Growth Rate Of Dominant Follicle Research Articles

Effect of feeding rumen-protected lysine through the transition period on postpartum uterine health of dairy cows.

Feeding rumen-protected methionine as an indispensable amino acid source has been shown to improve reproductive performance in dairy cows, but the effect of feeding rumen-protected lysine (RPL) during the peripartum period on reproductive performance is not well explored. Therefore, we aimed to determine the effects of feeding RPL (AjiPro-L Generation 3, Ajinomoto Heartland Inc.) prepartum, postpartum, or both on follicular dynamics, uterine health, and mRNA gene expression of the endometrium. Seventy-five multiparous Holstein cows were assigned to 1 of 2 dietary treatments with or without RPL in a randomized, complete block design. A 2 × 2 factorial arrangement of treatments was used. Prepartum (-28 d to calving), animals were fed a diet (68% of dietary DM from forage) with RPL [PRE-L; 0.54% RPL of dietary dry matter intake] or without RPL (PRE-C). After calving, half of the cows from each prepartum treatment group were assigned to a diet (56% forage) with RPL (PRE-L POST-L; PRE-C POST-L; 0.40% RPL of dietary dry matter intake) or without RPL (PRE-C POST-C; PRE-L POST-C) until 28 d in milk (DIM). Vaginal discharge was detected with a Metricheck device (Simcro) to detect metritis, and at 28 DIM polymorphonuclear leukocytes were evaluated as a percentage of the epithelial cells using a cytology brush (Andwin Scientific) and an endometrial tissue biopsy was collected for mRNA expression and histology. The first postpartum follicular growth cycle was monitored at 7, 10, 11, 13, 15, 17, 19, 21, 23, 25, 27, and 28 DIM via transrectal ultrasonography. Time to first ovulation did not differ between treatments and averaged 18 ± 1.6 DIM. Follicular diameter at first ovulation was not affected by the treatments, but the growth rate of dominant follicle before first ovulation tended to be lower for cows in POST-L in comparison with cows in POST-C. Prevalence of fetid vaginal discharge and metritis did not differ between treatments. Cows in PRE-L POST-L had lower polymorphonuclear leukocytes percentage at 15 and 28 DIM than cows in PRE-L POST-C, PRE-C POST-L, and PRE-C POST-C. Feeding RPL prepartum downregulates the expression of TLR4, SLC7A6, EHMT2, and tends to downregulate the expression of PTGES3 in uterine tissues at 28 DIM. Additionally, it upregulates the expression of APOL3 and NFKB1, and tends to upregulate the expression of AHCY and MAT2A. In conclusion, feeding RPL pre- and postpartum improved indicators of uterine immune status, but did not change days to first ovulation postpartum.

121 Ovulatory response to gonadotropin-releasing hormone relative to day and diameter of dominant follicle during the first follicular wave in Beetal goats

