Multiple Ovulation And Embryo Transfer Research Articles

Factors influencing ovum pick-up technique results in cattle

The Ovum Pick-Up (OPU) technique, which is used in in vitro embryo production (IVP) to retrieve immature oocytes from live donor animals, is one of the most important biotechnological procedures used in cattle breeding. The most important advantage of this technology is that it allows for the reproducible retrieval of immature oocytes from living donor animals. It is particularly useful in dairy cattle breeding to address infertility issues and boost the production of superior animals with high genetic value. The OPU technique offers several advantages, including its applicability to cows ranging from six-month-old calves to the first three months of pregnancy, its effectiveness in animals with genital tract infection or acyclic cattle, and its ability to yield a higher number of embryos within the same period compared to the Multiple Ovulation and Embryo Transfer (MOET) technique. Understanding and improving the technical and biological factors influencing the OPU procedure is necessary to increase and optimize donor animal use in IVP and the number of quality oocytes obtained. This review aims to examine the specifics of the OPU approach and the factors influencing its performance in light of contemporary literature, as well as to propose fresh ideas to researchers.

Factors affecting superovulation induction in goats (Capra hericus): An analysis of various approaches.

Goats are generally called a "poor man's cow" because they not only provide meat and milk but also other assistance to their owners, including skins for leather production and their waste, which can be used as compost for fertilizer. Multiple ovulation and embryo transfer (MOET) is an important process in embryo biotechnology, as it increases the contribution of superior female goats to breeding operations. The field of assisted reproductive biotechnologies has seen notable progress. However, unlike in cattle, the standard use of superovulation and other reproductive biotechnologies has not been widely implemented for goats. Multiple intrinsic and extrinsic factors can alter the superovulatory response, significantly restricting the practicability of MOET technology. The use of techniques to induce superovulation is a crucial step in embryo transfer (ET), as it accelerates the propagation of animals with superior genetics for desirable traits. Furthermore, the conventional superovulation techniques based on numerous injections are not appropriate for animals and are labor-intensive as well as expensive. Different approaches and alternatives have been applied to obtain the maximum ovarian response, including immunization against inhibin and the day-0 protocol for the synchronization of the first follicular wave. While there are several studies available in the literature on superovulation in cattle, research on simplified superovulation in goats is limited; only a few studies have been conducted on this topic. This review describes the various treatments with gonadotropin that are used for inducing superovulation in various dairy goat breeds worldwide. The outcomes of these treatments, in terms of ovulation rate and recovery of transferrable embryos, are also discussed. Furthermore, this review also covers the recovery of oocytes through repeated superovulation from the same female goat that is used for somatic cell nuclear transfer (SCNT).

Efficiency of Multiple Ovulation and Embryo Transfer (MOET) in a Cattle Farm over a Period of Ten Years in Gujarat

The present study was conducted at Sabarmati Ashram Gaushala, Bidaj, Gujarat. A total of 427 donor animals were investigated over a ten-year period to assess the efficiency of Standard protocol of Multiple Ovulation and Embryo Transfer (MOET). Simultaneously a season wise and breed wise study was also conducted. Breeds studied were Gir, HF, HFCB, Jersey, JYCB, Red Sindhi and Sahiwal. Overall average number of embryos, average number of viable embryos, number of pregnancies and conception rate (%) were found to be 7.8, 4.8, 281 and 39.4, respectively. The year-wise number of pregnancies and conception rates varied from 09 to 42, and 24.6% in 2009-10 to the highest 61.3% in 20014-15, respectively. Further, breed-wise results showed average viable embryo in different breeds as 2.8 in Gir, 4.1 in HF, 5.1 in HFCB, 6.3 in Jersey, 5.8 in JYCB, 3.7 in Red Sindhi and 6.6 in Sahiwal, with corresponding conception rates of 67.7. 34.6, 28.8, 53.1, 39.4, 47.1 and 36.4 %, respectively. A trend was observed that the efficiency of MOET programme was less during monsoon (31.2%) as compared to summer and winter (41.5 and 41.4%).

In vitro- and in vivo-produced male dairy calves show molecular differences in the hepatic and muscular energy regulation†.

