Ovarian response to porcine FSH in association with ablation-induced or spontaneous follicular wave development during the estrous cycle in crossbred and Brazilian Warmblood mares (original) (raw)
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Effect of eFSH on Ovarian Cyclicity and Embryo Production of Mares in Spring Transitional Phase
Journal of Equine Veterinary Science, 2007
The use of equine FSH (eFSH) for inducing follicular development and ovulation in transitional mares was evaluated. Twenty-seven mares, from 3 to 15 years of age, were examined during the months of August and September 2004, in Brazil. Ultrasound evaluations were performed during 2 weeks before the start of the experiment to confirm transitional characteristics (no follicles larger than 25 mm and no corpus luteum [CL] present). After this period, as the mares obtained a follicle of at least 25 mm, they were assigned to one of two groups: (1) control group, untreated; (2) treated with 12.5 mg eFSH, 2 times per day, until at least half of all follicles larger than 30 mm had reached 35 mm. Follicular activity of all mares was monitored. When most of the follicles from treated mares and a single follicle from control mares acquired a preovulatory size (R35 mm), 2,500 IU human chorionic gonadotropin (hCG) was administered IV to induce ovulation. After hCG administration, the mares were inseminated with fresh semen every other day until ovulation. Ultrasound examinations continued until detection of the last ovulation, and embryo recovery was performed 7 to 8 days after ovulation. The mares of the treated group reached the first preovulatory follicle (4.1 AE 1.0 vs 14.9 AE 10.8 days) and ovulated before untreated mares (6.6 AE 1.2 vs 18.0 AE 11.1 days; P < .05). All mares were treated with prostaglandin F 2a (PGF 2a ), on the day of embryo flushing. Three superovulated mares did not cycle immediately after PGF 2a treatment, and consequently had a longer interovulatory interval (22.4 vs 10.9 days, P < 0.05). The mean period of treatment was 4.79 AE 1.07 days and 85.71% of mares had multiple ovulations. The number of ovulations (5.6 vs 1.0) and embryos (2.0 vs 0.7) per mare were higher (P < 0.05) for treated mares than control mares. In conclusion, treatment with eFSH was effective in hastening the onset of the breeding season, inducing multiple ovulations, and increasing embryo production in transitional mares. This is the first report showing the use of FSH treatment to recover embryos from the first cycle of the year.
Theriogenology, 2007
A regimen of progesterone plus estradiol (P&E) was used as a standard for ovarian synchronization to test the efficacy and evaluate the commercial application of ultrasound-guided follicle ablation as a non-steroidal alternative for ovulation synchronization in mares. Recipient mares at a private embryo transfer facility were at unknown stages of the estrous cycle at the start of the experiment on Day 1 when they were randomly assigned to an ablation group (n=18-21 mares) or to a P&E group (n=20-21 mares). In the ablation group, mares were lightly sedated and all follicles > or = 10 mm were removed by transvaginal ultrasound-guided follicle aspiration. In the P&E group, a combination of progesterone (150 mg) plus estradiol (10mg) prepared in safflower oil was given daily (im) for 10 d. Two doses of prostaglandin F(2alpha) (PGF, 10mg/dose, im) were given 12 h apart on Day 5 in the ablation group, or a single dose on Day 10 in the P&E group. Human chorionic gonadotropin (hCG, 2500 ...
