Comparison between in vitro embryo production in Bos indicus and Bos taurus cows

The aim of this study was to evaluate the in vitro embryo production in Bos taurus and Bos indicus donors, evaluating from oocyte recovery to final embryo production. Data were collected during the months of January and February and August to October 2017. Bos taurus cows: Holstein and Senepol and Bos indicus cows: Nelore and Dairy Gir, were used as oocyte donors. In total, 3622 sessions of OPU were performed, divided between: Holstein donors: 925; Senepol donors: 1055; Nelore donors: 1202 and Dairy Gir donors: 440. In total, 103.399 oocytes were recovered, being viable oocytes: 90.807; cleaved: 65.252 and produced embryos: 24216. There was no statistical difference between the genetic groups for the total oocytes recovered (Bos taurus: 25.5 vs. Bos indicus: 30.1; P> 0.05). However, a statistical difference was observed between the cleaved (Bos taurus: 16 vs. Bos indicus: 20.4; P <0.05) and produced embryos (Bos taurus: 4.4 vs. Bos indicus: 8.3; P <0,05). Thus, the conclusion is that Zebu donors perform better in IVEP and the donor breed influences the IVEP results.

A Bladder Teratoma after Oocyte Retrievals

Oocyte recovery by means of transvaginal ultrasound-guided puncture was first described in 1985, and the procedure has gained widespread popularity. The literature consistently reports that complications related to oocyte retrievals are rare. Yet this report describes a woman with a long-term complication after egg retrievals.

145 Comparison of single to multiple injections of follicle-stimulating hormone before ovum pickup in Holstein heifers: Oocyte recovery and embryo production

The demand for invitro-produced embryos from heifers with high genetic merit has increased over time. Synchronization and stimulation of follicular growth before ovum pickup (OPU) has been used to improve oocyte quality and, consequently, embryo production. Multiple injections involve extra labour and stress for both personnel and cattle. The release of FSH can be prolonged by using 0.5% hyaluronan (HA) as a diluent, allowing a decrease in the number of injections. The objective of this study was to compare oocyte recovery and embryo production between single or multiple injections of FSH before OPU of Holstein heifers. During April and May 2020, 20 Holstein heifers (8 to 15 mo old) from Ruann Dairy (Riverdale, CA) were randomly divided and submitted to two different treatments (crossover design). Gonadotrophin-releasing hormone (GnRH; Fertagyl®, Merck, 129µg, IM) was given to synchronize the follicular wave emergence. Treatment 1×FSH consisted of a single intramuscular (IM) injection of 100mg of FSH (Folltropin®, Vetoquinol) 36h after GnRH. The FSH consisted of a 2.5-mL injection of 400mg of FSH diluted in 10mL of 0.5% HA. OPU was performed 48 to 50h after FSH. Treatment 5×FSH consisted of 100mg of FSH divided into 5 equal IM injections (10-14h intervals) 36h after GnRH. The FSH consisted of 5×1-mL injections of 400mg of FSH in 20mL of saline. OPU was performed 18 to 20h after the last FSH injection. All donors received both treatments at a 14-day interval and the recovered oocytes were fertilized with the same sexed female-sorted semen in both rounds. OPU, oocyte classification, IVM, IVF, and culture (IVC) were performed as described by Demetrio et al. (2020 Anim. Reprod. 17, e20200053). All oocytes went into IVM, except for degenerated oocytes. The number of 4-cell (or more) embryos on Day 3 of IVC divided by the number of oocytes in IVC after IVF is defined as the cleavage rate. The number of blastocysts (early to hatched) on Day 7 of IVP divided by the number of oocytes in IVC after IVF is defined as the blastocyst rate. Poisson-normal (count data) and Logistic-normal (proportion data) models were used to analyse the data. Treatment, donor (random effect), and sire were included in the models. The results are summarized in Table 1. There were no differences between the two treatments on the number of oocytes recovered per OPU (total and grade 1 and 2), percentage of grade 1 and 2 oocytes, cleavage rate, blastocyst rate and number of embryos (total and grade 1). Oocyte recovery and embryo production are highly donor dependent. Stimulation of the follicular growth before OPU with one single injection of FSH diluted in 0.5% HA 36h after GnRH can be efficiently used for IVP in Holstein heifers, without decreasing the number of oocytes recovered and/or embryos produced with the advantage of reducing labour and stress of handling cattle. Table 1. Number and quality of oocytes and cleavage and blastocyst rates Treatment OPU Oocytes per donor Grade 1 and 2 oocytes (%) Cleavage rate (%) Blastocyst rate (%) Total embryos per OPU Grade 1 embryos per OPU 1×FSH 20 17.0 45.7 84 39.8 6.2 3.8 5×FSH 20 19.9 46.5 82 35.6 6.3 4.0

54 Effect of clinical endometritis on the follicle growth dynamics, oocyte recovery, oocyte quality, and invitro developmental competence of oocytes using ovum pickup in Sahiwal cattle

