Reproduction in horses encompasses the biological processes and mechanisms involved in the breeding and development of equine offspring. This includes the study of reproductive anatomy, physiology, and endocrinology in both mares and stallions. Key areas of interest include the estrous cycle, ovulation, conception, gestation, and parturition. Researchers also examine factors influencing fertility, reproductive technologies such as artificial insemination and embryo transfer, and management practices that impact reproductive success. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, genetic, and environmental aspects of equine reproduction.
Squires EL.Marked changes in equine breeding technologies have occurred over the past 25 years. Although there have been numerous reviews on assisted reproduction techniques for horses, few publications include the acceptance and impact of these techniques on the horse industry. In this review, several techniques are discussed, with an emphasis on how they developed in the horse industry and altered equine reproductive medicine. Embryo transfer has become a widely used technology, allowing multiple foals to be produced per year. Embryos can be collected, cooled or frozen, and shipped to a distant facilit...
Petrizzi L, Guerri G, Straticò P, Cuomo A, Vullo C, De Amicis I, Robbe D, Varasano V.Mules are hybrids bred from the mating of a jack donkey and a horse mare, known for their strength and resistance and still used to work in agriculture. Although they have been for long considered sterile, evidence of estrus cycle has been demonstrated together with abnormal behavior related to ovarian activity. In this study, a bilateral standing laparoscopic ovariectomy technique using the LigaSure technology was applied in 10 mare mules for treating unwanted behavioral patterns. The technique was effectively performed on these animals avoiding the risk of general anesthesia, and the use of ...
Krakowski L, Brodzki P, Krakowska I, Opielak G, Marczuk J, Piech T.The aim of the study was to determine the level of prolactin (PRL), serum amyloid A (SAA), and selected biochemical markers (T-Chol, AST, TP, Mg, P, and Ca) in the blood of mares during the perinatal period. The study involved 14 mares of the Polish Coldblood Horse breed, which were in the third trimester of pregnancy. Blood was collected for testing 2 weeks before parturition and then 24 hours after delivery and in the foal heat (9 days) and 9 days after ovulation and breeding. The research revealed significant differences in the level of PRL and SAA before and after delivery. The highest...
Loux SC, Dini P, El-Sheikh Ali H, Kalbfleisch T, Ball BA.The placenta is a dynamic organ which undergoes extensive remodeling throughout pregnancy to support, protect and nourish the developing fetus. Despite the importance of the placenta, very little is known about its gene expression beyond very early pregnancy and post-partum. Therefore, we utilized RNA-sequencing to characterize the transcriptome from the fetal (chorioallantois) and maternal (endometrium) components of the placenta from mares throughout gestation (4, 6, 10, 11 m). Within the endometrium, 47% of genes changed throughout pregnancy, while in the chorioallantois, 29% of genes under...
Rodrigues JA, Gonçalves AR, Antunes L, Bettencourt EV, Gama LT.Breeding and parturition records collected over a period of 35 years in the Alter Real stud of Lusitano horses were used to calculate gestation length (GL). The 1027 gestations by 209 mares mated to 60 stallions had a mean GL of 338.1 ± 9.26 days. The mixed model analysis of variance indicated that the sex of the foal and inbreeding of the dam and foal had no significant effect on GL (P > .05). On the other hand, GL increased linearly with mare age, with an estimated regression coefficient of 0.155 ± 0.069 days/year (P < .05). Year and conception month affected GL (P < .05), with longer g...
Twenter H, Klohonatz K, Davis K, Bass L, Coleman SJ, Bouma GJ, Bruemmer JE.All epididymal regions are lined with multiple epithelial cell types, each with different functions to provide the luminal environment for spermatozoal maturation. Epithelial cells also create apical blebs, which are released from the apical surface via apocrine secretion and disintegrate in the lumen, thereby releasing epididymosomes. Epididymosomes transport proteins to spermatozoa and contain microRNAs. We hypothesized that epididymosomes also transfer miRNA from epididymal epithelium to spermatozoa. Quantitative real-time polymerase chain reaction was used to determine miRNA profiles of ep...
Delgado-Bermúdez A, Noto F, Bonilla-Correal S, Garcia-Bonavila E, Catalán J, Papas M, Bonet S, Miró J, Yeste M.Aquaporins (AQPs), a family of ubiquitous water channels divided into orthodox AQPs, aquaglyceroporins (GLPs), and superAQPs, are present in stallion spermatozoa. The aim of this study was to elucidate the functional relevance of each group of AQPs during stallion sperm cryopreservation through the use of three different inhibitors: acetazolamide (AC), phloretin (PHL) and propanediol (PDO). Sperm quality and function parameters were evaluated in the presence or absence of each inhibitor in fresh and frozen-thawed samples. In the presence of AC, different parameters were altered ( < 0.05), b...
