Factors influencing pregnancy rate and loss after laparoscopic artificial insemination with frozen-thawed semen in Lohi sheep under sub-tropical conditions.

This study evaluates factors influencing pregnancy rates per artificial insemination (P/AI) and pregnancy loss in Lohi ewes undergoing laparoscopic AI with frozen-thawed semen under sub-tropical conditions. Data from three experiments comprising ewes (n = 358) of mixed parity (nulliparous; NP and parous; P), various body condition score (BCS) and assigned to long-term (LTP, 11 days) and short-term (STP, 5 days) oestrus synchronization regimen across high breeding season (HBS) and low breeding season (LBS) were analysed. Laparoscopic insemination was conducted 54 h post-sponge removal. Pregnancy diagnosis and loss were evaluated on days 35 and 90 post-insemination via ultrasonography. Results showed parity significantly influenced P/AI, with nulliparous ewes achieving higher pregnancy ratios than parous ewes (p = .001). BCS significantly influenced P/AI (p < .05), with a quadratic relationship observed between BCS and season (BCS*BCS*Season; p = .07). Progestin treatment did not significantly influence the ratio of pregnant ewes (p = .07). Pregnancy losses were significantly higher during LBS than HBS (p < .05), irrespective of progestin treatment. In conclusion, parity and BCS significantly influenced P/AI, with BCS demonstrating a quadratic association with season. Ewes bred during LBS experienced higher pregnancy losses than HBS, irrespective of progestin treatment.

The use of sodium caseinate in the freezing of sheep semen.

The aim of this study was to assess the addition of 2% sodium caseinate in a commercial egg yolk-based medium in frozen ovine semen. Eight Dorper males were used for the study. The ejaculate was divided into two portions and frozen without (G1) or with the addition of 2% sodium caseinate (G2). Kinetic parameters were evaluated using CASA (computer-assisted sperm analysis), and membrane and acrosome integrity as well as oxidative stress were assessed using flow cytometry. After thawing, a thermoresistance test was conducted at time points T0 and T90. For the fertility test, 100 ewes were inseminated with semen from two rams selected based on in vitro parameters, one with good post-thaw quality (+70% total motility) and the other with low post-thaw quality (-55% total motility). For the fertility test, the females were divided into 4 groups for insemination: low-quality ram without caseinate (GBS = 25) and with caseinate (GBC = 25), and high-quality ram without caseinate (GAS = 25) and with caseinate (GAC = 25). Regarding the results of sperm kinetics, there was a statistically significant difference in the parameters of average path velocity (VAP) and curvilinear velocity (VCL) between the group frozen with BotuBov and the group with added caseinate. At time point T90, straight-line velocity maintained a trend (p < .06), with BotuBov® (BB group) being superior to caseinate this time, and in the linearity parameter, caseinate was superior to BotuBov®. Flow cytometry analysis showed no difference between any of the evaluated tests. In the fertility test, there was no statistically significant difference in the pregnancy rate between the BotuBOV® group (23%, 11/48) and the sodium caseinate group (BC group) (33%, 17/52), and no differences were observed in the male versus diluent interaction (p = .70). In conclusion, sodium caseinate supplementation did not influence sperm kinetic parameters and the fertility of sheep.

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.

Customized modified therapies for ovarian cyst and persistent follicle followed with TAI in early postpartum dairy cows.

Background: Postpartum ovarian dysfunction [ovarian cyst (OC) and persistent follicle (PF)] has been an important issue. Finding effective hormonal treatments to improve reproductive performance in dairy cows has become a necessity. Aim: Improve reproductive performance and ovarian activity in postpartum cows with specific customized treatment for OC and PFs. Methods: The study included 48 cows at 14 days P.P, which received two dosages of 500 µg IM cloprostenol, 14 days apart as presynchronization protocol. Ultrasound ovarian scans 14 days after the last injection for 4 weeks. The cows were divided into three groups according to ovarian status: OC (n = 14), PF (n = 12), and NE (n = 22). In the OC group, received 500 µg IM cloprostenol and 100 µg IM cystoriline, a second dose of cloprostenol 14 days later and a second dose of cystoriline 36 hours later, and AI after 24 hours (GnRH+ PG/PG/GnRH). In the PF group, was fitted with progesterone-releasing intravaginal device (PRID) for 9 days; the same day, they received 100 µg cystoreline then 500 µg cloprostenol 7 days later, after PRID removal AI 56 hours later (PRID + GnRH/PG). In the NE group, artificial insemination was implemented until 28 days depending on estrus detection. Results: The ovarian activity was greatly affected by the customized treatments, leading to enhanced follicular and luteal activity, particularly after the PGF2α injection. The OC and PF groups showed substantial estrus responses of 71.43% and 75.02%, respectively, during AI time. While the NE group had an ovulation rate of 54.5% and a pregnancy rate of 31.8%, the treatment groups showed marked improvements in reproductive performance. The ovulation rates in the OC and PF groups were 71.43% and 75% and the pregnancy rates at the 1st artificial insemination were 64.28% and 66.7%. Conclusion: Improving reproductive performance and minimizing the time to first service are possible advantages of early case-specific treatment for postpartum cows with OC and PFs.

