In order to observe the bactericidal effect of Ranunculus species on pathogenic bacteria, the minimal inhibitory concentration and bactericidal effect was tested Throughout the studies, the following experimental results were obtained and summarized. 1. Minimal inhibitory concentration of Ranunculus species extracts on E. coli was observed in the medium in which 1% Ranunculus species extracts added to brain heart infusion agar. 2. Minimal inhibitory concentration of Ranunculus species extracts on Salmonella species observed in the medium in which 1% Ranunculus species extracts added to brain heart infusion agar. 3. Minimal inhibitory concentration of Ranunculus species extracts on Staphylococcus and Streptococcus was observed in the medium in which 1.5% Ranunculus species extracts added to brain hrart infusion blood agar. 4. The Bactericidal effect of Ranunculus species extracts on E. coli and S. typhi was observed in 30 minutes. 5. The Bactericidal effect of Ranunculus species extracts on staphylococcus aureus was obserded in 40 minutes.

During the studies on the esophagogastric ulcers in swine, Anisakis type larvae were found associated with stomach lesions. 1. Of the 1,531 pigs examined, 11(0.7%) were infested with the parasite in the stomach. 2. The parasite was identified as Anisakis type I larvae, according to the morphological characteristics. 3. On gross examination, the parasites were seen penetrating gastric mucosa, resulting in hemorrhagic ulcers. 4. Main histopathological features were edema, massive eosinophilic infiltrations around the parasite, necrosis and perivascular eosinophilic accumulations in the submucosa.

서울 경마장(競馬場)의 경주마(競走馬) 517두를 대상으로 호흡기병상(呼吸器症狀)을 관찰하여 1978년 12월 중순(中旬)부터 1979년 1월 초순(初旬) 까지 42.9%의 호흡기병상발생률(呼吸器症狀發生率)을 보았고 1979년 1월 하순(下旬)부터 5월 중순(中旬)까지 임신마(姙娠馬)의 60%가 사산(死産)을 일으켰다. 사산(死産)된 태자(胎仔)는 육안적(肉眼的)으로 흉강수액(胸腔水液)의 저류, 각 장기(臟器)의 울혈성수종(鬱血性水種), 출혈성병변(出血性病變)과 간장(肝臟)의 소상괴사(巢狀壞死)를 나타내었고, 조직학적(組織學的)으로는 간장(肝臟)의 한국성괴사소(限局性壞死巢), 비장(脾臟), 임파절(淋巴節), 흉선(胸線)과 Peyer판(板)에서의 세강(細網) 세포(細胞)의 증식성(增殖性), 괴사성변화(壞死性變化)와 임파양세포(淋巴樣細胞)의 붕괴(崩壞)를 시현(示顯)하였다. 여기서 간세포(肝細胞), 담관상피세포(膽管上皮細胞), 소기관지상피세포(小氣管支上皮細胞) 및 비장(脾臟), 임파절(淋巴節), 흉선(胸線)의 세강(細網) 세포(細胞)에서 Cowdry type A 봉입체(封入體)를 확인하였다. 이상의 역학적(疫學的) 및 병리학적(病理學的) 소견(所見)에 의하여 본(本) 마유산증(馬流産症)을 말 바이러스성 비폐염(鼻肺炎)이라고 진단(診斷)할 수 있었으며 본(本) 발병예(發病例)가 한국(韓國)에서 초발생(初發生)인 것으로 추정(推定)되었다.

A total of 250 enteric bacteria (148 Escherichia coli, 41 Klebsiella pneumoniae, 46 Enterobacter spp. and 15 Proteus spp.) isolated from bovine udder infections in 1979 through 1980 were examined for drug resistance and prevalence of R. plasmids. The drug tested were streptomycin (SM), kanamycin (KM), ampicillin (AP), chloramphenicol (CP), tetracycline (TC), gentamicin (GM), oxolinic acid (OA) and nalidixic acid (NA). The detection of R. plasmids was performed with Escherichia coli ML 1410 NAr as the recipient. Of the 148 Escherichia coli isolated, 68(45.9%) were found to be resistant to one or more drugs tested, and about 50% of the resistant strains were multiply resistant. of the 68 drugresistant strains, 13(19.1%) were found to carry R. plasmids which were capable of performing a conjugal transfer. CP resistance was transfered together with the other resistance. Of 41 strains of Klebsiella pneumoniae isolated, 90.2% were resistant to the drugs, alone or in combination thereof. Strains resistant to AP and TC were 63.4%, and 48.8%, respectively. R. plasmids were detected in 78.4% of the drug-resistant strains, and these strains transfered all or a part of their drug resistance pattern. AP and CP resistance were transfered in 100% of AP and CP-resistant strains. Eleven (37.9%) of 29 R. plasmids showed a thermosensitive transfer. Of the 46 strains of Enterobacter spp. isolated, 37(80.4%) were resistant to the drugs tested. A high percentage of resistance was noted for AP(65.2%). All strains resistant to four or more drugs transferred their resistances to Escherichia coli ML 1410, but strains resistant to three or fewer drugs did not transfer the resistances. All of the 15 Proteus strains isolated were resistant to more than two drugs. of them, 6 were quadruple resistance to SM, KM, CP and TC, and 9 were double one to AP and TC. Three (20.0%) of the drug-resistant isolates had R.plasmids conferring AP and TC resistance. GM, OA and NA of the drugs tested were very active to all of 250 Gram-negative enteric bacteria isolated from bovine udder infections.

