This study was conducted in order to observe the changes in cellular association of seminiferous tubules from 4 to 22 weeks of age and to obtain the cycle and relative duration of seminiferous epithelia from 24 weeks of age in male ducks. Fifety-five male ducks were used in the experiment and divided into 11 groups, consisting of 5 male ducks each, with 2 weeks intervals from 4 to 24 weeks of age. The body and tests weight showed most rapid increase during 4 to 6 weeks and 18 to 22 weeks of age, respectively. The seminiferous tubules were abruptly enlarged in diameter of tubules during 18 to 22 weeks of age. Gonocytes were seen from 4 to 6 weeks of age, however they were not observed as from 8 weeks of age. Both type Ap spermatogonia and type Ad spermatogonia occurred from 8 to 12 weeks of age, while spermatocytes and spermatids were beginning to appear at 16 weeks and 18 weeks of age, respectively. Spermatozoa were first observed at 20 weeks of age. Full spermatogenic activity was completed at the age of 20 weeks. Average paired weight of the testes in male ducks was 78g at 24 weeks of age and its ratio spermatogenic activity was completed at the age of 20 weeks. Average diameter of seminiferous epithelium at 22 weeks of age was 232 micro m, and average numbers of Sertoli cell, spermatogonia, spermatocyte, spermatids and spermatozoa in the cross section of seminiferous epithelium were 15.30, 59.08, 41.78, 71.11 and 165.30, respectively. Spermatogonia and spermatids were classified into 2 and 4 types, respectively. The cycle of the seminiferous epithelium could be divided into 5 stages at 24 weeks of age. The relative frequencies of stages from I to V were 13.5 %, 25.0 %, 22.3 %, 20.6 % and 18.7 %, respectively. Thus, establishment of spermatogenesis in male ducks were beginning to appear at 20 weeks of age

The prospect of live vaccines consisting of genetically modified vaccinia virus expressing foreign genes is exciting, but important issues concerning safety and efficacy need to resolved. Vaccinia virus (VV) is an efficient expression vector with broad host range infectivity and large DNA capacity. This vector has been particularly useful for identifying target antigens for humoral and cell-mediated immunity. The WHO smallpox eradication program, involving the extensive use of VV vaccines, resulted in the late 1970s in the elimination of one of the world's most feared diseases. This achievement is a triumph for preventive medicine and for international collaboration in public health. In 1980, WHO recommended that the routine use of smallpox vaccine should be stopped. Against this background, the prospect of live vaccines consisting of genetically modified VV expressing foreign antigens arising from the work of Moss, and Paoletti and their colleagues in 1982 has been greeted with enthusiasm. These investigators have shown that genes coding for immunogenic proteins can be inserted into VV DNA without impairing the ability of the virus to grow in cell culture. Moreover experimental animals infected with VV recombinants containing genes coding for a variety of immunizing proteins have been shown to be protected against challenge infection with the corresponding infectious agent. In this communication, I describe current progress in the construction of a novel plasmid vector that facilitates the insertion and expression of foreign genes in VV as well as the selection of recombinants

In order to establish the extent of Streptococcal arthritis piglets, isolation of Streptococci from arthritic lesions of 34 piglets were undertaken from November 1987 to October 1988 in Korea. Also determined were isolation frequency of Streptococci in nasal cavity of 250 healthy sows and antibiotic susceptibilities of the isolates. Streptococci were isolated from 52.9 % of 34 arthritic piglets and 20 strains isolated belonged to 4 S suis type I, 8 S suis type II, 2 Lancefield group C and 6 group E. From 28.8 % of 250 healthy sows, 72 strains of Streptococci were isolated and these consisted of 9 S suis type I, 51 S suis type II and 12 group C. Streptococcal arthritis seemed to occur prominently in piglets aged 2 to 4 weeks and in male than female. No significant difference were recognized in tarsal and carpal joints as affecting site. All of 92 isolates were sensitive to ampicillin and penicillin, and all strains of S suis type I and group E Streptococcus were also sensitive to chloramphenicol and cephalothin. To cephalothin all strains of group C Streptococcus were sensitive. The 1.7 to 100 % of 92 isolates were resistant with different prevalence to colistin, erythromycin, kanamycin, tetracycline, gentamycin, chloramphenicol and cephalothin. The 92.5 % of these resistant Streptococci were multiply drug-resistant strains. The drug resistant patterns most frequently encountered were Tc Cl Em Km Gm (16.3 %) in quintuple pattern, Tc Cl Em Km (16.3 %) in quadruple pattern, Tc Cl Em (10.9 %) in triple pattern and Cl Em (14.1 %) in double pattern