Biochemical profile and oocyte quality of primiparous Bos indicus cows submitted to a timed artificial insemination protocol.

The objective of this study was to verify the causes of the lower response of primiparous Bos indicus cows to the ovulation synchronization protocol. Two experiments were performed to evaluate the biochemical profile, oocyte and follicular cell quality (Experiment 1) and pregnancy (Experiment 2). In Experiment 1, suckled primiparous (n = 24) and multiparous cows (n = 24) were submitted to ovum pick up (OPU). On Day 0 (D0), all cows received 2 mg of estradiol benzoate (EB) and an intravaginal progesterone insert (P4). Five days (D5) after the first hormonal administration (EB + P4), all follicles larger than 3 mm were counted on each ovary, and ovum pick-up (OPU) was performed. On day 12 (D12), the intravaginal progesterone insert was removed, and measurement and aspiration of the largest follicle were performed. Blood samples were collected on D5 and D12 to evaluate the concentrations of glucose, cholesterol, NEFA, IGF-1 and insulin. In Experiment 2, suckled primiparous (n = 50) and multiparous (n = 50) cows were subjected to an ovulation synchronization protocol based on E2/P4 (D0: 2 mg EB plus P4 intravaginal insert; D8: 500 µg of cloprostenol, 1 mg cypionate estradiol and 300UI of eCG; D10: artificial insemination). In addition, blood samples were collected on D10 for evaluation of the same hormones and metabolites described in Experiment 1. In all studies, calves remained with the cows during the experimental period. In experiment 1, the number of oocytes grade 1 (P = 0.83), grade 2 (P = 0.23) and grade 3 (P = 0.51), total number of retrieved oocytes (P = 0.14), oocyte quality index (P = 0.93) and total viable oocytes (P = 0.38) did not differ between primiparous and multiparous cows. The number of follicles at the time of follicular aspiration (20.7 ± 1.5 vs. 18.0 ± 1.9; P = 0.05) and the diameter of the largest follicle on D12 (13.5 ± 0.6 vs. 11.4 ± 0.6; P = 0.04) were greater in multiparous cows, and the number of degenerated oocytes was greater in primiparous cows (1.9 ± 0.7 vs. 1.2 ± 0.3; P = 0.05). On D5, the concentrations of IGF-1 (P = 0.47), insulin (P = 0.08), total cholesterol (P = 0.47), NEFA (P = 0.77) and glucose (P = 0.55) in the blood and IGF-1 (P = 0.97) and insulin (P = 0.11) in the follicular fluid did not differ between parity groups. On D12, there was no difference in the concentrations of IGF-1 (P = 0.26), total cholesterol (P = 0.32), NEFAs (P = 0.31) and glucose (P = 0.93) in the blood between primiparous and multiparous cows, however, the serum insulin concentration (P = 0.04) was higher in primiparous cows. There was no correlation between serum and follicular fluid insulin concentrations (r = 0.17; P = 0.31), however, there was a low correlation between serum and follicular fluid IGF-1 concentrations (r = 0.47; P = 0.002). Quantification of transcripts did not differ between parity groups. In experiment 2, concentrations of NEFA (P = 0.12) and insulin (P = 0.16) in the blood and P/AI (P = 0.93) did not differ between parity [60 % (30/50) primiparous vs. 60 % (30/50) multiparous]. In contrast, blood concentrations of IGF-1 (P = 0.0001), total cholesterol (P = 0.005) and glucose (P = 0.01) were greater in primiparous cows. It was concluded that the oocyte quality and expression of the genes evaluated in the granulosa cells were not different between primiparous and multiparous cows. Unexpectedly, the pregnancy rate did not differ between parity. Nevertheless, the blood concentrations of IGF-1, total cholesterol and glucose were greater in primiparous cows.

Optimizing ReBreed21 II: Fertility and reproductive efficiency in different parities during a shortened breeding season in beef cattle.

