A study on the early pregnancy diagnosis by changing of plasma progesterone concentration and morphology of ovary in pregnancy and non -pregnancy cows

In order to evaluate conception rate of Hanwoo in northwestern region of Gyeongsang-nam-do, we investigated conception rate and reduction of reproductive disorder rate after artificial insemination (AI) in 1,000 heads of breeding cows, This study showed that 80.9% of cows were classified as fertility after 1st and 2nd AI. For a accurate pregnancy diagnosis with practicing ovariectomy and histeotomy, we comparatively investigated each of 80 slaughtered cows, including 30 of non-pregnancy, and used enzyme-linked immunosorbent assay (ELISA) for estimation of plasma progesterone concentration and serum luteal hormone. The mean diameter of non-pregnant corpus luteum is and that of pregnant corpus luteum is . This indicates that corpus luteum is more developed in the ovary of pregnant than non-pregnant cows (P in early stage (1-3 month), in middle stage (4-6 month) and , in last stage (7-9 month). This indicates that corpus luteum in middle and last stage is more significantly developed than that of early stage(P and that of pregnant corpus luteum . Thus, it was more significantly increased in pregnant corpus luteum(P. in estrus (corpus albicans). The plasma progesterone concentration according to gestation period was high in proportion to the degree of development in corpus luteum and more significantly increased (P at parturition. As a consequence, we can practice the early pregnancy diagnosis by confirming non-pregnancy when the mean plasma progesterone concentration is below 1ng/ml 19 to 22 days after AI and this can be available to diagnose reproductive disorder.