Reproductive technology in horses encompasses a range of scientific techniques and procedures aimed at assisting and enhancing equine reproduction. These technologies include artificial insemination, embryo transfer, and cryopreservation of gametes and embryos. They are employed to improve breeding efficiency, manage genetic diversity, and preserve valuable genetic material. Artificial insemination involves the collection and introduction of semen into the mare's reproductive tract, while embryo transfer allows for the harvesting and implantation of embryos from donor to recipient mares. Cryopreservation involves freezing and storing sperm, oocytes, or embryos for future use. This page compiles peer-reviewed research studies and scholarly articles that investigate the methodologies, applications, and outcomes of reproductive technologies in equine breeding and management.
González N, Varela A, de Blas N, Gil L.At present, oviductal pathologies and their influence on mare fertility have not been clearly determined. Checking changes throughout the year in the oviductal structure may be relevant to understand the influence on the appearance of problems in oviductal functionality and, thus, the impact on fertility, which is the objective of this work. The oviducts of 56 mares were examined. Their anatomy, permeability, oviductal cellularity and the presence of pathologies were assessed to establish the correlations between the time of the year and each of these parameters. We cannot conclude whether the...
Alonso MA, Dos Santos GR, Fonte JS, Marques PC, Pereira DD, Toral FLB, Bordignon V, Junior JB, Squires E, Fernandes CB.This retrospective study evaluated whether different reproductive biotechnologies influence neonatal behaviour parameters in foals. Data from 102 foalings in two commercial breeding farms were analysed, including foals conceived by artificial insemination (AI), conventional embryo transfer (ET) and intracytoplasmic sperm injection (ICSI). Neonatal parameters recorded were birth weight, time to achieve sternal recumbency, time to stand, time to nurse and time to meconium elimination. Mixed statistical models were applied to assess the influence of reproductive technique, breed, sex and farm. Si...
Griffin RA, Miller K, Colyvas K, Sheridan A, De Iuliis G, Aitken RJ, Baker MA, Gibb Z, Swegen A.Exposure to systemic heat stress in male mammals adversely affects sperm production, fertility, and DNA integrity. To date, few studies have investigated this phenomenon in horses, particularly in industry-relevant environments. Therefore, this study examined the relationship between ambient climatic conditions and fertility within a population of commercially fertile stallions. Post-coital semen samples ( = 804) were collected weekly from 46 Thoroughbred stallions during two successive breeding seasons (NSW, Australia; 22 weeks total). Semen samples were processed via single-layer colloid...
Tsopp E, Kilk K, Gambini A, Tvrdà E, Viljaste-Seera A, Tuppits U, Jaakma Ü.Equine in vitro embryo production (IVP) via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) has gained prominence in sport-horse breeding due to high success rates, efficient semen utilization, and year-round embryo production, including from mares with fertility challenges or postmortem. However, assessing viability of early-stage ICSI-produced equine embryos remains challenging due to subjective morphological evaluations and limited visibility of developmental features. Non-invasive metabolomic analysis of culture media offers a promising alternative to enhance embryo selectio...
Amaral A, Cerveira-Pinto M, Santos C, Kordowitzki P, Skarzynski D, Ferreira-Dias G, Szóstek-Mioduchowska A.Transforming growth factor (TGF)-β1 is a pro-fibrotic cytokine that affects extracellular matrix (ECM) deposition and fibroblast activity. 17β-Estradiol (E), the dominant ovarian steroid during the follicular phase (FLP) of the estrous cycle, can also influence ECM remodeling and fibrosis, through prostaglandin (PG) synthesis. PGs have opposing roles in fibrosis, with PGE₂ showing anti-fibrotic effects and PGF₂α promoting fibrosis. Equine endometrosis, whose main pathological feature is fibrosis, is marked by chronic inflammation and ECM accumulation, and may involve mediators like TGF-...
Cortez JV, Cervi D, Ruiz AJ, Grupen CG.Nicotinic acid (NA) treatment during in vitro maturation (IVM) has been shown to elevate nicotinamide adenine dinucleotide (NAD) levels and improve oocyte developmental competence. Suboptimal equine oocyte IVM systems currently limit the efficiency of viable embryo in vitro production. This study evaluated NA supplementation during IVM for cloned equine embryo production, using oocytes from abattoir-sourced ovaries and live mares via ovum pick-up (OPU). Abattoir-derived oocytes (n = 694) were treated without or with 50 or 200 μM NA during the 18 h holding period (Pre-IVM). Next, OPU-deriv...
