Return Of Ovarian Activity Research Articles

175 FOLLICULAR DEVELOPMENT AND OVARIAN BLOOD FLOW IN MARES WITH EARLY OR LATE OVULATION POSTPARTUM

The postpartum period is characterised by the rapid uterine involution process and return of ovarian activity (foal heat), resulting in a fertile oestrus in most of the mares. However, the follicular development and selection processes during this period are not completely known in horses. We aimed to study the characteristics of follicular growth and vascular perfusion in the ovary during the early postpartum period in mares that demonstrated oestrous behaviour and had early (<10 days) or late (≥10 days) ovulation. Ten mares were scanned daily from the first day postpartum (Day 1) until the day of the first postpartum ovulation (Day 0). The animals were split in the early (n = 3) and late (n = 7) ovulation groups (averaged interval between parturition and ovulation: 8.0 ± 0.0 and 14.7 ± 1.2 days, respectively). For ultrasound exams a Duplex B-mode and colour Doppler instrument (M5VET®, Mindray, Shenzhen, China) was used with a multifrequency linear probe. Data were analysed for the main effects of group, day, and their interaction using the PROC MIXED procedure of SAS software (version 9.3, SAS Institute Inc., Cary, NC, USA). For the follicular growth, no difference (P > 0.05) was detected between the groups when the data were analysed for the days relative to ovulation (from Day 7 to Day 1). However, the dominant follicle was larger (P < 0.05) in the early-ovulated group (37.2 ± 1.6 v. 21.9 ± 1.1) in all days during early postpartum (Day 1 to Day 7). The number of follicles with >25 mm diameter was also greater (P < 0.05) in the early-ovulated group (1.1 ± 0.1 v. 0.1 ± 0.1) during the first 3 days postpartum. In addition, the late-ovulated mares showed greater number of follicles with 20–25 mm during Day 4 to Day 7 (2.0 ± 0.2 v. 0.7 ± 0.1). For the blood flow characteristics, no difference (P > 0.05) was detected in the coloured signals of blood flows in the follicular wall of the dominant follicle or in the ovarian pedicle ipsilateral to the largest follicle. Therefore, the characteristics of the follicle growth on the preceding days of ovulation were similar between the early- and late-ovulated mares and consistent with the follicular dynamics expected in non-pregnant and non-lactating mares. However, when the data were analysed for the days relative to parturition, a greater follicle development was present in mares that ovulate earlier during the postpartum period (<10 days). In conclusion, the results suggest that important events may occur previous to the parturition, resulting in an early follicle development, mainly in those mares that show heat signs and ovulate within 10 days postpartum. Research was supported by FAPESP process number 2010/10692-9 and CNPq process number 135954/2011-8.

Ovarian condition of Holstein dairy cows between 30 and 90 days postpartum in the microregion of Uberlândia, MG

Anestrous postpartum is a state of complete sexual inactivity without estrous manifestations and the return of ovarian activity in postpartum may be negatively affected by several factors, such as negative energy balance (NEB), loss of body condition score (BCS), season in which the calving occurs, nutritional deficiencies, dystocic calving, retained placenta, uterine infections and metabolic diseases. This study aimed to evaluate the effects of BCS and number of days in milk (DIM) on ovarian cyclicity of Holstein dairy cows. Ovarian conditions of 168 cows between 30 to 90 days in milk (DIM) were evaluated twice by ultrasonography with seven days of interval and cows were classified in four categories: ovaries with presence of small follicles (Category 1: up to 10 mm); ovaries with medium follicles (Category 2: 10 to 18 mm); ovaries with large follicles (Category 3: over 20 mm) and ovaries with presence of corpus luteum (CL) (Category 4). The cows classified in categories 1, 2 and 3 were considered in anestrous. Data were analyzed by logistic regression at Minitab (P 0.05) of DIM in the percentage of cycling cows, however there was a tendency (P=0.074) that cows with greater BCS (≥ 2.75) had a higher cyclicity rate (74.44% vs. 61.54%) than cows with lower BCS. Days in milk effect was not detected in cyclicity rate in cows between 30 and 90 DIM, but there was a tendency of Holstein cows with greater body condition score to had higher cyclicity rate.

