Injection Of Prostaglandin F2α Research Articles

15 Influence of early progesterone removal on follicular development, estrus expression, and pregnancy rates in presynchronized beef cows

Abstract The objective of this study was to evaluate the impact of early progesterone removal on pregnancy rates to fixed-time artificial insemination (FTAI) in presynchronized beef cows. Postpartum beef cows (n = 922; body condition score = 4.9 ± 0.77; days postpartum = 77.3 ± 20.77 d) from 7 locations were enrolled in a completely randomized design. Within location, cows were stratified by parity and days postpartum before being randomly assigned to 1 of 2 treatments: 1) 7&7 Synch: Cows received a controlled internal drug release insert (CIDR) and a 25-mg injection of prostaglandin F2α (PG1; d 0). Cows received 100 μg of GnRH on d 7 and the CIDR was removed 7 d later, concurrently with a second prostaglandin F2α (PG2) injection (d 14). Cows received a second injection of GnRH and were FTAI 60-66 h after PG2 (d 17); 2) 7&6 Synch: Cows received the same treatment as 7&7 Synch cows; however, CIDR removal and PG2 were performed on d 13, and cows were FTAI 60-66 h after CIDR removal. Ovarian ultrasonography was performed to determine follicle diameter and CL presence at PG2 and FTAI in a subset of cows (n = 40). Estrus detection patches were utilized to evaluate estrus expression between PG2 and FTAI. Pregnancy diagnosis was performed 28-35 d after FTAI. Cows exposed to the 7&7 Synch tended to have larger follicle diameter at PG2 compared with 7&6 Synch cows (P = 0.09); however, there were no differences in follicle diameter at FTAI. Cows that expressed estrus tended to have larger follicle diameter at FTAI compared with cows that failed to express estrus (P = 0.10). Follicular growth between PG2 and FTAI, percentage of cows with a corpus luteum at PG2, and ovulation rate were not impacted by treatment (P ≥ 0.56). No differences were determined between treatments for estrus expression (7&7 Synch: 77.1 ± 5.91; 7&6 Synch: 74.6 ± 6.28; P = 0.50) or pregnancy rates to FTAI (7&7 Synch: 60.1 ± 4.32; 7&6 Synch: 58.2 ± 4.26; P = 0.69). In conclusion, early removal of progesterone did not impact pregnancy rates in presynchronized beef cows. Thus, the 7&6 Synch protocol described herein may be used as an alternative to the conventional 7&7 Synch protocol without compromising fertility.

291 Impact of Early Resynchronization in Combination with Color Doppler Ultrasonography on Cumulative Pregnancy Rates in Postpartum Beef Cows

Abstract The objective of this study is to evaluate a GnRH and progesterone-based early resynchronization strategy combined with color Doppler ultrasonography for early pregnancy diagnosis. Postpartum Bos taurus beef cows (n = 375) from four locations were enrolled in a completely randomized design, where cows were randomly assigned to 1 of the 2 treatments: 1) Natural Service (NS), cows were exposed to a 7-d CO-Synch + CIDR protocol followed by fixed-time artificial insemination (day 0). On day 15, cows were exposed to natural service for the remainder of the study; or 2) Early Resynchronization (ER), cows were exposed to a 7-d CO-Synch + CIDR protocol followed by fixed-time artificial insemination (day 0). On day 15, a controlled internal drug release (CIDR) device was inserted. On day 20, CIDR was removed, and pregnancy was estimated based on luteal blood perfusion using color Doppler ultrasonography. Non-pregnant cows received a 25-mg injection of prostaglandin F2α at CIDR removal and were fixed-timed-AI concurrently with a 100-μg injection of GnRH 60 to 66 h later. Pregnancy diagnosis and fetal aging were performed on day 53 using conventional ultrasonography. Pregnancy rate to the first AI was greater (P = 0.03) for NS compared with ER (70.25% vs 59.29%, respectively). Pregnancy rates for the second service were also greater (P = 0.01) for NS compared with ER (65.67 vs 42.93%, respectively). Cumulative pregnancy rates to AI did not differ between treatments (P = 0.38); however, cumulative pregnancy rates (first and second service) were greater (P < 0.01) for NS compared with ER (90 vs 77.73%, respectively). In conclusion, the proposed early resynchronization strategy using color Doppler ultrasonography resulted in fewer pregnancies compared with natural service as the second service strategy. Moreover, the proposed ER decreased pregnancy rates to the first insemination, indicating a detrimental effect of ER on pregnancy establishment.

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.