This study evaluated the efficiency of a rapid reinsemination program allowing timed AI (TAI) every 21d (ReBreed21) in a commercial beef cow-calf operation. Nelore females from different parities (n = 2085) were synchronized for first TAI (D0 = TAI) using an estradiol/progesterone (E2/P4) protocol and assigned to one of three reinsemination programs: Resynch33 (n = 753), traditional resynch program with second TAI at D42 after first TAI; ReBreed21 (n = 687); or ReBreed21+EC (n = 670). The ReBreed females (n = 1357) received intravaginal P4 insert on D12, on D19 P4 was removed, and a dose of equine chorionic gonadotropin (eCG) was administered, then, ReBreed21 females received 0.6 mg of EC (ReBreed21+EC) or nothing (ReBreed21) and on D21, nonpregnancy (NP) was determined using Doppler ultrasound to detect corpus luteum (CL) blood flow (BF) (NP: <25 % BF pixels of total CL area) and NP cows received immediate TAI and GnRH to induce ovulation. Pregnancy diagnosis was performed at D33 after TAI following all TAIs. Cows considered pregnant at D21, based on CL BF, but NP on D33 were designated False-Positives (FP) and false negatives (FN) were number of nonpregnant cows/heifers on d21 based on the CL BF found to subsequently be pregnant on D33 divided by the total number pregnant. Pregnancy/AI (P/AI) did not differ for the first TAI (55.1 %) among the treatments. Heifers had similar P/AI at the second AI in all groups and similar to the first AI. Primiparous had greater P/AI in ReBreed21+EC and Resynch33 at s TAI compared to ReBreed21, 51.7 %, 55.8 %, 34.2 %, respectively. Multiparous had greater P/AI at second TAI in Resynch33 (60.9 %) than ReBreed21 programs (34.7 %). The percentage FP and FN among ReBreed21 programs did not differ, 13.8 and 0.2 %, respectively. Overall accumulative pregnancies on D21 of the breeding season were greater for ReBreed21 and ReBreed21+EC than Resynch33 (69.7 %, 71.6 %, and 55.5 %, respectively). However, on D42 of the breeding season, only heifers had greater pregnancies in ReBreed21 programs than Resynch33 (73.3 %, 74.3.6 %, and 63.2 %, respectively). Average days to pregnancy were less (P = 0.01) for ReBreed21 and ReBreed21+EC than Resynch33. Thus, the ReBreed21 strategy can improve the efficiency of TAI programs in beef cattle. Of interest, ReBreed21 was particularly effective in nulliparous, somewhat effective in primiparous when EC was added to the program, but relatively ineffective in multiparous beef cattle.

Accuracy of early pregnancy diagnosis and determining pregnancy loss using different biomarkers and machine learning applications in dairy cattle.

This study aimed to compare the accuracy of IFN-τ stimulated gene abundance (ISGs) in peripheral blood mononuclear cells (PBMCs), CL blood perfusion by Doppler ultrasound (Doppler-US), plasma concentration of P4 on Day 21 and pregnancy-associated glycoproteins (PAGs) test on Day 25 after timed-artificial insemination (TAI) for early pregnancy diagnosis in dairy cows and heifers. Holstein cows (n = 140) and heifers (n = 32) were subjected to a hormonal synchronization protocol and TAI on Day 0. On Day 21 post-TAI, blood samples were collected for PBMC isolation and plasma concentration of P4. The CL blood perfusion was evaluated by Doppler-US. Plasma samples collected on Day 25 were assayed for PAGs. The abundance of ISGs (ISG15 and RSAD2) in PBMCs was determined by RT-qPCR. Pregnancy was confirmed on Days 32 and 60 post-TAI by B-mode ultrasonography. Statistical analyses were performed by ANOVA using the MIXED procedure and GLIMMIX in SAS software. The pregnancy biomarkers were used to categorize the females as having undergone late luteolysis (LL); early embryonic mortality (EEM); late embryonic mortality (LEM); or late pregnancy loss (LPL). The abundance of ISGs, CL blood perfusion by Doppler-US, and concentrations of P4 on Day 21, and PAGs test on Day 25 were significant (P < 0.05) predictors of early pregnancy in dairy cows and heifers. Dairy cows had a greater (P = 0.01) occurrence of LL than heifers, but there was no difference (P > 0.1) for EEM, LEM, and LPL in heifers compared to cows. Cows with postpartum reproductive issues had a greater (P = 0.008) rate of LEM and a lesser (P = 0.01) rate of LPL compared to cows without reproductive issues. In summary, the CL blood perfusion by Doppler-US had the highest accuracy and the least number of false negatives, suggesting it is the best predictor of pregnancy on Day 21 post-TAI. The PAGs test was the most reliable indicator of pregnancy status on Day 25 post-TAI in dairy heifers and cows. The application of machine learning, specifically the MARS algorithm, shows promise in enhancing the accuracy of predicting early pregnancies in cows.

The effect of uterine massage and number of embryo flushing attempts on embryo recovery in mares.

