Estrus refers to the phase when the female is sexually receptive and ovarian follicles are maturing under regulation by gonadotropic hormones. Pregnancy is the process of fertilization and development of offspring. To study the ovarian proteome changes of Tianzhu white yak between estrus and pregnancy, 12 ovaries from 6 pregnant and 12 ovaries from 6 estrous yak cows were used and ovarian proteins were separated by 2-DE and analyzed by PDQuest 8.0 software. 20 differentially expressed spots were identified with MALDI-TOF-TOF/MS. Totally 15 different proteins were detected. COMMD1, PMK, TM, CG, VIM, ALDH1A1, SNX7, MRPs, MDH were related to steroid hormone synthesis and regulation, energy metabolism, pregnancy maintenance and early embryo development. These differentially expressed proteins might be useful to detect protein candidates of ovarian function, clarify the mechanisms of ovarian development and understand the reproductive physiological mechanism of the Tianzhu white yak.

Key words: Estrus, Ovarian proteomics, Pregnancy, Tianzhu white yak