In cattle, the in vitro production (IVP) of embryos is becoming more relevant than embryos produced in vivo, i.e. after multiple ovulation and embryo transfer (MOET). However, the effects of IVP on the developmental programming of specific organs in the postnatal calves are yet unknown. Previously, we reported an epigenomic and transcriptomic profile of the hypothalamus–pituitary–testicular axis compatible with its earlier activation in IVP calves compared to MOET animals. Here, we studied the hepatic and muscular epigenome and transcriptome of those same male dairy calves (n = 4 per group). Tissue samples from liver and semitendinosus muscle were obtained at 3 months of age, and the extracted gDNA and RNA were sequenced through whole-genome bisulfite sequencing and RNA-sequencing, respectively. Next, bioinformatic analyses determined differentially methylated cytosines or differentially expressed genes [false discovery rate (FDR) < 0.05] for each Omic dataset; and nonparametrically combined genes (NPCG) for both integrated omics (P < 0.05). KEGG pathways enrichment analysis showed that NPCG upregulated in the liver and the muscle of the IVP calves were involved in oxidative phosphorylation and the tricarboxylic acid cycle. In contrast, ribosome and translation were upregulated in the liver but downregulated in the muscle of the IVP calves compared to the MOET calves (FDR < 0.05). A model considering the effect of the methylation levels and the group on the expression of all the genes involved in these pathways confirmed these findings. In conclusion, the multiomics data integration approach indicated an altered hepatic and muscular energy regulation in phenotypically normal IVP calves compared to MOET calves.

In vivo embryo production in bovine donors with low and high antral follicle counts superovulated with low and high FSH doses

This study evaluated the embryo yield in Bos indicus donors with low and high antral follicle counts (AFCs) subjected to a multiple ovulation and embryo transfer (MOET) program using low and high FSH doses for superovulation. Donors (n = 16) underwent a presynchronization E2/P4-based protocol 30 days (D-30) before starting the MOET program. After AFC evaluation (D-26), donors with low (n = 8; ≤ 15 follicles; mean = 10.00 ± 0.91 follicles) and high AFCs (n = 8; ≥ 25 follicles; mean = 36.13 ± 6.05 follicles) underwent a first program involving a dose of 150 IU of FSH (low-dose). Then, 45 days later, all donors underwent a second program involving a dose of 300 IU of FSH (high-dose). MOET was performed using a conventional timed superstimulation protocol with decreasing FSH applications at 12 h intervals, and uterine flushing was performed 7 days after ovulation induction. Data were analyzed by two models employing ANOVA and Tukey's test in a procedure for an adjusted mixed effect model (P ≤ 0.05). The first model contemplated a split-plot scheme and second model considered the treatment effect. An effect of AFC was observed only for the number of corpora lutea (CLs), which was higher (P = 0.01) in donors with high AFCs than in those with low AFCs. For all other variables monitored, donors with low AFCs showed similar reproductive performance to high-AFC donors (P > 0.1). In general, the 300 IU of FSH dose resulted in significantly greater (P < 0.01) numbers of CL, total structures, and viable and freezable embryos than the 150 IU dose. There was no interaction of AFC*FSH (P > 0.05). However, a significant treatment effect was observed, which showed that donors with a high AFC treated with a high FSH dose presented the greatest mean numbers of CL (P = 0.002), total structures (P = 0.002), viable embryos (P = 0.04) and freezable embryos (P = 0.004). However, donors with a low AFC treated with 300 IU of FSH exhibited similar embryo yield to that of the high-AFC group treated with 300 IU of FSH (P > 0.1). In conclusion, the embryo yield was not influenced by the AFC category but was influenced by the FSH dose. Furthermore, the significant treatment effect revealed that high-AFC donors superovulated with the highest FSH dose presented the best performance in terms of embryo yield.

Multiple ovulation and embryo transfer in sheep: Effects of embryo developmental stage and quality on viability in vivo under farm conditions.

Multiple ovulation and embryo transfer (MOET) technologies are integral to genetic improvement programs in the sheep industries. Despite the protocols being well established, previous findings regarding the effects of embryo properties on MOET success remain contradictory. The objective of this study was to determine the effects of embryo developmental stage and quality on embryo viability following transfer to recipient ewes. Data including details of 377 embryos collected from 45 Merino donor ewes were obtained from MOET trials conducted on three separate farms on day 6 after laparoscopic artificial insemination (AI). A total of 270 embryos were classified as being of transferrable grade (grade 1: n = 233; grade 2: n = 37). One or two transferrable grade embryos were transferred to each of 256 synchronised recipient ewes and pregnancy diagnosis was performed on day 36 after embryo transfer. Embryos at the hatched blastocyst stage tended to have greater viability in vivo compared to embryos at the late morula stage (59.0 ± 10.6% vs. 36.2 ± 9.7%; P = 0.083). The viability of grade 1 embryos was greater than that of grade 2 embryos (53.6 ± 7.8% vs. 35.9 ± 10.2%; P < 0.05). The results suggest that the success of the MOET trials was influenced by the transfer of embryos at the late morula stage, almost half of which were classified as grade 2 embryos. These findings highlight the importance of following strict embryo quality grading criteria to inform the most economical management of recipient ewes and maximize pregnancy outcomes.