Scoggin KE, Rakha SI, Abdellatif AM, Adlan F, Helmy YA, Ruby R, Ball B, Boakari Y, Ali HE.Ascending placentitis is a significant cause of equine pregnancy loss, yet the upstream inflammatory triggers are poorly defined. Recently, we identified S100A8/S100A9 (S100A8/A9) alarmins as potential upstream regulators in a chronic equine placentitis model. The current study aimed to determine whether this upregulation is sustained in the acute model and in clinical cases, and to elucidate the expression of their downstream inflammatory mediators. Using an experimental model, we quantified mRNA expression in acute ( = 5) and chronic ( = 6) placentitis induced by ssp. . We found mRNA expre...
The research aims to study the dynamics of reproductive system pathologies in mares of Kazakh and Mugalzhar horse breeds and their impact on the reproductive traits of the breeding stock. The object of the research was horses of the Kazakh and Mugalzhar breeds. The formation of experimental groups was carried out using the pair-analog method. It was found that the frequency of detection of infertile mares is 13.8-25.0%. Subinvolution of the uterus from the total number of infertile mares is 8.3-10.7%, endometritis - 16.6-23.3%, atony and hypotonia of the uterus - 8.3-13.3%, ovarian diseases - ...
de Castro Sasahara TH, Gomes SP, Abdala FCM, Schimming BC, Miglino MA.Sexual differentiation in the equine fetus involves coordinated morphogenetic processes that shape both the gonads and the genital ducts. Although the formation of testes and ovaries has been relatively well documented, the temporal dynamics and morphometric patterns of the mesonephric (Wolffian) and paramesonephric (Müllerian) ducts remain insufficiently characterized. This study aimed to detail the timeline of gonadal and ductal differentiation in male and female equine fetuses during the critical developmental window between 60 and 80 days of gestation. Gross anatomical evaluation, histo...
Ramsaran LN, Byron M, Parry S, Lection J, Back B, Grenier J, Cheong SH, Diel de Amorim M.Real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) is a technique that allows for the semi-quantification of mRNA transcripts present within a tissue of interest. Differences in the relative abundance of mRNA between samples detected by RT-qPCR require normalization with a reference gene or genes whose transcript abundance is stable within the tissue of interest independent of experimental conditions. In the field of equine reproductive studies, ACTB, GAPDH and B2M genes are the most widely used as reference genes for the normalization of RT-qPCR results. However,...
Khalil WA, Sharf MI, Derbala MK, Hassan MAE, Abdelnour SA, El-Harairy MA.This study aims to investigate the cryoprotective effect of Omega-3 nano-emulsion (Omega-3 NE) on stallion sperm quality, kinematic parameters, acrosome status, subcellular ultrastructure, oxidative/antioxidant markers, and semen microbiota. Forty ejaculates were collected, extended, and cryopreserved from 5 fertile Pure Egyptian stallions (Equus caballus). The ejaculates were divided into five groups: a control group (without additive) and four groups supplemented with 25, 50, 100, and 200 μg of Omega-3 NE/mL. The Omega-3 NE exhibited an average particle size of 51-146 nm, a PDI of 0.58,...
Liu J, Yang Y, Wen L, Wen M, Zeng Y, Ren W, Yao X.The Kazakh horse is an outstanding dual-purpose dairy and meat breed in China, characterized by early maturity, tolerance to coarse feed, and strong stress resistance. Previous studies have examined gene expression patterns in the testicular tissues of Kazakh horses at different age stages, but the molecular mechanisms regulating testicular sexual maturation remain unclear. To address this gap, this study conducted HE staining and in-depth transcriptome sequencing analysis of Kazakh horse testicular tissue before and after sexual maturity. HE staining showed that the G3 group had well-formed s...
Martin-Pelaez S, Orsolini M, Verstraete M, de la Fuente A, Takahashi K, Meyers S, Dini P.Equine in vitro embryo production (IVP) offers a valuable opportunity to enhance the efficient utilization of genetically and economically valuable horses. In cases of subfertility, sudden death, emergency euthanasia, or limited sperm availability, IVP becomes the only viable option to produce offspring. Due to steadily improving success rates, IVP has become one of the most sought-after assisted reproductive techniques. The rising global demand has created a clear need for veterinarians and stallion owners to provide IVP-suitable sperm, where the selection of intact sperm for intracytoplasmic...