Biology of Reproduction, 1995
The aims of this study were to determine whether successive follicular puncture in the mare may influence future follicular growth, oocyte maturation, and embryo viability; to examine the correlation between follicular maturation and concentrations of steroid hormones in the follicular fluid (FF); and to analyze proteins through use of two-dimensional (2D) PAGE. Ovaries often ponies (26 cycles) were examined. When the dominant follicle reached 25 mm, three successive punctures (PI, P2, P3) were performed every second day (Day 1 = day of PI, Day 3 = day of P2, Day 5 = day of P3) and 0.4-0.6 ml of FF was aspirated by means of a transvaginal ultrasonograph-guided technique. On the day after P2, mares were inseminated and embryos were collected 7 to 9 days after ovulation. Of a total of 26 PI follicles, 4 ovulated, 5 became atretic, and 17 survived. Six of these 17 ovulated after P2, and 11 survived. After P3, 5 of the 11 ovulated, 3 luteinized, and 3 regressed. In the 17 mares whose follicles had been subjected to two or three punctures, embryo collection was attempted from the 6 and 5 mares that ovulated after P2 and P3, respectively, yielding 4 and 2 embryos. The average diameter of follicles was from 27.2 ± 0.4 mm before PI to 27.8 ± 1.3 mm at P2 and 26.5 ± 1.8 mm at P3. The follicles in some groups increased in diameter (p < 0.05), some showed little change, and follicles in one regressing group showed a significant decrease to 20.3 ± 1.8 mm. The average concentration of estradiol was from 3989 ± 771 ng/ml to 742 ± 172 ng/ml (p < 0.05). The average concentration of A 4-androstenedione at PI was 42 ± 10 ng/ml; this value increased to 120 ± 28 ng/ml at P2 (p < 0.01) and at P3 decreased to 96 ± 36 ng/ml. The mean concentration of progesterone at PI was 79 ± 14 ng/ml; this value increased (p < 0.05) to 487 ± 227 at P2 and to 4507 ± 1162 at P3 (p < 0.001). All the proteins present in FF after silver staining were also present in the serum sample. We measured some of the differences between individual follicles during their growth towards ovulation. We found that after two or three punctures and collection of small volumes of FF every second day, some follicles still had good environmental conditions for maturation of oocytes that remained able to produce embryos.
Exogenous eFSH, follicle coasting, and hCG as a novel superovulation regimen in mares
Journal of Equine Veterinary Science, 2006
The objective of this study was to evaluate various equine follicle-stimulating hormone (eFSH) treatment protocols and the effect of “follicle coasting” on ovulation and embryo recovery rates in mares. Cycling mares (n = 40) were randomly assigned to one of four groups 7 days after ovulation: (1) 12.5 mg eFSH twice daily until follicles were 35 mm or larger; (2)
Ultrasonic characteristics of preovulatory follicle and ovulation in Caspian mares
Animal Reproduction Science, 2004
The Caspian breed of horses is believed to be the direct descendant of the earliest equine animals. Some special characteristics of Caspian horse differentiate this breed of horses from other breeds. In the current study the ultrasonically observed characteristics of a preovulatory dominant follicle and the lengths of estrus, diestrus as well as some related parameters were studied during 42 interovulatory intervals in 11 healthy Caspian mares. The preovulatory dominant follicle deviated from subordinate follicles and became the largest follicle in the ovaries at Day −8.7 ± 0.53 (Day 0 = ovulation). Every mare was a single ovulator with ovulations more frequent from the left ovary than from the right (65% versus 35%). Mean length of estrus, diestrus, and interovulatory interval were 8.3 ± 0.86, 13.8 ± 0.59, and 22.1 ± 0.40 days, respectively. The time interval from ovulation until the time in which the mares were no longer in estrus was 1.9 ± 0.42 days.
Reproduction, 2005
Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different numbers (mean, 1.5 ± 0.2 surges/mare); the internadir interval was 3.9 ± 0.3 days. In contrast, mean FSH in women was low during the luteal phase and increased to a prolonged elevation during the follicular phase. The prolonged elevation was apparent in each individual (internadir interval, 15.2 ± 0.4 days). Changes in LH or oestradiol concentrations encompassing deviation were not detected in ...