Embryo biotechnologies in sheep: Achievements and new improvements.

To date, large-scale use of multiple ovulation and embryo transfer (MOET) programmes in ovine species is limited due to unpredictable results and high costs of hormonal stimulation and treatment. Therefore, even if considered reliable, they are not fully applicable in large-scale systems. More recently, the new prospects offered by in vitro embryo production (IVEP) through collection of oocytes post-mortem or by repeated ovum pick-up from live females suggested an alternative to MOET programmes and may be more extensively used, moving from the exclusive research in the laboratory to field application. The possibility to perform oocytes recovery from juvenile lambs to obtain embryos (JIVET) offers the great advantage to significantly reduce the generation interval, speeding the rate of genetic improvement. Although in the past decades several studies implemented novel protocols to enhance embryo production in sheep, the conditions of every single stage of IVEP can significantly affect embryo yield and successful transfer into the recipients. Moreover, the recent progresses on embryo production and freezing technologies might allow wider propagation of valuable genes in small ruminants populations and may be used for constitution of flocks without risks of disease. In addition, they can give a substantial contribution in preserving endangered breeds. The new era of gene editing might offer innovative perspectives in sheep breeding, but the application of such novel techniques implies involvement of specialized operators and is limited by relatively high costs for embryo manipulation and molecular biology analysis.

Towards Improving the Outcomes of Multiple Ovulation and Embryo Transfer in Sheep, with Particular Focus on Donor Superovulation.

Considerable improvements in sheep multiple ovulation and embryo transfer (MOET)protocols have been made; however, unlike for cattle, MOET is poorly developed in sheep, and thus has not been broadly applicable as a routine procedure. The tightly folded nature of the ewe cervix, the inconsistent ovarian response to various superovulatory treatments, and the requirement of labor to handle animals, particularly during large-scale production, has limited the implementation of successful MOET in sheep. Moreover, several extrinsic factors (e.g., sources, the purity of gonadotrophins and their administration) and intrinsic factors (e.g., breed, age, nutrition, reproductive status) severely limit the practicability of MOET in sheep and other domestic animals. In this review, we summarize the effects of different superovulatory protocols, and their respective ovarian responses, in terms of ovulation rate, and embryo recovery and transfer. Furthermore, various strategies, such as inhibin immunization, conventional superovulation protocols, and melatonin implants for improving the ovarian response, are discussed in detail. Other reproductive techniques and their relative advantages and disadvantages, such as artificial insemination (AI), and donor embryo recovery and transfer to the recipient through different procedures, which must be taken into consideration for achieving satisfactory results during any MOET program in sheep, are also summarized in this article.

MOET Efficiency in a Spanish Herd of Japanese Black Heifers and Analysis of Environmental and Metabolic Determinants.

Simple SummaryEmbryo transfer procedures have been widely implemented in bovine all around the world. These techniques help to accelerate the increase in the genetic merit and to keep the level of inbreeding under control, which is especially important in breeds, such as Japanese Black cattle, in areas outside of Japan, where there are scarce individuals and few herds. Our study describes an adequate embryo productivity of Japanese Black heifers under Spanish management and environmental conditions, like that which has been previously reported, demonstrating the adequate adaptation capacity of these animals. No effect on embryo production or quality was found due to plasma metabolic parameters of the donors, suggesting an optimal nutritional and body conditioning of the donors’ herd. Pregnant recipients after embryo transfer showed significantly higher levels of cholesterol-related parameters, glucose, and urea, which may be related to higher availability of nutrients for the future pregnancy. Heat stress at embryo transfer negatively impacted conception rates as expected, while larger parity and ET number corresponded to numerically higher conception rates.Multiple ovulation and embryo transfer (MOET) systems have been intensively implemented in Japanese Black cattle in Japan and to create Japanese Black herds out of these areas. Environmental conditions influence MOET efficiency. Thus, we describe results of 137 in vivo, non-surgical embryo flushings performed between 2016–2020, in a full-blood Japanese Black herd kept in Spain and the possible effects of heat, year, bull, donor genetic value, and metabolic condition. Additionally, 687 embryo transfers were studied for conception rate (CR) and recipient related factors. A total of 71.3% of viable embryos (724/1015) were obtained (5.3 ± 4.34/flushing). Donor metabolites did not affect embryo production (p > 0.1), although metabolite differences were observed over the years, and by flushing order, probably related to the donor age. CR was not affected by embryo type (fresh vs. frozen), recipient breed, and whether suckling or not suckling (p > 0.1). CR decreased significantly with heat (44.3 vs. 49.2%; (p = 0.042)) and numerically increased with recipient parity and ET-number. Pregnant recipients showed significantly higher levels of cholesterol-related metabolites, glucose, and urea (p < 0.05). Therefore, adequate MOET efficiency can be achieved under these conditions, and heat stress should be strongly avoided during Japanese Black embryo transfers. Moreover, recipients’ metabolites are important to achieve pregnancy, being probably related to better nutrient availability during pregnancy.