55 Investigating the Potential Benefits of an Immunostimulant (Mycobacterium Cell Wall Fraction) Treatment on Increased Pregnancy Success of Embryo Transfer Recipients

Abstract Modulating the vaginal and uterine microbiome through the use of immunostimulants has the potential to improve fertility in cattle. The object of this study was to evaluate the potential benefits of an immunostimulant, mycobacterium cell wall fraction (MCWF), to increase pregnancy success of embryo transfer (ET) recipients. The three main objectives of this study were: determining if injecting ET recipient cows with MCWF increased proportion of cows with a corpus luteum (CL) on ET day, identifying differences in CL volume and progesterone concentration at the time of ET, and determining if ET recipients that received MCWF have greater pregnancy rate. A total of 926 beef cows at eight different locations were enrolled in this study. Primiparous and multiparous cattle were enrolled in a 7-day CO-Synch + CIDR estrous synchronization protocol. During this protocol, cows received an injection of GnRH (100-μg) at CIDR (controlled internal drug release) insertion [d -9], a prostaglandin F2α injection (25 mg), and CIDR removal [d-2] followed by another injection of GnRH (100 μg; d 0) within 60-66 hours after CIDR removal. At each location at (d 0), cows were sorted based on BCS and days post-partum and randomly assigned to one of two treatments: 1) MCWF- a single intramuscular injection (5 mL) of MCWF at (d 0; Amplimune, NovaVive Inc.; n = 452) or 2) Control- a single intramuscular injection (5 mL) of saline (n = 474). Seven days after (d 7), cows were examined by ultrasonography to determine if a CL was present. Recipient cows that had a CL received ET with a frozen or fresh in vivo or in vitro produced embryo in the ipsilateral uterine horn to the CL, with embryo type and grade balanced between treatments. Blood samples were collected in one location (n = 98) for analysis of plasma concentration of progesterone on (d 7) ET day. Pregnancy diagnosis was then performed by ultrasonography between 30 and 90 days of gestation. Data were analyzed using the GLIMMIX and MIXED procedures of SAS. Cow BCS and days postpartum were similar (P &amp;gt; 0.10) between treatments (5.5 ± 0.6 and 103 ± 14 days, respectively). Recipient cow utilization rate was similar between treatments (P = 0.49; 81.2 ± 0.42%). At the time of ET MCWF had larger CL than Control cows (5,768.6 ± 133.7 and 5,408.0 ± 128.5 mm3, respectively, P = 0.03). and increased progesterone concentration (2.68 ± 0.17 and 2.18 ± 0.14 ng/mL, respectively, P = 0.01). However, pregnancy rate to ET was similar (P = 0.922) between treatments (60.9 and 61.3 ± 0.05% for Control and MCWF, respectively). In conclusion, treatment of ET recipient cows with MCWF increased CL volume and concentration of progesterone at the time of ET but failed to generate greater pregnancy rates.

The effect of reduced dose of PGF2α on certain reproductive parameters in awassi yearlings in anestrus synchronisation protocol following the end of the of the breeding season

The aim of this study was to investigate the effect of the administration of half or full dose of prostaglandinF2α (PGF2α; Gestavet Prost, d-cloprostenol, HIPRA®) injection in a routine synchronization protocol following theend of the breeding period including intravaginal sponge (medroxyprogesterone acetate; Espanjovet, HIPRA®) andeCG (Oviser 500, HIPRA®) on certain fertility parameters in ewes.Two hundred thirty-eight Awassi yearlings (agedone year old) divided into two groups:116 ewes received a half dose (HSDP; 37.5 μg) of PGF2α and 122 ewes receivedfull dose (FSDP;75 μg).The pregnancy rates were 67.2% and 72.1% for HSDP and FSDP, respectively (P&gt;0.05).The lambing rates were 64.7% and 63.9% for HSDP and FSDP, respectively (P&gt;0.05).The single lambing rate inHSDP(94.7%) was higher (P&lt;0.05) compared to that in FSDP (73.1%). The twin and multiple birth rates of FSDPwas higher (P&lt;0.05) than HSDP. As a result, it was inferred that aHSDP could be used in Awassi yearlings withoutexperience of lamb care and in a herd in which single lambing was preferable. Moreover, due to the fact that it is moreaffordable and not detrimentalto fertility, it was concluded that HSDPcan offer an advantage in large flocks and can beused for manipulating fecundity ratesin yearlings.

PSI-5 Comparison of 7&amp;7 Synch and 7-day Co-Synch + Cidr Protocols in a Fixed-Time ai System on Beef Cows Using Y-Sorted sex-Selected Semen