Busse NI, Uberti B.A 12-year-old, multiparous, parturient show jumper embryo-recipient mare presented at a veterinary hospital, seven days past her due date and with a dilated cervix, for evaluation of mild colic. Gastrointestinal or metabolic abnormalities and fetal maldispositions were excluded as causes of dystocia, and a diagnosis of uterine inertia was made. There was no uterine response to oxytocin treatment. A live filly was delivered via C-section, and severe selenium deficiency was eventually confirmed in the mare, her offspring, and in the herd of origin. The filly was born with severe white muscle dis...
Martino NA, Marzano G, Mastrorocco A, Lacalandra GM, Vincenti L, Hinrichs K, Dell Aquila ME.Time-lapse imaging was used to establish the morphokinetics of equine embryo development to the blastocyst stage after invitro oocyte maturation (IVM), intracytoplasmic sperm injection (ICSI) and embryo culture, in oocytes held overnight at room temperature (22-27°C; standard conditions) before IVM. Embryos that developed to the blastocyst stage underwent precleavage cytoplasmic extrusion and cleavage to the 2-, 3- and 4-cell stages significantly earlier than did embryos that arrested in development. We then determined the rate of blastocyst formation after ICSI in oocytes held for 2 days at ...
Lancheros-Buitrago J, Rodriguez-Villamil P, Gregory J, Bastos H, Camacho CA, Caballeros JE, Cazales N, Barros E, José de Jesus Silva M, Pimentel A....Characterization of the uterine proteome before the entry of the conceptus to the uterus is essential to know the factors involved in the physiological events of gestation. The objective of the study was to compare proteomic profile of uterine fluid collected on day 5 post ovulation of cyclic and inseminated mares. Samples of endometrial secretion were recovered over 2 cycles during the fifth day post ovulation. The first cycle constituted the Cyclic group and in the following cycle, the same mares were inseminated and considered as the Inseminated group. All the samples were subjected to two-...
Papas M, Catalán J, Fernandez-Fuertes B, Arroyo L, Bassols A, Miró J, Yeste M.While the removal of seminal plasma is a routine practice prior to equine sperm cryopreservation, this fluid contains the main source of antioxidant enzymes able to scavenge these reactive oxygen species. Therefore, stallion seminal plasma components may have an impact on ejaculate freezability. Against this background, this study was designed to investigate whether the activities of the main stallion seminal plasma antioxidant enzymes are related to sperm cryotolerance. With this purpose, 16 ejaculates were collected from 14 healthy stallions, and each ejaculate was split into two aliquots. T...
Swift LA, Christensen BW, Samocha MB, le Jeune SS, Millares-Ramirez EM, Dujovne GA.Although exercise and acupuncture are frequently used therapies to treat persistent postbreeding endometritis, their efficacy to date is unproven. The objective of this study was to determine if exercise and acupuncture are effective methods to reduce intrauterine fluid and compare the effectiveness of these treatments to the use of uterine ecbolics. Twelve mares susceptible to postbreeding endometritis were enrolled in the study with a randomized cross-over design using both positive and negative controls. During each estrous cycle, mares were randomized into one of six treatment groups, incl...
Canisso IF, Panzani D, Miró J, Ellerbrock RE.Donkeys are nonseasonal, polyestrous, territorial, and nonharem breeders. Although there are many similarities between horses and donkeys, there are also reproductive features that differ, from the longer cervix in the jenny to spermatogenic efficiency in the jack. Mules display reproductive cyclic activity but are rarely fertile. Frozen donkey semen has high pregnancy rates in mares, but lower rates in jennies. This article reviews key aspects of donkey and mule reproductive physiology, reproductive medicine, and assisted reproductive techniques that are useful for practitioners offering assi...
McLean AK, Navas González FJ, Canisso IF.Donkeys and mules often are misunderstood because of their behavioral differences compared with horses. Working with these animals requires more patience and ability to notice the slightest changes in behavior to diagnose disease. Mules and donkeys form strong bonds and trust with familiar people and other equids. Training mules and hinnies from an early age is key to modifying behavior and acceptance of unfamiliar people. Reproductive behavior is different from that of horses and requires more patience when collecting jacks. Practitioners working with mules and donkeys should take a methodolo...
