In order to study the etiological background of bovine necrotic enteritis, 51 animals having various diseases, including 14 animals with necrotic enteritis were examined forClostridium perfringensandEscherichia coli, especially as regards their ages. Normal 107 Holstein and 81 Japanese Black Cattle were also examined in like manner. In the former group, intestinal content of postmortem animals was used as material for isolating the organisms and for the latter group, feces were used. The results obtained are as follows: In 37 diseased animals, 12 of 20 less than 60 days of age and 12 of 17 more than 60 days of age had bothC. perfringens andE. coliwith a high bacterial order, 10^5-8cfu/g and 10⁸cfu/g, respectively. In feces of normal animals less than 60 days of age, Holstein cattle hadC. perfringensat an 80% isolation rate with 10^5.9cfu bacterial count and Japanese Black Cattle in 19.3% with ca. 10^5.5cfu/g at such a rate and count. ForE. coliin the former, it was 10^6.2cfu/g and in the latter, 107.7 cfu/g both on the average for all-age-group animals. The results with 4 or 5 times' samplings of feces until their 72-80 days of age for 3 Holstein and 13 Japanese Black Cattle also showed a similar trend regardingC. perfringens. Besides, 5 calf-replacers and 5 calf-starters used for Holstein cattle did not show any existence of C. perfringens. From these results, it is suggested that a greater number ofC. perfringensin feces of Holstein calves less than 60 days of age may be due to a calf-replacer feeding system andE. colicould increase in any diseased condition.

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Outbreaks ofActinobacillus pleuropneumoniaeinfection of swine occurred on 5 integrated swine farms in Chiba Prefecture from late 1988 to 1989. The disease was prevalent among feeder pigs aged 3 to 7 months and no seasonal partiality was observed in the incidence. The morbidity was varied among the 5 farms 0.3 to 25% with the maximum mortality being 14.6%. Pathological examinations revealed extensive pleuropneumonia in all cases and meningitis and pericarditis in some cases. A total of 52A. pleuropneumoniaestrains were isolated from the lungs of the 11 affected pigs examined. These isolates were serologically identified asA. pleuropneumoniaetypes 1 and 2. There were no farms in which both types of A. pleuropneumoniaewere isolated simultaneously. Thirty of 52 isolates belonged to serotype 1 and these were resistant to all kinds of antibiotics tested KM, SM, CP, TPH, TC and OTC. The remaning 22 isolates were serotype 2, and 5 of these isolates were resistant to SM, TC, OTC or TPH. From these results, the importance of susceptibility test of the isolates against antibiotics was emphasized for the treatment of the disease.

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In December 1989, eight adult minks died suddenly on a 232-head mink farm in Niigata Prefecture. Six animals were necropsied, but no characteric gross lesions were observed in any of them. Histopathologically, necrotic foci with intranuclear inclusion bodies in the degenerated nerve cells and neuroglial cells were found in the medulla oblongata of all cases. Neuronophagia, microgliosis and intranuclear inclusion bodies in nerve cells were observed in the trigeminal ganglia of two cases. In these same cases, intranuclear inclusion bodies were observed in the epithelial cells of the tonsil. Suid herpesvirus 1 (Aujeszkey's disease virus: ADV) antigen was identified in lesions of the medulla oblongata, trigeminal ganglia and tonsil by an immunoperoxidase technique. Viral agents were isolated from the brain. These isolates were identified as ADV by a neutralization test and an immunofluorescence technique. Cleavage patterns of DNA of the isolates by BamHI were similar to those of the Yamagata S-81 strain of ADV. A serologic survey on serum samples collected from the feeder swine of fattening farms in the same area using an enzyme-linked immunosorbent assay showed that none of them had ADV antibodies. The affected minks received rations containing swine offal deriurel from the Kanto area where AD is widespread, suggesting that the offal is the source of the infection.

