Serotypes of Yersinia pseudotuberculosis recovered from domestic livestock

The serological identity of 234 strains of Yersinia pseudotuberculosis recovered from domestic animals and birds in New Zealand was determined by slide agglutination test. Thirty strains were also examined by tube agglutination test. The strains were isolated from cattle (56), sheep (8), deer (117), goats (13), pigs (7), rabbits (6), guinea pigs (5), and aviary species of birds (22). All strains were isolated from animals or birds which had died or shown signs of ill health and amongst which diarrhoea was a common feature. Serotype I accounted for 23% (53) of strains, serotype II for 13% (30) of strains and serotype III for 64% (151) of strains. It was concluded that further investigations on the prevalence and serological identity of strains recovered from clinically healthy animals mav provide useful information in assessing the significance of various serotypes as a cause of disease in livestock.     

The duration of immunity to an inactivated adjuvanted canine parvovirus vaccine. A 52 and 64 week postvaccination challenge study

Dogs were successfully isolated for a period of either 52 or 64 weeks following vaccination with an inactivated, adjuvanted canine parvovirus-2 vaccine. Antibody persisted in all ten vaccinated dogs, although in one case by 52 weeks postvaccination only virus neutralizing antibody, and not hemagglutination-inhibiting antibody, could be detected. Sentinel unvaccinated dogs housed alongside the vaccinated dogs throughout the study remained free of canine parvovirus-2 antibody until challenged. Upon oral challenge with canine parvovirus-2 infected material all unvaccinated dogs developed one or more signs of canine parvovirus-2 disease, shed virus and developed antibody. None of the vaccinated dogs became overtly sick. Of the five vaccinated dogs challenged 52 weeks after vaccination, three shed virus and one showed a significant rise in antibody. At 64 weeks after vaccination only one of the five challenged dogs shed virus and showed a boost in antibody titer.     

The use of ultrasonography in the reproductive evaluation of boars

The objective was to study the use of ultrasound as a complementary test in the breeding soundness evaluation in male pigs and study the pattern of echogenicity of the testicular parenchyma in boars of different racial groups. Twenty‐six adult boars from four different racial groups were used, 10 from the Piau breed (group 1), four from the commercial and finishing group (group 2), six Pietrain breed (group 3) and six from the Duroc breed (group 4). All animals were evaluated for breeding soundness evaluation and the ultrasound examination of the testicles. The groups of animals that were evaluated showed no difference in the main semen parameters that were evaluated, except for the sperm volume, concentration of the ejaculated sperm and the supravital staining; the lowest figures were for the animals from the Piau breed (group 1). In relation to the testicular biometrics, Duroc animals (group 4) had a greater scrotal width compared to the other groups. But when we assessed the intensity of pixels of the testicles, there was a difference between groups. The groups 2 (finishing animals), 3 (Pietrain) and 4 had no difference between themselves. Group 3 had greater pixel intensity in relation to group 1. Of the 26 animals studied, five showed an abnormality during ultrasound evaluation, like hydrocele, hyperechoic mass in the testicular parenchyma, cyst in the head of the epididymis and the presence of fluid in the head and tail of the epididymis. The various animal groups studied did not differ in the principal reproductive parameters evaluated, showing that despite the great variability of reproductive traits between breeds and within the same breed, the breeding soundness evaluation, the more complete it is, is essential for the selection of breeders and the ultrasonography of the reproductive system becomes an important addition in this examination.     

2008年上半年度全国白羽肉鸡生产形势报告

2008年上半年,我国的白羽肉鸡市场还是国外引进品种一统天下。在引种数量上,全国共有9家企业先后从国外引进祖代肉种鸡34．16万套。在品种方面,爱拔益加（AA＋）的市场份额仍然保持第一,达到50．1％,罗斯308（Ross）和科宝（Cobb）分别占据第二和第三位,市场份额分别占到31．0％和18．9％。     

Detection of cattle infected with bovine viral diarrhea virus using nucleic acid hybridization.

A ribonucleic acid (RNA) hybridization assay to identify cattle infected by bovine viral diarrhea virus (BVDV) is described. The RNA probe was derived from the coding region at the 3' end of the genome of the NADL strain of BVDV. Total RNA from infected cell cultures or peripheral blood leukocytes from suspect animals was extracted and applied to nylon membranes with a slot blot apparatus. Peripheral blood leukocytes were tested concurrently for BVDV by virus isolation. The results of hybridization and virus isolation were in agreement for 92% of the cases. When compared with virus isolation, hybridization had a sensitivity of detection of 59.5% and a specificity of 95%. Cross-reactivity to RNA extracts of border disease virus-infected cells was noted. No cross-reactivity was detected to other common bovine viruses (bovine herpesvirus-1, bovine respiratory syncytial virus, parainfluenza-3 virus, and bluetongue virus), to viruses classified in related families (equine arteritis virus and Venezuelan equine encephalitis virus), or to viruses having similar genomic organization (dengue virus type 2 and Japanese encephalitis virus).     

Pathogenesis and clinical signs of equine herpesvirus-1 in experimentally infected ponies in vivo.

Equine herpesvirus-1 (EHV-1) causes respiratory disease, neonatal death, abortion and neurologic disease. The main purpose of this study was to identify viral antigen in respiratory tract samples by immunoperoxidase staining. Six pony foals were selected on the basis of demonstrating seronegativity to EHV-1 by virus neutralization and housed in isolation. They were infected experimentally by administering EHV-1 nebulized ultrasonically through a face mask. Successful infection was clinically apparent as each of the foals had febrile responses, nasal discharge, and enlarged submandibular lymph nodes. Sporadic coughing was also heard. EHV-1 was isolated from nasopharyngeal swabs of 4/6 ponies and seroconversion was demonstrated in all foals. Bronchoscopic examination of the large airways revealed hyperemia. The incidence of recovery of Actinobacillus suis from nasopharyngeal swabs increased initially, with recovery of Streptococcus zooepidemicus isolates predominating at 3 wk post-infection. Cytology brushes were used to sequentially sample the respiratory tract of the infected ponies at the nasopharynx, mid-trachea and the mainstem bronchus. Bronchoalveolar lavage provided lung cells. Immunocytochemistry techniques were applied to both types of samples to locate EHV-1 antigen. Indirect immunoperoxidase staining of samples utilizing monoclonal antibodies specific for EHV-1 demonstrated viral antigen associated with cellular debris, primarily in the nasopharyngeal samples on days 3-9 post-infection.     

Cellular morphology of Clostridium spiroforme

The helically-coiled bacterium, Clostridium spiroforme, has been shown to consist of an ordered aggregation of numerous individual semi-circular cells joined end to end.