The capsular serogroupes and drug susceptibility of 111 isolates of Pasteurella multocida from pigs with atrophic rhinitis and pneumonic lesions were investigated. Of the 111 P multocida isolates, 42 were from lung lesions, 47 from nasal turbinate lesions and the remaining 22 from the nasal swabs. P multocida isolates were typed for capsular serogroupes A by hyaluronidase inhibition of capsule and D by acriflavine auto-agglutination. Most isolates (64.9 %) were type A, 23.4 % were type D and the remaining 11.7 % were untypable. Resistance to triple sulfa (97.3 %) was most frequent, followed by resistance to tiamulin (71.2 %), tylosin (56.8 %), streptomycin (36.9 %), and neomycin (36.0 %). The majority of the organisms were susceptible in order of prevalence to baytril (100 %), ampicillin (98.2 %), linsmycin (97.3 %), cephalothin (94.6 %), gentamycin (93.7 %), amikacin (92.3 %), tetracycline (91.9 %), trimethoprim/sulfamethoxazole (91.0 %), and kanamycin (90.1 %). No differneces in drug resistance in relation to capsular serogroupes of P multocida and the origin of lesions were noted. A high prevalence of multiple drug resistance was observed and the most common resistant patterns were Sss, Tm, Ty (12.6 %) and Sm, Sss, Tm, Ty (8.1 %) patterns

A new sudden death in rabbits appeared in China and Korea in 1984 and 1985, respectively, and was recognized to be an acute infectious disease caused by a virus. The disease was reported as a "new viral disease", and thereafter, a tentative name of "viral hemorrhagic disease", "hemorrhagic pneumonia" or "viral hemorrhagic pneumonia" has been described in the case reports. But authors had called the viral disease "rabbit viral hepatitis" due to picornavirus infection, because the principal lesion of the disease was an acute hepatitis. The purpose of this report is to describe the electron microscopic findings on the livers in experimentally infected rabbits. All the livers of the affected rabbits were shown to have degenerative changes of a type that is characteristic of acute hepatitis. In the liver cells, there were dilation of rER and mitochondria, vacuole formation of various sizes, and appearances of many virus-like particles in the vicinity of rER, granular bodies and crystalline arrays of viral particles in the cytoplasm with necrotic changes of the nucleus. Clusters of virus-like particles and viral crystals appeared in the cytoplasm of sinusoid endothelial cells and Kupffer's cells with morphological changes of organelles. Also viral crystals were demonstrated in the cytoplasm of macrophages among the liver cells. On the whole, the liver cells had many virus-like particles and a few crystalline arrays of viral particles. Therefore, this implies that the liver cells are the main site of the viral replication in inducing the viremia. It was concluded that the liver was the primary target organ of this viral disease, and the pathological and the ultrastructural evidence suggest that the virus may belong to genus enterovirus

This investigation was conducted on 249 Jindo dogs aging from 2 to 12 months to determine body type and external appearance of the dogs. The withers height of male dogs growed rapidly during the period between 2 months and 7 months of age, and was 22.94cm and 49.77cm, respectively. Afterward the growth rate slowed down up to 12 months, 53.33cm. The growth rate of female was similar to male, and the withers height was 22.91cm, 46.81cm, 48.70cm at 2, 6 and 12 months of age. For male and female the body length was 27.21, 27.23cm at 2 months, 51.40cm, 51.62cm at 6 months, 58.33, 52.15cm at 12 months, respectively. Growth rate of the body length was very rapid from 2 to 6 months of age, but afterwards the growth rate was slow and somewhat retarded. For male and female, the withers height to body length ratio was 100 : 109.4 and 100 : 107.1 in 12 months old group. Cross over between the sexes in growth rate occurred between 5.3 to 6.5 months of age for wither height, between 6.0 to 7.2 months for body length, respectively. The average chest girths of male and female were 31.46, 30.46cm at 2 months, 54.92, 52.20cm at 7 months, 60.25, 57.90cm at 12 months, respectively. The growth rate of chest girth was rapid between 2 to 7 months of age and gradual between 7 to 12 months. The average skull lengths of male and female were 11.76, 11.32cm at 2 months, 21.83, 19.60cm at 12 months, respectively. The average head widths of male and female were 8.37, 7.94cm at 2 months, 15.47, 12.46cm at 12 months. Erected type of ear was completed from oblique type at 6 months in male and 7 months in female. On our detailed examinations, we concluded that Jindo dogs completed their growth at 6 to 7 months of age

This study was carried out to diagnostic test for bovine mastitis by the determination of adenosine triphosphate (ATP) based on firefly bioluminescence. The infection rate of bovine mastitis investigated with 521 cows in 47 dairy farms were found to be 3.6 % of clinical form and 44.1 % of subclinical form according to the degree of infection. The light yield produced in firefly bioluminescence system was proportional to the concentration of ATP giving stright line within the range of 100PM-luM. When the number of somatic cell in milk was determined by the ATP assay and compared with three conventional methods such Fossomatic. California mastatic test (CMT), and rolling ball viscometer (RBV), it was shown that r= 0.92 for Fossomatic, 0.63 for CMT and 0.7 for RBV. The microorganisms causing mastitis were isolated Staphylococcus sp. (53.3 %), Streptococcus sp. (17.9 %), Micrococcus sp. (13.5 %), Gram negative bacilli (6.3 %), Gram positive bacilli (5.5 %) and Yeast-like fungi (5.4 %). The endogeneous ATP levels of bacteria in a raw milk determined by the firefly bioluminescence system and compared with the results of the conventional methods. The correlation was 0.88 for raw milk

