Diameter Of Dominant Follicle Research Articles

Timed-artificial insemination protocols for Bos indicus beef heifers: Evaluation of protocol length and variations in prostaglandin F2α treatments

The aim was to compare reproductive outcomes of Nelore heifers submitted to timed AI (TAI) protocols, with 7 or 9 d of permanence of the intravaginal progesterone (P4) device and different times of prostaglandin F2α (PGF) administration, for first (n = 935) and second (n = 530) services. On Day −24, heifers without corpus luteum (CL) underwent a protocol for induction of ovulation. On Day 0, heifers received a P4 device (0.5 g) and 1.5 mg estradiol (E2) benzoate. In order for the TAI to be carried out on the same day, these treatments were performed 2 d later on the heifers treated with the 7-d protocol. Additionally, heifers received 0.5 mg PGF at different times, resulting in four experimental groups: 9dP4-PGFd9 (n = 365); 9dP4-PGFd7 (n = 369); 9dP4-PGFd0&9 (n = 364); 7dP4-PGFd0&7 (n = 367). These nomenclatures indicate for how many d the P4 device was kept and the specific day on which PGF was given. At P4 removal, all heifers received 0.5 mg E2 cypionate and 200 IU eCG, and TAI was performed 2 d later. Effects were considered significant when P ≤ 0.05 (superscript letters a,b) whereas a tendency was assumed when 0.05 < P ≤ 0.10. Groups 9dP4-PGFd0&9 and 7dP4-PGFd0&7 had lower percentage of heifers with CL at P4 removal. The diameter (mm) of the dominant follicle (DF) was affected by treatment at P4 removal (9dP4-PGFd9: 11.3 ± 0.3b; 9dP4-PGFd7: 11.8 ± 0.2ab; 9dP4-PGFd0&9: 12.6 ± 0.2a; 7dP4-PGFd0&7: 10.8 ± 0.2c) and at TAI (9dP4-PGFd9: 12.7 ± 0.3ab; 9dP4-PGFd7: 13.2 ± 0.2a; 9dP4-PGFd0&9: 13.4 ± 0.2a; 7dP4-PGFd0&7: 12.4 ± 0.3b). Expression of estrus (%) was affected by treatment (9dP4-PGFd9: 89.6a; 9dP4-PGFd7: 93.5a; 9dP4-PGFd0&9: 88.2ab; 7dP4-PGFd0&7: 85.6b). There were no differences among treatments for P/AI on Day 40 (30–35 d post AI), final P/AI (between Day 70 and parturition) and pregnancy loss (between Day 40 and final P/AI). When the permanence of the P4 device was compared, regardless of PGF treatments, 9-d protocols resulted in greater DF diameter at P4 removal and at TAI, and greater expression of estrus (90.4 vs. 85.6%) than the 7-d protocol. Despite that, the 7-d protocol resulted in greater P/AI on Day 40 (55.3 vs. 49.1%). In addition, there was an interaction between protocol duration and body weight, in which heavier heifers (≥ 307 kg) had greater P/AI when treated with the 7-d protocol, in comparison to 9-d. In conclusion, longer TAI protocols (9 d of P4 device duration) resulted in greater DF diameter and expression of estrus. However, the shorter TAI protocol (7 d of P4 device duration) produced greater P/AI on Day 40, particularly in heavier heifers. Within 9-d protocols, the additional dose of PGF on Day 0 or the anticipation of the PGF to Day 7 did not influence fertility.

102 Estradiol and follicular growth are associated with estrous behavior monitored by an accelerometer in grazing beef cows

Abstract In beef cattle, 40% of cows that display estrus do not remain pregnant after embryo transfer (ET). Estrus is a physiological behavior influenced by the concentration of sex-steroids. The use of accelerometer devices for estrus detection is a common practice in dairy operations. It remains unclear if this same artificial intelligence software can accurately measure reproductive behavior in beef females. We hypothesized that estrous variables detected by an accelerometer are associated with ovarian, hormonal, pregnancy outcome, and fertility-related variables measured in the cow. Fifty Bos indicus-influenced, cyclic, primiparous cows were fitted with an accelerometer collar (SCR Engineers, Israel) and a breeding indicator (Estrotectâ) to detect estrus after a synchronization protocol in five subsequent experimental replicates (n = 50*5 = 250). Only cows that showed estrus (d 0) remained in the study. The following variables were used from the accelerometer software: Activity Peak, Rumination Nadir, Estrus Duration, and Heat Index, calculated by proprietary algorithms. Dominant follicle (DF) diameter and plasma concentration of estradiol were measured on d -2 (day of progesterone device removal) and on d 0. On d -1 and d 4, endometrial thickness and luminal fluid accumulation were measured by ultrasonography. On d 7, two embryos were transferred/cow. Pregnancies were diagnosed on d 45 and terminated. After 30 d, a new replicate started. Cows included in at least two replicates that remained pregnant 100%, 99-50%, or less than 50% were classified as fertile, sub fertile, and infertile, respectively. Estrus display was recorded for 166 cows (66%). Estrus detection by accelerometer and Estrotect had excellent agreement rate (kappa coefficient 0.76). Cows detected in estrus only by Estrotect had 66% less pregnancy/ET than cows in estrus by both (9/21 vs. 97/145; P = 0.01). The DF diameter on d 0 was not associated with accelerometer variables. Cows with greater and moderate Activity Peak had a greater growth rate of the DF from d -2 to d 0 than lower Activity Peak cows (interaction day*Activity Peak; P = 0.06). Estradiol on d -1 was positively associated with the Activity Peak (P &amp;lt; 0.0001). Cows with lower Activity Peak had a thicker endometrium on both d -1 and d 4 (P=0.02), and greater uterine luminal fluid score on d -1 (P=0.03). Fertility status was not associated with any accelerometer variables. In conclusion, the Activity Peak is associated positively with estradiol concentration and DF growth, however no association was found with pregnancy outcome and fertility. Therefore, the main advantage of accelerometers in beef ranches is the ability to detect estrus at a similar accuracy as breeding indicators, using less labor. Future enhancements in hardware and software to allow prediction of pregnancy outcomes are expected to increase reproductive efficiency in cow-calf operations.

