Positive correlations of age and parity with plasma anti-Müllerian hormone concentrations in Japanese Black cows.

Anti-Müllerian hormone (AMH) is secreted from the preantral and small antral follicles. It regulates follicle development and inhibits follicular atresia. This study examined how age, parity, and time after parturition affect plasma AMH concentrations in Japanese Black cows. We measured plasma AMH concentrations in primiparous, secundiparous, and multiparous (third parity or higher) cows at four time points: day 2 (day 0 = parturition), day 8, 2 days before first postpartum ovulation (pre-1stOv), and 12 days after first ovulation (post-1stOV). We observed a positive correlation between plasma AMH concentration and age (in months) and parity on day 2, day 8, and post-1stOV, but not on pre-1stOv. The multiparous cows had higher AMH concentrations than primiparous cows throughout the postpartum period (P < 0.05). Our results indicate that age and parity significantly influence plasma AMH concentrations in Japanese Black cows during the voluntary waiting period.

Positive correlations of age and parity with plasma concentration of macrophage migration inhibitory factor in Japanese black cows.

Plasma Macrophage migration inhibitory factor (MIF) concentration correlates positively with age, and negatively with self-rated health in women, and optimal MIF concentration may promote proper reproductive function. This study was conducted to evaluate the hypotheses that plasma MIF concentration changes with parturition or postpartum first ovulation, and that age in months and parity correlate with plasma MIF concentration in Japanese black cows. Western blotting utilizing an anti-MIF mouse monoclonal antibody of various tissues and plasma from females indicated that MIF expression was stronger in the anterior pituitary than in other tissues. We developed a competitive EIA utilizing the same anti-MIF mouse monoclonal antibody with sufficient sensitivity and reliable performance for measuring bovine plasma samples. We then measured MIF concentrations in bovine plasma collected from 4 weeks before parturition to 4 weeks after postpartum first ovulation. There was no significant difference in plasma MIF concentration pre- and post-parturition, or before and after the postpartum first ovulation. Plasma MIF concentrations were positively correlated (P < 0.01) with parity (r = 0.703), age in months on the day of parturition (r = 0.647), and age in months on the day of the postpartum first ovulation (r = 0.553) when we used almost all data, except for that from a third-parity cow with an abnormally high plasma MIF concentration. We therefore concluded that plasma MIF concentrations may increase with age in months and parity, but do not change either before and after parturition or before and after postpartum first ovulation in Japanese black cows.

Detection of novel kobu-like viruses in Japanese black cattle in Japan.

During surveillance for bovine diarrhea of unknown causes in Japanese black cattle in Kagoshima Prefecture, Japan, we found two types of novel kobu-like viruses in fecal samples of calves. Sequence analyses revealed that they had L protein and 2A protein with H-box/NC sequence motif, which are present in kobuviruses. Phylogenetic analysis revealed that they were related to kobuviruses; however, they clustered apart from other kobuviruses. In the prevalence study of two types of novel kobu-like viruses, 16.9% and 10.4% prevalence of these viruses were observed in the feces of diarrheal calves in this area.

Full genome analysis of bovine astrovirus from fecal samples of cattle in Japan: identification of possible interspecies transmission of bovine astrovirus.

A viral metagenomics approach was used to investigate fecal samples of Japanese calves with and without diarrhea. Of the different viral pathogens detected, read counts gave nearly complete astrovirus-related RNA sequences in 15 of the 146 fecal samples collected in three distinct areas (Hokkaido, Ishikawa, and Kagoshima Prefectures) between 2009 and 2015. Due to the lack of genetic information about bovine astroviruses (BoAstVs) in Japan, these sequences were analyzed in this study. Nine of the 15 Japanese BoAstVs were closely related to Chinese BoAstVs and clustered into a lineage (tentatively named lineage 1) in all phylogenetic trees. Three of 15 strains were phylogenetically separate from lineage 1, showing low sequence identities, and clustered instead with an American strain isolated from cattle with respiratory disease (tentatively named lineage 2). Interestingly, two of 15 strains clustered with lineage 1 in the open reading frame (ORF)1a and ORF1b regions, while they clustered with lineage 2 in the ORF2 region. Remarkably, one of 15 strains exhibited low amino acid sequence similarity to other BoAstVs and was clustered separately with porcine astrovirus type 5 in all trees, and ovine astrovirus in the ORF2 region, suggesting past interspecies transmission.