In order to clarify the morphological changes in the mammary glands of cows affected with coliform (Escherichia coli) mastitis, histopathological observations were undertaken on the mastitis of the lactating rabbits which was experimentally induced with E. coli or its endotoxin isolated from cases of acute and chronic matitis in dairy cattle. In the bacterial suspension-infused groups the affected quarters of udder showed cloudy swelling, hyperemia and hemorrhage to local necrosis and firmness. The microscopic findings of early stage of the mastitis were appearance of large numbers of heterophils in the glandular lumina and ducts accompanied by degeneration, necrosis and desquamation of epithelial cells, and also infiltration of heterophils, hemorrhage and edema in the interstitial tissue, and destruction of alveoli. Later, proliferation of firoblasts, plasma cells, lymphocytes, eosinophils and histiocytes appeared in the glandular tissue and necrotic foci of glandular tissue were surrounded by highly proliferated connective tissue. Granuloma-like inflammatory changes could be observed in the glandular tissue on the 7th days after infusion. The inflammatory response in the group infused with E. coli strain isolated from the natural case of acute mastitis was rapid and severe as compared with that of chronic mastitis. In the endotoxin-infused group the morphological changes were similiar to those of the bacterial suspension-infused groups.

The occurrence of inclusion body hepatitis was confirmed for the first time in Korea from chickens submitted for diagnosis to this Institute from a farm located in the vicinity of Anyang. The chickens showed no specific clinical signs except for moderate anemic conditions. At autopsy, livers were swollen and mottled with numerous stellate subcapsular hemorrhages and necrotic foci. Severe nephritis and catarrhal enteritis were also seen. The most notable microscopic changes were seen in the liver. These included eosinophilic intra-nuclear inclusion bodies in the hepatocyes, massive hemorrhages and necrosis and fatty changes in the liver parenchema.

In the survey on the pig-stomach worms of the abattoir pigs in Gyeongbug province, some unusual nematodes were found by gross and microscopic inspection to the pig-stomach. The results obtained in the survey and identification were summarized as follows. 1. A natural infection of Anisakis type larvae in the pig gastric wall was newly confirmed in korea and in all cases, the larvae were identified as Anisakis type 1 (Berland, 1961). 2. A chronic granulomatous lesion with small lymphocytes, neutrophils and eosinophils was appeared in the gastric wall penetrated by the larvae. 3. Of total 318 pigs, 9 pigs were infected with the larvae and in each stomach, only one or two worms were detected from the abattoir pigs. 4. Ascarops strongylina was found as one percent.

Two experiments were conducted to establish a program for the prevention of swine parakeratosis occurred recently in Korea. In the first experiment, 11 rations which were considered to be related clinico-pathologically to the incidence of parakeratosis and 5 rations not to be related were collected at farms during the period from June, 1979 to December, 1980. In addition, 23 commercial rations and 10 ingredients were also collected at feed dealers or farms. The feed samples were analyzed for calcium, zinc and unsaturated fatty acid. In the second experiment, the efficiencies of adding zinc carbonate (150mg/kg diet) with or without soybean oil (5ml/kg diet) to two control rations were tested using 20 weanling pigs. One of the control rations had low zinc (41mg/kg) and normal calcium (0.64%) and the other low zinc (57mg/kg) and high calcium (1.42%). The results obtained are as follow: 1. Content of zinc in the rations induced parakeratosis ranged from 35 to 80mg/kg with a mean of 49mg/kg; whereas those of rations not induced ranged from 97 to 182mg/kg with a mean of 182mg/kg. The difference between two means was highly significant (p<0.01). 2. The calcium content in rations related to parakeratosis was ranged from 0.56 to 1.80% with a mean of 1.30% whereas that of not related was ranged from 0.63 to 1.37% with a mean of 1.07%. The highly significant difference of calcium content between two rations were recognized (p<0.01). The calcium contents of both rations were markedly higher than that of generally recommended value of 0.40~0.80%. 3. The contents of unsaturated fatty acid in induced rations was a mean of 4.42% and it was significantly lower (p<0.01) compared with those in not induced rations with a mean of 6.70%. The content of unsaturated fatty acid of commercial rations was ranged from 5.25 to 7.81% with a mean of 6.29%. 4. Zinc content of 15 commercial ration samples among 23 were less than 97mg/kg and 21 rations contained more than 1.03% of calcium. 5. Addition of zinc carbonate to the two control rations which are low in zinc content or high in calcium content were resulted in preventive effect on the incidence of swine parakeratosis. 6. It may be concluded that the incidence of swine parakeratosis was closely related to the low zinc, excess calcium and low unsaturated fatty acid in rations, most of the commercial rations contained low in zinc and high in calcium as compared with the recommended contents. Content of Unsaturated fatty acids in the commercial rations, however, were sufficient for the prevention of parakeratosis in swine.

Holstein-Friesian cows(n=284) were given $100{\mu}g$ of gonadotropin-releasing hormone(GnRH) or saline solution by intramuscular injection at 10 to 22 days after parturition, and were investigated their reproductive performance and frequency of ovarian cysts. Among them 28 cystic cows were injected with $150{\mu}g$ of GnRH intramuscularly and examined the recovery rate. The results obtained in this study were summarized as follows: 1. The interval from calving to 1st ovulation was reduced from 28.2 days in controls to 16.5 days for cows given GnRH (p<0.01). 2. The intervals from calving to 1st estrus and from calving to conception were extended significantly in control group (p<0.05). 3. Inseminations per conception and conception rate at 1st insemination did not reveal difference between two groups. 4. Frequency of ovarian cysts was reduced from 14.0% in control to 4.20% for cows given GnRH (p<0.05). 5. Of the 28 cystic cows receiving $150{\mu}g$ of GnRH, 23(82.1%) responded to 1st treatment and returned to estrus $24.2{\pm}4.3$ days after treatment. 6. These data provide evidence for reduction in infertility and reproductive disorders in early postpartum dairy cows given GnRH as a prophylactic.