In Beetal goats under subtropical conditions, ovulatory response of first-wave dominant follicle based on diameter and day of oestrous cycle is unknown to date. The objective of this study was to evaluate the ovulatory response to gonadotropin-releasing hormone (GnRH) relative to day and diameter of dominant follicle during the first follicular wave in Beetal goats. Fifty goats were synchronized using a single dose of prostaglandin F2α (75 µg; D+ cloprostenol, Fatro, Italy), and scanned every 6 hours for ovulation using a 7.5-MHz trans-rectal transducer (Honda HS: 1500, Japan). Following ovulation (Day 0), goats (n=40; 10/day) were given GnRH (25µg lecirelin, Fatro, Italy) on Days 2, 4, 6, and 8 of oestrous cycle. Follicular dynamics was monitored daily from D 0 until GnRH, and every 4 hours after GnRH until ovulation. Ovulation frequency relative to day and dominant follicular diameter was analysed by binary logistic regression, whereas diameter of dominant follicle at time of GnRH, ovulation time, time of wave emergence and growth rate of dominant follicle following GnRH were analysed by one-way ANOVA and independent sample t-test (SPSS 20, IBM Corp., Armonk, NY, USA). Eighty percent of the goats ovulated within 74.7±1.3h after prostaglandin F2α. Overall, 37% (14/38) of the goats ovulated following GnRH within 12.0±1.5h. Ovulations (%) following GnRH were higher (P=0.03) on Day 4 than 2 (60 v. 10%; i.e. 14 times higher than Day 2) and decreased gradually from Day 4 to 8 (P>0.05). Similarly, ovulations following GnRH were higher (P=0.00) in first-wave dominant follicles having diameter 6.1-7.0mm than those having less than 6.1mm (88v. 23%; i.e. 24 times higher than <6.1mm). Ovulations (%) decreased as the diameter of dominant follicle increased from 6.1-7.0mm (P>0.05). Diameters of ovulatory follicles at time of GnRH between Day 2, 4, 6, and 8 were not different (P>0.05). Regardless of day of GnRH treatment, diameter of ovulatory v. anovulatory follicles differed (6.44±0.03v. 5.1±0.4 mm; P=0.00). Overall, growth rate of dominant follicles following GnRH was 0.2±0.11mm and did not differ between ovulatory and anovulatory goats (0.29±0.13v. 0.13±0.15 mm; P>0.05). Interval to the emergence of a new wave following GnRH was prolonged for Day 4 compared to Day 2, 6, and 8 (i.e. 22v. 8, 11, and 12 h; respectively, P<0.05). In conclusion, GnRH treatment at Day 4 resulted in maximum ovulations as the first-wave dominant follicle reached a size of 6.1 to 7.0 mm.

Efeito da prostaglandina F2α no início do protocolo de sincronização da ovulação em novilhas leiteiras Bos indicus, Bos taurus e Bos indicus x Bos taurus

The objective of the present study was to evaluate the effect of treatment with prostaglandin F2α (PGF2α) at the beginning of the protocol for ovulation synchronization on follicular dynamics in Bos indicus (Gyr; n=11), Bos taurus (Holstein Black and White, HBW; n=10), and crossbred animals (Gyr x HBW; n=12). On a random day of the estrous cycles (day 0, D0), the animals received 2.0 mg estradiol benzoate (EB) intramuscularly plus an intravaginal progesterone (P4) device, which was maintained for 8 days (day 8, D8). Half the heifers of each group received a dose of 25 mg PGF2α intramuscularly at the time of insertion of the intravaginal P4 device. When the intravaginal device was removed (D8), all animals received another dose of 25 mg PGF2α intramuscularly, followed by intramuscular injection of 1.0 mg EB 24 h later (day 9, D9). Ultrasonographic evaluations were performed at intervals of 24 hours from D0 to D8 and at intervals of 12 hours from removal of the P4 device to 96 hours thereafter. Samples were collected on days 0, 3, 6, 8, 10 and 22 for the measurement of P4. The mean maximum diameter of the dominant follicle (DF) was smaller (P=0.01) in Gyr heifers (10.0 ± 0.8 mm) than in Gyr x HBW (13.0 ± 0.6 mm) or HBW (12.5 ± 0.8 mm). Furthermore, treatment with PGF2α on D0 increased (P=0.02) the maximum diameter of DF (12.9 ± 0.5 vs. 10.9 ± 0.7 mm) in the three genetic groups evaluated. The growth rate of the DF was lower (P=0.008) in Gyr heifers (0.8 ± 0.1 mm/day) than in crossbred heifers (1.3 ± 0.1 mm/day) or HBW (1.2 ± 0.1 mm/day). Heifers of the three genetic groups treated with PGF2α on D0 had higher (P=0.002) growth rates of DF (1.3 ± 0.1 vs. 0.9 ± 0.1 mm/day). The ovulation rate was lower (P=0.02) in Gyr heifers (36.4%) than in crossbred heifers (83.3%), but did not differ from HBW heifers (70.0%). However, higher (P<0.01) ovulation rates (93.7% vs. 35.3%) were observed in heifers treated with PGF2α on D0. The circulating concentration of P4 on removal of the intravaginal device (D8) was higher (P<0.05) in Gyr heifers (3.8 ± 2.2 ng/ml) than in crossbred heifers (2.2 ± 1.2 ng/ml), but no significant contrast was observed in HBW heifers (2.4 ± 1.6 ng/ml). Throughout the treatment period, the circulating concentrations of P4 were lower (P< 0.05) in heifers treated with PGF2α compared to untreated animals. Gyr heifers exhibited a lower growth rate and smaller maximum diameter of DF and a tendency towards a lower ovulation rate compared to HBW heifers. Treatment with PGF2α on the day of insertion of the intravaginal P4 device reduces circulating P4 concentrations and increases the growth rate and maximum diameter of DF, as well as ovulation rate.