Ghosh S, Serafini R, Love CC, Teague SR, Hernández-Avilés C, LaCaze KA, Varner DD.Effects of different media and promoters on lipid peroxidation (LPO) in viable stallion sperm have not been reported. Aims of this study were to determine effects of three media (INRA-96™, Equipro CoolGuard™, and Biggers, Whitten and Whittingham [BWW]), and promoters (iron sulfate-Fe; ultraviolet light-UV; or control-no exposure to promoters) on viable sperm LPO using four different flow cytometric assays (i.e., BODIPY, Liperfluo, 4-hydroxylnonenal [4HNE], malonaldehyde [MDA]). Significant media x promoter interactions were detected using the Liperfluo, 4HNE, and MDA assays (P < 0.05)...
Centromeres exert an inhibitory effect on meiotic recombination, but the possible contribution of satellite DNA to this "centromere effect" is under debate. In the horse, satellite DNA is present at all centromeres with the exception of the one from chromosome 11. This organization of centromeres allowed us to investigate the role of satellite DNA on recombination suppression in horse spermatocytes at the stage of pachytene. To this aim we analysed the distribution of the MLH1 protein, marker of recombination foci, relative to CENP-A, marker of centromeric function. We demonstrated that the sa...
Camargo CE, Rechsteiner SF, Macan RC, Kozicki LE, Gastal MO, Gastal EL.The aim of this study was to compare the embryonic and early fetal development of horse embryos between recipient mules and mares from day 10-60 of pregnancy, in addition to hormonal (eCG and progesterone), ovarian, and uterine characteristics for approximately 4 months. Embryo donor mares (n = 5) and two groups of recipients (acyclic mules, n = 7; cyclic mares, n = 7) were used. Donor mares were monitored daily by transrectal ultrasonography and inseminated using fresh semen. Cyclic recipient mares were synchronized with the donor's ovulation using PGF2α and deslorelin acetate. M...
Roser JF, Etcharren MV, Miragaya MH, Mutto A, Colgin M, Losinno L, Ross PJ.The effectiveness of different treatments with recombinant equine FSH to stimulate follicular growth, multiple ovulations and embryo production in seasonally anovulatory mares was evaluated. During mid-winter season (July-August in Argentina, South America) forty light breed donor mares, presenting follicles <10 mm in diameter and no CL at ultrasound examination (deep-anestrus), were randomly assigned (n = 10/group) to one of the following treatments: Group 1: twice daily intramuscular (IM) injections of 0.65 mg reFSH (AspenBio Pharma, CO), Group 2: once daily IM injection of 1.3 mg ...
Riera FL, Roldán JE, Espinosa JM, Fernandez JE, Ortiz I, Hinrichs K.Embryo biopsy for fetal sexing has clinical application, but few reports are available of its use within an active embryo transfer program. We evaluated results on biopsy of 459 embryos over one breeding season. There were no significant differences in pregnancy rate between biopsied and non-biopsied embryos (72% vs 73%) or for biopsied embryos recovered at the centre (73%) compared with those shipped overnight (72%). However, the pregnancy rate decreased significantly in shipped embryos biopsied ≥20h after collection. Overall, 86% of biopsies provided a sex diagnosis. The likelihood of a po...
Brom-de-Luna JG, Salgado RM, Canesin HS, Diaw M, Hinrichs K.Some basic parameters for equine invitro embryo production have not yet been established, including the optimum temperature for maturation and embryo culture, and the optimum CO2 concentration and pH during early embryo development. To explore this, we first performed cultures in incubators set at 37.2°C, 37.7°C or 38.2°C. At these temperatures, the corresponding maturation rates were 33%, 38% and 42%; cleavage rates were 84%, 86% and 88%; and blastocyst rates were 35%, 44% and 44% per injected oocyte. These rates did not differ significantly (P>0.2). We then evaluated three different CO...
Morris LH, Maclellan LJ.The increased commercialisation of intracytoplasmic sperm injection (ICSI) in horses creates more opportunities to incorporate advanced reproductive technologies, such as sex-sorted, refrozen and lyophilised spermatozoa, into a breeding program. This paper reviews the status of these semen-handling technologies in light of their use in equine ICSI programs. Pregnancies have been achieved from each of these advanced technologies when combined with ICSI in horses, but refinements in the semen-handling processes underpinning these technologies are currently being explored to produce more reliable...
Alonso MA, Silva LA, Affonso FJ, Lemes KM, Celeghini ECC, Lançoni R, Carvalho HF, de Arruda RP.Establishment of pregnancy after embryo transfer is the ultimate goal of an embryo transfer program and increasing pregnancy rates and reducing pregnancy loss are mandatory. The utilization of treatments to improve conception rates in recipient mares has been the focus of several research groups over the last years and the results are controversial. Some studies using human chorionic gonadotrophin (hCG) found promising results. Our hypothesis was that hCG administration would cause an additional stimulation on luteal function, uterine and luteal vascularization and progesterone concentration, ...