Reproduction, 2004
The changing diameter interrelationships among follicles during the interval from emergence to deviation (common-growth phase) were studied in 59 mares. All follicles of $ 6.0 mm were ablated 10 days after ovulation. The four largest follicles of the postablation wave were ranked D1, D2, D3 and D4 at the expected beginning of deviation (D1 $ 20.0 mm), according to descending diameter. The four follicles were also ranked independently, according to order of emergence at 6.0-6.9 mm as E1 (first to emerge), E2, E3 and E4. The follicles emerged during 1.3 6 0.1 to 3.1 6 0.1 days, and expected deviation began 6.5 6 0.1 days after ablation. The frequency of emerging follicles becoming the largest follicle at the beginning of deviation was different (P < 0.0001; chi-square test) among follicles E1 (61%), E2 (25%), E3 (9%) and E4 (5%). There were no differences in growth rates among the four follicles throughout the common-growth phase (overall, 2.8 6 0.04 mm/day). The differences in diameters between follicles E1 and E2 were similar between 3 days (2.7 6 0.2 mm) and 6 days (2.9 6 0.4 mm) after ablation. In controls and after ablation of D1; D1 and D2; or D1, D2 and D3 at the expected beginning of deviation, the largest remaining follicle became dominant in 26 of 34 mares (76%). In 10 of 15 mares (67%), the second-largest follicle became dominant when the largest follicle was ablated 1 or 2 days after the expected beginning of deviation. Results indicated the following: 1) the first follicle to emerge maintained its diameter advantage in most mares and average diameter growth rates were similar among the four follicles throughout the common-growth phase; 2) the hypothesis was supported that the capacity for dominance is similar among the four largest follicles at the beginning of deviation, but dominance by a smaller follicle is blocked when a larger follicle is present; and 3) the second-largest follicle retained the capacity for dominance in most mares for as long as 2 days after the beginning of deviation.
Anim. Reprod, 2009
During the recent years, mares have been shown as relevant follicle-related research comparative model for women because of similarities in the number and nature of ovarian follicular waves, a constant relative diameter of the largest follicle between the two species at definable events throughout the ovulatory wave, and similar ultrasonographic characteristics and changes of the preovulatory follicle. In the mare, as in other monovular species (cattle, women), usually only one dominant follicle develops as a result of the deviation mechanism. However, occasionally two or more dominant follicles may also occur. Few studies in mares have addressed the relationships between periovulatory circulating hormone concentrations and single versus multiple dominant/preovulatory follicles. Temporal and mechanistic studies performed recently (years 2005 to 2008) have contributed to elucidation of intriguing relationships among the dominant follicle and circulating hormones and will be the focus of this review. The main topics discussed herein are: (i) development of one versus two dominant follicles with a single ovulation; (ii) development of one versus multiple ovulatory follicles; (iii) conversion of two dominant follicles to double ovulations; (iv) role of hormones in development of double ovulations; (v) interrelationships of periovulatory reproductive hormones; (vi) repeatability of preovulatory follicle diameter and hormones; and (vii) factors that affect preovulatory follicle diameter and hormones, such as breeds and types of mares, season, body condition, and aging.
2001
Ovarian activity was monitored in 2181 oestrous cycles from 1136 thoroughbred brood mares to accurately determine overall ovulation rate, the relative distribution of ovulations between left and right ovary, whether mare age had an effect on these parameters and whether ovulation pattern in one cycle affected the pattern within the next. Ultrasonic scanning was used in preference to rectal palpation and slaughterhouse material due to its greater accuracy. Mare's ages ranged from 3 to 22 years. The results obtained indicated a similar incidence of ovulation occurring on the right (49.5% of all ovulations) or left ovary (50.5%). Multiple ovulations (MO) occurred in 22.4% of oestrous cycles. Significantly (P < 0.01), more double ovulations (DO) were bilateral (57.2%) than unilateral (42.8%); 20.7% were unilateral right and 22.1% were unilateral left. There were 828 mares grouped into six age groups: A (3-5 years), B (6-8 years), C (9-11 years), D (12-14 years), E (15-18 years), F (18-22 years). The distribution of ovulation between the left and right ovary was not affected by age group, but significant association (P < 0.01) was evident between age and MO. Group A had 15% of cycles resulting in MO compared to 19.4, 24.6, 25.8, 28.6 and 35.1% in groups B-F, respectively. A significant (P < 0.01) association between MO in successive cycles was also demonstrated, with a greater chance (P < 0.05) of successive single ovulations (SO) being on alternate ovaries. There was no significant repeatability of the classification of DO in one cycle compared to the next. We conclude that: (i) the mare is a symmetrical ovulator; (ii) 22.4% of cycles yield MO (ovulation rate 1.23); (iii) this MO incidence increased (P < 0.01) with age; (iv) the exhibition of MO in one cycle was linked to an increased probability (P < 0.01) of a MO occurring at the next one and (v) SO in one ovary was more likely (P < 0.05) to be followed by a SO on the alternate ovary during the next cycle.