Follicular dynamic and repeatability of follicular wave development in Peranakan Ongole (PO) cattle

&lt;p class="abstrak2"&gt;Superovulation treatment on PO cattle (Bos indicus) was less responsive compared to Bos taurus breed. It might due to the difference of their follicular dynamic. This study was conducted to investigate the follicular dynamics and its repeatability in PO cattle. Follicular dynamics observations conducted on 9 cows trough ultrasound scanning every day. Observations of wave patterns repeatability were performed in 6 cows which its wave pattern already known on the next consecutive IOI. Research result indicated that PO cattle had 3 (66%) and 4-waves (34%) pattern. The first wave of 3 and 4-waves pattern emerged on day -0.4+0.9 and 1.4+1.1 respectively. The second wave of 3 and 4-wave pattern emerged on day 9.8+1.5 and 7.4+1.9 respectively. The pattern of 3 waves has a longer follicle dominant duration (11.6+1.5 day) in the first wave of estrous cycle, compared with 4 waves pattern (10+2.92 and 7+1.00 day respectively). The growth rate of dominant follicle was not different significantly between the 3 and 4-waves pattern (0.87+0.23 and 0.94+0.25 mm/day respectively). Similarly, ovulatory follicle diameter between 3 and 4-waves pattern was also not different significantly (12.24+12.34 and 12.30+12.23 mm respectively). Observation of wave patterns repeatability in 6 PO cows indicated that PO cattle had high repeatability in follicular wave pattern (0.88) and the number of growing follicle was 0.91. This study resulted data for dynamic of follicular development, wave pattern, its repeatability which be expected to design the protocol of superovulation treatment or other reproduction technologies based on follicular dynamic to improve its result in PO cattle.&lt;/p&gt;&lt;p&gt; &lt;/p&gt;

Characterization of the estrous cycle of Asinina de Miranda jennies (Equus asinus)

This study aims to characterize the estrous cycle of Asinina de Miranda jennies in the breeding season, on the basis of data collected from serial ultrasonographic examination and serum progesterone determinations in 14 females during a total of 33 cycles. The length of the interovulatory interval was 23.8 ± 0.55 days, the diestrus and estrus lasting 17.9 ± 0.46 days and 6.65 ± 0.30 days, respectively. Age and body condition score (BCS) affected the length of the interovulatory intervals; BCS also influenced the diestrus length and the time in heat after ovulation (P > 0.05). The incidence of single, double, and triple ovulations was 57.58%, 36.36%, and 6.06%, respectively. Multiple ovulations affected neither the length of the interovulatory interval nor the individual cycle stages (P > 0.05) but lengthened the interval from the beginning of estrus to the last ovulation (P = 0.01). When combined with age, higher BCS affected the ovulation rate (P = 0.001). Deviation of the dominant follicle occurred around Day 8.7 (Day 0 = ovulation) when both single and multiple ovulations were considered. The dominant follicle was larger at divergence in single ovulators (19.18 ± 0.97 mm) compared with that in multiple ovulators (18.05 ± 1.16 mm). The overall maximum follicular diameter before ovulation was smaller in multiple ovulatory cycles than that in single ovulatory cycles (37.2 ± 0.83 mm vs. 40.2 ± 1.41 mm, respectively; P = 0.03). The daily growth rate of dominant follicles was independent of the ovulation rate (P > 0.05) for the intervals before and after the estrus onset. The dominant follicle size and the follicle growth rates were independent of BCS (P > 0.05). Data collected in this study revealed resemblances between Mirandese and other Iberian and Brazilian breeds with regard to estrous cycle characteristics.

