Biochemical and steroid concentrations in follicular fluid and blood plasma in different follicular waves of the estrous cycle from normal and superovulated beef cows.

The objectives of the current study were to (i) define the changes in size and number of follicles populations, (ii) determine the follicular fluid (FF) biochemical and steroid concentrations collected from different-sized follicles (5-9 and ≥ 10 mm) and (iii) compare between biochemical and hormonal concentrations of FF with those in blood plasma in relation to the first two follicular waves of the estrous cycle (days 4 and 13) from normal and cows primed for superovulation. After estrus, cows (n=20) were assigned randomly to each of four treatment groups. Group 1: ovariectomy on day 4 (day 0 = ovulation). Group 2: FSH treatment and ovariectomy on day 4. Group 3: dominant follicle ablation (DFA) on day 8 and ovariectomy on day 13. Group 4: DFA on day 8, FSH treatment and ovariectomy on day 13. Blood samples were collected and FF was aspirated and pooled per follicle class within cow to determine glucose, urea, triglycerides, cholesterol, total protein, albumin, lactate dehydrogenase, alkaline phosphatase, gamma-glutamyl transpeptidase, aspartate aminotransferase, creatin phosphokinase, estradiol-17β and progesterone concentrations. Follicular class×follicular wave interaction was detected for albumin and lactate dehydrogenase. Results showed that FF concentrations of cholesterol increased from medium to large follicles and decreased for urea and aspartate aminotransferase. Tryglycerides and total protein were greater in the second than in the first follicular wave. FSH treatment decreased FF alkaline phosphatase, E2 and P4 concentrations. Quantitative differences between these fluids are discussed with respect to follicular development.