Silva JA, Vasquetto A, Mouguelar H, Nader-MacÃas MEF, Pellegrino MS.Equine endometritis, a major cause of subfertility in mares, has a significant economic impact on horse breeding. In the face of rising antimicrobial resistance, the use of beneficial bacteria to prevent this disease is a non-antibiotic alternative which aligns with "One Health" principles. This study characterised vaginal autochthonous lactic acid bacteria (LAB) from healthy mares. Out of the 25 presumptive LAB isolates obtained from 15 clinically healthy thoroughbred mares, 24 were confirmed. Surface properties were assessed (autoaggregation, hydrophobicity, biofilm formation, exopolysacchar...
Broothaers K, Angel-Velez D, Molto FLG, Hedia M, Coster T, Govaere J, Soom AV, Menten B, Smits K.In 2022, a repeatable protocol for in vitro fertilization (IVF) using fresh semen was established in horses. This facilitated successful capacitation of equine semen allowing to explore novel applications. Objective: We aimed to extend this technique to IVF with frozen-thawed semen and intracytoplasmic sperm injection (ICSI), and determine the outcome parameters such as blastocyst production and euploidy rates. Methods: A total of 221 oocytes were subjected to either IVF with frozen-thawed semen, ICSI with frozen-thawed semen incubated under capacitating conditions (ICSI cap) or control ICSI w...
Newcombe JR, Claes AN, Cuervo-Arango J.Early embryonic loss (EEL), particularly between Days 14 and 42 of pregnancy, remains a key concern in equine reproduction. This study investigates the incidence of spontaneous luteolysis-used here as a marker of maternal recognition of pregnancy (MRP) failure-in both pregnant Thoroughbred (TB) broodmares and recipient mares carrying either in vivo-derived (IVD) or in vitro-produced (IVP) embryos. Retrospective reproductive data from 2078 pregnancies in TB and 532 pregnancies in recipients were analysed to determine the incidence and characteristics of clinical luteolysis during pregnancy. Ove...
Motta D, Pedrosa J, Lilenbaum W.Leptospirosis is a zoonotic disease caused by pathogenic bacteria of the genus Leptospira. A lesser-known form, equine genital leptospirosis (EGL), has been identified as a chronic and often silent infection involving the colonisation of the mare's genital tract. Despite its potential impact, EGL remains underdiagnosed and poorly understood, particularly in its association with reproductive inefficiency. This study showed the presence of Leptospira spp. DNA by lipL32-PCR in the genital tract of mares with a history of reproductive disturbances. Cervicovaginal mucus samples were collected from ...
Najjar A, Dhaouadi A, Ezzar S, Benaoun B, Khaldi S.Stallion sexual behavior during semen collection can be influenced by multiple factors, yet the role of sexual arousal intensity remains underexplored. Understanding how arousal modulates behavioral and physiological reproductive traits is essential for improving artificial insemination (AI) efficiency and semen quality. This study aimed to evaluate the effects of sexual arousal intensity, age, origin, and semen collection method on stallion sexual behavior and the quality of fresh and frozen semen. Unassigned: Thirteen Arabian stallions (7 Tunisian, 6 foreign parentage) aged 6-20 years (total...
Muñoz-GarcÃa CC, Soriano-Campos MP, Luis-Calero M, Gallardo-Soler A, González-Fernández L, MacÃas-GarcÃa B.The use of mesenchymal stromal cells (MSCs) in equine reproduction is increasing its interest in the treatment of specific pathologies. MSCs have been isolated from follicular aspirates obtained during transvaginal oocyte aspiration in women, offering a novel source for autologous therapies in reproductive treatments. However, this approach has not been tested in mares despite the common use of transvaginal oocyte aspiration for oocyte collection to produce equine embryos in vitro. Our study aimed to investigate the feasibility of isolating MSCs from equine ovarian follicular aspirates obtaine...
Martin-Pelaez S, de la Fuente A, Takahashi K, Monteiro H, Mendes M, Meyers S, Dini P.Despite significant advances, in vitro production (IVP) of equine embryos continues to lack standardised embryo classification criteria and is associated with increased rates of early pregnancy loss compared with in vivo-derived blastocysts. Objective: To evaluate morphokinetic characteristics of the first mitotic division and early embryonic development in IVP blastocysts and their association with embryo development, as well as pregnancy rate and early pregnancy loss following embryo transfer. Methods: Retrospective analysis of archived material and clinical records. Methods: We retrospectiv...