Ovarian Follicular Dynamics during the Estrous Cycle in Jennies in Upper Egypt

The objective of the current study was to describe follicular dynamics in Egyptian Jennies throughout the estrous cycle. In this experiment, 8 estrus cycles in 8 cyclic Jennies were studied from February to June using ultrasonography. The result revealed that one follicular wave per cycle was recorded throughout the studied period. Dominant follicle (DF) was firstly detected at −0.80 ± 0.84 day in Jennies. The growth rate of DF was 2.32 ± 0.18 mm/day. Left ovulations were nonsignificantly (P = .07) more than right ovulations (55.6% versus 44.6%). The CL was firstly detected at D 2.58 ± 1.2, developed in a rate of 1.19 ± 0.07 mm/day, reached a maximum diameter of 30.77 ± 1.28 mm at D 13.0 ± 0.70, and started to regress on D 17.05 ± 0.64 with a mean regression rate of 1.75 ± 0.17 mm d−1. Results of the present study indicated that Jennies had one follicular wave per cycle. The Day of the cycle has a significant effect on the number of different classes of the ovarian follicles, but not large ones. Ultrasonographic characteristics of the preovulatory follicles could be useful to predict ovulation. CL developed and regressed in a slow rate.

Avaliação ultra-sonográfica da dinâmica folicular e lútea em vacas da raça Guzerá

Caracterizaram-se o padrão de crescimento folicular e a função lútea ao longo do ciclo estral em vacas da raça Guzerá (n=5), multíparas, não-lactantes. Os animais utilizados apresentavam idade e condição corporal semelhantes e peso corporal médio de 518± 48.5kg. A dinâmica folicular foi monitorada diariamente a partir do dia da ovulação, durante dois ciclos consecutivos, utilizando-se um aparelho de ultra-sonografia equipado com uma probe linear retal de 5MHz. Amostras de sangue foram coletadas a cada 48h, a partir do momento da ovulação, durante os dois ciclos. O primeiro ciclo foi sincronizado pela administração de um luteolítico (cloprostenol), e o segundo foi natural. Os folículos foram identificados e mensurados; e os dados obtidos, registrados em função do dia do ciclo. O comprimento do ciclo estral foi de 19,10± 1,86 dias. Observou-se maior incidência de ciclos com três ondas de crescimento folicular (50%), mas ciclos com duas (37,5%) ou quatro ondas (12,5%) também foram identificados. O diâmetro máximo dos folículos dominantes não ovulatórios foi de 11,60± 2,37 mm, e dos folículos ovulatórios de 14,4± 0,5 mm. A taxa de crescimento dos folículos dominantes da primeira, segunda, terceira e quarta onda foi de 1,48± 0,60; 0,81± 0,13; 1,10± 0,27 e 1,33mm/dia, respectivamente. A concentração máxima de progesterona no diestro foi de 5,50± 0,92ng/ml. A raça Guzerá apresenta características da dinâmica folicular semelhantes àquelas observadas em outras raças zebuínas, como a tendência ao maior número de ondas de crescimento associadas à menor taxa de crescimento, diâmetro máximo e persistência dos folículos dominantes das ondas intermediárias.

Systemic and intraovarian effects of corpus luteum on follicular dynamics during estrous cycle in hair breed sheep

