Intestinal lesions caused by a strain of Chlamydia suis in weanling pigs infected at 21 days of age.

The objective of this study was to determine whether a strain of Chlamydia suis shown previously to be an intestinal pathogen in gnotobiotic piglets could cause diarrhea and intestinal lesions in young weanling pigs. Pigs from 2 sows were randomly assigned to 2 groups. Group 1 included 13 pigs that were weaned at 24 hours of age and then housed in isolator units and fed milk replacer and unmedicated starter ration. Group 2 included 8 pigs that nursed their respective sows, consumed unmedicated starter ration, and were weaned at 21 days of age. Ten pigs in group 1 and 6 pigs in group 2 were inoculated orally with 4 x 108 inclusion-forming units of C. suis strain R27 at 21 days of age. Control pigs were inoculated with sham inoculum. The pigs were necropsied 5-14 days postinoculation (DPI). None of the Chlamydia-infected pigs developed diarrhea. Villus atrophy was seen histologically in sections of ileum from Chlamydia-infected pigs in both groups 5 and 7 days DPI. Lymphangitis and multiple lymphohistiocytic and neutrophilic aggregates were seen in the submucosa, tunica muscularis, and serosa of the distal jejunum, ileum, and colon from Chlamydia-infected pigs in both groups 5-14 DPI. Immunostaining of sections of distal jejunum, ileum, and colon from infected pigs revealed chlamydial antigen in intestinal epithelium and in foci of lymphangitis/inflammation. The results indicated that C. suis strain R27 can cause intestinal lesions in young weanling pigs, and the lesions are similar to those seen in gnotobiotic piglets. The results also indicated that strain R27 causes asymptomatic intestinal infections in young weanling pigs, at least under the conditions of this study.     

柞蚕品种龄期经过与饲料效率的相关性研究

选用１６个饲料效率表现、化性、体色及龄期经过各异的品种,春秋分别单头室内育,采用干量折地,各２０次重复取平均值,统计春养、秋养和春秋养平均全龄经过,５龄经过日数与饲料效率对比分析、绘图展示等,发现：龄期经过都与品种的饲料效率有关,但无论全龄还是５龄经过最长、最短的,饲料效率表现都不好,而处于龄期经过第二高峰,即全龄比平均值长０．８４ｄ左右,５龄长０．７３ｄ左右,饲料效率表现最佳,这为高饲料效率品种     

Tumors of the ear canal

This discussion will focus on the clinical presentation, diagnostic evaluation, expected biologic behavior, and therapeutic options for tumours of the ear canal in the dog and cat. Particular emphasis will be placed on neoplasia of the ceruminous glands, squamous cell carcinoma, and non-neoplastic mass lesions.     

Effects of an orally administered live Escherichia coli pilus vaccine on duration of lacteal immunity to enterotoxigenic Escherichia coli in swine

Primigravid swine were vaccinated orally with a live enterotoxigenic Escherichia coli (ETEC) strain that produces pilus antigen K99. The titers of K99 antibody in colostrum and milk of vaccinates remained higher than those of nonvaccinated controls through the first lactation after vaccination (4 weeks). Some control swine had low titers of K99 antibody in colostrum or developed low titers of K99 antibody in milk during lactation. Lacteal K99 antibody titers of vaccinates dropped to control levels during the second lactation, 6 months after vaccination. Pigs suckling vaccinates and controls were equally susceptible to challenge exposure to K99+ ETEC during the second lactation. Orally vaccinated swine given a parenteral booster vaccination (with killed K99+ ETEC) during their second gestation had K99 antibody in milk through their second lactation. During the second lactation, these orally vaccinated parenterally revaccinated swine had higher titers of K99 antibody in postcolostral milk than did nonvaccinated controls, controls given only the parenteral booster injection, or controls vaccinated parenterally during both gestations.     

Wedge and Eggbar Shoes Change the Pressure Distribution Under the Hoof of the Forelimb in the Square Standing Horse

The shoe types most commonly applied to horses with navicular disease or other forms of palmar heel pain are shoes with heel wedges and eggbar shoes, although their efficacy has been a matter of debate among veterinarians and farriers for centuries. To quantify the effect of these different types of “navicular” shoeing on static hoof pressure distribution, 6 warmblood horses were shod with 6° wedge, eggbar, and plain shoes. While standing square with weight evenly distributed across both forelimbs, the center of pressure and pressures at selected areas of interest (AOI: toe, medial and lateral toe, medial and lateral heel) were measured using a Footscan (RsScan International, Belgium) pressure plate in a Latin square design using the plain shoe as a reference.Wedge shoes did not provide a significant shift in the center of pressure. The application of eggbar shoes did not alter the relative position of the center of pressure under the hoof. However, the absolute distance from the toe to the center of pressure was significantly larger with eggbar shoes (77 + 12 mm) compared with plain and wedged shoes (70 ± 8 mm, P < .05) resulting in an absolute, caudal shift of the center of pressure. When pressure (N/cm²) values at the five AOIs were averaged for each shoe type, the wedge and eggbar shoe recordings showed a significantly lower mean pressure than plain shoes (P < .05).In conclusion, mean AOI pressures decreased with wedge and eggbar shoes, and eggbar shoes provided a caudal shift in the center of pressure. These effects are believed to decrease the moment of the coffin joint and reduce the pressure on the navicular bone. Thus, the findings of this study might contribute to the scientific evidence of efficacy of the use of wedge and eggbar shoes in “navicular” lame horses.     

Epidemiologic studies on infectious coryza outbreaks in northern New South Wales, Australia, using serotyping, biotyping, and chromosomal DNA restriction endonuclease analysis

The epidemiology of 16 cases of infectious coryza, an upper respiratory tract disease of chickens caused by Haemophilus paragallinarum, was investigated in a retrospective study. The cases occurred over a 14-month period on 10 farms in northern New South Wales. The available field data indicated that the cases formed six unrelated outbreaks. The 16 isolates of H. paragallinarum were subjected to serotyping by the Page and Kume schemes and biotyping based on carbohydrate fermentation and antimicrobial drug-resistance patterns. As well, newer fingerprinting techniques--plasmid profiles, whole-cell protein profiles, immunoblots of whole-cell protein profiles and total DNA restriction endonuclease analysis (REA)--were evaluated. Antimicrobial biotyping and REA profile typing proved most useful, allowing the recognition of three groups among the isolates. The other techniques gave either limited or no subdivision among the isolates. The combined results of the laboratory study indicated that, rather than six unrelated outbreaks, the 16 isolates represented three pairs of related outbreaks. This study represents the first application of sensitive biotyping and fingerprinting techniques to outbreaks of infectious coryza. The results have established that farms can be repeatedly infected with a single strain of H. paragallinarum that re-emerges at intervals. This study also obtained the first detailed evidence that replacement stock are a major source of infectious coryza.