The aims of this study were to determine the effect of the embryo flushing technique and the number of flushing attempts performed by operators of different experience on embryo recovery (ER). Ten non-lactating mares were inseminated with the same stallion in six cycles each (n = 60). Embryo flushing (EF) was performed 7-9 days after ovulation by three operators (OP; 20 EF cycles each): OP1 had performed >500 EF before the study, while OP2 and 3 had performed 0 EF. Each EF was performed with 2 flushing attempts (FA) using 1L of ringer's lactate "in-and-out" using two EF techniques: 1) uterine massage (UM): continuous ballottement and massage of the uterus per rectum during ringer lactate recovery, 2) gravity flow (GF): the ringer lactate was allowed to flow back without massaging the uterus. In both groups, 20 IU of oxytocin were administered at the second FA and the ringer lactate was allowed to remain in the uterus for 3 min before recovery. An extra FA was performed in each group using 0.5 L of ringer lactate and uterine massage. More embryos (P < 0.05) per ovulation were recovered in the UM (17/33, 0.51) than in the GF group (8/36, 0.22). For the UM group, 16/17 embryos (94.1 %) were recovered in the first FA, while only one embryo in the second FA (1/17, 5.9 %). In the GF group, 4 embryos were recovered in each FA. No embryo was found in the extra FA in the UM group, while seven additional embryos were found in the GF group (5/7 flushed by OP1; P < 0.05). The overall ER per cycle was 70, 40, and 45 % for OP1, 2 and 3, respectively. In conclusion, highest embryo recovery is achieved in EF performed with UM, with the majority of embryos being flushed in the first FA.

Early prognostic markers to predict unsuccessful pregnancy in dairy cattle.

This study aimed to investigate maternal serum levels of some angiogenic factors and certain proteins in dairy cattle for (1) early prediction of unsuccessful fertilization and (2) early detection of possible pregnancy failures (early EM) after positive insemination Serum samples were collected from the same cattle at three distinct time points: 30 days before artificial insemination (B-AI), on the day of artificial insemination (AI), and 30 days after artificial insemination (A-AI). As a result of the pregnancy examination, the cows were divided into two main groups according to whether they were pregnant. The results showed that leucyl/cystinyl aminopeptidase (LNPEP) concentration was significantly decreased B-AI and Secreted frizzled-related proteins (SFRP-3), Vascular Endothelial Growth Factor (VEGF) and LNPEP levels were significantly decreased on day of AI, while PRL level was increased, and these data have prognostic significance as early indicator of the risk of potentially failed pregnancy. Additionally, a significant decrease in LNPEP, SFRP3, and VEGF levels, along with an increase in PRL levels was also observed in A-AI. These results suggest that these biomarkers can be used as a screening test to monitor the course of pregnancy. There were no significant differences in serum levels of Insulin-Like Growth Factor 2 (IGF-2), Tissue inhibitors of metalloproteinases (TIMP-1), angiopoietin (ANG), Endoglin (ENG), Fibroblast growth factor (FGF), Inhibine-A (INH-A) and Transforming growth factors-ß1 (TGF-ß1) between the evaluated periods neither unsuccessful nor the successful pregnancy groups. This is the first study reporting that the maternal serum levels of LNPEP, SFRP3, VEGF, and PRL have important roles in pregnancy success and may indicate whether insemination outcome will be successful B-AI and predict the risk of unsuccessful pregnancy after AI in dairy cattle. The increase in such studies will allow the development of more specific, practical, and applicable markers.

Seminal plasma hypersensitivity: A systematic review of clinical presentation, diagnostics, and management options.

INTRODUCTION: Seminal plasma hypersensitivity (SPH) is a rare and often misdiagnosed condition characterized by local and/or systemic reactions to seminal plasma proteins following exposure to semen. We aimed to summarize key symptomatology, diagnostic features, and management options for SPH. METHODS: The databases PubMed, EMBASE, Web of Science, Google Scholar, and Cochrane Review were searched with key words "seminal plasma hypersensitivity" and "seminal fluid allergy" through September 2023. Exclusion criteria included non-English articles, in vitro studies, publication before 1990, duplicates, and articles with no clinical relevance to SPH in women. RESULTS: The search yielded 53 articles for review. Of these, 60.5% described systemic SPH and 39.5% described localized. CONCLUSION: Diagnosis of SPH relies on a thorough patient history and confirmatory skin prick testing. The use of IgE assays is controversial and less accurate for cases of localized SPH. Knowledge of disease immunopathology, systemic versus localized symptom presentation, patient preference, and desire to conceive should guide management options. Artificial insemination has the potential for severe adverse reactions in systemic SPH so necessitates extra procedural precautions. SPH does not appear to impair fertility. Additional research on specific allergens implicated in SPH can aid in the development of more targeted immunotherapy approaches with improved safety and efficacy.

Impact of 17ß-estradiol administration at the moment of timed-AI in Nelore cows with small dominant follicle or not showing estrus.

