There is a new branch of veterinary medicine specializing in wildlife, which can be called wildlife veterinary medicine or veterinary wildlife biology, and which is a field of wildlife biology in the broader area of naure conservation or management. The main objective of this new field will be population management of wildlife, based on population dynamics. The basic processes of population dynamics are birth and death;the most experienced fields of veterinary medicine are reproductive biology and the analysis of deaths of livestock and zoo animals. Wildlife veterinary medicine is expected to make a significant contribution to population management of wildlife.
The species survival programme of animals has been valued more and more as zoo conservation in the zoo community. For such protection work, successive breeding in captivity of zoo animals(including wild animals)should be concentrated upon. However, the following problems need to be considered for continuing successive breeding: (1)Maintaining proper population within an enclosure with certain space is important for the health management of the group. Overpopulation leads to a high new-born mortality rate and is subject to infectious diseases due to soil pollution in the enclosure. (2)Precocious trend is observed in many animal species. (3)Minituarization and changes in figures are observed. The reason of the phenomenon seems decrease in osseo-dentisy(the osseo-dentisy of zoo animals is much lower compared with that of wild animals). (4)Careful treatments to avoid wrong imprinting is needed where hand rearing is under way. (5)A group of a small founder will end in deterioration if it is left as it is. Renewal of blood is essential. Above problems seem to relate with phases of domestication, and such domestication must be avoided where zoos aim to keep native characters of wild animals whenever possible. Zoos must do our best to give animals an ethologically/physically suitable breeding environment and to display the function fully as a captive breeding base of rare animals.
Female genital organs from 19 Japanese black bears(Selenarctos thibetanus japonicus)were collected at Gifu and Kyoto prefecture during the period from March 1991 to August 1993. Both weight and volume of the ovaries increased according to adding of the age. The existence of corpora lutea and its involuted matters showed Japanese black bear sexually matured at the age of four, though there were differences among individuals. From observation of the genital organs, the mean value of ovulation was indicated 1.89 and that of implantation 2.00. The mean value of cubs having observed by hunters was 1.86. Microscopical observation of ovaries showed that there was correlation between the number of corpora lutea including involuted matters and the number of the times adding up the chance of reproduction progressed.
A captive 75-day-old male red-crowned crane(EimeriaGrus japonensis)showed sudden weakness and died the day after medical treatment. A hemogram of the crane showed severe leukocytosis. A large number of comma and round shaped protozoan parasites were found in the cytoplasm of the monocytes and/or lymphocytes. The protozoa was similar to Hepatozoon sp.morphologically but it could not be defined because of the possibility of parasitemia caused by Eimeria sp. Pathological changes consisted of severe hepatosplenomegaly. Histopathologically, a focal necrosis in the liver and infiltration of inflammatory cells in the spleen with numerous protozoan parasites were observed. Protozoan infection of cranes must be considered in zoo and wild life management.
Adult sika deer(Cervus nippon)were inoculated with bovine viral vaccines[infectious bovine rhinotracheitis(IBR), Akabane disease(AD), bovine virus diarrhea-mucosal disease(BVD-MD) and parainfluenza type 3(PI-3)]to observe clinical signs and serological response. No animal exhibited clinical signs of respiratory and intestinal diseases. Serologic response was monitored using serum neutralization test for IBR, AD and BVD-MD, and hemagglutination inhibition test for PI-3. Except IBR, the antibodies for each virus were detected as early as 2 weeks post-inoculation and in almost all animals remained seropositive for >12 weeks. IBR antibody was not detected consistently by one-time vaccination but after second-time vaccination it was detected and persisted >10 weeks with low titers.
A seroepidemiological examination of 8 bovine viral pathogens was conducted on free-ranging and farmed sika deer(Cervus nippon)of Northern Japan. Blood samples were collected from 156 of these deer at 7 locations in Aomori, Iwate and Miyagi prefectures during 1991 through 1993. Antibodies to bovine corona virus(95%), bovine rotavirus(45%), Akabane disease virus(38%), bluetongue virus(25%), parainfluenza virus-3(18%), bovine virus diarrhea-mucosal disease virus(3%)and bovine herpesvirus 1(1%)were detected. No serologic reactor to bovine leukosis virus was found. The pathogenicity of these bovine viruses for the sika deer has not been well documented, but it has been suggested that these deer could be important viral reservoirs for some bovine viral pathogens in Japan.
A rare case of lung carcinoma originating from the left cranial lobe in an over 12-year-old male clouded leopard was studied. Grossly, a large nodule, 85×55×60 mm, in the left cranial lobe, and several small metastatic nodules were observed in the left lung. Dissemination in the left pleura and distinct metastasis in the tracheobronchial lymph nodes and spleen were observed. Microscopically, the pulmonary masses consisted of infiltrative growth of lung carcinoma. The tumor cells were round to cuboidal with high cell atypia and showed irregular glandular patterns. Mitotic figures were common. The tumor cells were positive for keratin and cytokeratin AE 1. Metastasis was observed in the pleura, tracheobronchial lymph nodes, spleen and adrenals. The present case was classified as a bronchiolar-alveolar carcinoma, undifferentiated type.
A 47-year-old male Asian elephant(Elephas maximus)died without clinical signs in 1994. Grossly, gallstones, splenic atrophy, and hemorrhages in adrenal cortex and cardial left ventlicle were observed. Microscopically, atrophic spleen showed severe lymphoid atrophy, and multiple hemorrhagic foci were seen in adrenal zona fasciculata. In the heart, myocardial hemorrhages and vein thrombosis were observed in left ventricle. β-amyloid protein was positive in the cerebral vessel wall. So-called"Sudden death"syndrome was suspected in the present case.