ABSTRACT. The relationship among nutritional status, systemic insulin-like growth factor-I (IGF-I) and ovarian function early postpartum were investigated. A total of 27 Holstein-Friesian cows, 10 that cycled normally within 20 days postpartum, 5 diagnosed with follicular cysts, 8 with persistent corpus luteum (CL) after the first ovulation postpartum and 4 with inactive ovaries were used for the study. Blood samples were collected 1-3 times per week, for 60 days pre-and postpartum, for IGF-I, progesterone, estradiol, free fatty acids (FFA), blood urea nitrogen (BUN), and aspartate aminotransferase (AST) determination. Inactive ovary and cystic cows had a higher body condition score before calving and lost more condition than normal or persistent CL cows. Immediately postpartum, IGF-I levels were higher and rose sharply in cows that cycled normally than in cystic, inactive ovary or persistent CL cows. At calving and early postpartum, FFA was higher in inactive ovary and cystic than in normal and persistent CL cows. There was a significant strong positive relationship between IGF-I and BUN, and strong negative relationships between IGF-I and FFA and AST in all groups. There was a positive relationship between serum IGF-I and estradiol in normal cystic and inactive ovary cows. This study found that overconditioned cows during the dry period or at calving, lost more body condition postpartum. These cows also had a deeper and longer period of negative energy balance (NEB), poor liver function and low circulating IGF-I concentrations early postpartum. Such cows were likely to have poor reproductive function as seen in development of cystic ovaries, persistent CL and inactive ovary. Changes in serum IGF-I early postpartum may help predict both nutritional and reproductive status in dairy cattle.

ABSTRACT. Reproductive diseases after parturition are a serious problem in dairy cattle. It is important to predict postpartum reproducti ve diseases early and to develop prophylaxis. The objectives of this study were to demonstrate changes in the peripheral blood con centration of interleukin-6 (IL-6) before parturition, which was mainly produced by T helper 2 type (Th2) cells, and to investigate a correlation between the IL-6 concentration and the occurrence of the postpartum retained placenta, endometritis and/or follicular cyst in da iry cattle. Twenty-seven Holstein-Friesian cows were used for this study. Thirteen had no clinical disease, 8 had retained placenta, 4 were diagnosed with endometritis by vaginal inspection, and 2 were diagnosed with follicular cyst by rectal palpation at 1 and 2 months a fter parturition. Blood samples were collected 60 days pre-and post-partum. They used for IL-6, progesterone (P 4 ) and estradiol-17β (E 2 ) concentration determination. This study showed that the IL-6 concentration prepartum was higher than postpartum. Low levels of IL-6 and P 4 in peripheral blood prepartum tended to affect retained placenta and a high level of IL-6 prepartum tended to affect endometrit is. These results indicate that measurement of change in the IL-6 concentration during pregnancy is one useful tool for predicting crisis in postpartum reproductive diseases in dairy cattle. KEY WORDS: cattle, endometritis, interleukin-6, pregnant, retained placenta.

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The aim of this study was to determine the relationships between early follicular development, the time at which follicles appear in early stages of follicular development, and changes in the serum concentrations of FSH in the female bovine fetus. Thirty-five female bovine fetuses aged between 59 and 285 days, as estimated from the crown-rump length, were obtained from dams at an abattoir. Serum samples were separated from fetal blood obtained from the heart. Fetal ovaries were removed and weighed. The content of oestradiol in one of the fetal ovaries and the serum concentrations of FSH and oestradiol were determined using radioimmunoassay. Sections of the other ovary were examined histologically for the appearance and number of follicles. The follicles were divided into four stages: primordial, primary, secondary and early antral. The appearance of primordial, primary, secondary and early antral follicles was observed at day 74, day 91, day 120 and day 150, respectively. Serum concentrations of FSH in female bovine fetuses increased between day 120 and day 150 of gestation. Fetal serum concentrations of oestradiol increased from day 120. The number of early antral follicles increased from day 180 together with an increase in the fetal ovarian content of oestradiol. These findings indicate that, in the female bovine fetus as well as in adult cows, the number of follicles and stages of follicular development are associated with changes in the concentration of FSH.