Snoeck PPDN, Pessoa THO, Pereira MGS, Bastos ICL, de Melo MIV.The objective of this study was to compare the BotuCrio extender with the Merk - egg yolk and the INRA 82 modified by the inclusion of acetamide, methyl cellulose and trehalose in substitution of glycerol for freezing equine semen. The semen was diluted after centrifugation to obtain 100 x 10 of sperm/ml in: BotuCrio (control); Merk - egg yolk or INRA 82 modified (Experiment 1). The extended semen was packaged in 0.5 ml straws, cooled and frozen in a freezing machine. The control extender was superior in preserving the motility, VCL, VSL, VAP, LIN, STR and the BCF when compared to the Merk - e...
Lodde V, Colleoni S, Tessaro I, Corbani D, Lazzari G, Luciano AM, Galli C, Franciosi F.Several studies report that a two-step culture where mammalian oocytes are first kept under meiosis-arresting conditions (prematuration) followed by IVM is beneficial to embryo development. The most promising results were obtained by stratifying the oocyte population using morphological criteria and allocating them to different culture conditions to best meet their metabolic needs. In this study, horse oocytes were characterised to identify subpopulations that may benefit from prematuration. We investigated gap-junction (GJ) coupling, large-scale chromatin configuration and meiotic competence ...
Bernstock JD, Ostby S, Fox B, Sotoudeh H, Janssen A, Kang YJ, Chen J, Prattipati V, Elsayed G, Chagoya G, Yamashita D, Friedman GK, Nabors B, Huh WK....Leptomeningeal metastasis is extremely rare in patients with ovarian cancer, but should be considered in patients presenting with neurologic deficits such as cauda equine syndrome. Given its poor prognosis and lack of data currently on management, additional studies are needed to optimize treatment regimens and improve outcomes.
Meyers S, Burruel V, Kato M, de la Fuente A, Orellana D, Renaudin C, Dujovne G.In this study we examined the timeline of mitotic events of invitro-produced equine embryos that progressed to blastocyst stage using non-invasive time-lapse microscopy (TLM). Intracytoplasmic sperm injection (ICSI) embryos were cultured using a self-contained imaging incubator system (Miri®TL; Esco Technologies) that captured brightfield images at 5-min intervals that were then generated into video for retrospective analysis. For all embryos that progressed to the blastocyst stage, the initial event of extrusion of acellular debris preceded all first cleavages and occurred at mean (±s.e.m.)...
Lewis N, Schnauffer K, Hinrichs K, Morganti M, Troup S, Argo C.The use of time-lapse imaging (TLI) in the evaluation of morphokinetics associated with invitro developmental competence is well described for human, cattle and pig embryos. It is generally accepted that embryos that complete early cleavage sooner are more likely to form blastocysts and that timing of later events, such as blastocyst formation and expansion, are predictive of implantation potential and euploid status. In the horse, morphokinetics as a predictor of developmental competence has received little attention. In this study we evaluated the morphokinetics of early equine embryo develo...
Cuervo-Arango J, Claes AN, Stout TAE.This study retrospectively examined the degree to which success within a commercial ovum pick-up (OPU)-intracytoplasmic sperm injection (ICSI) program varied between individual mares and stallions. Over 2 years, 552 OPU sessions were performed on 323 privately owned warmblood mares. For mares that yielded at least one blastocyst during the first OPU-ICSI cycle, there was a 77% likelihood of success during subsequent attempts; conversely, when the first cycle yielded no blastocyst, the likelihood of failure (no embryo) in subsequent cycles was 62%. In mares subjected to four or more OPU session...
Álvarez C, González N, Luño V, Gil L.The aim of this study was to evaluate the effect of trehalose and lactose extenders on ejaculated and epididymal stallion sperm vitrification. Ejaculated semen samples were collected from seven fertile stallions, and cauda epididymis samples were collected from ten stallion carcasses after slaughter. Both the ejaculated and the epididymis samples were diluted and vitrified using INRA 96® and bovine serum albumin as well as trehalose or lactose. As a control, ejaculated and epididymal samples were collected and frozen using the conventional method. Vitrification was performed by immersing sper...