Effects of Extra-Long-Acting Recombinant Bovine FSH (bscrFSH) on Cattle Superovulation.

Simple SummaryWhile the clinical effectiveness of medium-acting bovine follicle stimulating hormone (bFSH) is well-established for superovulation (SOV) protocols in cattle, the use of long-acting bovine recombinant follicle stimulating hormone (brFSH) remains the golden target. The application of a bFSH with prolonged half-life could improve substantially the results obtained regarding the ovarian superstimulation response and the quality and quantity of the embryos produced. Moreover, the management schemes may be improved by reducing the number of FSH applications needed during the SOV protocol. The development of a new extra-long-acting bovine single-chain recombinant follicle stimulating hormone (bscrFSH) provides interesting advantages to the SOV protocols as the present study shows, by improving the results obtained compared to the use of the conventional follicle stimulating hormone from purified pig pituitary extract (NIH-FSH-p).Over the last few years, several commercial FSH products have been developed for cattle superovulation (SOV) purposes in Multiple Ovulation and Embryo Transfer (MOET) programs. The SOV response is highly variable among individuals and remains one of the main limiting factors in obtaining a profitable number of transferable embryos. In this study, follicle stimulating hormone (FSH) from different origins was included in two SOV protocols, (a) FSH from purified pig pituitary extract (NIH-FSH-p; two doses/day, 12 h apart, four consecutive days); and (b) extra-long-acting bovine recombinant FSH (bscrFSH; a single dose/day, four consecutive days), to test the effects of bscrFSH on the ovarian response, hormone profile levels, in vivo embryo production and the pluripotency gene expression of the obtained embryos. A total of 68 healthy primiparous red Angus cows (Bos taurus) were randomly distributed into two experimental groups (n = 34 each). Blood sample collection for progesterone (P4) and cortisol (C) level determination was performed together with ultrasonographic assessment for ovarian size, follicles (FL) and corpora lutea (CL) quantification in each SOV protocol (Day 0, 4, 8, and 15). Moreover, FSH profiles were monitorised throughout both protocols (Day 0, 4, 5, 6, 7, 8, 9, 10, and 15). In vivo embryo quantity and quality (total structures, morulae, blastocysts, viable, degenerated and blocked embryos) were recorded in each SOV protocol. Finally, embryo quality in both protocols was assessed by the analysis of the expression level of crucial genes for early embryo development (OCT4, IFNt, CDX2, BCL2, and BAX). P4 and cortisol concentration peaks in both SOV protocols were obtained on Day 15 and Day 8, respectively, which were statistically different compared to the other time-points (p < 0.05). Ovarian dimensions increased from Day 0 to Day 15 irrespective of the SOV protocol considered (p < 0.05). Significant changes in CL number were observed over time till Day 15 irrespective of the SOV protocol applied (p < 0.05), being non- significantly different between SOV protocols within each time-point (p > 0.05). The number of CL was higher on Day 15 in the bscrFSH group compared to the NIH-FSH-p group (p < 0.05). The number of embryonic structures recovered was higher in the bscrFSH group (p = 0.025), probably as a result of a tendency towards a greater number of follicles developed compared to the NIH-FSH-p group. IFNt and BAX were overexpressed in embryos from the bscrFSH group (p < 0.05), with a fold change of 16 and 1.3, respectively. However, no statistical differences were detected regarding the OCT4, CDX2, BCL2, and BCL2/BAX expression ratio (p > 0.05). In conclusion, including bscrFSH in SOV protocols could be an important alternative by reducing the number of applications and offering an improved ovarian response together with better embryo quality and superior performance in embryo production compared to NIH-FSH-p SOV protocols.