Short Estrous Cycle Post-ovulation in Peri-pubertal Sahiwal and Jersey Crossbred Heifers

This investigation focuses on analysing the follicular dynamics exhibited during peri-pubertal period in Sahiwal and Jersey crossbred heifers. The aim of the study was to assess first ovulation in the heifers following puberty (N=20; 10 for each breed). Heifers were subjected to alternate day trans-rectal ultrasonography (TRUS) when the diameter of dominant follicle surpassed 9 mm diameter. Transrectal ultrasonography (TRUS) was performed to observe and assess first ovulation in heifers. The size of the first pre-ovulatory follicle in Sahiwal and Jersey Crossbred heifer in peri-pubertal stage was 10.52±0.13 and 10.15±0.51 mm, respectively and the corpus luteum attained its maximum size of 13.89 and 11.26 mm, was significantly different (p&lt;0.01) at day 8.6±0.4 and 8.2±0.48 in Sahiwal and Jersey crossbred heifers, respectively. The regression of corpus luteum (CL) adjudged by the Colour Doppler initiated on 10.6±0.4 and 11.0±0.63 day for Sahiwal and Jersey crossbred heifers, respectively. Some other follicular dynamics parameters i.e. day of wave onset, number of follicles recruited, inter-wave duration along with maximum diameter of dominant follicle, day of maximum diameter, growth rate, length of growth and static phase, duration of static phase and onset of atresia was recorded, however, no significant difference (p&gt;0.05) was recorded between breeds. On an interesting note, the next estrous cycle for heifers did not lead to ovulation despite having follicular size more than10 mm in both the breeds.&#x0D; Conclusion: In peroration, peri-pubertal Sahiwal and Jersey crossbred heifers had notably precocious luteal regression after first ovulation, without subsequent ovulation in next estrous cycle.

PSIV-16 Factors Affecting the Lh Release and Ovulatory Response to a Gnrh Treatment in Lactating Dairy Cows on Day 7 of the Estrous Cycle

Abstract This study evaluated factors affecting LH release and ovulation in response to a treatment with a conventional dose of gonadorelin (GnRH), in lactating dairy cows on day 7 of the estrous cycle. Factors evaluated were: GnRH preparation (ready-to-use vs. lyophilized), body condition score (BCS), parity, days in milk (DIM), milk yield and dominant follicle (DF) diameter, at the time of GnRH treatment. Seven days after an artificial insemination, preceded by a synchronization protocol, lactating Holstein cows were evaluated by ultrasound and those with a corpus luteum (CL) and a DF ≥10 mm were randomly assigned to receive 100 µg GnRH ready-to-use solution (Fertagyl; MSD, Brazil) or lyophilized (Profertil; J.A. Animal Health, Brazil) diluted just before its administration. Overall, 106 cows (BCS = 3.1 ± 0.1; DIM = 96.7 ± 4.2; 39.7 ± 0.7 kg of milk/d) were assigned to GnRH treatments. Ovulation was determined by ultrasound examinations 2 d after GnRH treatment, by disappearance of the DF, and confirmed 5 d later by the presence of an accessory CL. In a subset of cows (n = 33), blood samples were collected just before the GnRH treatment, and 2 and 4 h later, to evaluate circulating P4 and LH concentrations. Data were analyzed by GLIMMIX (SAS 9.4). Treatment effect and its interaction were included in the analyses of all other factors. Differences were declared when P ≤ 0.05 and tendency when 0.053.0 (1.4 ± 0.2 vs 0.7 ± 0.1 ng/mL; Table 1). Moreover, cows with DF ≤12 mm had greater LH peak than cows with DF &amp;gt;12 mm (1.3 ± 0.2 vs. 0.9 ± 0.1 ng/mL; Table 2). However, these factors did not affect ovulation. Neither milk yield nor DIM affected LH peak or ovulation. In conclusion, although no differences were detected on LH peak, primiparous cows on day 7 of the estrous cycle had greater ovulation when treated with Profertil compared with Fertagyl. Moreover, regardless of treatment, greater BCS and larger DF (&amp;gt;12 mm) at the time of GnRH treatment were associated with decreased LH peak, however, without impairing ovulation.

Ovarian Dynamics and Changes in Estradiol-17β and Progesterone Relationship with Standing Estrus, Preovulatory Follicles, and Ovulation Using Single Prostaglandin F2α Injection in Barbari Goats.

The purpose of the present research was to define ovarian follicular dynamics and plasma endocrine profiles in response to a single PGF2α injection, administered indiscriminately during the breeding season of Barbari goats. Ovarian dynamics were observed at every 12 h interval by using B mode ultrasonography, blood samples for hormonal analysis such as estradiol 17β and progesterone were collected at every 12 h interval, and bucks with aprons were used to identify standing estrus at every 6 h interval. Relative to PGF2α, the start of standing estrus and ovulation differ (p < 0.05) between early- (n = 7), intermediate- (n = 6), and late-responding (n = 6) goats. The highest plasma level of estradiol 17β was detected 12 h prior to ovulation. The average diameter of the ovulatory follicle and length of standing estrus were comparable (p > 0.05) between the goats. The corpus luteum degenerated more quickly (p < 0.05) in early- than intermediate- and late-responding goats. Dominant follicle diameter and estradiol 17β concentration also differ (p < 0.05) among groups. Although the plasma level of progesterone did not vary (p = 0.065), the variation in progesterone concentration with time differed (p < 0.05) amongst the goats. As a result, this research indirectly reveals that the beginning of standing estrus, end of estrus, and ovulation after PGF2α might fluctuate in Barbari goats because of follicular and hormonal dynamics during the luteal phase.