We aimed to evaluate the effects of administering estradiol (E-17ß) at the moment of timed-AI (TAI) on uterine gene expression, estrous expression rate (EER), and pregnancy rate (P/TAI) in Nelore cows with a small dominant follicle (DF) or not showing estrus at TAI. In Experiments 1 and 2 (Exp1, Exp2) cows were submitted to a P4/E-17ß-based protocol (day 0) for synchronization of ovulation. On day 7, devices were removed, cows received 1 mg E-17ß cypionate and 12.5 mg dinoprost. On day 9, cows with DF < 11.5 mm in diameter were split into different groups. In Exp1 (n = 16/group): Control (no treatment), E-2 (2 mg E-17ß) and E-4 (4 mg E-17ß). In Exp2: Control (n = 12); E-2 (n = 14); GnRH (0.1 mg gonadorelin acetate, n = 13); and E-2+GnRH (association of GnRH and E-17ß, n = 13). Between days 9 and 11, endometrial thickness (ET), time of ovulation detection, and EER were recorded. In Exp1, a uterine cytological sample was collected 4 h after treatment to evaluate the transcript expression of receptors for E-17ß (ESR1 and ESR2), oxytocin (OXTR), and P4 (PGR). In Experiment 3 (Exp3), 3829 suckled cows were submitted to a P4/E-17ß-based protocol for TAI. On day 9, devices were removed and cows received 1 mg E-17ß cypionate and 0.4 mg sodium cloprostenol. On day 11, TAI was performed and cows that did not demonstrate estrus received 0.1 mg gonadorelin acetate, and were allocated into two groups: GnRH (n = 368) and E-2+GnRH (2 mg E-17ß; n = 363). In Exp1, plasma E-17ß concentrations increased at 4 h after treatment in a dose-dependent manner but reduced at 12 h. The E-17ß-treated cows had greater transcript abundance for OXTR and lesser for ESR1 and ESR2, and the ET was reduced 12 h after treatment (P < 0.05). No significant difference (P > 0.1) was observed between the E-17ß doses in estrus or ovulation rate. In Exp2, the interval from treatment to ovulation was longer (P < 0.05) in the E-17ß group. GnRH-treated cows showed higher ovulation rates (89 vs. 35 %) compared to cows not treated with GnRH, as E-17ß-treated cows (P < 0.01) had a lower ovulation rate compared to those not receiving E-17ß (44 vs. 78 %). In Exp3, P/TAI was 55 % for cows in estrus. For those not showing estrus, no difference (P > 0.1) in P/TAI was observed between GnRH (34 %) and E-2+GnRH (31 %) groups. Cows with a DF ≥ 11 mm (n = 192) had a greater (P < 0.05) P/TAI (49 %) than those with DF < 11 mm (n = 377; 29 %). In conclusion, E-17ß administration in the moment of TAI modulates the mRNA expression of uterine receptors in cows with a small DF but does not impact the P/TAI compared with GnRH treatment in suckled Nelore not showing estrus previous to TAI.

Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches.

Early pregnancy loss is a primary cause of low reproductive rates in dairy cows, posing severe economic losses to dairy farming. The accurate diagnosis of dairy cows with early pregnancy loss allows for oestrus synchronization, shortening day open, and increasing the overall conception rate of the herd. Several techniques are available for detecting early pregnancy loss in dairy cows, including rectal ultrasound, circulating blood progesterone, and pregnancy-associated glycoproteins (PAGs). Yet, there is a need to improve on existing techniques and develop novel strategies to identify cows with early pregnancy loss accurately. This manuscript reviews the applications of rectal ultrasound, circulating blood progesterone concentration, and PAGs in the diagnosis of pregnancy loss in dairy cows. The manuscript also discusses the recent progress of new technologies, including colour Doppler ultrasound (CDUS), interferon tau-induced genes (ISGs), and exosomal miRNA in diagnosing pregnancy loss in dairy cows. This study will provide an option for producers to re-breed cows with pregnancy loss, thereby reducing the calving interval and economic costs. Meanwhile, this manuscript might also act as a reference for exploring more economical and precise diagnostic technologies for early pregnancy loss in dairy cows.

Metabolic imprinting in beef calves supplemented with creep feeding on performance, reproductive efficiency and metabolome profile.