Abstract The 7&amp;7 Synch and the 7-day CO-Synch+CIDR fixed-time estrous synchronization protocols were compared among mature and two-year-old lactating postpartum Angus and SimAngus cows (n=201). Mature (n=63) and two-year-old (n=36) cows treated with the 7&amp;7 Synch received an injection of prostaglandin F2α (PGF; 25 mg dinoprost tromethamine) at the same time as insertion of an intravaginal progesterone-releasing insert (CIDR; 1.38g progesterone) on Day -17, gonadotrophin-releasing hormone (GnRH; 100 μg gonadorelin) on Day -10, and PGF at time of CIDR removal on Day -3. Mature (n=65) and two-year-old (n=37) cows in the 7-day CO-Synch+CIDR groups received an injection of GnRH on Day -10 that coincided with CIDR insertion and received PGF at the time of CIDR removal on Day -3. Fixed-timed AI (FTAI) by a single technician using Y-chromosome-bearing sex-sorted semen (4x106 sperm/unit of SexedULTRA 4M) from one of two Charolais bulls occurred on Day 0, 70 hours after PGF injection. Seven days later bulls were pastured with cows for the remainder of the breeding season. Transrectal ultrasound was performed 77-83 days after AI and fetal size was used to differentiate AI and natural service pregnancies. Within the mature cows and two-year-old age groups, the GLIMMIX procedure in SAS was used to compare FTAI and breeding season pregnancy rates with estrous synchronization treatment and sire as main effects. No differences (P=0.41) were observed amongst mature cows in FTAI pregnancy rates between the 7&amp;7 Synch (52.4%) and the 7-day CO-Synch+CIDR (44.9%) treatments. A greater (P=0.05) proportion of two-year-old cows were pregnant to FTAI following treatment with the 7-day CO-Synch+CIDR (56.7%) as compared to the 7&amp;7 Synch (33.4%). A greater (P=0.02) proportion of two-year-old cows in the 7-day CO-Synch+CIDR treatment (91.9%) were pregnant at the conclusion of the breeding season as compared with the 7&amp;7 Synch (69.7%).

The vaginal and uterine blood flow changes during the ovsynch program and its impact on the pregnancy rates in Holstein dairy cows

AimOvSynch is a hormonal protocol for synchronization of estrus and use of artificial insemination (AI) at an optimal time without adverse effects on the ovaries or uterus. This study investigated the use of noninvasive color Doppler ultrasound to assess changes in uterine and vaginal blood flow during the Ovsynch program for synchronization of estrus and its relation to the pregnancy rates in Holstein cows.Materials and methodsThe experimental cows received an intramuscular dose of 10 μg of a GnRH analogue (G1), followed 7 days later with an intramuscular injection of synthetic prostaglandin F2α (P: PGF2α) analogue (500 μg cloprostenol sodium), and given a 10 μg, injection of the GnRH analogue (G2) i.m. 48 h after the PGF2α treatment, and the cows were bred 14-16 h after. Uterine and vaginal perfusion were investigated by performing transrectal Doppler ultrasonography of both the uterine and vaginal arteries in Holstein cows at different time points during the Ovsynch program to determine: peak systolic velocity (PSV), time-averaged maximum velocity (TAMV), the volume of blood flow (BFV), pulsatility index (PI), resistance index (RI), resistance impedance (S/D) and diameters of uterine (UA) and vaginal (VA) arteries. Steroid hormones were also assayed. Transrectal ultrasonography (TUS) was performed at 32 and 60 days to confirm the pregnancy per artificial insemination (P/AI).ResultsThe uterine PSV, TAMV, and PV were greater at the time of the cloprostenol sodium and second GnRH injections (p<0.05) than at the time of the first GnRH injection. The vaginal PSV, PV were greater at the time of the cloprostenol sodium than at the time of the first and second GnRH injections (p<0.05). The receiver operating characteristic curve (ROC curve) indicated a high correlation between the uterine and vaginal blood flow and the rate of the pregnancy (p<0.05). The area under the ROC curve was 0.920 and 0.87 (p<0.05) for vaginal and uterine arteries respectively at time of G2. The serum levels of progesterone, estrogen and cortisol were correlated with the P/AI (p<0.05). The P/AI significantly decreased from 43.9 % at 32 d to 35.37 % at 60 d.ConclusionThese results indicate that noninvasive Doppler ultrasonography is a valid method to evaluate changes in the characteristics of uterine and vaginal blood flow in cows during the Ovsynch protocol. Furthermore, vaginal and uterine blood flow are two determinant factors for the higher conception rates in Holstein dairy cows.

Nanodelivery System for Ovsynch Protocol Improves Ovarian Response, Ovarian Blood Flow Doppler Velocities, and Hormonal Profile of Goats.