Influence of GnRH analog and dose on LH release and ovulatory response in Bos indicus heifers and cows on day seven of the estrous cycle

This study evaluated the influence of GnRH analogs (gonadorelin vs. buserelin) and doses (single vs. double) on LH release and ovulatory response in Bos indicus (Nelore) females on Day 7 of the estrous cycle. Cycling heifers and non-lactating cows were pre-synchronized: Day −10: progesterone (P4) implant insertion plus 2 mg of estradiol benzoate; Day −2: implant removal and 0.53 mg of cloprostenol sodium (PGF); Day 0: 25 μg of lecirelin (GnRH). Over four replicates, heifers (n = 57) and cows (n = 53) that ovulated to the GnRH treatment on Day 0, having a visible corpus luteum (CL) and a dominant follicle (DF) ≥ 8.5 mm, were allocated to receive the following GnRH treatments on Day 7: G-Single (100 μg of gonadorelin); G-Double (200 μg of gonadorelin); B-Single (10 μg of buserelin); and B-Double (20 μg of buserelin). At GnRH treatment, a P4 implant was inserted in heifers (0.5 g) and cows (1 g). Ultrasound examinations were done on Days −10, −2, 0, 2, 7, 9, 12, and 14 to evaluate DF diameter, ovulation and presence of CL. Blood samples were collected on Day 7 at 0, 2, and 4 h from GnRH treatment, to evaluate circulating P4 and LH concentrations. On Day 12, the P4 implant was removed, females received two PGF treatments (24 h apart), and 2 d later, 25 μg of GnRH was given to start the next replicate. In both heifers and cows, P4 concentrations were elevated on Day 7, and similar among groups (3.9 and 4.2 ng/mL, respectively). In heifers, buserelin induced greater LH peak (9.5 vs. 2.6 ng/mL; P < 0.01) and greater ovulation (88.9 [24/27] vs. 16.7% [5/30]; P < 0.01) than gonadorelin treatments, regardless of the dose. Similarly, in cows, buserelin induced greater LH peak than gonadorelin (9.9 vs. 4.9 ng/mL; P < 0.01). However, ovulation was only increased in cows from the B-Double group (90.9% [10/11]), whereas in the other groups the ovulatory response was similar (35.7% [15/42]). Regardless of treatment, heifers had similar P4 concentrations (P = 0.22), but smaller DF (P < 0.01) than cows on Day 7. Only in G-Double group the LH peak was lower (P = 0.05) in heifers than in cows, with no difference within other groups. In heifers, but not in cows, the single dose of buserelin resulted in high ovulatory response, equivalent to that produced by the double dose. In conclusion, in Bos indicus heifers and cows on Day 7 of the cycle, with elevated P4 concentrations, buserelin induced greater LH release and ovulatory response than gonadorelin treatments. Double doses increased the LH release, however, only resulted in greater ovulation in females treated with buserelin. Finally, although circulating P4 concentrations did not differ between parities, heifers were more likely to ovulate in response to a GnRH-induced LH peak than cows.

Impact of the corpus luteum and follicular parameters on the levels of plasma progesterone and the prediction of pregnancy in Holstein dairy cows.

The objective of this study was to investigate the reliability of corpus luteum and dominant follicles, imaging parameters on the plasma progesterone, and prediction of pregnancy in cows. In total, 48 cows were used in this study and underwent Ovsynch program. Ultrasound imaging of the ovaries was done at the time of PG shots. Corpus luteum diameter (CL_d), area (CL_area), volume (CL_vol), and pixels (CL_PXL), as well as dominant follicle diameter (F_d) and area (F_area), were estimated using the ImageJ program. Blood samples were taken to assess progesterone (P4) concentrations. Pregnancy status was determined at 32 ± 3 days after insemination using an ultrasound "Sonoscape-5 V." Data were analysed using correlation analysis and ROC curves. Plasma P4 concentration showed positive correlation with CL_d (r = .68, p < .01), CL_area (r = .45, p < .01), CL_volume (r = .41, p < .01), and CL_pixels (r = .67, p < .01). The ROC curve indicated that P4 concentrations and CL parameters, especially the CL_pixels, were the best predictors of the pregnancy, among the others that were able to detect pregnancy at the time of PG with the best P4 and CL_pixels cut-off value (4.1 ng/mL and 43.18) and AUC was (0.95 and 0.89); resp. (p < .001). Regarding the other parameters, it was possible to set AUC 0.79, 0.79, and 0.68 for CL_d, area, and volume with a sensitivity of 66.7%, 70.8%, and 66.7% and a specificity of 88.2%, 82.4%, and 70.4% (p < .01), respectively. The AUC for both the follicular diameter and F_area was (0.56) with a sensitivity of 58.33% and 70.8% and a specificity of 62.5% and 50% (p > .05), respectively. In conclusion, CL measurements and progesterone concentrations had the greatest pregnancy prediction in Holstein dairy cows.

Effect of melatonin implantation prior to ovsynch plus cidr protocol on subsequent ovarian activity and pregnancy rate in summer anestrous Murrah buffaloes

For assessing the impact of melatonin pre-treatment in summer anestrous Murrah buffaloes on subsequent reproductive activity of a fixed time artificial insemination (FTAI) protocol, 83 anestrous Murrah buffaloes were subcutaneously inserted 2x4 mm size absorbable melatonin (MT) implants (18 mg/50 kg b wt) at the base of left ear and 38 Murrah buffaloes were used as non-implanted controls. On day 35 post-MT, the treatment and control group Murrah buffaloes were subjected to FTAI protocol (Ovsynch plus CIDR). Ovarian ultrasonography and jugular vein blood sampling was carried out on day 7 and 10 of protocol and on day 7-post AI. Overall pregnancy rate on day 90 post-AI in MT group was higher compared to control group (55.4 vs 31.6%, P&lt;0.05), along with the higher (P&gt;0.05) plasma progesterone on day 7 of FTAI protocol in Murrah buffaloes of the former group which conceived subsequently compared to their non-pregnant counterparts. Moreover, MT group had higher (P&gt;0.05) increase in dominant follicle diameter between day 7 and 10 of protocol compared to control group. On day 7 post-AI, the luteal profile in pregnant murrah buffaloes of MT group was better (P&lt;0.05) compared to their counterparts in control group (CL: 14.80±0.70 vs 10.82±0.46 mm, P4: 1.54±0.07 vs 1.04±0.08 ng/ml). In conclusion, melatonin pre-treatment in summer anestrous Murrah buffaloes could be associated with better luteal activity and higher pregnancy rate in the Ovsynch+CIDR protocol.