441 EFFECTS OF BYPASS LIPID SUPPLEMENTATION IN THE TRANSITION PERIOD ON REPRODUCTIVE PARAMETERS IN DAIRY GOATS AFTER PARTURITION

The use of lipids for nutrition supplementation during reproduction phases is called flushing and directly influences body weight and body condition score, which could alter ovulation and fertility rate. Studies have reported the effects of its use for dairy cattle, but for goats this kind of information is incipient. The aim of this study was to evaluate the use of bypass lipid enriched in polyunsaturated fatty acids (Megalac® Arm and Hammer, Church & Dwight Company, Princeton, NJ, USA) in the transition period (i.e. 3 weeks before and after parturition) on the return of ovarian activity. This study was conducted from March to May 2009, in Piau/MG (21°35′S latitude and43°15′W longitude), Brazil. Nineteen Toggenburg (n = 16) and Saanen (n = 3) goats were equally assigned according to breed, body weight, and condition score into 4 treatments: animals received 2% dry matter of fat supplementation 21 days before and after parturition (T1), only before parturition (T2), or only after parturition (T3); the control group received no supplemental fat (T4). Goats were fed a complete mixture of napier grass and corn silage in a 50:50 forage/concentration ratio 4 times daily. Transrectal ultrasonography (5-MHz transducer; Aloka SSD 500®, Tokyo, Japan) was performed daily from 10 days after parturition until detection of ovulation. Estrous onset and its duration were detected daily with a fertile buck. Statistical analysis were performed using all tests at the 95% confidence interval with a SAEG® program (Funarbe, Viçosa, Brazil). The results are presented as mean ± SD. The interval (days) from parturition to first estrus was 20.5 ± 2.2 (T1), 30.0 ± 17.4 (T2), 20.2 ± 2.1 (T3), and 19.0 ± 2.5 (T4), and to first ovulation was 26.3 ± 4.0 (T1), 22.4 ± 3.3 (T2), 24.4 ± 1.1 (T3), and 24.2 ± 3.6 (T4) (P > 0.05). The diameter of ovulatory follicles (mm) was similar (P > 0.05) for T1 (7.21 ± 0.30), T2 (6.86 ± 0.31),T3 (6.66 ± 0.27), and T4 (7.32 ± 0.64). The number of ovulations was also not different (P > 0.05) for T1 (1.5 ± 0.3),T2 (1.2 ± 0.2), T3 (1.4 ± 0.2), and T4 (1.0 ± 0.0). A negative correlation (r = -0.68; P < 0.005) was detected between body condition score at the parturition and the interval from parturition to the first estrus, as well as to the first ovulation (r = -0.48; P < 0.05). A positive correlation (r = 0.47; P < 0.05) was found between body weight on the day of ovulation and the number of ovulations. These data show the importance of body weight and condition score to reproductive performance after parturition. No significant differences were registered among all treatments on reproductive parameters for goats after this amount of lipid supplementation. There is a need for more studies to be done using different supplement concentrations in order to achieve better reproductive performances after parturition. Financial support: Embrapa Goats and Sheep, Fapemig, CNPq.

Twenty-four hour patterns of prolactin secretion during lactation and the relationship to suckling and the resumption of fertility hi breast-feeding women