Simple SummaryDrug delivery systems depending on nanotechnology have been recently created to improve biological activity of drugs including hormones. Nanoformulated drugs have different pharmacokinetic properties in biological systems compared to their conventional forms due to the acquired new physicochemical properties such as lesser size, high size-to-weight ratio, and different surface charges and shapes. These properties enable them to efficiently deliver into target sites coping with existing biological barriers. Ovsynch protocol, GPG, is one of the most important estrous synchronization protocols due to the possibility of applying timed insemination with this protocol. This protocol is commonly used in many farm animals, as it aids in herd management and eliminates the need for the detection of estrus. However, there are still some shortcomings that restrict the outcomes of this protocol, such as scattering ovulation time, short luteal phase and inadequate luteal function, and low conception rates. Therefore, this study aims to evaluate ovarian response, blood flow of the ovarian and luteal arteries, and hormonal profile of goats receiving either a standard Ovsynch protocol or an Ovsynch protocol delivered via a nanodelivery system with different dosages of hormones. The present study is the first one that poses the idea that the nanodelivery system for the Ovsynch protocol enables lower hormone dose administration and improves the results of the protocol by inducing tighter synchrony of ovulation and better luteal function of synchronized goats.Fifteen cyclic, multiparous goats were equally stratified and received the common Ovsynch protocol (GPG: intramuscular, IM, injection of 50 mg gonadorelin, followed by an IM injection of 125 µg cloprostenol 7 days later, and a further IM injection of 50 mg gonadorelin 2 days later) or the Ovsynch protocol using nanofabricated hormones with the same dosages (NGPG) or half dosages (HNGPG) of each hormone. The ovarian structures and ovarian and luteal artery hemodynamic indices after each injection of the Ovsynch protocol using B-mode, color, and spectral Doppler scanning were monitored. Levels of blood serum progesterone (P4), estradiol (E2), and nitric oxide (NO) were determined. After the first gonadotrophin-releasing hormone (GnRH) injection, the number of large follicles decreased (p = 0.02) in NGPG and HNGPG, compared with GPG. HNGPG resulted in larger corpus luteum (CL) diameters (p = 0.001), and improved ovarian and luteal blood flow, compared with GPG and NGPG. Both NGPG and HNGPG significantly increased E2 and NO levels compared with GPG. HNGPG increased (p < 0.001) P4 levels compared with GPG, whereas NGPG resulted in an intermediate value. After prostaglandin F2α (PGF2α) injection, HNGPG had the largest diameter of CLs (p = 0.001) and significantly improved ovarian blood flow compared with GPG and NGPG. Both NGPG and HNGPG increased (p = 0.007) NO levels, compared with GPG. E2 level was increased (p = 0.028) in HNGPG, compared with GPG, whereas NGPG resulted in an intermediate value. During the follicular phase, HNGPG increased (p = 0.043) the number of medium follicles, shortened (p = 0.04) the interval to ovulation, and increased (p < 0.001) ovarian artery blood flow and levels (p < 0.001) of blood serum P4, E2, and NO, compared with GPG and NGPG. During the luteal phase, the numbers of CLs were similar among different experimental groups, whereas the diameter of CLs, luteal blood flow, and levels of blood serum P4 and NO increased (p < 0.001) in HNGPG, compared with GPG and NGPG. Conclusively, the nanodelivery system for the Ovsynch protocol could be recommended as a new strategy for improving estrous synchronization outcomes of goats while enabling lower hormone dose administration.

The Steroid Hormone Profile in Etawah Crossbreed Goat While Ovulation Induced using The Selectsynch Method

This study aimed to provide alternative information and solutions in an effort to increase reproductive productivity in etawah crossbreed goats (PE). The sample used in this study was 10 female PE with an average age of 2.5 - 3 years and primiparous at least . Ovulation induction was performed using 0.1 mg intra-muscular Gonadotropin-Releasing Hormone (GnRH), after seven days injection of Prostaglandin F2α (PGF2α) was given as much as 2.5 mg submucosa of the vulva, followed by a second injection of GnRH as much as 0,2 mg intramuscular in samples that have really experienced heat and selected selectively according to the signs of natural heat shown by the sample and followed by insemination as much as 2 doses or 0.50 ml of frozen semen. Blood sampling was performed at H0, H7th, H14th and H21th after insemination. All blood samples were collected and progesterone and estrogen hormone profiles were examined using the ELISA method. From the results of the ELISA test, the mean progesterone hormone profile H0 = 4.798 ng / ml, H7th = 4.887 ng / ml, H14th = 4.824 ng / ml, H21th = 5.148 ng / ml. The profile of the hormone estrogen at H0 = 19,461 pg / ml, H7th = 17,457 pg / ml, H14th = 18,248 pg / ml, H21th = 17,515 pg / ml. This study showed an increase in the levels of the progesterone hormone at H0 to H7th, then slightly decreased in H14th and a significant increase in H21th. For the estrogen hormone, there is a decrease from H0 to H7th then there is a slight increase in H14th and decreases again in H21th.

PSV-3 Ovarian dynamics of brahman cows submitted to five-day or twelve-day progesterone-based estrus synchronization protocol