This experiment evaluated the influence of creep feeding supplementation on productive and reproductive performance and on serum metabolome profile in Nelore (Bos indicus) heifers. Female calves were assigned to treatments: Creep (n = 190), with ad libitum access to a nutritional supplement from 70 to 220 days after birth, or Control (n = 140), without supplementation. After weaning (Day 220), both groups followed the same pasture and nutritional management. Body weight (BW) and backfat thickness (BFAT) were measured over time. Blood samples were collected at 220 and 360 days for LC-MS/MS targeted metabolomics. On day 408, during the synchronization timed artificial insemination (TAI) protocol, reproductive status (RS: diameter of uterine horn and largest follicle, and presence of CL) was assessed. Creep feeding increased BW and BFAT at weaning, but no differences in BW, BFAT, or RS after weaning were observed. Nonetheless, the pregnancy per AI (P/AI) for 1st service was 28.9% higher in the Creep group. On day 220, 11 significant metabolites influenced five metabolic pathways: Glucose-alanine cycle, alanine, glutathione, phenylalanine and tyrosine metabolism, and urea cycle. On day 360, 14 significant metabolites influenced eight metabolic pathways: Malate-aspartate shuttle, arginine and proline metabolism, urea cycle, aspartate, beta-alanine, glutamate metabolism, ammonia recycling and citric acid cycle. In conclusion, creep feeding supplementation improved calf performance and induced metabolic changes at weaning and 360 days of age. Although heifers had similar productive performance and reproductive status, when submitted to TAI, those supplemented with creep feeding had greater P/AI.

Multifetal Pregnancy After Implementation of a Publicly Funded Fertility Program.

Importance: A publicly funded fertility program was introduced in Ontario, Canada, in 2015 to increase access to fertility treatment. For in vitro fertilization (IVF), the program mandated an elective single-embryo transfer (eSET) policy. However, ovulation induction and intrauterine insemination (OI/IUI)-2 other common forms of fertility treatment-were more difficult to regulate in this manner. Furthermore, prior epidemiologic studies only assessed fetuses at birth and did not account for potential fetal reductions that may have been performed earlier in pregnancy. Objective: To examine the association between fertility treatment and the risk of multifetal pregnancy in a publicly funded fertility program, accounting for both fetal reductions and all live births and stillbirths. Design, Setting, and Participants: This population-based, retrospective cohort study used linked administrative health databases at ICES to examine all births and fetal reductions in Ontario, Canada, from April 1, 2006, to March 31, 2021. Exposure: Mode of conception: (1) unassisted conception, (2) OI/IUI, or (3) IVF. Main Outcomes and Measures: The main outcome was multifetal pregnancy (ie, a twin or higher-order pregnancy). Modified Poisson regression generated adjusted relative risks (ARRs) and derived population attributable fractions (PAFs) for multifetal pregnancies attributable to fertility treatment. Absolute rate differences (ARDs) were used to compare the era before eSET was promoted (2006-2011) with the era after the introduction of the eSET mandate (2016-2021). Results: Of all 1 724 899 pregnancies, 1 670 825 (96.9%) were by unassisted conception (mean [SD] maternal age, 30.6 [5.2] years), 24 395 (1.4%) by OI/IUI (mean [SD] maternal age, 33.1 [4.4] years), and 29 679 (1.7%) by IVF (mean [SD] maternal age, 35.8 [4.7] years). In contrast to unassisted conception, individuals who received OI/IUI or IVF tended to be older, reside in a high-income quintile neighborhood, or have preexisting health conditions. Multifetal pregnancy rates were 1.4% (95% CI, 1.4%-1.4%) for unassisted conception, 10.5% (95% CI, 10.2%-10.9%) after OI/IUI, and 15.5% (95% CI, 15.1%-15.9%) after IVF. Compared with unassisted conception, the ARR of any multifetal pregnancy was 7.0 (95% CI, 6.7-7.3) after OI/IUI and 9.9 (95% CI, 9.6-10.3) after IVF, with corresponding PAFs of 7.1% (95% CI, 7.1%-7.2%) and 13.4% (95% CI, 13.3%-13.4%). Between the eras of 2006 to 2011 and 2016 to 2021, multifetal pregnancy rates decreased from 12.9% to 9.1% with OI/IUI (ARD, -3.8%; 95% CI, -4.2% to -3.4%) and from 29.4% to 7.1% with IVF (ARD, -22.3%; 95% CI, -23.2% to -21.6%). Conclusions and Relevance: In this cohort study of more than 1.7 million pregnancies in Ontario, Canada, a publicly funded IVF program mandating an eSET policy was associated with a reduction in multifetal pregnancy rates. Nevertheless, ongoing strategies are needed to decrease multifetal pregnancy, especially in those undergoing OI/IUI.

Uterine tone influences fertility of Merino ewes following laparoscopic artificial insemination.