Effects of source of supplementary trace minerals in pre- and postpartum diets on reproductive biology and performance in dairy cows

Our objectives were to evaluate the effects of complete replacement of inorganic salts of trace minerals (STM) with organic trace minerals (OTM) in both pre- and postpartum diets on ovarian dynamics, estrous behavior measured by sensors, preimplantation conceptus development, and reproductive performance in dairy cows. Pregnant cows and heifers (n = 273) were blocked by parity and body condition score and randomly assigned to either STM or OTM diets at 45 ± 3 d before their expected calving. Pre- and postpartum diets were formulated to meet 100% of recommended levels of each trace mineral in both treatments, taking into consideration both basal and supplemental levels. The final target concentrations of Co, Cu, Mn, Se, and Zn were, respectively, 0.25, 13.7, 40.0, 0.3, and 40.0 mg/kg in the prepartum diet, and 0.25, 15.7, 40.0, 0.3, and 63.0 mg/kg in the postpartum diet. The STM group was supplemented with Co, Cu, Mn, and Zn sulfates and sodium selenite, while the OTM group was supplemented with Co, Cu, Mn, and Zn proteinates and selenized yeast. Treatments continued until 156 d in milk (DIM) and were assigned to individual cows using automatic feeding gates. Starting at 21 DIM, ultrasonography examinations of the ovaries were performed weekly to determine the presence of a corpus luteum and postpartum resumption of ovarian cyclicity. Cows were presynchronized with 2 injections of PGF2α at 42 and 56 DIM. Estrous behavior was monitored using electronic activity tags that indirectly measured walking activity. Cows detected in estrus after the second PGF2α were inseminated, and those not detected in estrus by 67 DIM were enrolled in a synchronization program. Cows that returned to estrus after artificial insemination (AI) were reinseminated. Pregnancy diagnosis was performed 33 d after AI, and nonpregnant cows were resynchronized. Transcript expression of interferon-stimulated genes in peripheral blood leukocytes was performed in a subgroup of cows (STM, n = 67; OTM, n = 73) on d 19 after AI. A different subgroup of cows (28 STM, 29 OTM) received uterine flushing 15 d after AI for recovery of conceptuses and uterine fluid for analyses of transcriptomics and metabolomics, respectively. In addition, dominant follicle diameter, luteal size and blood flow, and concentration of progesterone in plasma were measured on d 0, 7, and 15 relative to AI. After flushing, PGF2α was given and the dominant follicle was aspirated 2 d later to measure the concentration of trace minerals by mass spectrometry. Estrous behavior, size of the dominant follicle and corpus luteum, concentration of progesterone, time to pregnancy, and proportion of cows pregnant by 100 d of the breeding period did not differ between treatments. A greater proportion of cows supplemented with OTM had a corpus luteum detected before presynchronization (64.3 vs. 75.2%), and primiparous cows supplemented with OTM tended to resume cyclicity earlier than their STM counterparts. Cows supplemented with OTM had a greater concentration of Cu in follicular fluid than cows supplemented with STM (0.89 vs. 0.77 µg/mL, respectively). In pregnant multiparous cows, expression of receptor transporter protein 4 in peripheral blood leukocytes was 42% greater in the OTM group. Conceptuses of the 2 treatments had 589 differentially expressed transcripts, with many indicating advanced conceptus elongation and greater transcript expression of selenoproteins in the OTM group. In pregnant cows, 24 metabolites were more abundant in the uterine fluid of OTM, including spermidine, sucrose, and cholesterol. In conclusion, replacing STM with OTM caused modest improvements to resumption of ovarian cyclicity and important changes in preimplantation conceptus development, but it did not alter conception risk and pregnancy rate.

Effect of progesterone from corpus luteum, intravaginal implant, or both on luteinizing hormone release, ovulatory response, and subsequent luteal development after gonadotropin-releasing hormone treatment in cows

This study aimed to determine the effect of circulating progesterone (P4) concentrations produced by a corpus luteum (CL) or released by an intravaginal P4 implant (IPI) on GnRH-induced LH release, ovulatory response, and subsequent CL development, after treatment with 100 μg of gonadorelin acetate (GnRH challenge). Nonlactating multiparous Holstein cows were synchronized and GnRH was used to induce ovulation (d -7). Over 4 replicates, cows that ovulated (n = 87) were randomly assigned to a 2 × 2 factorial arrangement (presence or absence of CL and insertion or not of an IPI at GnRH challenge), creating 4 groups: CL_IPI, CL_NoIPI, NoCL_IPI, and NoCL_NoIPI. On d -1.5, NoCL_IPI and NoCL_NoIPI received 2 doses of 0.53 mg of cloprostenol sodium (PGF2α), 24 h apart to regress CL. On d 0, cows were treated with 100 μg of GnRH and, simultaneously, cows from IPI groups received a 2-g IPI maintained for the next 14 d. Diameter of dominant follicle, ovulatory response, and subsequent CL volume were assessed by ultrasonography on d -1.5, 0, 2, 7, and 14. Blood samples were collected on d -1.5, 0, 1, 2, 3, 5, 7, and 14 for analysis of circulating P4 and at 0, 1, 2, 4, and 6 h after GnRH challenge for analysis of circulating LH. In a subset of cows (n = 34), the development of the new CL was evaluated daily, from d 5 to 14. The presence of CL at the time of GnRH challenge affected the LH peak and ovulatory response (CL: 5.3 ng/mL and 58.1%; NoCL: 13.2 ng/mL and 95.5%, respectively). However, despite producing a rapid increase in circulating P4, IPI insertion did not affect LH concentration or ovulation. Regardless of group, ovulatory response was positively correlated with LH peak and negatively correlated with circulating P4 on d 0. Moreover, new CL development and function were negatively affected by the presence of CL and by the IPI insertion. In summary, circulating P4 produced by a CL exerted a suppressive effect on GnRH-induced LH release and subsequent ovulation of a 7-d-old dominant follicle, whereas the IPI insertion at the time of GnRH had no effect on LH concentration or ovulation. Finally, elevated circulating P4, either from CL or exogenously released by the IPI, compromised the development and function of the new CL, inducing short cycles in cows without CL at the time of GnRH treatment.