Abstract The aim of this study was to investigate the ovarian response of Brahman cows submitted to two different estrus synchronization protocols and to determine the estrus response and ovulation time. A total of 153 Brahman cows were randomly assigned to receive one of the following estrus synchronization protocols: 1) CIDR insert and an injection of prostaglandin F2α (25 mg, PGF) on Day -5 and CIDR removal with PGF on Day 0 (CIDR5; n = 77); 2) CIDR insert on Day -12 and an injection of PGF on Day -12, Day -5 and Day 0 upon CIDR removal (CIDR12; n = 76). Estrotect breeding indicator patches were placed on Day 0 and cows were artificially inseminated (AI) 12h after estrus detection; cows not detected in estrus after 96h received TAI coupled with 100 µg of GnRH. Ovarian dynamics were observed during the protocol and follicular diameter were measured every 12h after AI until ovulation. Cows synchronized with CIDR12 had increased follicular diameter (CIDR5, 10.19 ± 0.51 vs. CIDR12, 13.12 ± 0.52 mm; P = 0.01) and decreased serum concentrations of progesterone (CIDR5, 1.68 ± 0.12 vs. CIDR12, 0.81 ± 0.12 ng/ml; P &amp;lt; 0.01) at CIDR removal. The percentage of cows exhibiting estrus did not differ between treatments (CIDR5, 66.2 vs. CIDR12, 64.5%; P = 0.25). No difference was observed in ovulation rate (CIDR5, 94.1 vs. CIDR12, 94.1%; P = 0.6). Time of estrus expression and ovulation time after CIDR removal did not differ (CIDR5, 59.9 ± 2.3 vs. CIDR12, 61.5 ± 2.3h; P = 0.71 and CIDR5, 88.1 ± 2.6 vs. CIDR12, 90.9 ± 2.6h; P = 0.75; respectively). In conclusion, extended length of CIDR with additional PGF increased follicular diameter and decreased concentrations of progesterone but did not influence estrus response and ovulation time in Brahman cows.

The use of fixed time artificial insemination programmes for the use of sexed semen in block calving dairy heifers

In seasonal block calving herds reproductive efficiency can have a significant impact on productivity and profitability. Within this it is key that the nulliparous heifers calve down promptly in the block, and if these heifers can have heifer calves it will expediate genetic gain. There is extensive research into the conception rates of differing protocols and the literature is reviewed to support the choice of protocol used in the subsequent case study. The case study uses a 6-day progesterone protocol with two injections of prostaglandin F2α and sexed semen; it demonstrated acceptable conception rates as well as the variability that can occur between different bulls' semen straws. Finally, the case study assesses the costs and benefits of the synchronisation programme and concludes a cost benefit of £88.55 per heifer.

Effects of prolonging the interval from progestin removal to prostaglandin F2α injection from 16 to 17 d in a long-term estrus synchronization protocol in beef heifers.

To determine effects of delaying the injection of prostaglandin F2α (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG protocol, 1,049 Angus heifers at six locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to one of two treatment groups: 1) PG16 (n = 518), heifers received a controlled internal drug release (CIDR) insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal (d 30), and a 100-µg injection of gonadotropin-releasing hormone concurrent with TAI 66 ± 2 h later; or 2) PG17 (n = 531), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal (d 31), and heifers were TAI 66 ± 2 h later. Estrus detection patches were applied to a subset (n = 482) of heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 116). Transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI differed by treatment where PG17 heifers had greater (P < 0.01) expression of estrus than PG16 heifers (57.8 ± 6.1% vs. 43.4 ± 6.1%, respectively). Nevertheless, dominant follicle diameters at PGF and at TAI were similar (P ≥ 0.59) between PG16 and PG17 heifers. In addition, PR/AI did not differ (P = 0.29) between PG16 and PG17 treatments (50.5 ± 3.2% vs. 45.7 ± 3.1%, respectively). Results of this experiment indicate that delaying the injection of PGF and TAI in the 14-d CIDR-PG protocol increased estrus expression prior to TAI yet did not improve fertility in beef heifers.

2 Intrafollicular injection of asprosin in water buffaloes and the potential role of FBN1 mRNA and asprosin in follicular function

Fibrillin-1 (FBN1) functions as a structural protein in the ovary, whereas the role of its protein product asprosin remains unknown. Both proteins are encoded by the FBN1 gene; when it is cleaved at the C-terminal end, asprosin is produced. Asprosin acts as an orexigenic hormone and is associated with various metabolic parameters and sex related hormones in women. One goal of this research was to quantify FBN1 and the presumed asprosin receptor, olfactory receptor family 4 subfamily M member 1 (OR4M1) mRNA in water buffalo granulosa cells (GC) and correlate them to aromatase (CYP19A1) gene expression. A second goal was to determine the effect of asprosin on follicular growth invivo. In Experiment 1, ovaries were collected from a local slaughterhouse, GC from small (&amp;lt;6mm) and large (6–13mm) follicles were aspirated, RNA was extracted, and gene expression analysis conducted. In Experiment 2, an intrafollicular injection of asprosin (6μL of asprosin in 194μL of phosphate-buffered saline; to achieve 20ng mL−1) or vehicle (200μL of phosphate-buffered saline; Controls) was given via the ovarian stroma below the dominant follicle of synchronized cows (n=5/group) 1 day after injection of prostaglandin F2α, and follicle sizes were measured daily via transrectal ultrasonography until the day of ovulation. Means were compared using t-test for gene expression analysis, and Pearson correlation coefficients calculated among FBN1, OR4M1, and CYP19A1 gene expression. A repeated-measures ANOVA was used to determine the effect of asprosin on follicle size and growth rate of follicles. In Experiment 1, FBN1 mRNA abundance was 7.51-fold greater in GC of small than large follicles (P&amp;lt;0.05). There was no significant difference in the OR4M1 (57.83±39.89 vs. 38.98±4.86) or CYP19A1 (11.46±3.72 vs. 8.27±4.81) mRNA abundance between the 2 sizes of follicles (P&amp;gt;0.10). Abundance of CYP19A1 mRNA was positively correlated with FBN1 (r=0.55, P&amp;lt;0.05) and OR4M1 mRNA (r=0.50, P&amp;lt;0.05). In Experiment 2, there was a treatment×day interaction (P&amp;lt;0.10) for follicle size and growth rate of follicles. Cows treated with asprosin had a higher growth rate from Day 1 to 2 (1.09±0.39 to 2.37±0.32 mm/day) than placebo cows (1.74±0.55 to 1.05±0.61 mm/day) after injection. Most of the follicles from both treatment groups ovulated 3 days post injection. These findings suggest that FBN1 (and thus asprosin) are present in buffalo GC and may be developmentally expressed. Also, asprosin may induce follicular growth when given invivo. Whether these proteins directly regulate aromatase expression, and therefore oestradiol production, during follicle development will require further study.

