In recent years, diagnostic imaging has advanced in the veterinary field, and digital radiography has become more common in livestock animals. This review summarizes image characteristics obtained by different imaging parameters and the pitfalls of image interpretation using actual clinical cases.

　Low milk fat syndrome in dairy cows is characterized by marked milk fat depression. Diagnosis and treatment are difficult because it is often asymptomatic. Its causes are various and include nutritional factors such as changes in the rumen fermentation environment as well as genetic and seasonal factors. In 2016, the bulk milk fat percentage decreased to 3.2% in the summer and 3.35% in the winter at a dairy farm located in Fukuoka Prefecture. Low milk fat syndrome was diagnosed based on the farm record of increased percentage（33%）of lactating cows producing low fat milk（≤3.2% fat）in January 2017. The lactose percentage in bulk milk was unchanged in the summer but increased in the winter of 2016. After a detailed review of the farm records, subacute rumen acidosis was suspected as a possible primary cause based on the increased lactose percentage, increased ratio of concentrate feed and decreased ratio of ruminating cows as well as the large number of cows with a fecal consistency score of ≥4. After appropriate treatment and improved management, the bulk milk fat percentage increased to ≥3.6% in the summer of 2017. In addition, the milk fat percentage significantly increased from 3.29 ± 0.80%（mean ± SD） to 3.73 ± 0.56%（p < 0.05）, and the ratio of lactating cows producing low fat milk（<3.2%）significantly decreased from 33% to 16%. Thus, production records and farm monitoring seem to be a useful approach for the diagnosis and improvement of low milk fat syndrome.

　A 10-year-old Japanese Black cow was presented for prolonged gestation and underwent induced parturition in April 2016. Because of a previous history of theileriosis, a hematological examination was performed. A blood sample collected in a vacuum tube for serum separation showed delayed blood clotting, and the blood smear revealed microorganisms on the surface of the red blood cells （RBCs）. On the basis of these findings, hemoplasmosis was suspected. No clinical symptoms were evident, and RBC count, hematocrit and hemoglobin concentration were within the lower reference ranges immediately before parturition and until two days after parturition. Candidatus Mycoplasma haemobos was detected from a blood sample by real-time polymerase chain reaction（PCR）. The percentage of pathogen-positive RBC was highest（23.9%）a day before parturition and subsequently declined, accompanied by normalization of the blood clotting time a day after parturition. The percentage of eosinophils also decreased over time from the day before to immediately before parturition. In addition, blood smears immediately before parturition and up to two days after parturition showed the presence of Theileria sp. Although the immunosuppressed status in the peripartum period appeared to play a role in the presence of hemoplasma in blood, parasitemia was not observed in other PCR-positive cows raised on the same farm either before or after parturition.