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Acid–Base Parameters and Steroid Concentrations in Pre-Ovulatory Follicles and Plasma of Lactating Dairy Cows with Spontaneous and Synchronized Oestrus or Follicular Cyst


Author's address (for correspondence): Hassan A. Hussein, Department of Theriogenology, Faculty of Veterinary Medicine, Assiut University, 71526 Assiut, Egypt.



The study aimed to compare the acid–base balance and steroid concentrations between follicular fluids (FF) of pre-ovulatory follicles derived from a spontaneous oestrus (SO), synchronized or induced oestrus (IO) and follicular cysts (CYS) and between FF and blood in dairy cows. Forty-two dairy cows were included in this study. The animals were allocated to three groups: SO (n = 23); IO (n = 11) using GnRH at day 0 and day 9 and PGF2α at day 7; and animals with CYS (n = 10). The follicular fluids (FF) were aspirated from the cyst/pre-ovulatory follicles (∅ ≥ 15 mm) after SO and after second GnRH dose in IO by transvaginal ultrasound-guided ovum pick-up technique. Blood samples (BL) were collected in heparinized vacutainer tubes. The oxygen tension (pO2) in FF of IO was higher (p < 0.05) than in SO and CYS groups. There were negative correlations (p < 0.001, r = −0.89) between FF and blood pO2. The carbon dioxide tension (pCO2) and lactate level in FF of CYS group were higher (p < 0.05) than in SO and IO groups. There were negative correlations (p < 0.01, r = −0.73) between blood and FF pO2. Oestradiol-17β concentration in pre-ovulatory follicles and plasma of the SO group was higher (p < 0.001) than in IO and CYS groups. Progesterone concentration in pre-ovulatory follicles and plasma of the SO and IO groups was lower (p < 0.01) than in CYS group. Plasma androstenedione concentration in SO and IO groups was higher (p < 0.05) than in CYS group. In conclusion, acid–base parameters, E2 and P4 levels in the follicular fluid of both IO and CYS groups were deviated greatly from the physiological level (disturbances of intrafollicular/intracystic environment), which may affect the quality of both the oocyte and the granulosa cells.