Occurrence of premature regression of corpus luteum in MOET programs in Dorper ewes under subtropical climate

Premature regression of corpus luteum (PRCL) is a functional alteration that occurs mainly in superovulated females hampering the widespread use of multiple ovulation and embryo transfer (MOET). This study evaluated the association of donor age (3–9 years old), body condition score (2 to 4.5), number of MOET (1 to 5) repetitions and season (breeding, transition, or non-breeding) with the occurrence of PRCL in ewes. Multiparous Dorper ewes (n = 44) were subjected to MOET during four consecutive years, with the same superovulatory treatment. Before embryo collection, ovaries were laparoscopically performed to assess the corpora lutea (CL). Overall, the total PRCL occurrence was 24.7% (26/105) and it had no association with the studied factors. Percentages of ewes that presented PRCL once or twice were 45.5% (20/44) and 6.8% (3/44), respectively, while the percentage of ewes that had no PRCL was 47.7% (21/44). Proportions of PRCL were similar (P > 0.05) among breeding (21%), transition (31%), and non-breeding (24%) season; and also (P > 0.05) in lower/thin (20%), average/good (24%), and higher/fat (29%) females. In conclusion, although this phenomenon had no association to the factors studied, the occurrence of PRCL affects ∼25% of ewes subjected to MOET procedures and future alternatives to circumvent this obstacle need to be developed.

Superovulation response of Peranakan Ongole (PO) and Simmental cows after FSH stimulation in multiple ovulation and embryo transfer program

Multiple ovulation and embryo transfer (MOET) is a reproductive technology to increase the livestock population in a short period. The success of ovary stimulation programs is influenced by an individual’s response to follicle-stimulating hormone (FSH) stimulation. In this study embryo production was carried out on local cows represented by Peranakan Ongole (PO) cows and exotic cows represented by Simmental cows. FSH stimulation was performed on 10 PO cows and 10 Simmental cows. On Day-1 Cue Mate® (progesterone) was inserted intravaginally. FSH injection (400 mg) was carried out intramuscularly from D-10 at reduced dose with 12 hours intervals (Day-10: 100 mg; Day-11: 60 mg; Day-12: 40 mg per injection). On Day-12, prostaglandin (PGF2α) was injected and Cue Mate® was removed. Artificial insemination (AI) was performed 48 hours after PGF2α injection for 3 times at 12 hours intervals. The embryo was collected 6 days after the last AI (Day-21). Superovulation response was detected on 70% of PO cows and 90% of Simmental cows. The average number of transferable embryos in Simmental cows (9.11±7.27) was higher than PO cows (7.86±7.78). This research shows that Simmental cows are more responsive to FSH stimulation, and can produce more transferable embryos than PO cows.

GnRH or estradiol benzoate combination with CIDR improves in-vivo embryo production in bovines (Bos indicus and Bos taurus) under subtropics.

Multiple Ovulation and Embryo Transfer (MOET) technology is a potential technique to upgrade livestock species’ genetics. The varied response to super-stimulatory treatments remains one of the limiting factors to this technology’s widespread use. The present study was aimed to improve the superovulation response and in-vivo embryo production by using controlled internal drug release (CIDR)-GnRH or CIDR-EB (Estradiol Benzoate) along with conventional superovulation protocol in Holstein Frisian (HF): Bos taurus; n = 42) and Crossbred (XB: Cholistani (Bos indicus) × HF; n = 28) cows. In the CIDR-GnRH/CIDR-EB treatment, CIDR was implanted in the cows after confirming the presence of a corpus luteum (CL) on the 8th day after estrus. 2 ml GnRH (Lecirelin acetate 0.0262 mg/ml) or 2 mg EB was also administered in CIDR-GnRH/CIDR-EB groups, respectively. Both groups were given super-stimulatory treatment from the 11th day after estrus (FSH in tapering doses twice a day for four consecutive days). On day 13, two doses of 2 ml prostaglandin (75 µg/ml of dextrorotatory cloprostenol) were administered (am: pm), and CIDR was removed the following day. Two artificial inseminations (AI) of the cows were performed (12 h apart) on the 15th day. No CIDR and GnRH/E.B were given in the control group, but the remaining superovulation protocol was the same. Later on, seven days after the first AI, non-surgical embryo flushing was done. The transferable embryos produced from three different superovulation protocols were then transferred into the recipient cows (n = 90) for determining their fertility. Statistical analysis revealed that the number of super-estrus follicles (SEF), multiple corpora lutea (MCL), ovulation/fertilization percentage, fertilized structures recovered (FSR), and transferable embryos (TEs) remained significantly higher (p < 0.05), and days taken for return to estrus (RTE) after embryo collection remained significantly lower (p < 0.05) in CIDR-GnRH (n = 18) and CIDR-EB (n = 15) groups as compared to the control (n = 37). The comparison between XB and HF cows revealed that the TEs production in CIDR-GnRH (XB = 5 vs HF = 13) and CIDR-EB (XB = 6 vs HF = 9) based superovulation protocols were 11.60 ± 4.08 vs 04.31 ± 0.98 and 09.33 ± 1.78 vs 05.22 ± 1.36, respectively. TEs production in XB cows (n = 5) of the CIDR-GnRH group was significantly higher (11.60 ± 4.08) than other groups. On the other hand, the days taken for RTE after embryo collection remained significantly lower (p < 0.05) in HF cows of treatment groups. However, the fertility of TEs was neither affected significantly (p > 0.05) by the superovulation protocol used nor by breed differences among donor cows. In conclusion, using CIDR-GnRH or CIDR-EB along with conventional superovulation protocol may enhance the efficiency of MOET programs in cattle. Furthermore, XB donor cows demonstrated a better performance than HF donor cows under subtropical conditions.