108 Synchronization and artificial insemination of South African communal cattle

The present study aimed to evaluate an oestrous synchronization protocol and oestrus response before AI in cows from an organised communal production system. A total of 74 cows Bos indicus (Brahman) and Bos taurus/indicus hybrid (Nguni) type from different communal farmers were screened based on: age (3 to 8 years), body condition score of ≥3 (1–5 scale), not pregnant (excluding heifers), 90 days postpartum, number of parities, good mothering ability, and negative for contagious abortion. Selected cows were subjected to a 9-day OvSynch+CIDR protocol. In brief, the protocol included the insertion of controlled intravaginal drug release (CIDR®, Pfizer Laboratories) devices in the reproductive tract (vagina) containing 1.9g of progesterone in each cow on Day 0 with first oestradiol benzoate (Oestradiol benzoate®, VTech) 2-mL intramuscular (IM) injection. Pregnant mare serum gonadotrophin (PMSG; Chronogest®, Intervet International B.V.) 2.5-mL (IM) injection on Day 5. Removal of CIDR and (IM) injection of prostaglandin F2α (PGF2α; Estrumate®, Intervet South Africa (Pty.) Ltd.) 2mL on Day 8. Following CIDR removal, a heat mount detector (Kamar®) was applied on the individual cow’s tail head for oestrus observation (signs of heat) with second oestradiol benzoate 1-mL (IM) injection on Day 9. AI was performed 36h following withdrawal of the CIDR. Frozen/thawed semen from Bonsmara bulls (n=2) of known and proven fertility was used for AI. The GameteTek Cryo-Mobile laboratory was used during thawing of semen straws. and sperm motility and morphological traits were immediately evaluated by computer-assisted sperm analysis (Sperm Class Analyzer®) before each individual cow was inseminated. Pregnancy diagnosis was performed 90 days after timed AI by ultrasound and transrectal palpation. Data were analysed using the logistic regression procedure of SAS (SAS Institute Inc.), with synchronisation response and conception being treated as binary response variables. All cows were synchronized successfully and an oestrus response rate of 100% was recorded. Pregnancy rates were similar (37.8% vs. 38.9%) for both Bos indicus and Bos taurus/indicus hybrid cattle. Bulls total sperm motility of ≥75% were recorded, following thawing of semen straws. Thus, there was no effect of bull on pregnancy. In conclusion, acceptable oestrus synchronization response was achieved in this communal setup. Superior genetic materials can be successfully introduced through assisted reproductive technologies in organised communal production systems.

75 Effect of mycobacterium cell wall fraction immunostimulant on conception rates in heifer recipients

In cattle, the average pregnancy for IVF embryos around Days 45 to 90 is 35% (Ealy et al. 2019 J. Anim. Sci. 97, 2555–2568). Among other factors, uterine contamination with pathogens from the vagina during embryo transfer may affect pregnancy success. Prophylactic antibiotic treatment for this purpose in embryo recipients is considered malpractice. An alternative to antibiotics is the use of mycobacterium cell wall fraction (MCWF) immunostimulant (Amplimune, NovaVive Inc.) against these pathogens. Therefore, the objective was to determine the effect of MCWF on conception rates in heifer recipients. For this purpose, Holstein heifers were synchronized with 2 injections of prostaglandin F2α 14 days apart and randomly allocated to 2 groups: (1) MCWF (n=292), single intramuscular injection of 5mL of Amplimune on the day of pretransfer oestrus; (2) Control (n=296): no Amplimune treatment. Embryo transfers using quality 1 frozen IVF embryos were performed in all recipients 7 to 8 days after oestrus and with a corpus luteum ≥22mm, using a double sanitary sheath technique. Data were analysed using the generalized linear mixed model (GLMM). Results are shown in Table 1. In conclusion, treatment with MCWF increased the number of recipients to be used for embryo transfer and improved the conception rate at Day 60. Importantly, MCWF treatment was more efficient for getting a recipient pregnant by Day 60 per total of synchronized recipients. Table 1. Effect of mycobacterium cell wall fraction (MCWF) on pregnancy in heifer recipients transferred frozen embryos (quality 1) Variable MCWF Control Utilisation rate 227/292a 174/296b (No. of transferred recipients/no. of synchronized recipients) (78%) (59%) Pregnancy Day 30 144/227 94/174 (No. of pregnant recipients at Day 30/no. of transferred recipients) (63%) (54%) Pregnancy Day 60 131/227a 83/174b (No. of pregnant recipients at Day 60/no. of transferred recipients) (58%) (48%) Embryo mortality 13/144 11/94 (No. of embryo loss at Day 60/no. of pregnant recipients at Day 30) (9%) (12%) Pregnancy Day 60 per total of synchronized 131/292a 83/296b (No. of pregnant recipients/no. of synchronized recipients) (45%) (28%) a,bValues with different superscripts within a row are different (P ≤ 0.05).

