This study aimed to investigate the relationship between increases in luteinizing hormone (LH) profiles induced by gonadotropin-releasing hormone (GnRH) in the serum and vaginal mucus of Japanese Black beef cows. A peak serum LH concentration was identified at 2.5 h post-GnRH administration, with serum concentrations returning to near-pre-GnRH-administration values after 6.5 h, whereas the peak LH concentration of vaginal mucus was identified 4.5 h after GnRH administration.

Serum amyloid A (SAA), C-reactive protein (CRP), and some energy substrates were evaluated in 40 healthy dairy cows. Along lactation, SAA and CRP tended to increase, peaking at 240–300 d, and decrease thereafter. Along gestation, they increased in the first 4 months and then decreased. SAA and CRP were very variable and positively correlated with each other in both phases and with glucose during pregnancy, suggesting that they may play a role in physiological and non-pathological processes.

The aim of this review was to evaluate the relationship between the body condition of cows and reproduction. Reproduction was evaluated from the viewpoint of animal husbandry traits, ovarian activity and embryo transfer.

The objective of this study was to clarify the interaction between postpartum endometritis and cystic ovarian disease (COD) in Japanese Black cattle. The prevalence of endometritis increased in cows with COD. The percentage of polymorphonuclear neutrophils in smears is high in cows with COD at 40–60 d postpartum. The results suggest that Japanese Black cattle with COD have potential implications for endometritis at 40–60 d postpartum compared to the cows with normal ovarian cycle.

We tested whether prostragladin (PG) injection on day 30 pp and detection of estrus can affect the efficacy of injection on days 5 and 6 in the TAI protocol compared to the Cosynch protocol. The proportion of cows in estrus on the day of TAI was higher than those that received two PGs than those cows that received one PG. Treatments with PG on days 5 and 6 after the first GnRH injection increased P/AI.