Epigenomic and transcriptomic analyses reveal early activation of the HPG axis in in vitro-produced male dairy calves.

In cattle, several calves born after IVP ("in vitro" embryo production) present similar birthweight to those generated after MOET (multiple ovulation and embryo transfer). However, the underlying molecular patterns in organs involved in the developmental process are unknown and could indicate physiological programming. The objectives of this study were: (1) to compare epigenomic and transcriptomic modifications in the hypothalamus, pituitary, gonadal and adrenal organs between 3months old ovum pick-up-IVP and MOET male calves (n=4 per group) and (2) to use blood epigenomic data to proxy methylation of the inner organs. Extracted gDNA and RNA were sequenced through whole-genome bisulfite sequencing and RNA sequencing, respectively. Next, bioinformatic analyses determined differentially methylated cytosines (DMC) and differentially expressed genes (DEG) (FDR<0.05) in IVP versus MOET samples and the KEGG pathways that were overrepresented by genes associated with DMC or DEG (FDR<0.1). Pathways related to hypothalamus, pituitary, gonadal (HPG) axis activation (GnRH secretion in the hypothalamus, GnRH signaling in the pituitary, and steroidogenesis in the testicle) were enriched in IVP calves. Modeling the effect of the methylation levels and the group on the expression of all the genes involved in these pathways confirmed their upregulation in HPG organs in IVP calves. The application of the DIABLO method allowed the identification of 15 epigenetic and five transcriptomic biomarkers, which were able to predict the embryo origin using the epigenomic data from the blood. In conclusion, the use of an integrated epigenomic-transcriptomic approach suggested an early activation of the HPG axis in male IVP calves compared to MOET counterparts, and the identification of potential biomarkers allowed the use of blood samples to proxy methylation levels of the relevant internal organs.

Prospects in the utilization of assisted reproductive technologies (ART) towards improved cattle production in Nigeria

Cattle production and the beef and dairy industry are important sources of financial revenue for the government and the individual farmers and employees involved in livestock husbandry. Nigeria has a huge potential for cattle production but sadly this has been poorly developed. The estimated national cattle population of 19 million is grossly inadequate in meeting the national human demand for meat, milk and other cattle products or in contributing to the gross domestic product. The low cattle productivity is partly attributable to the poor utilization of assisted reproductive technologies (ART) in dairy and beef cattle breeding and production. These technologies generally include oestrus synchronization, artificial insemination (AI), multiple-ovulation and embryo transfer (MOET), in vitro fertilization (IVF), sex determination, cloning and genetic engineering. ART have been applied extensively in the yearly production of millions of cattle in many developed and developing countries worldwide. This review highlights the applications and potentials of ART in cattle production and suggests how stakeholders in the Nigerian cattle industry can exploit these potentials. It is clear that the utilization of ART will enhance national livestock productivity so that Nigeria can feed her growing population and possibly increase her foreign exchange earnings by becoming a livestock-exporting country.