The present study aimed to determine systemic and local effects of corpora lutea (CL), on follicular dynamics throughout the estrous cycle. All follicles ≥2 mm and CL were assessed by daily transrectal ultrasonography in 12 West African ewes. Blood samples were collected to determine plasma concentration of progesterone. Fifteen estrous cycles were evaluated with a mean interovulatory interval of 16.8 ± 0.2 days. Two (13.3%), 10 (66.7%) and 3 (20%) of the estrous cycles had 2, 3 and 4 waves of follicular development, respectively. In sheep with three waves of follicular development, both the length of growing phase and the growth rate of dominant follicles from midluteal wave II were diminished (3.4 ± 0.3 days, P < 0.0001, and 0.4 ± 0.1 mm/day, P < 0.01, respectively) when compared to follicles from early luteal phase (wave I, 4.1 ± 0.2 days, and 0.7 ± 0.1 mm/day) or late luteal phase (wave III, 6.3 ± 0.4 mm and 0.6 ± 0.1 mm/day). The diameter of the dominant follicle was smaller during the midluteal phase (3.9 ± 0.1 mm, P < 0.0001) than in the early and late luteal phase (5.0 ± 0.2 and 5.7 ± 0.2 mm; respectively). The effect of the dominant follicle was less during midluteal phase, because number of accompanying smaller follicles was fewer ( P < 0.01) in waves I and III (6.3 ± 0.9 compared with 3.4 ± 0.8 and 2.3 ± 0.7). The number of follicles was also different between ovaries that had CL and those that did not. The total number of large follicles during the luteal phase was less in ovaries with CL (0.9 ± 0.5 compared with 2.7 ± 0.3; P < 0.01), as was the mean daily number of both large (0.1 ± 0.02 compared with 0.2 ± 0.02; P < 0.001) and total number of follicles ≥2 mm (2.5 ± 0.1 compared with 3.3 ± 0.1; P < 0.01). Current results indicate that the presence of a functional CL may exert both systemic and local effects on the population of follicles, affecting the dominance exerted by large follicles.

Ovarian follicular wave characteristics in alpacas

The objectives were to describe in detail ovarian follicular growth characteristics and to establish the interval between successive large follicles in unmated alpacas. The ovarian follicular status of 16 non-pregnant, non-lactating mature alpacas was recorded using ultrasound every second day for between 46 and 100 days. An inverse relationship was observed between the diameter of the largest follicle and the total number of follicles indicating that follicular growth in alpacas occurs in waves. There were 15/38 (39%) inter-wave intervals of 12 days and 12/38 (32%) intervals of 16 days. The maximum follicular diameter in each follicular wave was 8.8±0.3 mm ( n=38). Inter-wave intervals of longer duration were associated with a larger maximum follicle diameter ( P<0.001). However, the growth rate of dominant follicles was consistent over the first 10 days after emergence. They reached a diameter capable of ovulation by this time, regardless of subsequent inter-wave interval. The latter observation suggested that the optimal time of mating might be predicted in alpacas, provided that the emergence of ovarian follicular waves was controlled.

Effects of suckling frequency and breed on productive performance, follicular dynamics and postpartum interval in beef cows

One experiment was conducted to determine the influence of suckling frequency (restricted suckling (RS) versus ad libitum suckling (AS)) and breed (Brown Swiss versus Pirenaica) on productive performance, follicular dynamics and postpartum cyclicity resumption in beef cows. Twenty-four spring-calving cows (12 Brown Swiss and 12 Pirenaica) were used. After calving cows were assigned, within breed, to the two suckling frequencies (RS versus AS). During the postpartum period, cows were fed 100% of the daily energy estimated requirements. The study was conducted from calving to either day 90 postpartum or to detection of the second ovulation whenever it came later. The pattern of follicular development was monitored daily by transrectal ultrasonography, and blood samples were collected three times a week to analyse progesterone concentrations by RIA. Body condition score at calving was 2.5 (from 1 to 5). Productive parameters were not significantly affected by suckling frequency. Pirenaica cows gained more weight ( P<0.001), while Brown Swiss cows had higher milk yield ( P<0.001) and thus their calves grew faster ( P<0.05). In the present moderate conditions of nutrition, either suckling frequency or breed did not affect follicular dynamics (on average there were 6.5 follicles in emergence, growth rate of dominant follicle (DF) was 1.3 mm per day and maximum diameter of dominant follicle was 13.9 mm). There were gradual increases in maximum diameter and growth rate of dominant follicle related to the proximity of the ovulatory waves, and they were defined by third order polynomial equations. Postpartum anoestrous interval (PPI) was markedly affected by the interaction between suckling frequency and breed ( P<0.001): ad libitum suckling prolonged significantly the interval from calving to first ovulation in Brown Swiss cows (31.8 day versus 82.7 day, in RS and AS groups, respectively, P<0.05), but not in Pirenaica cows (43.5 day versus 32.6 day, in RS and AS groups, respectively, not statistically significant). It is concluded that in moderate pre- and postpartum nutritional conditions Brown Swiss cows were more susceptible to the suppressor effect of ad libitum suckling on postpartum anoestrous interval than Pirenaica cows, although this breed difference did not seem to be mediated by differences in energy balance or in ovarian follicular dynamics.

