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This study investigated effects of maternal overnutrition on gonadal development and pituitary-gonadal gene expression in cattle fetuses at mid- and late-gestation. Twenty-seven multiparous dry cows were fed either high (ad libitum, H) or moderate (M) intake of the same diet. Twelve cows from H (n = 6) and M (n = 6) intake carrying females fetuses were euthanized at 199 and 268 d of gestation (DG; n = 3 for H or M on each DG). Fifteen cows from H (n = 6) and M intake (n = 9) carrying male fetuses were euthanized at 139, 199, and 241 DG (n = 2 for H and n = 3 for M on each DG). Fetal gonads and pituitary gland were sampled for gene expression and histological analyses. Sex-specific responses to maternal intake were observed. Primordial and total follicle numbers were lower in fetal ovaries from H than in M intake cows. These results were the reverse for preantral and antral follicles. Volumetric proportion and diameter of seminiferous cord were lower in fetal testis of H than M intake cows. The expression level of FSHB was greater in pituitary gland of the female fetus from H compared with M intake cows, irrespective of DG, whereas LHB gene expression did not differ. In males, FSHB and LHB gene expression levels were similar between maternal intake groups. Fetal ovarian expression of P450 aromatase, StAR, BMPR2, TGFBR1, GDF9, FSHR, Bax, and CASP3 genes were higher in H than in M intake cows, irrespective of DG. Fetal testicular expression of StAR, HSD17B3, IGF1, IGF2, and IGF1R genes was higher in M than in H intake cows. The differences in gene expression for steroidogenesis, folliculogenesis, and apoptosis may explain the distinct pattern of follicular growth between offspring of M and H intake cows. By contrast, the lower volumetric proportion, diameter, and length of seminiferous cord may relate to decreased gene expression in fetal testis from H intake cows. In conclusion, maternal H intake seems to affect fetal ovarian follicular growth and number of follicles, which may affect the size of ovarian reserve in their offspring. In male fetus, maternal H intake seems to disturb testicular development and may have implications on sperm production. The underlying mechanism of differential gene expression and the effect on offspring reproductive potential should be the focus of further research, especially considering larger sample size, reducing the chance for type I errors. [ABSTRACT FROM AUTHOR]

The periparturient period presents major physiological challenges for the dairy cow. It is a period that is affected by metabolic stressors, major changes in endocrine status, and altered immune function, which together result in an increased risk of disease. Immunological, hematological, and metabolic profiles from the periparturient period of heifers (primipara) were compared with those of cows (pluripara) to test the hypothesis that at the time of calving they have qualitatively different peripheral blood profiles. Blood samples were collected from 22 Holstein-Friesian animals on 3 occasions: approximately 2 wk before calving, within 24 h after calving, and approximately 2 wk after calving. Quantitative PCR was used to measure the expression of a selected set of cytokines and receptors by peripheral blood leukocytes. Additional analyses included hemoglobin concentration, red cell, platelet and white cell counts (total and differentiated), and clinical diagnostic biochemical profiles. Total leukocyte counts, neutrophils, and lymphocytes were higher in heifers than cows before calving and within 24 h after calving. Alkaline phosphatase was consistently higher in heifers than cows and several significant differences were observed between the 2 groups with regards to cytokine and cytokine-receptor mRNA expression. The results warrant further investigation from the perspective of identifying risk factors for metabolic and parturient disease in dairy cattle. [ABSTRACT FROM AUTHOR]