Impact of embryo technologies on secondary sex ratio in rabbit

Increasing evidence indicates that assisted reproductive technologies (ARTs) disturb skewed sex-ratio and induce sex-dimorphic postnatal effects. Undoubtedly, the combination of multiple ovulation and embryo transfer (MOET) together with the use of vitrification technique (MOVET) is currently being used in breeding programs. However, since the first case of sex skewing reported in 1991, the accumulative and long-term transmission of skewed sex-ratio to future generations has not been thoroughly evaluated. Here we test as MOVET program induce a skewed sex ratio, and we consider skewed sex ratio transmission to future generations. To this end, we first evaluated the F1 generation, demonstrating that a MOVET program causes a severe imbalance skewed secondary sex ratio (SSR) towards male by 12%. This imbalanced persist after a second MOVET program (F2 generation), with an accumulative skewed SSR towards male by 25%. Finally, using a crossbred generation derived from crossing F1 males derived from a MOVET program with naturally-conceived (NC) females, we show that the imbalance skewed SRR persist. Bodyweight comparison between MOVET animals and NC counterparts revealed significant changes at birth, weaning and adulthood. However, there was a significant interaction between F2 MOVET animals and sex, demonstrating an apparent accumulative sex-dimorphic effect. At adulthood, MOVET derived males presented a lower body weight. In conclusion, we show that the MOVET program causes a direct, accumulative and long-term transmission of skewed SSR.

Possibilities for a specific breeding program for organic dairy production

Organic dairy production differs from conventional dairy production in many aspects. However, breeding programs for the 2 production systems are the same in most countries. Breeding goals (BG) might be different for the 2 production systems and genotype × environment interaction may exist between organic and conventional dairy production, both of which have an effect on genetic gain in different breeding strategies. Other aspects also need to be considered, such as the application of multiple ovulation and embryo transfer (MOET), which is not allowed in organic dairy production. The general aim of this research was to assess different environment-specific breeding strategies for organic dairy production. The specific aim was to study differences in BG weights and include the effect of genotype × environment interaction, MOET, and the selection of breeding bulls from the conventional environment. Different scenarios were simulated. In the current scenario, the present-day situation for dairy production in Denmark was emulated as much as possible. The BG was based on a conventional dairy production system, MOET was applied in both environments, and conventional bulls could be selected as breeding bulls in the organic environment. Four alternative scenarios were simulated, all with a specific organic BG in the organic breeding program but differences in the usage of MOET and the selection of conventional bulls as breeding bulls. Implementation of a specific BG in organic dairy production slightly increased genetic gain in the aggregate genotype compared with the breeding program that is currently implemented in organic dairy production. Not using embryo transfer or only selecting breeding bulls from the organic environment decreased genetic gain in the aggregate genotype by as much as 24%. However, the use of embryo transfer is debatable because this is not allowed according to current regulations for organic dairy production. Assessing genetic gain on trait levels showed that a significant increase for functional traits was possible compared with the current breeding program in the organic environment without a decrease in genetic gain in the aggregate genotype. This difference on trait level was even more present when selection of conventional bulls as breeding bulls in the organic environment was not possible. This finding is very relevant when breeding for the desired cow in organic dairy production.

Oocyte and embryo evaluation by AI and multi-spectral auto-fluorescence imaging: Livestock embryology needs to catch-up to clinical practice

A highly accurate ‘non-invasive quantitative embryo assessment for pregnancy’ (NQEAP) technique that determines embryo quality has been an elusive goal. If developed, NQEAP would transform the selection of embryos from both Multiple Ovulation and Embryo Transfer (MOET), and even more so, in vitro produced (IVP) embryos for livestock breeding. The area where this concept is already having impact is in the field of clinical embryology, where great strides have been taken in the application of morphokinetics and artificial intelligence (AI); while both are already in practice, rigorous and robust evidence of efficacy is still required. Even the translation of advances in the qualitative scoring of human IVF embryos have yet to be translated to the livestock IVP industry, which remains dependent on the MOET-standardised 3-point scoring system. Furthermore, there are new ways to interrogate the biochemistry of individual embryonic cells by using new, light-based methodologies, such as FLIM and hyperspectral microscopy. Combinations of these technologies, in particular combining new imaging systems with AI, will lead to very accurate NQEAP predictive tools, improving embryo selection and recipient pregnancy success.

Towards Improving the Outcomes of Assisted Reproductive Technologies of Cattle and Sheep, with Particular Focus on Recipient Management.

