ABSTRACT. To clarify the relationship between tumor necrosis factor (TNF) and insulin resistance in dairy cows affected with fatty liver, naturally occurring cases were investigated. The affected cows were classified into following three groups according to histopathologic findings of the liver: mild fat droplet deposition (group 1; n=11), severe fat droplet deposition (group 2; n=10), and cloudy swelling (group 3; n=8). Serum TNF activities in Group 2 (8.67 ± 2.16 U/ml) and Group 3 (11.65 ± 1.92 U/ml) were significantly higher than that in Group 1 (3.57 ± 0.81 U/ml) (p<0.05). The insulin-tolerance tests showed that the insulin-stimulated glucose disposal rates (GDR) in Group 2 (27.6 ± 7.8%) and Group 3 (15.8 ± 9.1%) were significantly lower than that in Group 1 (41.7 ± 9.8%). There was a significant negative correlation between serum TNF activity and GDR in affected cows (r=-0.56, p<0.01). These results indicate that serum TNF activity is correlated with insulin resistance in cows with fatty liver. KEY WORDS: fatty liver, insulin resistance, TNF activity.

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ABSTRACT. Changes in the activities of serum cytokines and in acute phase response were observed in dairy cows with naturally occurring coliform mastitis. Seven cows with severe mastitis showed systemic and mammary inflammatory response throughout the observation period, and 11 cows with mild mastitis recovered and were able to be milked within 3 days of onset of mastitis. Serum interleukin (IL)-1 and tumor necrosis factor (TNF) activities were higher in the severe group than in the mild group at the first appearance of symptoms. Elevated IL-1 activity was evident in the severe group throughout the observation period. Serum α-1-acidglycoprotein (α1AG) concentration began to rise with the beginning of mastitis in the severe group, and peaked at 9 days. Serum haptoglobin (Hp) concentrations peaked at 3 days, and decreased gradually after 3 days in the severe group. These results showed that there are dynamic changes in serum IL-1 activity and in serum α1AG and Hp concentrations in cows with severe coliform mastitis. KEY WORDS: acute phase protein, coliform mastitis, cytokine.

ABSTRACT. In order to obtain basic information about bovine interleukin-1 (IL-1β), levels of IL-1β in sera and milk of clinically normal mature Holstein cattle before and after parturition and in sera of newborn calves were examined by ELISA. The level of IL-1β was undetectable in sera of mature cattle around the time of artificial insemination, but the concentration gradually increased and reached a peak at parturition and then decreased again to an undetectable level. IL-1β in milk was detected on the day of parturition but not thereafter. IL-1β mRNA was detected by reverse transcription-polymerase chain reaction in the cells from milk collected during 20 days before and 2 to 3 days after parturition, but was not detected thereafter. Although IL-1β was not detected in all the sera of newborn calves, the concentration transiently increased with peak titers on day 3 and became undetectable by day 14 after birth. Newborns that showed serum IL-1β on day 3 had been fed on colostrum in which the IL-1β concentration was significantly higher than that in colostrum that had been fed to newborns having no detectable IL-1β on day 3. These results indicate that IL-1β is induced in association with pregnancy in healthy dairy cattle and that the cytokine might be transferred to neonates via colostrum. -KEY WORDS: cattle, colostrum, interleukin-1, pregnancy.

MicroRNA (miRNA) in tissue and liquid samples have been shown to be associated with many diseases including inflammation. We aimed to identify inflammation-related miRNA expression level in the bovine mastitis milk. Expression level of inflammation-related miRNA in milk from mastitis-affected and normal cows was analyzed using qPCR. We found that expression level of miR-21, miR-146a, miR-155, miR-222, and miR-383 was significantly upregulated in California mastitis test positive (CMT+) milk. We further analyzed these miRNA using a chip-based QuantStudio Digital PCR System. The digital PCR results correlated with those of qPCR, demonstrating upregulation of miR-21, miR-146a, miR-155, miR-222, and miR-383 in CMT+ milk. In conclusion, we identified miRNA that are upregulated in CMT+ milk. These miRNA exhibited sensitivity and specificity greater than 80% for differentiating between CMT+ milk and normal milk. Our findings suggest that inflammation-related miRNA expression level in the bovine milk was affected by mastitis, and miRNA in milk have potential for use as biomarkers of bovine mastitis.