Zhao Y, Liu Y, Tao J, Cao J, Lin Y, He Q, Fang X, Yun S, Du M, Su S, Bao T, Bai D, Zhang X, Dugarjaviin M.Reproductive health in mares is pivotal for the sustainability of the equine industry, yet vaginal microbiota dysbiosis remains an underrecognized contributor to infections such as endometritis and bacterial vaginosis. While spp. dominate healthy vaginal ecosystems in humans and livestock, their role in equine reproductive health, particularly in resilient breeds like Mongolian mares, is poorly understood. This study aimed to isolate and characterize a novel strain from the vaginal microbiota of healthy Mongolian mares and evaluate its probiotic potential for mitigating equine reproductive d...
Lu Z, Wen M, Yao X, Meng J, Wang J, Zeng Y, Li L, Ren W.The reproductive performance of horses is closely associated with testicular development, which involves a complex network of gene regulation. The molecular mechanisms underlying the reproductive traits of Kazakh horses are yet to be fully understood. In this study, transcriptomic analysis was performed on testicular tissues from Kazakh horses at different developmental stages using whole-transcriptome sequencing, aiming to investigate differential gene expression and regulatory mechanisms during testicular development. The results revealed significant differential expression of 7678 mRNAs, in...
Werle J, Nunes GT, Machado CS, Silva CBD, Vogel FSF, Vargas APC, Cargnelutti JF.The genus Corynebacterium encompasses versatile bacteria that act as natural microbiota or pathogens, causing infections in humans and animals, including equine reproductive disorders. Corynebacterium uterequi (C. uterequi) is a potential pathogen in mares, associated with reproductive disorders including endometritis, embryonic loss, and infertility, raising concerns for equine reproductive health. This study aimed to characterize C. uterequi isolates from mares in southern Brazil and deepen the understanding of this species. Phenotypic, molecular, and phylogenetic analyses were performed on ...
Wen X, Bou G, He Q, Liu Q, Yi M, Ren H.The reproductive ability of equine species is a critical component of equine breeding programs, with sperm quality serving as a primary determinant of reproductive success. In this study, we perform an integrative analysis of proteomics and metabolomics in seminal plasma to identify proteins and metabolites associated with sperm quality and reproductive ability in equine species. Methods: We utilized the CEROS instrument to assess the morphology and motility of sperm samples from three horses and three donkeys. Additionally, we statistically analyzed the mating frequency and pregnancy rates in...
Wilsher S, Ismer A, Grippo A, Hoogewijs M, Bussade P, Kovacsy S.Different cryoprotectants can influence the ability of embryos to successfully survive vitrification and subsequent warming before transfer. Objective: To compare pregnancy rates for embryos ≤500 μm vitrified, without puncture or aspiration of the blastocoele cavity, with one of three commercial human embryo vitrification kits containing the same penetrating cryoprotectants (DMSO and EG) but varying in their non-penetrating cryoprotectants (NPCPAs; sucrose, trehalose, dextran serum supplement [DSS], and hydroxypropyl cellulose [HPC]). Methods: In vivo experiments. Methods: Embryos (n =â...
Li J, Matsumoto T, Liu H, Li C, Murase H, Yamamoto Y, Nagaoka K.Accurate prediction of the timing of parturition is crucial to ensure the health and well-being of both mares and foals. However, equine pregnancies are characterised by significant variability in gestation length, unique endocrine mechanisms, and subtle physiological changes before parturition. Objective: To investigate the characteristic changes in the peripheral metabolites of mares before and after parturition using metabolomic approaches. Methods: Longitudinal in vivo metabolic study. Methods: Plasma samples (n = 95) were collected from successfully foaling Thoroughbred mares (n =â€...