153 Do pre and postnatal nutrition interact to program reproductive phenotype in sexually mature heifers?

Abstract Objectives were to test the hypothesis that nutritional extremes during pregnancy in the bovine female negatively affect phenotypic characteristics of the estrous cycle of sexually mature offspring, and to determine whether these effects interact with postnatal diets during the juvenile period. Beginning at 90 d of pregnancy, Brangus and Braford (n = 108) beef cows with a female fetus were fed to achieve body condition scores of 7.5–8 (H, obese), 5–5.5 (M, moderate) or 3–3.5 (L, very thin) by the start of the third trimester. Heifer offspring were weaned and fed to gain at either a high (H; 1 kg/d) or low (L; 0.5 kg/d) rate between 4 and 8 months of age, then fed a common growth diet until puberty. Estrous cycles of a subgroup (n = 53) were synchronized using 2 injections of prostaglandin F2α(PGF). Transrectal ultrasonography was employed during the follicular phase of two estrous cycles to evaluate antral follicle count(AFC), rate of growth and size of the ovulatory follicle, size of corpus luteum(CL), and endometrial thickness. Blood samples were collected daily for assay of plasma concentrations of progesterone(P4) and estradiol-17β(E2) by RIA. Preliminary data (n = 35) were analyzed using ANOVA and mixed model procedures. Least Squares Means estrous cycle length (20.9 ± 0.2 days), AFC (19.7 ± 1.0), follicular growth rate (0.81 ± 0.11), ovulatory follicle size (12.8 ± 0.2 mm), CL size (16.8 ± 0.6 mm), and endometrial thickness (14.6 ± 0.3 mm) did not differ among treatments. Heifers in postnatal H group tended (P &amp;lt; 0.1) to have a greater area (arbitrary units) under the E2 curve (12.6 ± 0.6) than postnatal L (11.3 ± 0.5) during the follicular phase. Normalized AUC for P4 was greater (P &amp;lt; 0.03) in L/H (56.94 ± 3.22) than both M/H (42.98 ± 3.61) and L/L (43.66 ± 3.22) groups. Despite marked pre- and postnatal nutritional contrasts, independent and interactive effects of nutritional treatments have been of minor significance or undetectable to date.

PSII-29 Effects of delayed injection of prostaglandin F2α and TAI in the 14-d CIDR-PG &amp; TAI protocol in replacement beef heifers

Abstract To determine the effects of delaying the injection of prostaglandin F2α (PGF) and fixed-time artificial insemination (TAI) in the 14-d CIDR-PG &amp; TAI protocol, 911 Angus heifers at 5 locations were enrolled in a completely randomized design. Within location heifers were randomly assigned to 1 of 2 treatment groups: 1) PG16 (n = 452), heifers received a CIDR insert on d 0 for 14 d, a 25-mg injection of PGF 16 d after CIDR removal [d 30], and a 100-µg injection of gonadotropin-releasing hormone concurrently with TAI 66 ± 2 h later; or 2) PG17 (n = 459), heifers were treated the same as PG16, however, PGF was administered 17 d after CIDR removal [d 31], and heifers were TAI 66 ± 2 h later. Estrus detection patches were applied to heifers at the time of PGF administration and were examined for activation at TAI. Dominant follicle diameter was determined via transrectal ultrasonography at PGF administration and TAI in a subset of heifers (n = 171). Furthermore, transrectal ultrasonography was performed to determine pregnancy rates to TAI (PR/AI) between 30 and 45 d after TAI. Estrus expression prior to TAI was similar (P = 0.50) between treatments (48.9 vs. 52.0%, respectively). Moreover, dominant follicle diameter at PGF and TAI was similar (P ≥ 0.43) between PG16 and PG17 heifers. Pregnancy rates to TAI did not differ (P = 0.48) between treatment groups (46.4 vs. 48.9%, respectively). The results of this experiment indicate that delaying the injection of PGF from d 30 to d 31 along with TAI in the 14-day CIDR-PG &amp; TAI protocol had no effects on fertility parameters in beef heifers. In conclusion, the PGF injection and TAI in the 14-d CIDR-PG &amp; TAI protocol may be delayed, providing more flexibility in scheduling without negatively affecting fertility.

