禽支原体病是一项持久的经济挑战

禽支原体病由一些致病性支原体引起的疾病,其中鸡毒支原体(Mycoplasma gallisepticum,MG)和滑液支原体(Mycoplasma synoviae,MS)是最主要的病原.它们属于典型的软体纲,是一类非常小的原核生物(0.25 ～ 0.5μm).它们的主要特征之一是缺失细胞壁,仅被细胞膜包被.致病性支原体,如MS和MG往往生长相当缓慢(37℃琼脂培养基需3～10d).此外,MS的生长需要NAD(辅酶Ⅰ)的协助.然而,非致病性支原体,如鸡支原体(Mycoplasma gallinarum)和雉支原体(Mycoplasma gallinaceum)在1d内可形成菌落.     

Development of a fetal challenge method for the evaluation of bovine viral diarrhea virus vaccines

A method to evaluate the efficacy of bovine viral diarrhea virus (BVDV) vaccines using a multiple challenge model was investigated. Four pregnant heifers were challenged intranasally with a type I and type II isolate of BVDV at 75 days of gestation. At 60 days postinoculation, virus isolation and RT-PCR from blood and tissues of fetuses indicated that all fetus were persistently infected with both type I and type II isolates. Differing results of detection by PCR and virus isolation between the type I and type II isolates were obtained. These preliminary studies may indicate differences in the level of replication between type I and type II BVDV as well as predilected sites of replication in certain tissues.     

Treatments for elephants: a challenge fo the zoo veterinarian

The existence of the elephant is heavily threatened. It is of great importance--for saving our largest land mammal on earth--to research into biology of the elephant quickly and thoroughly. Keeping elephants in Zoos and circus should be improved, breeding efforts must be enhanced and veterinary treatment has to be intensified. This is imperative for all zoo veterinarians.     

Coccidioidomycosis: a diagnostic challenge

Coccidioidomycosis is a systemic fungal infection acquired endemically in the southwestern United States. Clinical disease is quite common in the dog; though less frequently recognized in the cat, disease is often severe at the time of diagnosis. Diagnosis can be a challenge because serology, while specific, is not very sensitive and quantitative titration of antibodies does not correlate entirely with clinical disease in dogs. Radiographs, serum biochemistry tests and complete blood counts are beneficial additions to the database when establishing a diagnosis; cytology, histopathology, and culture are definitive when available. Advanced imaging can detect central nervous system and subtle skeletal lesions. Disease can occur in most organs of the body and may prove a diagnostic challenge requiring several modalities. Coccidioidomycosis may need to be considered both in animals in the endemic region and in those with a travel history through it.     

Evidence for a major QTL associated with host response to porcine reproductive and respiratory syndrome virus challenge

Porcine reproductive and respiratory syndrome (PRRS) causes decreased reproductive performance in breeding animals and increased respiratory problems in growing animals, which result in significant economic losses in the swine industry. Vaccination has generally not been effective in the prevention of PRRS, partially because of the rapid mutation rate and evolution of the virus. The objective of the current study was to discover the genetic basis of host resistance or susceptibility to the PRRS virus through a genome-wide association study using data from the PRRS Host Genetics Consortium PRRS-CAP project. Three groups of approximately 190 commercial crossbred pigs from 1 breeding company were infected with PRRS virus between 18 and 28 d of age. Blood samples and BW were collected up to 42 d post infection (DPI). Pigs were genotyped with the Illumina Porcine 60k Beadchip. Whole-genome analysis focused on viremia at each day blood was collected and BW gains from 0 to 21 DPI (WG21) or 42 DPI (WG42). Viral load (VL) was quantified as area under the curve from 0 to 21 DPI. Heritabilities for WG42 and VL were moderate at 0.30 and litter accounted for an additional 14% of phenotypic variation. Genomic regions associated with VL were found on chromosomes 4 and X and on 1, 4, 7, and 17 for WG42. The 1-Mb region identified on chromosome 4 influenced both WG and VL, exhibited strong linkage disequilibrium, and explained 15.7% of the genetic variance for VL and 11.2% for WG42. Despite a genetic correlation of -0.46 between VL and WG42, genomic EBV for this region were favorably and nearly perfectly correlated. The favorable allele for the most significant SNP in this region had a frequency of 0.16 and estimated allele substitution effects were significant (P < 0.01) for each group when the SNP was fitted as a fixed covariate in a model that included random polygenic effects with overall estimates of -4.1 units for VL (phenotypic SD = 6.9) and 2.0 kg (phenotypic SD = 3 kg) for WG42. Candidate genes in this region on SSC4 include the interferon induced guanylate-binding protein gene family. In conclusion, host response to experimental PRRS virus challenge has a strong genetic component, and a QTL on chromosome 4 explains a substantial proportion of the genetic variance in the studied population. These results could have a major impact in the swine industry by enabling marker-assisted selection to reduce the impact of PRRS but need to be validated in additional populations.     