Fakhar-I-Adil M, Angel-Velez D, Araftpoor E, Amin QA, Hedia M, Bühler M, Gevaert K, Menten B, Van Soom A, Chuva de Sousa Lopes SM, Stoop D, De Roo C....In vitro maturation (IVM) of oocytes retrieved from ovum pick-up (OPU) or ovarian tissue (OT) is a standard approach for patients with specific conditions where prior hormonal stimulation is contraindicated. However, the developmental competence of oocytes matured in vitro is still inferior to that of oocytes matured in vivo. Capacitation IVM (CAPA-IVM) includes an extra step of pre-maturation culture (PMC) with c-type natriuretic peptide (CNP) as a meiotic arrestor to better synchronize cytoplasmic and nuclear maturity in oocytes by allowing the cytoplasm additional time to acquire essential ...
Lection J, Schnobrich M, Wagner B, Byron M, Back B, Rollins A, Castro Alves RF, Cheong SH, Diel de Amorim M.To evaluate inflammatory cytokine and chemokine concentrations in endometrial samples collected by cytobrush or swab as a potential screening diagnostic marker for equine endometritis. Unassigned: 88 mares had endometrial samples collected, which included cytobrush, swab, and/or biopsy. Clinical reproductive records, reproductive ultrasound examination, endometrial cytology and culture results, and biopsy grading score were recorded. Fluorescent bead-based multiplex assays for the inflammatory markers interferon-γ, interferon-α, IL-1β, IL-4, IL-10, IL-17A, soluble CD14, tumor necrosis facto...
Ziadi C, Valera M, Laseca N, Perdomo-González D, Demyda-Peyrás S, de Los Terreros AR, Molina A. By simultaneously integrating both genotyped and non-genotyped animals into genetic evaluation, the single-step genomic BLUP method enhanced the accuracy of genetic assessments. This study aimed to compare the increase in prediction reliability (R) between restricted maximum likelihood (REML) and single-step genomic REML (ssGREML) in the Pura Raza Española (PRE) horse breed. The dataset comprised reproductive records for seven fertility traits from 47,502 females, with a total of 57,316 animals represented in the pedigree. A total of 4009 animals were genotyped using the EQUIGENE 90K SNP ar...
Furukawa S, Kuroda Y, Sugiyama A.The primary function of the placenta is to act as an interface between the dam and fetus. The anatomic structure of the chorioallantoic placenta in eutherian mammals varies between different animal species. The placental types in eutherian mammals are classified from various standpoints based on the gross shape, the histological structure of the materno-fetal interface, the type of materno-fetal interdigitation, etc. Particularly, the histological structure is generally considered one of the most useful and instructive classifications for functionally describing placental type. In this system,...
Fortune JE.Evidence from several species indicates that the initial stages of follicular growth proceed very slowly. In contrast, the stages after antrum formation are much more rapid. Atresia seems to be most prevalent as follicles approach the size at which they could be recruited for potential ovulation. Although most follicles become atretic around that stage, a few are recruited into a cohort or wave of follicles that continue to grow beyond the stage at which atresia normally occurs. Next, a species-specific number of follicles is selected for dominance. In some species (e.g. rats, primates, pigs),...
Galli C, Duchi R, Colleoni S, Lagutina I, Lazzari G.Assisted reproductive techniques developed for cattle in the last 25 years, like ovum pick up (OPU), intracytoplasmic sperm injection (ICSI), and somatic cell nuclear transfer, have been transferred and adapted to buffalo and horses. The successful clinical applications of these techniques require both the clinical skills specific to each animal species and an experienced laboratory team to support the in vitro phase of the work. In cattle, OPU can be considered a consolidated technology that is rapidly outpacing conventional superovulation for embryo transfer. In buffalo, OPU represents the ...
Carnevale EM.Reproductive aging and assisted reproduction are becoming progressively more relevant in human medicine. Research with human subjects is limited in many aspects, and consequently animal models may have considerable utility. Such models have provided insight into follicular function, oocyte maturation, and reproductive aging. However, models are often selected based on factors other than physiological or functional similarities. Although the mare has received limited attention as a model for reproduction in women, comparisons between these species indicate that the mare has many attributes of a...
Loomis PR, Graham JK.One of the challenges for those attempting to cryopreserve stallion spermatozoa is dealing with the stallion to stallion variability in the cryosurvival of their semen. In the dairy industry, each bull stud, essentially utilizes a single cryopreservation technique, and bulls that produce sperm that do not cryopreserve well using that technique are replaced by other bulls. However, replacing stallions is unlikely to prove acceptable to the equine industry, where specific genotypes are desired. Instead, to increase the number of stallions that can be effectively utilized for cryopreserved semen ...