Negative impact of high doses of follicle-stimulating hormone during superovulation on the ovulatory follicle function in small ovarian reserve dairy heifers†.

When women with small ovarian reserves are subjected to assisted reproductive technologies, high doses of gonadotropins are linked to high oocyte and embryo wastage and low live birth rates. We hypothesized that excessive follicle-stimulating hormone (FSH) doses during superovulation are detrimental to ovulatory follicle function in individuals with a small ovarian reserve. To test this hypothesis, heifers with small ovarian reserves were injected twice daily for 4 days, beginning on Day 1 of the estrous cycle with 35, 70, 140, or 210IU doses of Folltropin-V (FSH). Each heifer (n=8) was superovulated using a Williams Latin Square Design. During each superovulation regimen, three prostaglandin F2α injections were given at 12-h interval, starting at the seventh FSH injection to regress the newly formed corpus luteum (CL). Human chorionic gonadotropin was injected 12h after the last (8th) FSH injection to induce ovulation. Daily ultrasonography and blood sampling were used to determine the number and size of follicles and corpora lutea, uterine thickness, and circulating concentrations of estradiol, progesterone, and anti-Müllerian hormone (AMH). The highest doses of FSH did not increase AMH, progesterone, number of ovulatory-size follicles, uterine thickness, or number of CL. However, estradiol production and ovulation rate were lower for heifers given high FSH doses compared to lower doses, indicating detrimental effects on ovulatory follicle function.

Administering an additional prostaglandin F2α injection to Bos indicus beef cows during a treatment regimen for fixed-time artificial insemination

Two experiments were conducted to evaluate if an additional prostaglandin F2α (PG) injection during an estradiol-based estrous synchronization treatment regimen affects pregnancy rates resulting from fixed-time artificial insemination (FTAI) in Nelore cows. In Experiment 1, 1039 cows were administered estradiol benzoate and an intravaginal progesterone releasing device (CIDR) on d -11, an injection of PG on d -4, with CIDR removal and administration of estradiol cypionate and eCG occurring on d -2, and FTAI on d 0. Cows were administered an additional injection of PG (PG2) or saline (PG1) on d -2. Percentage pregnancy per FTAI on d 30 was greater (P = 0.01) in cows of the PG2 than PG1 group (54.5 % and 46.6 %, respectively). In Experiment 2, there was use of the same treatment regimen for estrous synchronization of 934 cows as that for Experiment 1 followed by FTAI, with there being diagnosis of whether cows had or did not have a corpus luteum on d -4. Response to estrous synchronization, largest follicle diameter at FTAI, and pregnancy per FTAI were greater (P ≤ 0.05) in cows of the PG2 than PG1 group with a body condition score (BCS) < 5.0 at FTAI (81.2 % and 72.6 %, 11.9 and 11.2 mm, 55.5 and 45.6 %; respectively). These treatment responses did not differ (P ≥ 0.18) in cows with BCS ≥ 5.0. Collectively, results indicate that treatment with PG2 increased pregnancy per FTAI in B. indicus cows deficient in body energy reserves, by enhancing follicle development and estrous synchronization response.

Effect of a second treatment of prostaglandin F2α during the Ovsynch program on fixed‐time artificial insemination conception rates and luteolysis in split‐calving, pasture‐fed dairy cows

To compare fixed-time artificial insemination (FTAI) conception rates and serum progesterone concentrations at the time of FTAI for cows treated with the original Ovsynch program (OV) with those treated with a modified Ovsynch (MO) program. This was a randomised clinical trial. The study used five split-calving, pasture-based dairy herds in Southwest Victoria, Australia. Controls (n = 851) received the OV program: day 0 gonadotropin-releasing hormone, day 7 prostaglandin F2α (PGF), day 9 gonadotropin-releasing hormone and FTAI at day 10. The treatment group (n = 852) received a MO program with an additional prostaglandin injection on day 8. Subsets of cows from each group were sampled for blood progesterone at the time of FTAI. The treatment group demonstrated FTAI conception rates that were 7% (95% confidence interval 2%-12%) greater than the control group. After adjusting for the effect of age, days in milk at Mating Start Date and herd, the odds of conception using FTAI was 1.36 (95% confidence interval 1.12-1.66) times greater for treatment group cows compared with control group cows. The variability of serum progesterone concentrations at the time of FTAI was significantly less for treatment group cows compared with control group cows. For Holstein-Friesian and Holstein-Friesian cross-bred cows managed in pasture-based dairy herds in southern Australia, a MO protocol, including a second injection of prostaglandin F2α on day 8, increased FTAI conception rates compared with cows receiving the OV protocol.