Artificial insemination (AI) plays a critical role in facilitating rapid genetic and production gains within the sheep industry. However, variable rates of AI success remain a concern for the industry and a barrier to adoption. Furthermore, the degree to which female factors influence the success of intrauterine laparoscopic AI rather than natural mating remains unknown. As such, this study investigates the effect of several factors collected during the time of AI, on the success of intrauterine laparoscopic AI. Data was generously donated by artificial breeding companies and stud breeders during routine commercial AI operations. AI data was collected over 3 breeding seasons during commercial AI programs (N = 24 programs) using Merino ewes (N = 24,700). Sire ID (N = 253), time of AI following progesterone removal (approx. 43-59 h post removal), uterine tone and intra-abdominal fat (both scored 1-5) as well as age of the ewe were all recorded at the time of AI. Transcutaneous ultrasound subsequently determined pregnancy rate approximately 55 days post-AI. A multivariate regression analysis was performed and revealed pregnancy success to increase when semen was inseminated into a ewe with a uterine tone score of 4 or 5 (P < 0.001). The remaining factors fell short of significance within the multivariate model. An interclass coefficient variation matrix was also used to determine the proportion of variation contributed to AI success by random factors allocated in the model; site, sire, AI date and breeding season (45.99 %, 29.94 %, 15.15 % and 8.92 %, respectively). These results highlight the influence of uterine tone on ewe fertility following laparoscopic AI, but also that program location and the sire used can further modify this influence on pregnancy rate. These factors must now be considered in combination with semen factors per individual sire used during AI to ascertain the contribution of several factors to the success of laparoscopic AI in Australia.

Effects of short and long - term nutrition and progesterone supplementation on the success of fixed - time artificial insemination in the ewe.

The success of fixed - time artificial insemination (AI) in the ewe is variable due to poor synchrony of estrus. We examined the effects of long-term nutrition (LTN; low, medium, high - 6 months), short-term nutrition (STN; 1.0 M, 1.5 M - 14 days) and progesterone supplementation (P; single pessary, replacement on Day 9) on synchrony and reproductive outcomes. High LTN advanced (P < 0.05) estrus, increased (P = 0.06) pregnancy (range 71.1 - 81.1%) and improved (P < 0.01) litter size (range 1.30 - 1.50). STN increased (P < 0.05) pregnancy (79.0 versus 72.3%) but not litter size or timing of estrus. A LTN x STN interaction (P < 0.01) for time of estrus indicates that the effects of LTN were moderated by STN depending on the level of LTN. Pessary replacement delayed (P < 0.05) the onset of estrus, improved synchrony but did not affect pregnancy or litter size. High LTN increased (P < 0.05) the number of large (≥ 3.8 mm) and medium - size follicles (2.0 - 3.7 mm) but the diameter of large follicles tended to be reduced (P = 0.08) on Day 12. STN did not affect follicle number or size whilst P reduced (P < 0.05) the diameter of large follicles on Day 12 (4.83 versus 5.10 mm) and increased the number of medium - size follicles (3.56 versus 2.74 mm). In conclusion, both LTN and STN are major sources of variability in AI programs whilst pessary replacement has potential to reduce variability.

Factors influencing pregnancy per artificial insemination (AI) and embryonic mortality in Nelore females subjected to timed-AI in Brazil.

A greater understanding of factors influencing fertility is essential to improve pregnancy rates and reduce the occurrence of embryonic mortality in beef herds. The objective of the current study was to evaluate retrospective data of pregnancy per artificial insemination (P/AI) and pregnancy loss in Nelore females subjected to timed-AI (TAI) in Brazil. Data from 40,104 TAI collected from six breeding seasons (2016-2022) were analyzed, and the effects of animal category (e.g., classification based on age and parity), farm, month of parturition, sire, sire breed (Nelore vs Angus), estrus expression at TAI, animal temperament, and body condition scores (BCS) were evaluated. P/AI and pregnancy loss were affected (P < 0.001) by animal category. There was also an effect of farm (P = 0.0013) on P/AI and pregnancy loss (P = 0.001), as P/AI ranged from 49.28% and 55.58% and pregnancy loss from 3.37% to 6.89% across the herds evaluated. Month of parturition also affected (P < 0.001) P/AI and was higher for cows that became pregnant at the beginning of the previous breeding season. Calmer animals, presenting lower velocity scores while exiting the chute following TAI, achieved higher P/AI (P < 0.001). Lower BCS at TAI was associated (P < 0.001) with increased pregnancy loss, and BCS gain following AI was associated (P < 0.001) with reduced rates of embryonic mortality. There was a major effect (P < 0.001) of sire on P/AI and pregnancy loss, as P/AI ranged from 11% to 79%, and embryonic mortality from 0% to 40% for the bulls used in the study, highlighting the importance of the sire fertility on overall pregnancy success. Results from the current study reinforce the idea that animal age and parity at the beginning of the breeding season, BCS at the onset of estrous synchronization, BCS gain following AI, estrus expression at TAI, sire, and month of parturition are important factors influencing P/AI and rates of embryonic mortality in beef herds.

Impact of presynchronization and Ovsynch on early postpartum ovarian activity and fertility of dairy cows in Libya.