Dahmani M, Davoust B, Sambou M, Bassene H, Scandola P, Ameur T, Raoult D, Fenollar F, Mediannikov O.Our study aimed to assess the diversity of the species of Anaplasmataceae in Senegal that infect animals and ticks in three areas: near Keur Momar Sarr (northern region), Dielmo and Diop (Sine Saloum, central region of Senegal), and in Casamance (southern region of Senegal). Methods: A total of 204 ticks and 433 blood samples were collected from ruminants, horses, donkeys and dogs. Ticks were identified morphologically and by molecular characterization targeting the 12S rRNA gene. Molecular characterization of species of Anaplasmataceae infecting Senegalese ticks and animals was conducted usin...
Stahlbaum CC, Houpt KA.The role of the Flehmen response in equine behavior was investigated under field and laboratory conditions. In Experiment 1, a field study made of five stallions on pasture with between three and eighteen mares each during the season indicated the following: 1) The Flehmen response was most frequently preceded by nasal, rather than oral, investigation of substances; 2) The stallions' rate of Flehmen varied with the estrous cycles of the mares; 3) The rate of Flehmen response did not show a variation with time of day; and 4) The Flehmen response was most frequently followed by marking behaviors...
Pozor MA, Macpherson ML, McDonnell SM, Nollin M, Roser JF, Love C, Runyon S, Thomas BF, Troedsson MH.The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baselin...
Leemans B, Stout TAE, Soom AV, Gadella BM.Procaine directly triggers pH-dependent cytokinesis in equine oocytes and induces hypermotility in stallion spermatozoa, an important event during capacitation. However, procaine-induced hyperactivated motility is abolished when sperm is washed to remove the procaine prior to sperm-oocyte co-incubation. To understand how procaine exerts its effects, the external Ca2+ and Na+ and weak base activity dependency of procaine-induced hyperactivation in stallion spermatozoa was assessed using computer-assisted sperm analysis. Percoll-washed stallion spermatozoa exposed to Ca2+-depleted (+2 mM EGTA) p...
Desantis S, Zizza S, Accogli G, Acone F, Rossi R, Resta L.Morphometric, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations have displayed regional differences in the mare oviductal epithelium. The entire mucosa of the oviduct was lined with a pseudostratified epithelium, which consisted of two distinct cell types, ciliated and non-ciliated. Ciliated cells were predominant in the three different segments of the oviduct and their percentage increased from fimbriae to ampulla and significantly decreased in the isthmus. SEM revealed in the infundibulum finger-like mucosal folds, some of them interconnected, in th...
Gadella BM, Rathi R, Brouwers JF, Stout TA, Colenbrander B.During sexual reproduction, the sperm and oocyte must fuse before the production of a diploid zygote can proceed. In mammals such as equids, fusion depends critically on complex changes in the plasma membrane of the sperm and, not surprisingly, this membrane differs markedly from that of somatic cells. After leaving the testes, sperm cease to synthesize plasma membrane lipids or proteins, and vesicle-mediated transport stops. When the sperm reaches the female reproductive tract, it is activated by so-called capacitation factors that initiate a delicate reorientation and modification of molecul...
Legacki EL, Corbin CJ, Ball BA, Wynn M, Loux S, Stanley SD, Conley AJ.Mammalian pregnancies need progestogenic support and birth requires progestin withdrawal. The absence of progesterone in pregnant mares, and the progestogenic bioactivity of 5α-dihydroprogesterone (DHP), led us to reexamine progestin withdrawal at foaling. Systemic pregnane concentrations (DHP, allopregnanolone, pregnenolone, 5α-pregnane-3β, 20α-diol (3β,20αDHP), 20α-hydroxy-5α-dihydroprogesterone (20αDHP)) and progesterone) were monitored in mares for 10days before foaling (n=7) by liquid chromatography-mass spectrometry. The biopotency of dominant metabolites was assessed using luci...
Jiménez-Trejo F, Coronado-Mares I, Boeta M, González-Santoyo I, Vigueras-Villaseñor R, Arriaga-Canon C, Herrera LA, Tapia-Rodríguez M.Assisted reproductive techniques have been used on several domestic animals to preserve desirable traits in strains of high genetic and commercial value; however in equines its efficiency rate is relatively low. To increase the conception ratio in stallions, some research groups have used pharmacological treatments which promote sperm hyperactivation in order to increase male's fertility rates. In this way, our previous work suggests that serotonin (5-HT) could be a good pharmacological candidate that facilitates conception rate in domestic horses. 5-HT is a neurohormone involved in several re...