Ortega Ferrusola C, González Fernández L, Morrell JM, Salazar Sandoval C, MacÃas GarcÃa B, RodrÃguez-Martinez H, Tapia JA, Peña FJ.Lipid peroxidation (LPO) of stallion spermatozoa was assessed in fresh semen and in samples of the same ejaculates after freezing and thawing. Particular attention was paid to individual differences in the susceptibility to LPO and its possible relationship with freezability. Innate levels of LPO were very low in fresh spermatozoa but increased after thawing, a change that was largely stallion-dependent. The level of LPO in fresh spermatozoa was not correlated with that of the thawed spermatozoa. Negative correlations existed between LPO and intact membranes post-thaw (r=-0.789, P<0.001), a...
Colenbrander B, Gadella BM, Stout TA.Pregnancy rates in managed horse populations depend on the innate fertility of the mares and stallions involved and on the quality of breeding management. Of course, because a single stallion usually mates many mares, stallion fertility is a critical factor in the overall success of a breeding program. Unfortunately, accurate evaluation of stallion fertility per se requires a large number of normal mares to be mated and is necessarily retrospective. Rather, the ideal is to predict fertility in advance of the stallion's breeding career, and this is currently attempted by way of a thorough physi...
Rambags BP, van Boxtel DC, Tharasanit T, Lenstra JA, Colenbrander B, Stout TA.In many mammalian species, reproductive success decreases with maternal age. One proposed contributor to this age-related decrease in fertility is a reduction in the quantity or functionality of mitochondria in oocytes. This study examined whether maternal age or (in vitro maturation). IVM affect the quantity of mitochondria in equine oocytes. Oocytes were collected from the ovaries of slaughtered mares categorized as young (<12 years) or aged (≥12 years) and either denuded and prepared for analysis immediately (not-IVM) or matured in vitro for 30 hours before preparation (IVM). The m...
Allen WR, Brown L, Wright M, Wilsher S.Previous surveys of reproductive efficiency in British Thoroughbreds included only mares and stallions standing on studfarms in and around Newmarket. The present study was widened to compare Flatrace (FR) (Group A) and National Hunt (NH) (Group B) mares and stallions on studfarms throughout England. Objective: To assess the influences of mare type, status and age, and veterinary manipulations on reproductive efficiency parameters. To compare the inherent fertility of stallions, based on singleton and twin pregnancy rates and pregnancy loss rates, in Groups A and B Thoroughbred breeding stock. ...
Galli C, Crotti G, Notari C, Turini P, Duchi R, Lazzari G.Embryo production by in vitro techniques has increased steadily over the years. For cattle where this technology is more advanced and is applied more, the number of in vitro produced embryos transferred to final recipients was over 30,000 in 1998. An increasing proportion of in vitro produced embryos are coming from oocytes collected from live donors by ultrasound-guided follicular aspiration (ovum pick up, OPU). This procedure allows the repeated production of embryos from live donors of particular value and is a serious alternative to superovulation. Ovum pick up is a very flexible technique...
Carnevale EM, Ginther OJ.The uterine function and reproductive efficiency of 31 nonlactating pony mares were compared for two age groups: young (5 to 7 years, n=9) and old (>/=15 years, n=22). For pregnant mares, differences between age groups were not significant for the diameter of the largest follicle, cross-sectional area of the corpus luteum, growth profile of the embryonic vesicle or embryo mobility characteristics. Uterine contractility scores were lower (P<0.05), day of fixation of the embryonic vesicle was later (P<0.05), and uterine tone tended (P<0.10) to be lower in the old than the young mares...
Driancourt MA.In this review, the main features of folliculogenesis are summarized and compared among species. In the past few years, ultrasonography has clarified follicle growth patterns, and our understanding of follicle maturation has improved considerably. As the follicles develop towards the ovulatory stage, three features appear to be highly conserved across all species: 1) the sequence of events (recruitment, selection and dominance); 2) the sequential need for gonadotropins (FSH for recruitment, LH for dominance) and 3) the large variability of numerical parameters (number of waves per cycle, numbe...
Gibb Z, Aitken RJ.In vitro sperm storage is a necessary part of many artificial insemination or in vitro fertilization regimes for many species, including the human and the horse. In many situations spermatozoa are chilled to temperatures between 4 and 10°C for the purpose of restricting the metabolic rate during storage, in turn, reducing the depletion of ATP and the production of detrimental by-products such as reactive oxygen species (ROS). Another result of lowering the temperature is that spermatozoa may be "cold shocked" due to lipid membrane phase separation, resulting in reduced fertility. To overcome ...