创新是饲料企业核心竞争力的源动力

<正>从饲料企业发展的角度上看,其核心能力是企业可持续发展的重要支撑。而核心能力的形成、发展乃至维护和再创都要依赖于企业的创新活动。一句话,创新是通向饲料企业核心竞争力的源动力!30余年来,饲料企业为我国畜牧业的快速发展起到了巨大的推动作用。然而随着产业环境的     

Plastination—A scientific method for teaching and research

Over the last four decades, plastination has been one of the best processes of preservation for organic tissue. In this process, water and lipids in biological tissues are replaced by polymers (silicone, epoxy, polyester) which are hardened, resulting in dry, odourless and durable specimens. Nowadays, after more than 40 years of its development, plastination is applied in more than 400 departments of anatomy, pathology, forensic sciences and biology all over the world. The most known polymers used in plastination are silicone (S10), epoxy (E12) and polyester (P40). The key element in plastination is the impregnation stage, and therefore depending on the polymer that is used, the optical quality of specimens differs. The S10 silicone technique is the most common technique used in plastination. Specimens can be used, especially in teaching, as they are easy to handle and display a realistic topography. Plastinated silicone specimens are used for displaying whole bodies, or body parts for exhibition. Transparent tissue sections, with a thickness between 1 and 4 mm, are usually produced by using epoxy (E12) or polyester (P40) polymer. These sections can be used to study both macroscopic and microscopic structures. Compared with the usual methods of dissection or corrosion, plastinated slices have the advantage of not destroying or altering the spatial relationships of structures. Plastination can be used as a teaching and research tool. Besides the teaching and scientific sector, plastination becomes a common resource for exhibitions, as worldwide more and more exhibitions use plastinated specimens.     

Parasites in meat: a challenge for veterinarians in meat hygiene

Meat hygiene is an important instrument of preventive public health since the end of the nineteenth century. The methods used during ante-mortem and post-mortem inspection are partly quite traditional. This is in particular true for the identification of parasites in meat. The aim of this review was to present facts on aetiology, prevalence and importance of meat-borne parasitic hazards. The capacity and the limits of the ante-mortem and post-mortem inspection for the identification of parasitic hazards are considered. Further, suggestions for the improvement of the meat hygiene are given. Cysticercosis, Toxoplasmosis and Sarcocystosis are exposed in detail. With regard to Cysticercosis, the integration of serological methods in the inspection procedure could result in a tenfold improvement of diagnostical sensitivity. With regard to Toxoplasmosis, it is obvious that meat containing Toxoplasma-cysts may reach the consumer, as animals infected with Toxoplasma gondii can neither be recognised in the ante-mortem inspection nor in the meat inspection. Systematical serological investigations on farm level would allow an appropriate judgement during meat inspection and minimize the consumer exposure to this parasite. Further, reliable methods for the detection of Toxoplasma-cysts have to be developed. With regard to Sarcocystosis, the compulsory inspection of the muscle surfaces to recognise a "massive infection with Sarcocystis" is very doubtful in its interpretation. There is a need for suitable microscopic, serological and molecular biological methods for the detection of Sarcocystis-species and reliable informations on the seroprevalence of the parasite in slaughtering animals.     

Probiotics: Is there a scientific basis for their effects?]

Probiotic microorganisms have been used with increasing frequency in nutrition and for therapeutic purposes during the last years. Their application is generally based upon empirical experiences, since their mode of action has been the topic of investigations only recently. It became apparent that probiotics exert a wide spectrum of different effects ranging from direct antagonism against pathogens to influence upon intestinal epithelium and immune system of the host's organism. In this review, the current knowledge is summarized.     

Developing group practices: a management challenge

SUMMARY: The advantages and disadvantages of forming larger professional practices are often debated. This paper reports an exploration of the issues through three case studies involving clusters of Sydney general medical practitioners who had expressed a desire to amalgamate their solo or small group practices. Their most frequently stated goals were to reduce financial overheads, to improve the range of services offered to their patients and to improve the opportunities for recreational and study leave. Several barriers to successful amalgamation were identified, and methods of overcoming these were explored. Practices can successfully amalgamate, but only where there is a group of like-minded general practitioners who are willing to invest time to achieve mutually agreed objectives. Amalgamation will not be appropriate in all circumstances. Larger group practices should benefit from the employment of a professional practice manager. These findings may be relevant to veterinary and dental practices.     

Another challenge for the profession

Extract

The veterinary profession is being offered an unique opportunity to extend its activities to encompass a new concept of animal production; the farming of deer. New Zealand is pioneering techniques of deer farming on a large scale and is considered to possess the most advanced deer farming operation in the western world. The farming of deer was established after the enactment of the Deer Farming Regulations 1969.