Effects of early weaning on the reproductive performance of suckled Nelore cows in the subsequent breeding season.

This study aimed to evaluate the effects of early weaning (EW) on body composition, hormone concentrations and metabolites, and reproductive performance of Nelore cows in the subsequent breeding season (BS). Suckled cows that became pregnant by timed-AI (TAI) in the 2020-BS were exposed in 2021 to early weaning at 150 d (27 primiparous [PRI] and 74 multiparous [MUL]) or conventional weaning (CW) at 240 d postpartum (30 PRI and 77 MUL). Body weight (BW) and body condition score (BCS) were determined at 2020-BS, EW, CW, prepartum, and 2021-BS. Blood samples were collected at EW, CW, prepartum (54.75 ± 0.56 d prepartum), and 2021-TAI and assayed for insulin-like growth factor-1 (IGF-I), non-esterified fatty acid (NEFA), and β-hydroxybutyrate (BHB) concentrations. In 2021-BS, cows were exposed to a P4/E2-based protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in females detected with luteolysis (D20) by Doppler ultrasound. The presence of corpus luteum (CL) on D10, estrous expression, and dominant follicle (DF) diameter, and blood perfusion (BP) on D2 and D0 were determined. Data were analyzed by ANOVA or logistic regression of SAS as a 2 × 2 factorial with main factors of parity (PRI or MUL) and weaning strategy (EW or CW). An interaction of parity and weaning strategy was not observed (P > 0.1), but the weight (kg) and BCS were greater (P < 0.05) in MUL cows at the five timepoints, and EW cows were heavier than CW at the moment of CW (541 vs. 493 kg; and 5.3 vs. 4.3), prepartum (551 vs. 506 kg; and 5.2 vs. 4.4) and 2021-BS (475 vs. 450 kg; and 4.5 vs. 3.7). Plasma urea concentration at 2021-BS was greater (P = 0.01) for PRI than for MUL. A parity-by-time interaction was observed (P ≤ 0.05) for concentrations of IGF-I, NEFA, and BHB. PRI cows had greater (P ≤ 0.05) concentrations of IGF-I at EW and greater (P ≤ 0.05) prepartum concentrations of NEFA and BHB than MUL cows. The proportion of cows with CL at D10 was not affected (P > 0.1) by weaning but was greater (P < 0.05) in MUL than in PRI cows (40.4 vs. 15.7%). The diameter of DF and proportion of BP on D0 were greater (P < 0.05) in EW cows than in CW cows. The pregnancy rate (P/AI, %) at the first TAI was greater (P < 0.05) in EW cows (60% vs. 45%), whereas no difference (P > 0.1) was observed at the second TAI. Cumulative P/AI (first and second TAIs) was greater (P < 0.05) in EW cows (81% vs. 63%). In conclusion, weaning at 150 d in Nelore cattle is a strategy to successfully recover the parous cow's body condition and to improve pregnancy success in the next BS, regardless of the cow's parity order.

Effects of early weaning on productive and reproductive performance of Nelore heifers

Abstract We aimed to evaluate the effects of early weaning on the productive and reproductive characteristics of Nelore heifer progeny. Ninety-five calves from primiparous (PRI) and multiparous (MUL) dams were assigned to one of two weaning strategies; 1) early weaning at 150 d (149 ± 1.97) of age (EW; n = 16 from PRI and 31 from MUL); or 2) conventional weaning at 240 d (247 ± 2.41) of age (CW; 16 from PRI and 32 from MUL). All heifers received ~5 g/kg of body weight (BW) of creep-feed as fed from 90 d of age until weaning. After weaning, each group of heifers was transferred to a Brachiaria spp. paddock and received 5 g/kg of BW of a protein-energy supplement until 12 mo of age. Then, heifers were confined and fed a diet with a ratio of 79:31 (corn silage: concentrate) for 4 mo, during which they were submitted to a hormonal protocol to induce puberty and timed artificial insemination (TAI). Reproductive tract score (RTS, 1 to 5 scale: 1 being infantile and 5 being cyclic) and endometrial thickness were determined at 12 mo of age, rump fat thickness (RFT), and BW every 28 ± 4 d through the breeding season, and plasma concentrations of IGF-I were evaluated at 12, 14, and 16 mo. At 15.6 mo of age heifers were submitted to a P4/E2 protocol for TAI at day 0 (D0), and a second TAI was performed at D22 in nonpregnant heifers. Ultrasound was used to determine the presence of corpus luteum on D10 and dominant follicle (DF) diameter and blood perfusion on D2 and D0. Data were analyzed using SAS by ANOVA or logistic regression. Though heifers from EW were lighter (P &amp;lt; 0.05) than CW at postweaning time points and CW presented a greater (P = 0.002) RFT than EW heifers from 11 to 15 mo, weaning strategy did not affect (P &amp;gt; 0.1) body condition score at TAI. Concentrations of IGF-I did not differ (P &amp;gt; 0.1) between heifers weaned at 150 and 240 d. The proportion of pubertal heifers, endometrium tone and thickness, and RTS at 16 mo did not differ (P &amp;gt; 0.1) between EW and CW groups. The diameter of DF on D2 and D0 and follicular blood perfusion on D0 were greater (P &amp;lt; 0.05) for heifers in the CW group than EW group, but P/AI at first and second TAI did not differ (P &amp;gt; 0.1) between groups. In conclusion, early weaning in Nelore heifers moderately reduces postweaning growth but does not affect puberty and reproductive performance before the breeding season when submitted to confinement.