In breast-feeding women prolactin released in response to suckling is essential for the maintenance of lactation. This physiological hyperprolactinaemia is also associated with lactational infertility. However, it is not clear whether there is any direct relationship between changes in prolactin per se and the duration of infertility. To address this question, our study determined the pattern of prolactin secretion in relation to suckling and the return of ovarian activity in the same cohort of breast-feeding women. Blood samples were withdrawn at 10 min intervals for 24 h from 09:00 to 09:00 h at either 4 (n = 9) or 8 weeks (n = 11) post-partum when the women had completely suppressed ovarian activity, at the time of the introduction of supplements to the baby (n = 17), a time associated with reduction of suckling activity, at first menses while still breast-feeding (n = 13) and in the follicular phase (n = 9) of the first menstrual cycle after weaning. During sampling, mothers and babies continued their normal pattern of suckling activity. The pattern of prolactin release was very variable at each stage of lactation, depending on the pattern of suckling. Frequent suckling was associated with elevated prolactin concentrations during the 24 h period throughout lactation. When suckling was less frequent, prolactin concentrations fell to baseline values between breast-feeds, but prolactin was released in response to all suckling episodes. An increase in prolactin concentrations at night, independent of suckling, was only evident once breast-feeding had ceased. The prolactin response to suckling declined significantly only after the return of menses at 33.6 +/- 3.5 weeks post-partum. There was no relationship between the duration of amenorrhoea and the plasma concentrations of prolactin over 24 h, or day or night separately, throughout lactation. However, there was a strong correlation (r = 0.843; P < 0.01) between the timing of the introduction of dietary supplements to the baby and the duration of amenorrhoea. These results suggest that there may be no precise link between the release of prolactin during lactation and the duration of lactational infertility in breast-feeding women.

The return of postpartum fertility monitored by enzyme-immunoassay for salivary progesterone.

A longitudinal study in which daily salivary progesterone and estrone were measured by solid-phase enzyme-immunoassays was performed in 30 postpartum women to monitor the return of ovarian activity. Ovulation was inferred from a sustained rise in salivary progesterone over 251 pmol/l, but salivary estrone measurements were not as informative as progesterone in this regard. Recovery of ovarian activity was slower in lactating women compared with non-lactators; the mean delivery-menstruation interval were 123 (+/- 10) and 57 (+/- 7) days, respectively. An abnormal luteal phase was noted in 35% of the first ovulatory cycles, 20% had short luteal phases and 15% were less than the 5th percentile of a normal control corridor. The pregnancy rate in this study of 3.3% was lower than the anticipated rate of 8.8%. We conclude that salivary progesterone measurements are useful for monitoring the return of ovarian activity postnatally.

The return to ovulation following early abortion: a comparison between vacuum aspiration and prostaglandin

The return to ovulation following early abortion (less than or equal to 56 days amenorrhea) has been assessed after both vacuum aspiration under general anesthesia (N = 14) and menstrual induction with 16,16 dimethyltrans-delta 2PGE1 methyl ester in pessary form (N = 18). The urinary excretion of hCG, total estrogen and pregnanediol was similar in each group. There was an initial rapid decline in hCG excretion (t1/2 48 h), reaching 10% of the pre-treatment value after 6 days. Twenty-nine (91%) women showed a luteal phase rise in pregnanediol excretion, with ovulation occurring on day 29 (16-37) and 24 (16-32) in the vacuum aspiration and prostaglandin groups, respectively (median (range) NS). The wide range in the return of ovarian activity was related to the variation in decline of progesterone secretion (as reflected by excretion of pregnanediol) by the corpus luteum. Asynchrony between the ovarian and menstrual cycles resulting from a delay to ovulation presents a major constraint to the use of early pregnancy interruption as a routine method of fertility control.

Postpartum Return of Ovarian Activity in Nonbreastfeeding Women Monitored by Urinary Assays

Assays of first morning urine samples for pregnanediol - 3α - glucuronide (PdG), estradiol -17β - glucuronide (E2G), and LH were used to monitor endocrine function in 16 regularly cycling women and 22 postpartum nonbreastfeeding women. Twice weekly blood samples were also obtained from the postpartum group. Ovulation was inferred by a significant rise in LH and PdG, and reversal of the E2G to PdG ratio. Luteal phase PdG excretion was measured by the peak of smoothed PdG levels and the area under the smoothed luteal phase PdG curve. The lower limits of normal established in 16 cycling women were a peak luteal phase PdG of 4 μg/ml and an area under the PdG curve of 20 μg/ml. In the postpartum women, 32% of first cycles were anovulatory, and among ovulatory cycles, 73% had abnormally low luteal phase PdG excretion or short luteal phases. In second and subsequent cycles, 15% were anovulatory and 26% had luteal phase abnormalities. There was a progressive increase in luteal PdG excretion from the first to thir...