To obtain basal blood biochemical data during fattening for Japanese Black heifers in Kagoshima Prefecture, serum samples from 1,381 clinically healthy, 9- to 30-month-old Japanese Black heifers, which were raised on 61 farms, were collected at five time points during fattening [n = 257 at 9~13 months old (early fattening stage), n = 283 at 14~16 months old (early middle stage), n = 266 at 17~19 months old (late middle stage), n = 325 at 20~23 months old (late stage) and n = 250 at 24~30 months old (finishing)]. The mean activities of aspartate aminotransferase and gamma-glutamyl transferase were high from the late middle to late stages. The mean concentration of albumin was 3.5g/dℓ from the late middle to late stages. The mean concentration of total cholesterol was above 140mg/dℓ after the early middle stage. The mean concentration of inorganic phosphorus decreased gradually. The mean concentration of vitamin A decreased gradually from the early stage, and it was 39 IU/dℓ in the finishing stage. The mean concentration of vitamin E was above 200μg/dℓ after the early middle stage. These results suggest that blood biochemical values of Japanese Black heifers in Kagoshima Prefecture are different depending on the fattening stage and may be used as an index for prevention and diagnosis of production diseases.

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Currently, mastitis is commonly treated with antibiotics, although in some cases the desired effect cannot be achieved when the causative organism is resistant to antibiotics. This study investigated the effect of a Sasa senanensis extract (SanSTAGE), which has shown immunostimulatory effects in humans, on chronic mastitis in Holstein cows. A total of 32 cows with mastitis caused by gram-positive bacteria were used in the study; SanSTAGE was fed to 26 cows for 2 weeks, while the remaining 6 cows were untreated as controls. Milk and blood samples were collected before and 1 and 2 weeks after the start of treatment and 1 week after the end of treatment (Weeks 0 to 3). For milk, somatic cell count (SCC), the modified California mastitis test and bacterial isolation/culture were performed. Udders were classified into two groups according to the pre-treatment SCC: a high SCC group (≧ 200,000 cells/mℓ; 26 udders in treated cows) and a low SCC group (< 200,000 cells/mℓ; 15 udders in treated cows). Seven udders from the control group were similarly classified. For blood, acute-phase protein levels (21 treated cows and 2 controls), leukocyte subpopulations and cytokine gene expression (12 treated cows) were analyzed. Pre- vs. post-treatment comparisons were performed for each parameter. In the treated group, cows with high SCC showed a significant decrease in SCC at Weeks 2 and 3, while cows with low SCC showed a significantly increased SCC at Week 1. No significant change was observed in SCC in the untreated group. The results of the modified California mastitis test did not change significantly in both groups. By bacterial isolation/culture from milk, the same bacteria were isolated throughout the study period in both groups. Among acute-phase proteins, haptoglobin significantly increased at Week 1 in treated cows. Among leukocytes, a significant increase was seen in the number of WC1-N1⁺ cells at Week 2 in treated cows. In the treated group, furthermore, MX2 gene expression was significantly upregulated at Week 1. These results suggest the possible use of 2-week continuous feeding of SanSTAGE as an adjunct therapy in the treatment of chronic mastitis, since the treatment led to activation of some immune components and, in cows with high SCC, a decrease in SCC.

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Milk fever is a hypocalcemic disorder seen at the onset of lactation in dairy cows. Although various methods, such as low-calcium prepartal diet, vitamin D₃ (VD₃) injection, low dietary cation-anion difference forages and oral calcium salts, have been practiced for the prevention of milk fever, all of these methods remain controversial. Since the average milk yield per cow has been increasing in recent years, milk fever is estimated to be at even higher risk. However, its incidence rate has not increased remarkably. The aim of this questionnaire survey was therefore to investigate milk fever preventive strategies implemented in Kamikawa District in Hokkaido, one of the high-yielding dairy farming areas in Japan. The study was conducted in a sample of randomly selected 82 dairy farmers and all of the 41 veterinary practitioners registered with the agricultural mutual aid association of Kamikawa District using a questionnaire form, which included five questions prepared separately for dairy farmers and veterinary practitioners. The results showed that dairy farmers preferred a combination of a prepartal preventive method, either by low-calcium prepartal diet or VD₃ injection, and postpartal intravenous or subcutaneous calcium salt. Satisfaction in milk fever prevention was higher among the farmers compared to preventive methods used for other important diseases of dairy cows such as reproductive disorders, mastitis and hoof disorders. The veterinary practitioners were also satisfied with this combination of preventive methods. These results also indicate that parenteral administration of calcium salt plays an important role in prevention of milk fever.

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[in Japanese]

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