Effect of an orally active progestin on follicular dynamics in cycling and anestrous postpartum beef cows.

Although treatment of cycling cows with low concentrations of melengesterol acetate (MGA) results in formation of persistent follicles, in the absence of corpora lutea, it is not known whether persistent follicles form in anestrous cows in response to a similar treatment. The objective of this experiment was to determine the effect of long-term MGA treatment (14 d) on follicular dynamics and the secretion of estradiol in anestrous postpartum beef cows. Treatment groups (replicated over 2 yr) included the following: anestrous control (AC; n = 11), anestrous MGA (AM; n = 16), and cycling MGA (CM; positive control; n = 16). Angus-crossbred cows were assigned to treatment by age, cow body condition, and days postpartum. Cows were fed carrier (AC group) or 0.5 mg MGA x animal(-1) x d(-1) (AM and CM groups) for 14 d beginning approximately 38 d postpartum. Cows allotted to the CM group were injected with PGF2alpha, on the first day of MGA treatment to induce luteolysis. The preceding treatment (CM) results in formation of persistent follicles and secretion of elevated concentrations of estradiol. Ovaries of each cow were examined daily by transrectal ultrasonography beginning 5 to 7 d preceding the initiation of feeding MGA or carrier and continued until ovulation or 7 d following MGA feeding. There was no difference among groups in the stage of follicular wave or diameter of the largest follicle at the start of carrier or MGA feeding. The length of the follicular wave present at the start of MGA feeding was greater (P < 0.01) for cows in the CM (14.5 d, yr 1; 18.3 d, yr 2) group compared to the AM (9.4 d, yr 1; 7.9 d, yr 2) or AC (9.7 d, yr 1; 10.7 d, yr 2) groups. Maximum follicular diameter over both years was greater (P < 0.01) for the CM (20.6 mm) group than the AM (15.1 mm) or AC (16.4 mm) groups. Circulating concentrations of estradiol were also increased (P < 0.05) in the CM group compared to the AM or AC groups. However, MGA appeared to have no effect (P > 0.05) on the number of follicles recruited, growth rate of the dominant follicle during the first 6 d oftreatment, or growth rate to the maximum follicular diameter. In summary, MGA treatment did not increase the duration ot the follicular wave, maximum follicular diameter, or secretion of estradiol in anestrous postpartum cows, nor did MGA affect the number of follicles recruited or growth rate of dominant follicles in cycling or anestrous animals.

Ovarian follicular dynamics in water buffalo

The pattern of growth and regression of ovarian follicles was characterized during 7 complete estrous cycles in 5 water buffalo by daily ultrasonographic examinations of the ovaries. Follicles ≥ 4 mm were measured and their relative locations within the ovary were determined to follow the sequential development of each individual follicle. Results indicated the presence of either one (n = 3 estrous cycles) or two (n = 4 estrous cycles) waves of follicular growth per cycle. Each wave was characterized by the development of 1 large (dominant) follicle and a variable number of smaller (nondominant) follicles. In the single follicular wave pattern, the wave started on Day 1.3 ± 0.7 (Mean ± SEM; estrus = Day 0). In the 2-wave pattern, first and the second waves started on Days 1.8 ± 0.6 and 7.8 ± 2.0, respectively, and the dominant follicle in the second wave was the ovulatory follicle. The maximal size and growth rate of the dominant follicle in the first and second wave of the 2-wave cycles did not differ significantly. However, the growth rate of the ovulatory dominant follicle in the 2-wave cycles was greater (P < 0.05) than that in the single-wave cycles. On the day of estrus, the ovulatory follicle was always the largest follicle present on either ovary. In conclusion, this study shows that in buffalo the development of ovarian follicles ≥ 4 mm occurs in 1 or 2 waves per estrous cycle.