Allen WR, Wilsher S, Tiplady C, Butterfield RM.The growth parameters exhibited by seven Thoroughbred (Tb) foals that had experienced a 'restricted' in utero existence following transfer as embryos to the uteri of smaller Pony (P) mares (Tb-in-P) and, conversely, six P foals that experienced a 'luxurious' in utero existence after transfer to larger Tb mares (P-in-Tb), were compared from birth to 3 years of age with those exhibited by six normal Tb-in-Tb and six P-in-P foals conceived by within-breed artificial insemination. Bodyweight, height at the withers, girth, poll-to-nose length, crown-rump length and three foreleg longbone measuremen...
Foote RH.Several inherited conditions associated with testicular defects, abnormal spermatogenesis and morphologically abnormal sperm have been found. These usually are controlled by single gene pairs. A notable exception is testicular size, with heritability in young bulls ranging from .42 to .88. Testicular size directly affects sperm output potential. The major contributor to variation in semen quality is the environment. Environmental effects may be temporary or permanent. Permanent effects occurring during prenatal and prepubertal periods and temporary or permanent factors acting after spermatogen...
Ransom JI, Hobbs NT, Bruemmer J.Abiotic inputs such as photoperiod and temperature can regulate reproductive cyclicity in many species. When humans perturb this process by intervening in reproductive cycles, the ecological consequences may be profound. Trophic mismatches between birth pulse and resources in wildlife species may cascade toward decreased survival and threaten the viability of small populations. We followed feral horses (Equus caballus) in three populations for a longitudinal study of the transient immunocontraceptive porcine zona pellucida (PZP), and found that repeated vaccinations extended the duration of in...
The proteins galectin-1 and Progesterone Induced Blocking Factor (PIBF) are present on human and murine trophoblast and are thought to influence both immunomodulation and trophoblast invasion. In equids, the invasive component of the placenta, the endometrial cups, stimulate maternal cell-mediated and humoral immune responses. It was therefore of interest to know if galectin-1 or PIBF could be immunolocalised to the invasive and/or non-invasive components of the equine placenta. Horse and mule (♀ horse X ♂ donkey) embryos and placental tissues between Days 12 and 124 of gestation were stai...
Hirota K, Kakoi H, Gawahara H, Hasegawa T, Tozaki T.We characterized the SNP 53 JPN System for parentage verification during horse registry. The SNP 53 JPN System was constructed using 53 highly polymorphic single nucleotide polymorphisms (SNPs), which were amplified and genotyped with 2 multiplex assays. The SNP 53 JPN System showed good resolution for 95 unrelated thoroughbreds, and the exclusion probability (PE01) for each SNP ranged from 11.5 to 23.0%, resulting in a total PE01 value of 99.996%. These results indicate that the SNP 53 JPN System is useful for parentage testing of thoroughbreds. Of the 53 SNPs, 8 SNPs could be used to exclude...
Gibson C, de Ruijter-Villani M, Rietveld J, Stout TAE.Maternally derived amino acids (AA) are essential for early conceptus development, and specific transporters enhance histotrophic AA content during early ruminant pregnancy. In the present study we investigated AA transporter expression in early equine conceptuses and endometrium, during normal pregnancy and after induction of embryo-uterus asynchrony. 'Normal' conceptuses and endometrium were recovered on Days 7, 14, 21 and 28 after ovulation. To investigate asynchrony, Day 8 embryos were transferred to recipient mares on Day 8 or Day 3, and conceptuses were recovered 6 or 11 days later. Endo...
Pirhonen A, Linnala-Kankkunen A, Mäenpää PH.Protamines isolated from ejaculated human, stallion, bull, boar, and ram spermatozoa were subjected to phosphoserine conversion reaction and protein sequencing. Phosphoserines were detected as S-ethylcysteines. Endogenously phosphorylated protamines have previously been found only in ejaculated human sperm. In this study, we demonstrate that ejaculated sperm from other species also contain protamines phosphorylated at serine residues. In P1-protamines, the endogenously phosphorylated serines were located at the N-terminal region in all species studied, whereas in major forms of human and stall...
Heninger NL, Staub C, Blanchard TL, Johnson L, Varner DD, Forrest DW.Apoptosis in testicular germ cells has been demonstrated in many mammalian species. However, little is known about the stallion (Equus caballus) and rates of apoptosis during spermatogenesis. Morphological and biochemical features of apoptosis reported in other species were used to confirm that the TdT-mediated dUTP Nick end labeling (TUNEL) assay is an acceptable method for identification and quantification of apoptotic germ cells in histological tissue sections from stallion testis. Seminiferous tubules from eight stallions with normal testis size and semen quality were evaluated according t...
