A series of experiments was designed and carried out to assess the variation of feeding performance of the adult female ticks of Haemaphysalis longicornis in the primary and repeated feeding trials on the same experimental host rabbit under laboratory conditions. It was concluded that an acquired immunity was indeed developed, that the feeding performance was reduced by repeated feeding of the ticks on the same host, and that it was not true economy to use a rabbit more than twice for the colonization of the tick H. longicornis.

An investigation on various causes of milking disturbances resulting from injuries and abnormalities of mammary system were made on 2,179 Holstein cows. To perform this investigation, 69 dairy farms of the suburban area of Seoul city, Gyeonggi-do and Chungnam provinces were randomly selected and subjected. Diagnosis was made by means of inspection and palpation of teat, insertion of teat canula, checking milk machines, anamneses and farm records. Dry off quarters were found in 158 quarters which turned out to be 1.8% of 8,716 quarters inspected. Among them 53.59% had one, 43.72% had two, 2.47% had three, and 0.22% had four supernumerary teats, respectively. Teat sphincter stenosis was 1.76% of 8.716 teats, loose sphincter was 0.89% of 8.716 teats and injured teat tip caused by over milking of milk machine was 2.63% of 8.716 teats.

Somatic, Envelope (O.K.) serogroups of 268 cultures of Escherichia coli isolated from piglets with colibacillary diarrhea were determined by the use of the simplified routine diagnostic procedures of Sojka. Of 268 cultures of Escherichia coli tested, 190 cultures were classified into 15 OK groups and the remaining 78 (29.1%) were untypable. The most frequently isolated enteropathogenic E. coli in order of prevalence were 0157:K'V17' (14.2%), 0149:K91, K88a, c (13.7%), 064:K'V142' (11.6%), 08:K87, K88a, b (10.5%) and 0141:K85a, b, K88a, b (7.9%).

A total of 210 dairy cows were epidemiologically investigated for mastitis by Milk Quality Test (MQT) Method. Milk samples from cows infected with mastitis were also bacteriologically studied. 71(42.5%) of 174 dairy cows were positive for mastitis and 59(79.7%) among them were infected with subclinical mastitis and 15(20.3%) with clinical mastitis. The incidence rate of subclinical mastitis for herd showed tendency to increase at the barn located on a lower place (30.7-7-43.9%), whereas, the barn which was on a higher place and with bucket type milking system showed tendency to decrease causative organisms. A total of 230 strains of etiological agents were isolated from 578 infected duarters which shown MQT score (+) or more. The relevant causative organisms isolated in this study were Staphylococcus aureus (18.3%) Staphylococcus epidermidis (16.9%), fungi (16.5%), Pseudomonas aeruginosa (15.2%), E. coli (7.8%) and Serratia marcescens (2.2%), respectively.

Amblyomma testudinarium Koch, 1844, previously known to occur in India, Sri Lanka, Burma, Thailand, Malaysia, Indonesia, Indochina, the Philippines, Taiwan and Japan, is here initially discovered and recorded in Korea [R.]. A male specimen was collected from grazing Frisian cattle of the Dae Weon Farm on Jeju island (Korea R.) by a local veterinary official on the 28th June in 1981. The specimen was examined and identified as A. testudinarium. The morphological characteristics of the male specimen were redescribed. A total of 18 species of ticks belonging to 7 genera, such as Argas, Amblyomma, Boophilus, Dermacentor, Haemaphysalis, Hyalomma and Ixodex, has now been recorded to occur in Korea [R.].

It has long been believed for the presence of infectious coryza affecting serious economic loss of domestic poultry industry. However, the etiologic agent has not been isolated until quite recently. From 1979, several strains of Haemophylus-like organism were isolated from chickens with symptoms similar to infectious coryza, and their colonial morphology, growth requirement, biochemical properties and pathogenicity were assessed. In addition, serological properties of the isolate by cross hemaglutination inhibition test was also investigated. The results indicated that all the isolates were identified as Haemophilus gallinarum which had similar characteristics to the reference strains.

To observe the histopathological changes on the bite lesion produced by the tick Haemaphysalis longicornis Neumann with particular reference to the acquired immunity in the host, a series of experiments was carried out. The major histopathological changes of the lesion produced by the tick were characterized by a hemorrhagic and edematous inflammatory reaction, leukocyte infiltration and some nectoric signs.

This experiment was undertaken to determine the causative agent of dermatophytosis that occurred in the 3 common seals and an elephant which were derived from the Tae-gu and Busan zoological gardens. Direct microscopic examination, culture and pathogenicity test were performed for the samples obtained from the skin lesions of the animals. The causative agent was identified as Trichophyton mentagrophytes exclusively in these cases, and the present report describes the first cases of the common seal and elephant as ringworm.

Reproductive performance of gilts and sows in ordinary piggeries was investigated with special reference to litter size, piglets weaned per litter, the cause of preweaning mortality and the incidence of diarrhea. Biochemical properties of Escherichia coli isolated from piglets with diarrhea were also determined. Of the 2,226 gilts and sows farrowed, average number of piglets born alived and weaned piglets per litter were 8.9 and 7.1, respectively, indicating that both gilts and sows lost more than 20% of all their piglets prior to weaning. The causes of preweaning mortality in order of prevalence were diarrhea (39.3%), pneumonia (20.0%), crushing (13.8%), starvation (11.0%) and born weak (10.3%). Incidence of 3 diarrheal syndromes of piglets, i.e. 1 week diarrhea, 3 week diarrhea and post-weaning diarrhea were 18.4%, 66.1% and 15.5%, respectively, showing that most farms were suffering from so called 'white scours' in piglets 14-28 days old.

The immune response to bluetongue virus in sheep and cattle was studied by applying a newly developed indirect enzyme-linked immunosorbent assay (ELISA). Purified virus obtained by sucrose gradient centrifugation was used at a concentration of 0.01 optical density units (formula: see text) to coat individual wells (200 microliter) of a microtitration plate. Dilution of antigen was performed in 0.05 M carbonate buffer, pH 9.6, and adsorption lasted for at least 16 hours at 4 C. Coated plates retained their activity for 10 weeks when stored at 4 C. Sera recovered from experimentally infected sheep and cattle were tested together with known negative sera. A good correlation between results was obtained with the modified complement-fixation test and the ELISA; however, the ELISA proved to be more sensitive. The group specificity of the ELISA was proven by testing various type-specific sheep and cattle immune sera. The ELISA has potential for the detection of group-specific antibodies to bluetongue virus infection.