Plasma estrogen and progesterone concentrations in relation to embryo yield in superovulated buffaloes

ABSTRACT

The relationships between plasma estradiol-17 beta and progesterone concentrations and each of the ovarian response and embryo yield were investigated in thirteen adult buffaloes. Superovulation was induced in these animals using FSH in combination with prostaglandin F2 alpha. Blood samples were collected daily for hormonal analysis from the day of treatment [day-4] to the day of embryo recovery [day 6 post-estrus]. The results revealed that 30.77% [G I] of the treated buffaloes did not respond to the superovulatory treatment [developed two or less copora lutea] whereas 69.23% [G II] responded to FSH-treatment by experiencing more than two corpora lutea. Progesterone [P[4]] concentration at the initiation of superovulation was higher [P < 0.01] in G II than in G I. This difference continued during all treatment days [days -4 to -1] and reappeared at day three post-estrus onwards. Estradiol-17B [E[2]] level differed significantly [P < 0.01] between the two groups on the day of estrus as well as one day before and after estrus. In G II, significant correlations existed between the number of recovered embryos and P[4] concentration at the initiation of superovulation, at estrus and on the day of embryo recovery. This revealed the P[4] level at the start of superovulation can be used as a reliable method to predict the embryo yield in buffalo species. E[2] concentration was correlated with the number of recovered embryos on the day of estrus and on the day of embryo collection. On the other hand, no correlations were found between P[4] or E[2] levels and the ovulation rate on the first day of treatment or on the day of embryo recovery. Hormonal profiles in buffaloes of G II showed marked changes in pre-and post-ovulation phase. However, in animals of G I no significant changes in hormone concentration were noted and this was considered a clear indication of the ovaries that are non-responsive to exogenous gonadotrophin