Kydd JH, Case R, Winton C, MacRae S, Sharp E, Ricketts SL, Rash N, Newton JR.Identification of risk factors which are associated with severe clinical signs can assist in the management of disease outbreaks and indicate future research areas. Pregnancy loss during late gestation in the mare compromises welfare, reduces fecundity and has financial implications for horse owners. This retrospective study focussed on the identification of risk factors associated with pregnancy loss among 46 Thoroughbred mares on a single British stud farm, with some but not all losses involving equid herpesvirus-1 (EHV-1) infection. In a sub-group of 30 mares, association between pregnancy ...
Minervini F, Giannoccaro A, Nicassio M, Panzarini G, Lacalandra GM.Ochratoxin A (OTA) is a renal mycotoxin and transplacental genotoxic carcinogen. The aim of this study was to evaluate the natural occurrence of OTA in equine blood samples and its placental transfer. For the assessment of OTA levels, serum samples were collected from 12 stallions, 7 cycling mares and 17 pregnant mares. OTA was found in 83% of serum samples (median value = 121.4 pg/mL). For the assessment of placental transfer, serum samples were collected from the 17 mares after delivery and from the umbilical cords of their foals, after foaling. Fourteen serum samples from pregnant mares con...
Alm H, Torner H, Blottner S, Nürnberg G, Kanitz W.Little information is available on methods of sperm capacitation for IVF in the horse. In this study, we summarized results of several independent trials that compared acrosome reaction, hyperactivation and chromatin integrity of fresh or cryopreserved stallion spermatozoa after treatment with heparin or with calcium ionophore. We also examined the influence of spermatozoa storage (fresh vs. cryopreserved), capacitation treatment, oocyte maturation time and cumulus morphology on the penetration rate and fertilization rate. We recovered cumulus-oocyte-complexes (COCs) from ovaries by ultrasound...
Kindahl H, Knudsen O, Madej A, Edqvist LE.Blood samples from 4 mares during the late luteal phase, oestrus, early pregnancy and up to about 150 days of gestation were analysed for 15-keto-13,14-dihydroprostaglandin F-2 alpha (PGFM), progesterone, PMSG and oestrone sulphate by radioimmunoassays. During the late luteal phase, at the time of corpus luteum regression and decreasing progesterone levels, PGFM peaks were recorded. During early pregnancy (i.e. from mating and up to about Day 30) no such peaks were detected. After mating the progesterone levels increased and remained high throughout the observation period. During the oestrous ...
Ferreira-Dias G, Costa AS, Mateus L, Korzekwa AJ, Galvão A, Redmer DA, Lukasik K, Szóstek AZ, Woclawek-Potocka I, Skarzynski DJ.Cytokines and nitric oxide (NO) are potential mediators of luteal development and maintenance, angiogenesis, and blood flow. The aim of this study was to evaluate (i) the localization and protein expression of endothelial and inducible nitric oxide synthases (eNOS and iNOS) in equine corpora lutea (CL) throughout the luteal phase and (ii) the effect of a nitric oxide donor (spermine NONOate, NONOate) on the production of progesterone (P4) and prostaglandin (PG) E(2) and factor(s) that stimulate endothelial cell proliferation using equine luteal explants. Luteal tissue was classified as corpora...
Sayasith K, Lussier J, Doré M, Sirois J.Little is known about the expression and regulation of epiregulin (EREG) and amphiregulin (AREG) in ovarian follicles of large monoovulatory animal species. To characterize the gonadotropin-dependent regulation of EREG and AREG mRNAs in equine follicles prior to ovulation, extracts were prepared from equine follicles collected during estrus between 0 and 39h post-hCG and corpora lutea obtained on day 8 of the estrous cycle (day 0=day of ovulation). Results from RT-PCR/Southern blot analyses showed that levels of EREG and AREG mRNAs were very low in follicles obtained at 0h but increased therea...
Scarlet D, Walter I, Hlavaty J, Aurich C.In mares, FSH and its receptor (FSHR) are essential for ovarian function. The objective of the present study was to analyse FSHR gene expression at the mRNA and protein levels in ovarian tissue from newborn and adult horses. Expression of mRNA was analysed by reverse transcription polymerase chain reaction, whereas FSHR protein was visualised by immunohistochemistry (IHC), immunofluorescence labelling (IF) and western blot. FSHR mRNA was detected in ovarian follicles and luteal tissue from adult mares, as well as in the ovaries of neonates. Follicular growth up to 4mm in diameter was already p...
Betteridge KJ.Carl Hartman's title of 47 years ago is invoked in tribute to his first recovery of a bovine embryo 30 years before that, and his legacy of an emphasis on the value of descriptive and comparative studies in reproductive biology. The horse's qualification as a farm animal has waned since those times but, in a conference understandably dominated by research in ruminants and pigs, there are lessons to be learned from some peculiarities of equine embryonic development. Morphological and physiological features of the conceptus and its interaction with its environment during the first month of pregn...