Das PJ, Paria N, Gustafson-Seabury A, Vishnoi M, Chaki SP, Love CC, Varner DD, Chowdhary BP, Raudsepp T.Sperm mRNA transcriptional profiles can be used to evaluate male fertility, yet differences between species in sperm attributes and packaging require adjustments in sperm RNA isolation protocols. The objective was to optimize RNA isolation methodology for fresh, frozen, and extended ejaculates, and epididymal sperm of stallions. Additionally, a protocol for RNA isolation from testis biopsies was established. Separation of sperm from somatic cells was critical for assuring the isolation of sperm-specific RNA. The highest purity was obtained by centrifuging ejaculates and epididymal sperm at 200...
Salamone DF, Canel NG, RodrÃguez MB.Intracytoplasmic sperm injection (ICSI) has become a useful technique for clinical applications in the horse-breeding industry. However, both ICSI blastocyst and offspring production continues to be limited for most farm and wild species. This article reviews technical differences of ICSI performance among species, possible biological and methodological reasons for the variable efficiency and potential strategies to improve the outcomes. One of the major applications of ICSI in animal production is the reproduction of high-value specimens. Unfortunately, some domestic species like the bovine s...
Weber JA, Freeman DA, Vanderwall DK, Woods GL.The hypothesis that treatment of pregnant mares with prostaglandin E2 (PGE2) hastens the oviductal transport of equine embryos was tested by treating bred mares with PGE2 on Day 3 after ovulation and subsequently measuring the rate of hastened oviductal transport (estimated by the uterine embryo recovery rate on Day 4 after ovulation). In a preliminary, noncontrolled experiment, oviductal transport was apparently not hastened after intramuscular, intrauterine, or intraperitoneal PGE2 administration to bred mares (0/6, 0/3, and 0/3 mares, respectively). Oviductal transport appeared to be hasten...
Okamura H, Yamamura T, Wakabayashi Y.The hypothalamo-pituitary-gonadal (HPG) axis is the regulatory system for reproduction in mammals. Because secretion of gonadotropin-releasing hormone (GnRH) into the portal vessels is the final step at which the brain controls gonadal activities, the GnRH neuronal system had been thought to be central to the HPG axis. A newly discovered neural peptide, kisspeptin, has opened a new era in reproductive neuroendocrinology. As shown in a variety of mammals, kisspeptin is a potent endogenous secretagogue of GnRH, and the kisspeptin neuronal system governs both the pulsatile GnRH secretion that dri...
Troedsson MH, Desvousges A, Alghamdi AS, Dahms B, Dow CA, Hayna J, Valesco R, Collahan PT, Macpherson ML, Pozor M, Buhi WC.Seminal plasma has been suggested to be involved in sperm transport, and as a modulator of sperm-induced inflammation, which is thought to be an important part of sperm elimination from the female reproductive tract. This article reports on recent experiments on the importance of seminal plasma components in sperm transport and elimination. In Experiment 1, hysteroscopic insemination in the presence (n = 3) or absence (n = 3) of 2 ng/mL PGE showed an increased portion of spermatozoa crossing the utero-tubal junction in the presence of PGE in two mares, while no difference was observed between ...
Ortega-Ferrusola C, GarcÃa BM, Gallardo-Bolaños JM, González-Fernández L, RodrÃguez-Martinez H, Tapia JA, Peña FJ.In an attempt to identify valuable markers for potential freezeability of the equine spermatozoa, three ejaculates were collected from five Andalusian stallions and frozen using a standard protocol. Before freezing, three apoptotic cell markers were studied by flow cytometry (early changes in sperm membranes, mitochondrial membrane potential and caspase activity). Post-thaw, spermatozoa were again evaluated for these parameters. Sperm kinematics using CASA were also studied before and after freezing and thawing. Receiving operating system curves were used to evaluate the relative value of the ...
