Mean Number Of Small Follicles Research Articles

Effect of season and breed group on the follicular population and cyclicity of heifers under tropical conditions.

The aim was to determine the effect of season and breed group on follicular population, and presence and size of CL of heifers under tropical conditions. The seasons were hot-dry (March-June), hot-humid (July-October), and fresh-humid (November-February). Thirty Zebu (Brahman) and 38 F1 (Simmental × Brahman) heifers were used. Five evaluations were made in each season, at intervals of 7days, to assess ovarian activity by ultrasound. Follicles were classified as small (≤4mm), middle (4.1-8mm), and large (≥8.1mm) sizes, and also the size of CL, when present, was measured. Data were analyzed using analysis of variance and logistic regression procedures. Mean number of small follicles was 11.6 ± 2.3 with no effect of season, breed group, or their interaction (P > 0.05). Mean number of middle follicles was influenced by season and breed group; the highest average was found in the fresh-humid season (4.0 ± 0.2) and in F1 heifers (3.6 ± 0.2; P < 0.05). The highest mean number of large follicles was in the hot-humid season (1.4 ± 0.1; P < 0.05). The highest maximum follicle diameter (MFD) mean was registered in the hot-humid season (1.3mm; P < 0.05) and the lowest proportion of heifers with CL occurred in fresh-humid season (33.3%; P < 0.05). No effect of season, breed group, and interaction on the maximum diameter of the CL was found. In conclusion, season was a very important source of variation. Heifers in the hot-humid season had the largest follicles and MFD, and better cyclicity.

Characterization of ovarian follicular development and steroid profile during estrous cycle and seasonal anestrous in buffalo

The experiment was conducted to study ovarian follicular population, its diameter, steroid profile (estradiol 17ß and progesterone) and corpus luteum development during estrous cycle and seasonal anestrous in Murrah buffaloes. They were categorized into 2 groups based on the estrus signs i.e. cyclic (6) and anestrous (6) and subjected to ultrasound scanning of ovaries on day 0 (day of estrus in cyclic and day of first scanning in anestrous buffaloes), 6, 10 and 16 using B-mode scanner equipped with 6.0 MHz linear array transducer. Blood samples were collected on the above days for the estimation of the progesterone and estradiol-17ß. The mean number of small follicles on day 0 and 10 and medium follicles on day 10 were significantly higher within as well as between the cyclic and anestrous buffaloes, while mean number of large follicles on day 0, 10 and 16 were significantly higher in the cyclic as compared to anestrous buffaloes. However, mean number of total follicles were significantly higher in cyclic as compared to anestrous buffaloes on all the days of scanning. The maximum diameter of large follicle was observed in cyclic buffaloes on day 0 (1.40±0.49 cm). The diameter of CL increased with its development and reached to its peak on day 10 (1.39±0.04 cm), thereafter, it reduced on day 16 (0.72±0.30 cm) of the cycle. The mean serum progesterone concentration was significantly higher on day 6, 10 and 16 than day 0 of the estrous cycle indicating development of functional corpus luteum, however, mean serum estradiol-17ß concentration was significantly higher on day 0 than the other days of cycle signifying follicular growth and development secreting higher amount of estrogen.

Contribution of preovulatory-phase small follicles to the ovarian response in stimulated cycles

The usual criteria for ovulation induction in stimulated cycles take into account the number of follicles greater than 14-16 mm in diameter. We have retrospectively investigated how the presence of small (8-12 mm) follicles at the time of the last scan influences the ovarian response for in-vitro fertilization (IVF). The mean number of small follicles was nearly constant (3.8 to 5.9) and did not correlate with the number of large (greater than 12 mm) follicles in various protocols for ovarian stimulation. In patients stimulated under the influence of a gonadotrophin releasing hormone (GnRH) agonist, the number of small follicles was correlated with the oestradiol (E2) peak level and with the number of recovered oocytes. Our data demonstrate a significant contribution of follicles less than or equal to 12 mm to peripheral E2 levels and oocyte production for IVF.