The Use of Ultrasound for Monitoring the Relationship Between the Diameter of the Dominant Follicle, The Inter-ovulatory Interval, and Follicular Waves in Dairy Cattle

The aim of the current study was to use ultrasound imaging to follow the follicular dynamics in dairy cows and to determine the relationship between the diameter of the dominant follicle (DF), the life span of the corpus luteum (CL), interovulatory interval (IOI), and the number of follicular waves. Twenty nine Holstein normal cyclic cows 60 days postpartum were used in this study. The ovaries of the experimental cows were scanned for the DF and CL every three days from ovulation to ovulation. Cows undergo the Ovsynch program to unify the beginning of the ovulation per cycle. The results revealed that, cows that exhibit the two wave patterns have a longer time of IOI than a cow with a one wave pattern (P&lt;0.05), and a shorter length of IOI than cows with three follicular wave patterns (P&lt;0.05). The duration of the DF growth phase in the first follicular wave (Wave 1) was prolonged in a cow that exhibited a one-wave pattern than in the cows that exhibited the two or three-wave patterns (p&lt;0.05). The maximum diameter of DF for a single follicular wave pattern (17.6 ± 0.67 mm). The maximum diameter of the anovulatory follicle in the two-wave patterns (12 ± 2.53 mm) was larger than the maximum diameter of the anovulatory follicle (10.75 ±1.33 mm, p&lt;0.05) of wave one in cows that exhibited three-wave patterns. The lifespan of the corpus luteum in the one-wave pattern was significantly shorter (p&lt;0.05) than in two-wave patterns and three-wave patterns. The length of the IOI was positively increased with the number of the follicular wave and the length of the luteal phase but was negatively related to the diameter of the first dominant follicle in the wave and the duration of the (DF) growth phase in the first wave (p&lt;0.05). In Conclusion, these results demonstrate that the length of the IOI in cows exhibiting the two-wave patterns is shorter than in cows exhibiting three-wave patterns due to the larger diameter of the dominant follicle in wave one, the longer duration of the DF growth phase in the first wave, and the shorter life span of the CL in the cows exhibiting two-wave patterns than in cows exhibiting three-wave patterns.

Follicular Dynamics and Endocrine Profile during Normal Estrous Cycle and Early Pregnancy in Surti Buffaloes

The study was conducted on Surti buffaloes for follicular dynamics and endocrine profile during normal estrous cycle (n=6) and early pregnancy (n=6). In cyclic and early pregnant buffaloes, one-wave (33.33% vs. 50.00%) and two-waves (66.66% vs. 50.00%) follicular development was recorded, without three-wave pattern. In cyclic buffalo, the length of estrous cycle and duration of inter-ovulatory interval were little shorter in one wave cycles than in two wave cycles (22.50±0.50 and 23.25±0.25 days). The number of follicles differed non-significantly within and between cyclic and early pregnant buffaloes. The mean maximum diameter of dominant follicle of second wave was significantly larger in cyclic than early pregnant animals for two wave pattern (1.09±0.02 vs 0.73±0.02 cm). In cyclic buffaloes, the mean maximum CL size recorded was 1.21±0.02 and 1.52±0.05 cm (P&lt;0.05) in one- and two-wave cycles, respectively, whereas in early pregnant buffaloes, the corresponding CL size was 1.50±0.04 and 1.55±0.07 cm without significant difference. Thus the mean maximum CL size of early pregnant buffaloes was significantly larger than the cyclic buffaloes with one-wave cycle (1.50±0.04 vs. 1.21±0.02 cm). In the normal cyclic animals, the CL size increased gradually up to day 8 (1.30±0.04 cm) and then remained stable up to day 18 (1.26±0.15 cm), followed by regression and display of next estrus between day 19 and 21, whereas in early pregnant animals the CL size gradually increased up to day 10 (1.48±0.07 cm) and then it was maintained till day 22 (1.46±0.04 cm) of monitoring. The mean diameter of largest follicle recorded was on the day of estrus (0.98±0.07 cm) with variable development of follicles during metestrus to diestrus phase with a new follicles developed during proestrus to estrus phase reaching maximum diameter of ovulatory size (0.99±0.09 cm) between days 19 and 21, whereas in early pregnant animals, the diameter of larger follicle (0.76±0.05 cm) was not recorded up to ovulatory size. The mean concentrations of serum progesterone were lowest during peri-estrus phase, increased through early-luteal phase to a maximum concentration during mid-luteal phase (4.50±0.88 to 4.67±0.95 ng/ml) and then gradually declined through late-luteal phase of diestrus in normal cyclic animals with inverse trend in estradiol profile. However, in early pregnant animals the progesterone levels gradually increased initially and then were maintained higher (6.17±0.32 to 8.13±0.55 ng/ml) with basal estradiol throughout the luteal phase. The serum progesterone/estradiol levels were in harmony with the ovarian dynamics in both cyclic and early pregnant buffaloes. The mean concentrations of serum FSH, LH and kisspeptin in normal cyclic and early pregnant animals did not vary statistically between periods within the status or between reproductive status of animals at any of the periods. The concentration of serum kisspeptin dropped significantly in advanced pregnancy as compared to first and second trimester.