Rizzo M, Ducheyne KD, Deelen C, Beitsma M, Cristarella S, Quartuccio M, Stout TAE, de Ruijter-Villani M.Advanced mare age is associated with declining fertility and an increased risk of early pregnancy loss. Compromised oocyte quality is probably the primary reason for reduced fertility, but the defects predisposing to embryonic death are unknown. In women, advanced age predisposes to chromosome segregation errors during meiosis, which lead to embryonic aneuploidy and a heightened risk of miscarriage. Objective: To evaluate the effect of advanced mare age on chromosome alignment and meiotic spindle morphology in in vitro-matured (IVM) oocytes. Methods: Morphometric and morphological analysis. M...
Nath LC, Anderson GA, McKinnon AO.To evaluate the reproductive efficiency of horse farms in north-east Victoria and identify aspects of management to be targeted for improving reproductive efficiency. Methods: Retrospective study. Methods: Records from seven Thoroughbred (TB) and four Standardbred (STB) studs in north-east Victoria from 1990 to 2001 were reviewed; 8813 cycles in 4455 mares were analysed. TB mares were inseminated by natural mating, whereas STB mares (89%) were artificially inseminated. Results: The overall early pregnancy rate per cycle was 68.8% for TB mares and for STB mares, 68.3%. Multiple pregnancy per cy...
López-Fernández C, Crespo F, Arroyo F, Fernández JL, Arana P, Johnston SD, Gosálvez J.The mixed success of equine artificial insemination programs using chilled and frozen-thawed semen is most likely associated with the variable response of the sperm cell to the preservation process and the fact that stallions are not selected on the basis of reproductive performance. We propose that the traditional indicators of sperm viability do not fully account for male factor infertility in the stallion and that knowledge of sperm DNA damage in the original semen sample and during semen processing may provide a more informed explanation of an individual stallion's reproductive potential. ...
Wiebke M, Hensel B, Nitsche-Melkus E, Jung M, Schulze M.This review is part of the Festschrift in honor of Dr. Duane Garner and provides an overview of current techniques for cooled storage of semen from livestock animals. The first part describes the current state of the art of liquid semen preservation in boars, bulls, and stallions, including the diluents, use of additives, processing, temperature, and cooling of semen. The species-specific physiology and varying extents of cold shock sensitivity are taken into consideration. In addition, factors influencing the quality of cooled-stored semen are discussed. Methods, trends, and the most recent a...
Hinrichs K, Love CC, Brinsko SP, Choi YH, Varner DD.Three experiments were conducted to evaluate the effect of oocyte and sperm treatments on rates of in vitro fertilization (IVF) in the horse and to determine the capacity of in vitro-matured horse oocytes to be fertilized in vivo. There was no effect of duration of oocyte maturation (24 vs. 42 h) or calcium ionophore concentration during sperm capacitation (3 microM vs. 7.14 microM) on in vitro fertilization rates. Oocytes matured in 100% follicular fluid had significantly higher fertilization (13% to 24%) than did oocytes matured in maturation medium or in 20% follicular fluid (0% to 12%; P <...
Zuidema D, Kerns K, Sutovsky P.Artificial insemination of livestock has been a staple technology for producers worldwide for over sixty years. This reproductive technology has allowed for the rapid improvement of livestock genetics, most notably in dairy cattle and pigs. This field has experienced continuous improvements over the last six decades. Though much work has been carried out to improve the efficiency of AI, there are still many areas which continue to experience improvement, including semen analysis procedures, sperm selection techniques, sperm sexing technologies, and semen storage methods. Additionally, the use ...
Hall V, Hinrichs K, Lazzari G, Betts DH, Hyttel P.Over many decades assisted reproductive technologies, including artificial insemination, embryo transfer, in vitro production (IVP) of embryos, cloning by somatic cell nuclear transfer (SCNT), and stem cell culture, have been developed with the aim of refining breeding strategies for improved production and health in animal husbandry. More recently, biomedical applications of these technologies, in particular, SCNT and stem cell culture, have been pursued in domestic mammals in order to create models for human disease and therapy. The following review focuses on presenting important aspects of...
Swegen A.Maternal recognition of pregnancy (MRP) is a process by which an early conceptus signals its presence to the maternal system and prevents the lysis of the corpus luteum, thus ensuring a maternal milieu supportive of pregnancy continuation. It is a fundamental aspect of reproductive biology, yet in the horse, the mechanism underlying MRP remains unknown. This review seeks to address some of the controversies surrounding the evidence and theories of MRP in the equine species, such as the idea that the horse does not conform to the MRP paradigm established in other species or that equine MRP invo...