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In May and June 1989, 333 cattle suffered from pyrexia, anorexia, shortness of breath, orbital edema, muscular tremor, and ataxia in the Yaeyama Islands, Okinawa Prefecture. A neutralizing antibody against bovine ephemeral fever (BEF) virus was detected in 26 of 41 (63%) serum samples collected from these cattle. Eight cytopathogenic viral strains were isolated in the HmLu-1 cells, and neutralized with antiserum against the YHL strain of the BEF virus. From these results, the present cases were diagnosed as BEF.

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In a fluoroscopic situation supposing heartworm removal using flexible alligator forceps, the radiationprotective effect of lead-containing screens was examined. Regarding measurements using a gamma-survey meter, X-ray exposure to the operator was reduced from 24.6±7.5 micro-Sievert (μSv)/hr to 0.47±0.08μSv/hr by using protective screens at position A, which corresponds to the operator's face level. At position B, which corresponds to the position of operator's left-hand fingers, the exposure level decreased from 33.1±1.37μSv/hr to 3.01±1.23μSv/hr when screens were used, and decreased more to 0.44±0.16μSv/ hr with the use of protective gloves. At position C, which was at the operator's foot, the exposure level decreased from 0.65±0.27μSv/hr to 0.24±0.10μSv/hr. Regarding measurements using a film badge for 20 experimental dogs, in which each dog was fluoroscopied for 20 sec×15 times, the operator would be totally exposed to 0.1 mSv in H_3mm, dose equivalent value against the eye lens and H_70μm, dose equivalent value against the skin at position B, but below the minimal limit for detection of X-ray (0.1 mSv) in H_1cm, effective dose-equivalent value. Exposure levels were below the minimal limit at positions A and C and at all positions which were protected with screens. Also, dogs were exposed to X-ray 2.20±0.96 mSv on fluoroscopy for 20 sec x 15 times.

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Many clinicians may have encountered dogs with toad poisoning. However, the nature of the poisoning still remains unclear. Thus, we experimentally induced toad poisoning in dogs and studied this poisoning from various aspects.
Nine dogs thought to be clinically healthy were exposed to wild toads; the dogs ate and/or bit the toads. Then, the dogs were observed sequentialy. The results are as follows.(1) Regardless of the size of the toads or the dog's body weight, vomiting occurred in 2 dogs about 60 min after eating the toads and in all the other dogs within 10-12 hr. Except for one dog (No.7), all the dogs gradually returned to their normal conditions. Two dogs which bit and licked the toads immediately showed salivation, head waving, etc., which were similar to symptoms caused by digitalis poisoning. Thereafter, they gradually returned to their normal conditions.(2) Hematological changes determined before and after eating toads in some dogs were almost within the range of the physiological fluctuation.(3) At autopsy, the severity of inflammation differed according to the dog. Enteritis was observed in 88.8%(8/9) of the dogs.

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The clinical signs, autopsy findings and clinicopathological changes in 143 dysuric fattening cattle with urolithiasis were studied. They were brought into a meat processing plant and assessed using the level of blood urea nitrogen (BUN) as an indicator of disease severity.
BUN increased in those animals having a gloomy look, enophthalmos and tenesmus, compared to those without these symptoms. It was markedly higher in ananastatic cattle.
The cattle were divided by BUN levels into five groups (I-V) to compare the gross lesions and serum biochemical changes with disease severity. Liver discoloration, edema of the skeletal muscles, congestion and hemorrhage in the intestinal mucous membrane and rupture of the bladder were more frequent in groups IV-Vin which the BUN level had increased much more than those in groups I-III in which the BUN level in-crease was mild to moderate. No difference was found in the incidences of urinary organ lesions other than rupturing of the bladder among these groups.
Serum creatinine increased constantly as the BUN level increased. Glucose, inorganic phosphorus and GOT increased significantly in group V. These metabolic disorders accompanied by the BUN level increase were almost similar to the time course of the uremic changes reported previously by us in goats with experimental ischuria. These findings verified the appropriateness of using BUN in the judgement of uremia in cattle with urolithiasis by meat inspection.

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