Effect of recombinant LH supplementation timing on clinical pregnancy outcome in long-acting GnRHa downregulated cycles

BackgroundTimely and moderate luteinizing hormone (LH) supplementation plays positive roles in in vitro fertilization/intracytoplasmic sperm injection and embryo transfer (IVF/ICSI-ET) cycles with long-acting gonadotropin-releasing hormone agonist (GnRHa) pituitary downregulation. However, the appropriate timing of LH supplementation remains unclear.MethodsWe carried out a retrospective cohort study of 2226 cycles at our reproductive medicine centre from 2018 to 2020. We mainly conducted smooth curve fitting to analyse the relationship between the dominant follicle diameter when recombinant LH (rLH) was added and the clinical pregnancy outcomes (clinical pregnancy rate or early miscarriage rate). In addition, total cycles were divided into groups according to different LH levels after GnRHa and dominant follicle diameters for further analysis.ResultsSmooth curve fitting showed that with the increase in the dominant follicle diameter when rLH was added, the clinical pregnancy rate gradually increased, and the early miscarriage rate gradually decreased.ConclusionsIn long-acting GnRHa downregulated IVF/ICSI-ET cycles, the appropriate timing of rLH supplementation has a beneficial impact on the clinical pregnancy outcome. Delaying rLH addition is conducive to the clinical pregnancy rate and reduces the risk of early miscarriage.

Clinical efficacy of Wenjing decoction in the treatment of ovulatory disorder infertility: A systematic review and meta-analysis.

Wenjing decoction (WJD) was widely used in the treatment for ovulatory disorder infertility (ODI) in China, while its efficacy was not clearly known. In this study, we evaluated the clinical efficacy of WJD by meta-analysis. Eight electronic databases including Cochrane Library, PubMed, Embase, Web of Science, China National Knowledge Infrastructure, WanFang Data, VIP Database, and China Biology Medicine were searched for randomized controlled trials (RCTs) published from the inception of each database to July 1, 2021, of which the interventions involve WJD and clomiphene. Outcomes included clinical efficacy rate, pregnancy rate, ovulation rate, dominant follicle diameter, endometrial thickness, estradiol, follicle-stimulating hormone, and luteinizing hormone. Meta-analysis and risk of bias were performed by RevMan 5.3 software. Eleven RCTs including 915 patients, of which 476 in the intervention group and 439 in the control group. Meta-analysis showed that WJD was better than clomiphene for patients with ODI in terms of clinical effective rate (odds ratio [OR] = 1.22, 95% confidence interval [CI]: 1.08-1.34), pregnancy rate (OR = 1.54, 95% CI: 1.15-2.07), ovulation rate (OR = 1.34, 95% CI: 1.07-1.67), endometrial thickness (mean difference [MD] = 1.50, 95% CI: 0.90-2.10), and dominant follicle diameter (MD = 1.85, 95% CI: 0.68-3.02). The estradiol level (MD = 91.0, 95% CI: 80.3-101.88) in patients taking WJD was significantly higher than those taking clomiphene, while the follicle-stimulating hormone level (MD = -0.93, 95% CI: -1.13 to -0.72) and the luteinizing hormone level (MD = -4.41, 95% CI: -4.80 to -4.03) in patients taking WJD was significantly lower than those taking clomiphene. Our results also indicated that WJD combined with clomiphene was better than clomiphene alone for patients with ODI in terms of pregnancy rate (OR = 1.79, 95% CI: 1.37-2.35). WJD may be effective in the treatment of patients with ODI. Due to the quality and quantity of literature, RCT with large sample size and high quality need to be performed to verify our conclusion.

Temporal evaluation of follicular dynamics and endocrine patterns of Holstein (Bos taurus), Gir (Bos indicus), and Murrah (Bubalus bubalis) heifers kept under the same nutritional, management and environmental conditions

The objective of the study was to simultaneously compare ovarian follicular dynamics and endocrine parameters of taurine (Holstein; n = 14), zebuine (Gir; n = 5), and bubaline (Murrah; n = 15) heifers kept under the same environmental, nutritional and management conditions. Heifers were synchronized with two PGF treatments 14 days apart. Ovaries of cyclic heifers were scanned daily during two consecutive ovulations and blood samples were collected every 24 h from each animal. No significant difference was found for length of interovulatory interval, however, zebuine heifers presented a greater number of follicular waves, number of antral follicles on day of ovulation, and higher insulin concentration than the other two breeds. Taurine heifers had highest maximal diameter of first wave dominant and ovulatory follicles and CL volume. Taurine and bubaline heifer's dominant follicle of first wave had longer static and regression phases than zebuine heifers. Bubaline heifers presented overall lowest progesterone concentrations and CL volume, but higher IGF1 levels. No difference was observed between taurine and zebuine heifers regarding IGF1 concentration. Despite higher CL volume found in taurine heifers, no difference in mean progesterone concentration was observed between them and zebuine heifers. Insulin and IGF1 concentrations were greater in follicular phase than in luteal phase when breed was not evaluated. After evaluating the three breeds simultaneously, at the same nutritional and management status it is possible to conclude that each genetic group has a specific follicular development and endocrinology of the estrous cycle.

Ovarian follicular dynamics, hormonal profiles and ovulation time in Mithun cows (Bos frontalis).