Twenty Holstein steers subclinically infected with coccidia were allotted to 2 groups of 10 steers each. One group received a diet containing 0.5 mg of decoquinate/kg of body weight. After 25 days on the diet, there was no difference between the groups in lymphocyte blastogenic responsiveness mitogens; however, there were differences in neutrophil function. Lymphocytes from steers of the decoquinate-fed group had decreased random migration under agarose, enhanced cytochrome C reduction, and enhanced iodination activity. Other measures of neutrophil function evaluated (chemotactic index, Staphylococcus aureus ingestion, and antibody-dependent and-independent cell-mediated cytotoxicity) were not affected. After 30 days of decoquinate feeding, half of the cattle in each group received 5 daily IM injections of dexamethasone (0.04 mg/kg of body weight). The dexamethasone-treated steers from the group that did not have decoquinate in the diet developed clinical coccidiosis, whereas the decoquinate-treated steers remained clinically normal. Lymphocyte and neutrophil function were again evaluated for a 3-day period beginning 4 days after dexamethasone treatment was halted. Neutrophils from the steers that developed clinical coccidiosis after dexamethasone administration had significantly (P less than 0.05) inhibited random migration under agarose, cytochrome C reduction, and iodination activity, but significantly (P less than 0.01) enhanced S aureus ingestion. The feeding of decoquinate prevented the inhibition of neutrophil cytochrome C reduciton and lessened the inhibition of neutrophil iodination in the dexamethasone-treated group. Dexamethasone treatment was associated with an inhibition of lymphocyte blastogenic responsiveness to phytohemagglutinin in principals as well as controls.

Whole blood platelet aggregation was determined in response to collagen, arachidonic acid, and adenosine diphosphate in 20 dogs with liver disease and in 20 control dogs. Platelet aggregation in response to collagen and arachidonic acid was reduced in dogs with liver disease, compared with control dogs (P less than 0.05), whereas there was no significant difference in platelet response to adenosine diphosphate between the 2 groups of dogs. Adenosine diphosphate was found not to be a reliable aggregation agent for determination of whole blood platelets aggregation in dogs. Dogs whose platelet did not aggregate in response to collagen and/or arachidonic acid manifested bleeding tendencies that could be attributed to platelet dysfunction.

Thirteen critical tests (n = 11 horses and 2 ponies) and 4 controlled tests (n = 4 donkeys and 6 horses) were performed to evaluate the activity of the experimental macrocyclic lactone compound F28249-alpha against internal parasites of equids. In the critical tests, activity was determined mainly against the large parasites, but 1 critical test also included benzimidazole-resistant small strongyles. In the controlled tests, evaluation of drug activity included large parasites and stomach worms in all 4 tests and lungworms in 2 tests. The period between treatment and euthanasia was 6 to 9 days for the critical tests and 14, 17, or 52 days for the controlled tests. The compound was administered by stomach tube at dose rates of 1, 2, 3, 3.5, or 4 mg/kg of body weight. In the critical tests, removal at all 5 dose rates was 100% for Gasterophilus nasalis (2nd and 3rd instars), Parascaris equorum (mature), Strongylus vulgaris, and Strongulus edentatus from the gastrointestinal tract. For Gasterophilus intestinalis in the stomach, mean removals of 2nd instars were 88% at the rate of 2 mg/kg and 93% to 100% at rates greater than or equal to 3 mg/kg. For the 3rd instars, mean removals were 7% at 1 mg/kg, 77% at 2 mg/kg, 90% at 3 mg/kg, and 98% at 3.5 mg/kg. Discharge of G intestinalis in feces was typically a slow, prolonged process and probably higher removal values, especially at lower dose rates, would have attended a longer interval after treatment before necropsy examination. There was 100% removal of population B, benzimidazole-resistant small strongyles in the single critical test. Controlled tests at the 4 dose rates between 2 and 4 mg/kg resulted in variable activity against G intestinalis and Oxyuris equi, but efficacious removals were recorded for S vulgaris, S edentatus, Draschia megastoma Habronema muscae, Trichostrongylus axei, and Dictyocaulus arnfieldi. In critical and controlled tests, there was some indication of drug activity against parenteral stages of S edentatus and S vulgaris; activity was best in the control test equids euthanatized 52 days after treatment. There did not appear to be drug activity on eyeworms (Thelazia lacrymalis) or tapeworms (Anoplocephala spp). Toxicosis of transient nature was observed in 1 horse treated at 4 mg/kg.