Simple SummaryThe Australian livestock industry has grown significantly over the last decade. In order to meet national consumer demands, as well as the growing export market, more efficient means of producing lamb and beef products are required. Assisted reproductive technologies (ARTs) can be used to increase genetic gain and improve overall herd reproductive potential. This review focuses particularly on the management and selection of recipient animals utilised in ARTs. The condition and quality of the recipient animal is pivotal to the efficiency of reproductive technologies, as the inability of an embryo to establish and maintain pregnancy is the most significant cause of reproductive losses. A variety of external, uncontrollable factors affect the reproductive potential of an individual within any given reproductive season, limiting reproductive efficiency. Therefore, improved selection and management of recipient animals can help to increase the productivity of the Australian livestock industries.The Australian agricultural industry contributes AUD 47 billion to the Australian economy, and Australia is the world’s largest exporter of sheep meat and the third largest for beef. Within Australia, sheep meat consumption continues to rise, with beef consumption being amongst the highest in the world; therefore, efficient strategies to increase herd/flock size are integral to the success of these industries. Reproductive management is crucial to increasing the efficiency of Australian breeding programs. The use of assisted reproductive technologies (ARTs) has the potential to increase efficiency significantly. The implementation of multiple ovulation and embryo transfer (MOET) and juvenile in vitro fertilization and embryo transfer (JIVET) in combination with genomic selection and natural mating and AI is the most efficient way to increase genetic gain, and thus increase reproductive efficiency within the Australian livestock industries. However, ARTs are costly, and high variation, particularly between embryo transfer recipients in their ability to maintain pregnancy, is a significant constraint to the widespread commercial adoption of ARTs. The use of a phenotypic marker for the selection of recipients, as well as the better management of recipient animals, may be an efficient and cost-effective means to increase the productivity of the Australian livestock industry.

223 Multiple ovulation and embryo harvest in relation to energy balance in Latvian native cow breeds

The numbers of animals of two Latvian native cow breeds are very limited because almost all cows intended to be donor cows were used to acquire embryos. Most of these cows were kept on small private farms by local farmers. Many were at an advanced age and did not meet the necessary requirements to be a good embryo donor. Multiple ovulation and embryo transfer (MOET) was restarted after an interruption of more than 35 years in Latvia. The new team was educated to improve saving of these breeds using MOET in the frame of ERAF project no. 1.1.1.1/16/A/025. Energy balance (EB) and metabolic status affect ovarian function and oocyte quality, and impair early embryo development as well as endometrium and udder health. The aim of this study was to investigate success of multiple ovulation (MO), total (ToE) and transferable (TE) embryo harvest in the Latvian native breed donor cows in relation to EB and somatic cell count (SCC) in milk. MO was induced using FSH in 21 cows included in this study. Cows were 6.4±3.26 years (average±s.d.; range: 2.3 to 15 years), in 4.1±2.45 lactation (range: 1 to 10 lactations), and body condition score (BCS) was in the range from 1.5 to 4.5 (5-point scale). Blood samples were taken on Day 7 after AI. The level of glucose (Glc), β-hydroxybutyric acid (BHB), and triglycerides (TG) in blood and the SSC in milk were determined using Agricultural Data Center information. Means, standard deviations, 2 independent samples t-test, Mann-Whitney test, and bivariate correlations (two-tailed) were calculated using SPSS-21 (SPSS Inc./IBM Corp.). MO was successful in 16 cows and unsuccessful in 5 cows; the main differences were for BHB in blood (0.62±0.25 and 1.1±0.50mM, respectively) and SCC (673.2±1272.71 and 958.3±1329.66 ×103 cellsmL−1 respectively; P&amp;lt;0.05). No significant differences within groups were found regarding Glc (3.1±0.57 and 2.9±0.48mM, respectively) and TG (0.19±0.06 and 0.18±0.06mM, respectively) relative to success of MO (P&amp;gt;0.05) in our study. The ToE and TE harvested depended on success of MO (r=0.51 and r=0.39; P&amp;lt;0.05). In total, 9.7±6.5 embryos from cow were acquired, but 6.5±5.05 embryos were TE. The count of ToE was negatively correlated with TG in blood (r=−0.27; P&amp;lt;0.05). The ToE and TE count were significantly negatively correlated with SCC in milk (r=−21 and r=−0.32, respectively; P&amp;lt;0.05). Donor cows that produced TE had less SCC in milk compared with those that produced non-transferable embryos (291.8±288.11 and 917.6±1631.41 ×103 cellsmL−1, respectively) and higher BCS (2.8±0.84 and 2.1±0.37 points, respectively; P&amp;lt;0.05). SCC in milk could be one of the parameters to reject cows as embryo donors.