Follicular dynamics and dominance in Booroola x Finnish Landrace and Booroola x Suffolk ewes heterozygous for the F gene

To study the influence of the F gene on follicular dynamics and dominance, 2-year-old Booroola x Finnish Landrace (BFL, N = 17) and Booroola x Suffolk (BS, N = 18) ewes were compared with contemporary purebred Finn (FL, N = 18) and Suffolk (S, N = 18) ewes. In Exp. 1, oestrous cycles of ewes were synchronized during the breeding season with progestagen-impregnated sponges. At sponge removal (Day 0), 14 days after insertion, ewes of each of the 4 genetic groups were assigned to Group 1 in which all follicles visible on both ovaries were destroyed by electrocauterization except for the largest (F1) which was marked, Group 2 in which all visible follicles on both ovaries were destroyed, or Group 3 in which the 3 largest follicles of both ovaries were identified as F1, F2 and F3 and marked. At 48 h after treatment (Day 2), follicular growth was evaluated. At Day 0, the mean number of small follicles (1-3 mm) was higher (P less than 0.05) for BS, S and BFL (35.8, 35.1 and 32.9) than FL (24.9) ewes. Large follicles (greater than or equal to 4 mm) were more numerous (P less than 0.05) in FL (3.5) than in BS (2.1) ewes, BFL and S ewes being intermediate. Diameter of the F1 follicle was larger (P less than 0.05) for S (7.6 mm) than FL, BS and BFL (5.8, 5.1 and 5.1 mm) ewes. In Group 1, all F1 follicles marked at Day 0 ovulated at oestrus after sponge removal for BFL, BS and S ewes while in FL ewes, 2 of 6 F1 follicles regressed. In ewes ovulating, only the F1 follicle ovulated except for one S ewe which shed one more ovum. In Group 2, there were no follicles greater than or equal to 4 mm at Day 2 and no ewes ovulated after treatment. In Group 3, the proportion of marked follicles that ovulated was higher for S ewes than in those of the prolific genotypes. The number of follicles not marked at Day 0 but ovulating (compared to the total number of ovulations) was higher in BFL, BS and FL (8/11, 9/13 and 9/13) than S (3/10) ewes. In Exp. 2, prolific (BFL + BS) and non-prolific (S) ewes were compared following destruction of follicles greater than or equal to 3 mm with the F1 left intact (Treatment 1) or destroyed (Treatment 2), 12 days after sponge insertion.(ABSTRACT TRUNCATED AT 400 WORDS)

Study of follicular development and heredity of morphological types of ovaries in prepuberal gilts.

Two different morphological types of ovaries ("grape" and "other" types) previously described by microscopic examination were studied on 107 live gilts. The ovarian type and distribution of macroscopic follicles during the prepuberal period were determined at 140, 160 and 180 d of age by laparoscopic examination. The incidence of grape-type (GT) ovaries was higher (P less than .05) at 140 d of age (50.5%) than at 160 d (38.3%) or 180 d (35.5%). At maturity (d 19 of the first postweaning estrus), 37.7% of the ovaries were classified as GT. The proportion of gilts that maintained their initial type (at 140 d of age) at 160 d, 180 d and at maturity was higher (P less than .05) for the gilts having the other-type (OT) ovaries (49% and 25% for OT and GT, respectively). The mean number of small follicles (1 to 3 mm in diameter) was higher (P less than .05) for the OT ovaries at 140 d (71.5 vs 18.0), at 160 d (79.3 vs 26.2) and at 180 d (77.0 vs 32.8). The number of follicles of 4 to 5 mm was higher (P less than .05) for GT ovaries at 140 d (16.4 vs 4.8), at 160 d (20.9 vs 4.8) and at 180 d of age (21.4 vs 5.7). The large follicles (greater than or equal to 6 mm) were more numerous for the GT at 140 d (7.0 vs .3), at 160 d (5.7 vs .5) and at 180 d (4.4 vs .6). No statistical difference was observed at maturity in the distribution of follicles between the two types.(ABSTRACT TRUNCATED AT 250 WORDS)