The study aimed to evaluate follicular dynamics and concentrations of estradiol-17β (E2), progesterone (P4), follicle stimulating hormone (FSH) and luteinizing hormone (LH) during the oestrous cycle and to determine ovulation time in Mithun cows. Ovaries of experimental cows (n=7) were examined daily by transrectal-ultrasonography for three consecutive oestrous cycles (n=21). The characteristics of follicular waves, dominant follicle, largest subordinate follicle and corpus luteum and ovulation time were evaluated. The plasma samples were analysed throughout the interovulatory interval to determine the differences in the hormonal profiles (E2, P4, FSH and LH) between different follicular wave cycles. Out of eighteen oestrous cycles analysed, three-wave follicular cycles were maximum (n=12: 66.66%) followed by two (n=4: 22.22%) and four waves (n=2: 11.11%). The two and three waves were statistically compared, and no significant (p > .05) differences were observed in day of wave emergence, number of follicles (≥3 mm) recruited, maximum diameter of the ovulatory dominant follicle, growth rates of ovulatory and anovulatory dominant follicles and maximum diameter of corpus luteum. The diameter of dominant follicles was significantly (p < .05) greater than subordinate follicles in both ovulatory and anovulatory waves. No significant differences were observed in peak concentrations of estradiol-17β and follicle stimulating hormone between ovulatory and anovulatory waves in all wave cycles. A preovulatory luteinizing hormone surge was observed a day before ovulation in all wave cycles. Progesterone concentrations were lower than 0.5ng/ml during oestrus and increased sharply to the maximum levels of ≥3.8ng/ml in all wave cycles. Ovulation time (mean ± SEM), irrespective of follicular waves was 10.5 ± 0.64 h after the end of oestrus. It was concluded that Mithun cows have a preponderance of three follicular waves with little difference between the two- and three-follicular waves and ovulation occurred 10.5h after the end of oestrus.

P-441 a study in status of use and live birth rates of cryopreserved oocyte for social reasons

Abstract Study question What is status of use and live birth rates of cryopreservation oocyte for social reasons? Summary answer 11.2% of the cryopreserved oocytes were warmed and transferred, and the oldest of the successful live birth was 39 years old. What is known already More people nowadays tend to delay marriage and childbearing due to the social circumstances. It is now gradually known that the pregnancy rate decreases with increasing age, since the donation of gametes from third parties is regulated by the Japanese society, oocyte cryopreservation for social reasons has been becoming common practice. However, not much is known about the subsequent pregnancy and childbirth. Therefore, we conducted a survey on the use and clinical outcomes of cryopreserved oocytes for social reasons in our clinic. Study design, size, duration This retrospective single-center study was conducted with a total of 285 women, 424 cycles from March 2014 to December 2019. A total of 2696 oocytes were cryopreserved by vitrification. Written informed consent was obtained from all women who participated in this study. Participants/materials, setting, methods Ovarian stimulation was performed mainly with GnRH antagonist protocol. An injection of 5000IU of HCG was administered when the diameter of dominant follicle reached 18mm. All oocytes were denuded enzymatically with 80 IU/ml hyaluronidase, followed by mechanical denudation. The oocytes were then evaluated at metaphase II by confirming the presence of the first polar body. Mature oocytes were cryopreserved by vitrification. The partner's sperm was injected into the vitrified-warmed oocytes. Main results and the role of chance The age groups in the first freezing cycle were 30-34 years (7.4%), 35-39 years (49.8%), 40-44 years (37.2%), and 45 years and older (5.6%), respectively. The mean number of OPU cycles was 1.1±0.4, 1.4±1.4, 1.5±1.1, and 1.7±1.7. The average number of retrieved oocytes was 9.5 ± 5.4, 7.3 ± 4.5, 5.6 ± 4.6, and 2.2 ± 2.2. The total number of cryopreserved oocytes was 10.4±5.9, 10.4±7.1, 8.8±6.8, and 3.3±3.4. Sixty-seven women had partners after oocyte cryopreservation, and 33 women (49.3%) had oocytes thawed. The mean age at oocytes freezing was 39.6±2.6 years, and the mean age at thawing was 42.2±2.5 years. The oocytes survival rates, fertilization rates, blastocyst rates and clinical pregnancy rates per embryo transferred of vitrified oocytes were 92.7% (328/354), 69.5% (228/328), 43.9% (87/198) and 31.1% (19/61), respectively. Of these, 15 women (45.5%) became pregnant with vitrified-warmed oocytes, and 10 (30.3%) had livebirth. 18 women did not become pregnant with vitrified-warmed oocytes. Subsequently, 3 of the 18 women then became pregnant in ART (5.6%), by IUI (5.6%), or spontaneously (5.6%), respectively. Limitations, reasons for caution Not applicable. Wider implications of the findings Of the 33 cases, 10 (30.3%) successfully gave birth, indicating the usefulness of oocyte cryopreservation for social reasons. However, considering that most of our patients were already around 40 years old, awareness of the benefits of oocytes cryopreservation at younger ages and education of reproductive health and rights is essential. Trial registration number none

Contagem de folículos antrais, parâmetros produtivos e reprodutivos em novilhas pré-púberes Bos indicus e Bos indicus-taurus com indução precoce de puberdade

ABSTRACT Prepubertal Nelore (G-N = 15) and crossbred Nelore x Aberdeen Angus heifers (G-NA = 15) were used for this study. AFC, live weight, body condition score (BCS), ovary and dominant follicle (DF) diameters were determined in each animal. Puberty induction was performed by insertion of a 4th use progesterone device (D0) which was removed on D12. Also, 1 mg estradiol benzoate was administered, and estrus intensity was classified (D12). At D21, the presence and diameter of the corpus luteum (CL) were registered. AFC was highly repeatable, regardless of hormone induction in both G-N (r=0.79) and G-NA (r=0.90). The mean AFC was greater in G-N compared to G-NA (24.2±8.5 vs. 17.7±9.0 follicles). A variation in BCS throughout the study occurred in G-NA, but not in G-N. The average weight gain (AWG) was greater in G-NA compared to G-N (0.69±0.33 vs. 0.40±0.29kg/day). The G-NA resulted in a larger diameter of DF at D12 than G-N (11.6±2.7 vs. 9.3±1.5mm). In conclusion, AFC was greater in Nelore heifers, although in both breeds this count was highly repeatable during puberty induction. Crossbred heifers had greater BCS and AWG with greater diameter of DF, indicating higher precocity when compared to Nelore heifers.