cjs-201504-0003 ArticleInAPeriodical 2015 Czech Journal of Animal Science 60 4 164-170 KourousekosG.D. TheodosiadouE.K. LymberopoulosA.G. BelibasakiS. BoscosC. Effect of prolonged aflatoxin B<sub>1</sub> administration on blood serum oestradiol-17β and progesterone concentrations of goats during the anoestrus period -- The effect of prolonged aflatoxin B<sub>1</sub> (AFB<sub>1</sub>) administration on blood serum oestradiol-17β and progesterone concentrations in goats during the anoestrus period was investigated. Thirty Greek indigenous goats were used; 10 goats received, per os, 50 μg (treated group T50) and 10 goats received 100 μg (treated group T100) AFB<sub>1</sub>/day/head, respectively, for 31 days, while 10 goats served as controls (C). Blood samples were collected from each goat twice a week to determine serum oestradiol-17β and progesterone concentrations by radioimmunoassay. Multiple linear regression analysis revealed a significant (P &lt; 0.05) positive dependence of blood serum oestradiol-17β concentration over group (C = 0, T50 = 50, T100 = 100), in a dose-dependent manner, and a significant (P &lt; 0.05) negative dependence over time (0-31 days, from the onset to the end of AFB<sub>1</sub> administration). Linear regression analysis revealed a significant (P &lt; 0.05) positive dependence of blood serum progesterone concentration over group (C = 0, T50 = 50, T100 = 100), in a dose-dependent manner. Pearson's correlation coefficient revealed a significant (P &lt; 0.05) positive correlation between blood serum oestradiol-17β and progesterone concentration, but only in the goats of the control group. In conclusion, the prolonged administration of 100 or even of 50 μg AFB<sub>1</sub>/day/head during the anoestrus period, increased blood serum oestradiol-17β and progesterone concentrations of goats, in a dose-dependent manner, and in the treated groups disturbed the positive correlation between oestradiol-17β and progesterone concentration shown in the goats of the control group.