probability is 98.8% that only one strain is on the plate. These results are specific for this cellulitis E. coli scenario. For systems in which the number of bacterial strains per sample is variable, this model provides a quantitative means by which sample sizes can be determined. 相似文献
19.
Lean growth rate (LGR) in pigs is a nonlinear biological function of growth rate and lean quantity. According to animal breeding theory, genetic progress for LGR is maximized with selection on a linear index of its component traits, but selection on direct EBV for LGR is also common. In this study, the performance of five criteria for selection on estimated LGR in pigs was evaluated through simulation over five generations: linear indexes of multiple-trait EBV of component traits with or without updating index weights in each generation; a nonlinear index of multiple-trait EBV of component traits; and direct selection on EBV for LGR from a single-trait model or a multiple-trait model that included LGR and component traits. The nonlinear index yielded the highest response in LGR in Generation 5, but the linear index with updating performed almost as well. Not updating weights for the linear index reduced response in LGR by 1.1% in Generation 5 (P < 0.05). Direct selection on single-trait EBV for LGR yielded the lowest responses in Generation 5. Direct selection on EBV for LGR from a multiple-trait animal model yielded a 3.1% greater response in LGR in Generation 5 than direct selection on EBV for LGR based on a single-trait animal model (P < 0.05), but yielded a 1.9% lower response than the nonlinear index. Although differences in response in LGR were limited, alternative selection criteria resulted in substantially different responses in component traits. Linear index selection for LGR placed more emphasis on lean quantity, whereas direct selection for LGR emphasized growth rate. Based on the relative changes in the responses in LGR, selection for estimated LGR based on a nonlinear index or a linear index with updating is recommended for use in the swine industry. 相似文献
20.
The way production animals are treated is a matter of public concern, and public opinion is often a driving force to introduce new animal welfare legislation. In Norway, a Council on Animal Ethics has been appointed by the authorities since 1993. The composition of the council is broad and it encounters both lay people and experts. The council is independent and advisory, only. It shall be a “guard dog” and follow the developments in animal production and other areas where man makes use of animals, and give advice to the authorities on the need for change in legislation and administrative practices. An important task for the council is also to contribute to and facilitate an informed public debate on animal welfare standards and animal ethics. 相似文献