Sahiwal cattle is the premium quality milk breed of cattle in Pakistan. Uterine infections often lead to culling of valuable animals from a herd, resulting in genetic drain. The genetic potential of problematic females could be reaped by invitro embryo production. The objective of the present study was to evaluate the effect of clinical endometritis on follicle growth dynamics, recovery, quality, and invitro developmental competence of oocytes using ovum pickup (OPU) in Sahiwal cattle. The animals, 5–7 years of age, third or fourth parity, and 160 to 170 days in milk (DIM), were inspected for any discharge at the vulva or inside the vagina. Then, B-mode ultrasonography was performed to measure the diameter of cervix and to examine the uterus for the presence of pus. The animals (n=12) were divided into 2 groups: (1) healthy (n=6), and (2) clinical endometritis (n=6), based on the presence or absence of pus at the vulva or in the vagina. The first OPU was performed after 7 days of dominant follicle puncture and subsequently repeated OPUs (54 and 50), after every 7 days over 9 OPU sessions, were performed in the healthy group and clinical endometritis group, respectively. Follicles were aspirated using transvaginal ultrasound–guided needle. Viable COCs were considered for further processing only and were placed in the 100-µL droplets of BO-IVM medium and incubated at 37°C, 5% CO2, and 95% humidity for 24h. Nuclear maturation was estimated by staining the oocytes with Hoechst 33342. Frozen semen from the same Sahiwal bull was thawed and processed for IVF throughout the study. Sperm were prepared using swim-up protocol. Sperm and COCs were co-incubated in 100-µL droplets of BO-IVF for 18h. Finally, presumptive zygotes were cultured in 100-µL drops of BO-IVC medium at 37°C, 5% CO2, 5% O2, and 95% humidity for a period of 7 days. Cleavage rate and blastocyst rate were recorded on Day 2 and 7 following IVF, respectively. The data were analysed using the GLIMMIX procedure of SAS (SAS Institute Inc.). The results revealed that the number of medium-sized follicle (1.32±0.11 vs. 0.56±0.11) and total follicles (9.14±0.70 vs. 6.58±0.72) were higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. Similarly, the number of oocytes recovered (5.05±0.39 vs. 2.78±0.41), viable oocytes (2.87±0.25 vs. 1.46±0.26), COCs with grade AB, having minimum of 2 cumulus cell layers and homogeneous cytoplasm, (33 vs. 20%) and nuclear maturation (68 vs. 55%) were also higher (P&lt;0.05) in the healthy group than in the clinical endometritis group, respectively. However, cleavage rate (55 vs. 46%) and blastocyst rate (29 vs. 26%) did not differ (P&gt;0.05) between the groups. In conclusion, clinical endometritis has a negative effect on follicle growth dynamics, oocyte recovery, oocyte quality, and nuclear maturation; however, the developmental competence of COCs is not compromised by it.

146 Single injection of follicle-stimulating hormone before ovum pickup in lactating Holstein donors: Oocyte recovery and embryo production

Lactating donor cows frequently have decreased oocyte quality, lower fertilization rates, and impaired early embryonic development due to their lactational metabolic challenges. Synchronization and stimulation of follicular growth before ovum pickup (OPU) has been used to improve oocyte quality and consequently, embryo production. The objective of this study was to evaluate the effects of a single injection of FSH before OPU on oocyte recovery and embryo production in lactating Holstein donors. During June and July 2020, 22 lactating Holstein donors (open, 40 to 90 DIM, producing &gt;90 lbs of milk) from Ruann Dairy (Riverdale, CA) were randomly assigned to one of two treatments (crossover design). Donors did not receive any injections before OPU when assigned to the No FSH treatment. Treatment 1×FSH consisted of a single intramuscular (IM) injection of 140mg of FSH (Folltropin®, Vetoquinol) 36h after gonadotrophin-releasing hormone (GnRH; Fertagyl, Merck®, 129µg, IM). The FSH consisted of a 3.5-mL IM injection of 400mg of FSH diluted in 10mL of 0.5% hyaluronan (HA). OPU was performed 48 to 52h after FSH. All donors received both treatments on a 14-day interval. The recovered oocytes were fertilized with the same sexed female-sorted semen in both rounds (3 different sires were used). OPU, oocyte classification, IVM, IVF, and culture (IVC) were performed as described by Demetrio et al. (2020 Anim. Reprod. 17, e20200053). All oocytes went into IVM, except for degenerated occytes. The number of 4-cell (or more) embryos on Day 3 of IVC divided by the number of oocytes in IVC after IVF is defined as the cleavage rate. The number of blastocysts (early to hatched) on Day 7 of IVP divided by the number of oocytes in IVC after IVF is defined as the blastocyst rate. Poisson-normal (count data) and Logistic-normal (proportion data) models were used to analyse the data. Treatment, donor (random effect), and sire were included in the models. The results are summarised in Table 1. Oocyte recovery and embryo production were highly donor dependent. There were no differences in the number of recovered oocytes among treatments. Stimulation of the follicular growth before OPU with one single injection of FSH diluted in 0.5% HA 36h after GnRH improved oocyte quality, cleavage rates, blastocyst rates, embryo quality, and the total number of embryos per OPU in lactating Holstein donors. Table 1. Oocyte recovery, cleavage rate, and embryo production results Treatment OPU Oocytes per donor Grade 1 and 2 oocytes Cleavage rate (%) Blastocyst rate (%) Total embryos per OPU Grade 1 embryos per OPU No FSH 22 18.2 30a 69a 22a 3.4a 1.6a 1×FSH 22 17.5 34b 77b 34b 5.3b 3.3b a,bValues with different superscripts in the same column differ (at least P&lt;0.05).