Allen WR, Wilsher S, Stewart F, Stewart F, Ousey J, Ousey J, Fowden A.Within-breed artificial insemination and between-breed embryo transfer were carried out in small pony (P) and large Thoroughbred (Tb) mares to create 4 types of horse pregnancy in which the fetus experienced spatial and nutritional deprivation (Tb-in-P; n=8), luxury (P-in-Tb; n=7) or normality (Tb-in-Tb; n=7 and P-in-P; n=7) in utero. Measurement of equine chorionic gonadotrophin (eCG), total conjugated oestrogens and progestagen concentrations in serial peripheral serum samples recovered from all the mares throughout gestation showed that the amount of eCG produced during the first half of ge...
Leemans B, Gadella BM, Stout TA, Heras S, Smits K, Ferrer-Buitrago M, Claes E, Heindryckx B, De Vos WH, Nelis H, Hoogewijs M, Van Soom A.Coincubating equine gametes in the presence of procaine has been reported to facilitate in vitro fertilization, with cleavage rates exceeding 60%. We report that while procaine does trigger sperm hyperactivation, it independently induces cleavage of equine oocytes. First, we found that procaine (1-5 mM) did not facilitate stallion sperm penetration of equine oocytes but instead induced sperm-independent oocyte cytokinesis in the absence of the second polar body extrusion. Indeed, 56 ± 4% of oocytes cleaved within 2.5 days of exposure to 2.5 mM procaine regardless of sperm presence. However, t...
Valera M, Blesa F, Dos Santos R, Molina A.The length of gestation in Andalusian, or Spanish Purebred (SPB) and Arabian (AB) mares reared in Spain was analysed, based on 766 spontaneous full-term deliveries appertaining to 141 mares of SPB breed and 72 mares of AB breed in 31 breeding seasons. The data were obtained from the Yeguada Militar de Jerez de la Frontera stud farm in Cádiz, Spain. The mean length of gestation was of 336.8+/-0.48 days in the SPB mares and 340.3+/-0.63 days in AB mares. To assess the accurate prediction of time of birth the potential effect of a number of factors was investigated. The influences of the breed, ...
Yu X, Fang C, Liu L, Zhao X, Liu W, Cao H, Lv S.This study was designed to provide a basis for further understanding of the mechanism of lactation based on mRNA expression differences in milk fat between different milk yields in Kazakh horses. Total RNA was extracted from the milk fat during the peak of lactation period. A total of 310 differentially expressed genes (DEGs) were identified by comparative transcriptome analysis of the high-yield and low-yield group. These DEGs regulate lactation by participated in AMPK signaling pathway, FoxO signaling pathway, ErbB signaling pathway, VEGF signaling pathway. In addition, we performed quantita...
Slocombe JO.Aims of this study with 13 equids naturally infected with Anoplocephala perfoliata were to document (i) a critical test with a period of 48 h from treatment to necropsy to assess the efficacy of an anthelmintic against the tapeworm, (ii) the efficacy of pyrantel pamoate oral paste at 13.2 mg pyrantel base/kg body weight, and (iii) the time after treatment when fecal egg counts would best estimate the tapeworm's prevalence in a herd. Feces passed in successive 12-h periods after treatment were examined for tapeworms. At necropsy, tapeworms in equids were identified as attached to the mucosa or ...
Alghamdi AS, Foster DN, Carlson CS, Troedsson MH.Breeding-induced endometritis (BIE) in the mare is resolved by 36 hr after insemination in resistant mares. However, 10-15% susceptible broodmares fail to do so because of impaired uterine contractility between 7 and 19 hr after exposure to seminal or bacterial challenge, which reduces their fertility. Methods: Nitric oxide (NO) in uterine secretions, and expression of nitric oxide synthase (NOS) in uterine biopsies were compared between susceptible and resistant groups 13 hr after insemination. Results: Susceptible mares had a higher NO in their uterine secretions and greater inducible NOS (i...
Meyers SA, Rosenberger AE.Sperm hyaluronidase has been implicated in sperm penetration of the extracellular matrix of the cumulus oophorus and may play a crucial role in gamete interaction and fertility in mammals. The objectives of this study were to characterize the enzyme activity of equine sperm hyaluronidase and to investigate its cellular distribution. Zymography of stallion sperm plasma membrane extracts was used to identify hyaluronidase activity in protein bands. Affinity-purified polyclonal IgG raised against equine sperm hyaluronidase was used to label fresh and capacitated stallion sperm, followed by indire...