Background: Reproductive efficiency affects dairy cow profitability. Ovarian function in postpartum (P.P.) has been better understood using ultrasound and hormonal assays. Optimizing ovulation synchronization and carefully timing artificial insemination (TAI) can greatly enhance reproductive rates in dairy cows. Aim: This experiment was designed to investigate the reproductive performance and ovarian activity in early postpartum lactating dairy cows using the Presynch-PGF2α, Ovsynch protocol, and TAI. Methods: Randomly the cows were assigned to a control group and a treatment group, based on the chronological order of their calving date. On day 14 P.P., both groups received two cloprostenol treatments, 14 days apart. Ultrasonographic inspections were conducted on day 14 to check ovarian activity and uterine contents. On day 11, after presynchronization, cows in the treatment group were given 100 µg IM. of cystorelin, followed by a luteolytic dose of 500 µg IM., cloprostenol on day 7, and a second dose of cystorelin on day 8 (36 hours later). After the second cystorelin injection by 16-20 hours, cows were inseminated, while the control group had all cows displaying spontaneous estrus between day 0 and day 28 were artificially inseminated. Results: Ovarian activity began to improve at 82.61% on day 19 P.P., with complete recovery between days 24 and 27 P.P. The second cloprostenol injection approached, causing follicular size to reach 8.41 ± 1.04 mm. After the second injection, ovarian activity switched from follicular to luteal, with corpus luteum rates of 23.91% and 26.1%. The presynchronized PGF2α regimen significantly enhanced ovarian activity from days 19-35 P.P. Ovulation and pregnancy rates in the Ovsynch group were 54.2% and 41.7% at the first timed artificial insemination (TAI), compared to 54.5% and 31.8% in the control group. There was no significant impact between them; it was just high in the presynchronized Ovsynch group. However, the P.P. period was minimized to 47-49 days till the first AI reached a 41.7% pregnancy rate and 20.8% at the second AI, for an overall 62.5%. Conclusion: The current study concludes that presynchronization during preservice in clinically normal P.P. dairy cows reduces P.P. duration, increases ovarian activity performance, and reduces ovarian dysfunctions from day 19 to day 35 P.P., as well as improves the pregnancy rate.

Changes in interleukin-2, -4, -6 and -8 expression in the postovulatory sow endometrium after artificial insemination based on conceived or failed to conceive.

The establishment and maintenance of a pregnancy requires proper interaction between the endocrine and immune systems in the uterus. Therefore, it is crucial to understand how changes in endometrial cytokine levels facilitate reproduction. This study aimed to investigate how representative cytokines sequentially changed in the endometrium and whether conception could be attributed to these changes. In this study, artificial insemination was performed twice in 160 sows and ovulation was examined every 3 h using transrectal ultrasonography. Uterine endometrial tissues were obtained via repeated biopsies at 2, 4, 6, 8, 12, 16, and 20 h after ovulation and interleukin (IL)-2, IL-4, IL-6, and IL-8 expression was examined using real-time polymerase chain reaction. The conception rate was 91.9%. The IL-2 levels showed no differences in conception or time. The expression peaks of IL-4 and IL-6 were delayed in sows that failed to conceive within 4-6 h and 2 h, respectively, compared to those that did conceive. In sows that conceived, IL-8 was highest after 2 h, and no difference was observed at other time point, regardless of conception. In sows that failed to conceive, the increase in IL-8 levels might have been cancelled or terminated before the first sampling time. These results highlight the importance of timely increases and subsequent declines in the levels of some cytokines for the establishment of pregnancy. Differences in uterine capacity start just after ovulation; detection and correction of these deviations can improve the reproductive efficiency of sows.

Supplementing a carbohydrate-rich diet from late lactation to insemination increased glucose and insulin levels in weaned sows, leading to improved subsequent piglet birth weight.

Premating maternal nutrition is crucial for postweaning follicle growth, thereby influencing piglet birth weight in subsequent litters. The present study investigated the impact of supplementing a carbohydrate-rich premating diet in sows on metabolic hormones, subsequent piglet birth weight and reproductive performance. Sows were distributed into three groups, control (n=42) received standard diets; treatment I (n=41) received the same diets supplemented with 500 g of a carbohydrate-rich premating diet from weaning until insemination; treatment II (n=42) received the same diets supplemented with 500 g of a carbohydrate-rich premating diet from 7 days before weaning until insemination. Blood samples were taken from sows around weaning to measure serum insulin-like growth factor-1 and insulin, and blood glucose after feeding. The study found that sows on a carbohydrate-rich diet (treatment II) had higher postprandial glucose (P<0.05) and insulin levels (P=0.06) than others. This diet did not affect overall reproductive performance, but it did increase piglet birth weight and reduce the number of low-birth weight piglets compared to the control (P<0.001) and treatment I groups (P<0.05). Supplementing a carbohydrate-rich premating diet for 7 days before weaning until insemination enhanced postprandial glucose and insulin concentrations in weaned sows. This dietary intervention led to improved subsequent piglet birth weight and reduced the proportion of low-birth weight piglets.