In dairy cows, bacterial, inflammatory uterine diseases such as metritis and endometritis are associated with ovarian dysfunction. However, the exact mechanism of how ovarian dysfunction develops from these uterine diseases is unclear. Lipopolysaccharide （LPS）, a component of the bacterial cell wall, influences physiological events in animals, although there are few reports on the effect of LPS on ovarian function. In this review, we discuss biological insights into the pathogenesis of post-metritis ovarian dysfunction by highlighting some research findings that include post-parturient high blood LPS concentrations, varying LPS concentrations in the follicular fluid within the same individual follicles and association between high follicular LPS concentration and low steroid hormone production in metritis cows.

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Bovine leukemia virus （BLV） is the etiological agent of enzootic bovine leukosis （EBL）, which is a notifiable infectious disease of cattle in Japan. The number of EBL notifications and the rate of BLV infections have increased in recent years. BLV causes lifelong infection due to integration of the provirus into the host chromosome. There is no effective vaccine or treatment for BLV infection or EBL development. Therefore, on-farm BLV control programs primarily center on quarantine and replacement of infected cattle. Accurate diagnosis is important to maximize the effectiveness of these eradication programs. Diagnostic methods for BLV infection can be divided into two groups: those that detect the BLV antibody and those that detect proviral DNA. In Japan, enzymelinked immunosorbent assays, passive hemagglutination tests and agar gel immunodiffusion tests are the most common methods used for detection of the BLV antibody. Real-time polymerase chain reaction （PCR） and nested PCR are the primary techniques employed for detection of proviral DNA. Each method has a different sensitivity, specificity and window period. Therefore, choosing the appropriate diagnostic method is important. Furthermore, blood-sampling mistakes can occur in large animal clinical facilities. Well-planned testing, which includes accurate interpretation of the diagnostic outcome and addressing blood-sampling mistakes, leads to effective BLV countermeasures. In this article, methods for diagnosing BLV infection and interpretation of each result are reviewed.

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Neutralizing antibodies to bovine viral diarrhea virus （BVDV） type 1 and 2 strains were measured on 1,849 serum samples collected at 50 dairy farms from 2007 to 2011 in order to understand the BVDV infection status in dairy cattle in Nagasaki Prefecture. As a result, the central, north and south areas of the prefecture as well as the Goto area showed high positive rates for type 1, while the type 2 infection rate was low in the Goto area （4.2%） but high in the other three areas. Positive infection rates and antibody titers for type 1 and 2 were higher in the cattle introduced from other prefectures compared to home-produced cattle. Moreover, the antibody titers in homeproduced cattle raised with introduced ones increased in proportion to the rates of cattle introduced from other prefectures. In addition, when 994 serum samples with antibody titers less than 1:2 were used for genetic testing to detect persistently infected （PI） animals, the type 2 gene was detected from one sample. This cow was suspected of being PI, but infection was not confirmed because of culling. The geometric mean titer for type 2 （202.4） was significantly higher than that for type 1 （28.5） in cattle raised in the same barn. From these results, it was confirmed that BVDV type 1 was widely distributed in the prefecture and that type 2 was also prevalent except in the Goto area. The infection risk for BVDV was likely higher in the farms raising cattle from other prefectures. In addition, the cow suspected of being PI was a possible source of type 2 infection in the farm. It was concluded that isolation and physical examination of introduced cattle, vaccination for both types and aggressive pathological confirmation of suspected PI cattle are important for prevention and reduction of the prevalence of BVDV infections.

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The present case report describes the clinical and histopathological characteristics as well as the surgical outcome of malignant melanoma in two calves. Case 1 was a 6-month-old Japanese Black steer with a soft mass （5 cm × 4 cm） on the right shoulder detected 1 month before. The mass was surgically separated from surrounding tissue and resected. Histopathologically, the mass was occupied by cells containing abundant cytoplasmic black granules, seemingly melanin pigments. Infiltration of these cells from the dermis into the subcutaneous tissue was also noted. From these findings, the mass was diagnosed as malignant melanoma. The steer showed good growth and there was no evidence of metastasis at 70 days postoperatively and was subsequently entered into the 25-month fattening stage. Case 2 was a 7-month-old Japanese Black heifer with a mass （5 cm × 5 cm） on the left abdomen. The mass was soft, covered with white hair and well separated from surrounding tissue. The mass was surgically resected. By histopathological examination, proliferation and infiltration of cells occupying the mass were noted from the dermis to the muscle layer. These cells were also observed between muscle fibers around the mass. Vascular invasion was confirmed by the presence of black granules in endothelial cells of a small artery, and the mass was diagnosed as malignant melanoma. The heifer was euthanized at Day 136 due to recurrences on the right buccal and dorsal lumbar regions. Necropsy revealed metastases in the lungs, liver, spleen and fascia of the hind limb. These cases suggest that preoperative biopsy of the mass and regional lymph nodes as well as histopathological evaluation of mitotic figures, vascular invasion and surgical margin may be useful for diagnosis and determining the prognosis of malignant melanoma.

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