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.
Etcharren V, Mouguelar H, Aguilar Valenciano JJ.Telocytes (TCs), a recently discovered special type of stromal cells, have been identified in many organs of many species, including the female and male reproductive system, with proposed multiple potential bio-functions such as homeostasis, immunomodulation, tissue remodeling and regeneration, embryogenesis, angiogenesis and even tumorigenesis. The aim of this study was to investigate the existence, and characteristics of telocytes in normal equine oviduct. To identify them, we used routine light microscopy, non-conventional light microscopy (NCLM), transmission electron microscopy (TEM), and...
Hedia M, Leroy JLMR, Govaere J, Van Soom A, Smits K.The application of trans-vaginal ovum pick up (OPU) and intracytoplasmic sperm injection (ICSI) is well established for commercial in vitro embryo production in horses. These assisted reproductive techniques are especially applied during the non-breeding season of the mare. However, little is known about how the health of the oocyte donor may affect the biochemical composition of the follicular fluid (FF) in small and medium-sized follicles routinely aspirated during OPU. This study aimed to investigate associations between systemic and FF concentrations of interleukin-6 (IL-6), total choleste...
Orellana-Guerrero D, Uribe-Salazar JM, El-Sheikh Ali H, Scoggin KE, Ball B, Daels P, Finno CJ, Dini P.The placenta is a temporary organ that is essential for the survival of the fetus, with a lifelong effect on the health of both the offspring and the dam. The functions of the placenta are controlled by its dynamic gene expression during gestation. In this study, we aimed to investigate the equine placental DNA methylome as one of the fundamental mechanisms that controls the gene expression dynamic. Chorioallantois samples from four (4M), six (6M), and ten (10M) months of gestation were used to map the methylation pattern of the placenta. Globally, methylation levels increased toward the end o...
Di Pietro R, Arroyo LG, Leclere M, Costa M.Bacterial imbalances are observed in intestinal diseases and fecal microbiota transplantation (FMT) has been used to restore the intestinal microbiota of horses. However, there is evidence that the current methods proposed for FMT in horses have limited efficacy. The objective of this study was to concentrate the bacteria present in the donor stool by centrifugation, and to test the effect in horses with antibiotic-induced dysbiosis. One healthy 11-year-old horse was selected as a fecal donor and 9 horses were given trimethoprim sulfadiazine (TMS) for 5 days to induce dysbiosis. Horses receive...
Angel-Velez D, Meese T, Hedia M, Fernandez-Montoro A, De Coster T, Pascottini OB, Van Nieuwerburgh F, Govaere J, Van Soom A, Pavani K, Smits K.In the last decade, in vitro embryo production in horses has become an established clinical practice, but blastocyst rates from vitrified equine oocytes remain low. Cryopreservation impairs the oocyte developmental potential, which may be reflected in the messenger RNA (mRNA) profile. Therefore, this study aimed to compare the transcriptome profiles of metaphase II equine oocytes vitrified before and after in vitro maturation. To do so, three groups were analyzed with RNA sequencing: (1) fresh in vitro matured oocytes as a control (FR), (2) oocytes vitrified after in vitro maturation (VMAT), a...
Martin-Pelaez S, Rabow Z, de la Fuente A, Draheim P, Loynachan A, Fiehn O, Meyers S, Lyman C, Dini P.Postmortem and pre-euthanasia oocyte retrieval provides the last opportunity to preserve the genetic material in mares. Pentobarbital (PB) is the most common euthanasia agent; however, its effect on the developmental competence of oocytes has not been determined. Here, we evaluated the concentration of PB in equine follicular fluid (FF) and investigated its effect on the developmental competence of oocytes using a bovine IVF model to overcome the low availability of equine oocytes. The concentration of PB was measured by gas-chromatography/mass-spectrometry in FF collected from mare ovaries im...
Alpoim-Moreira J, Szóstek-Mioduchowska A, Słyszewska M, Rebordão MR, Skarzynski DJ, Ferreira-Dias G.Endometrosis negatively affects endometrial function and fertility in mares, due to excessive deposition of type I (COL1) and type III (COL3) collagens. The pro-fibrotic transforming growth factor (TGF-β1) induces myofibroblast differentiation, characterized by α-smooth muscle actin (α-SMA) expression, and collagen synthesis. In humans, fibrosis has been linked to epigenetic mechanisms. To the best of our knowledge, this has not been described in mare endometrium. Therefore, this study aimed to investigate the in vitro epigenetic regulation in TGF-β1-treated mare endometrial fibroblasts an...
Istanbullugil FR, Risvanli A, Salikov R, Bayraktar M, Kadiraliyeva N, Zhunushova A, Yilmaz O, Yuksel BF, Turanli M, Uz M, Asinbekovic MI.Immune compatibility between mare and foal is one of the important topics of reproductive immunology. At this point, although there are many studies on antibodies, there are not many publications on the relationship between the cytokine levels of mare, foal and milk and the effects of milk composition on this relationship. Here we investigate the relationship between Th1/Th2 cytokine balance and milk composition in Kyrgyz mares and foals. Samples were taken soon after the foal was born and on days 5, 10 and 20 after birth. Th1 (IFN-γ, IL-2, TNF-α) and Th2 (IL-4, IL-5, IL-10) cytokine levels ...
Medica AJ, Lambourne S, Aitken RJ.This study aimed to determine whether an analysis of stallion ejaculate could accurately predict the likelihood of pregnancy resulting from artificial insemination in mares. This study involved 46 inseminations of 41 mares, using 7 standardbred stallions over a 5-week period at an Australian pacing stud. Semen quality was assessed immediately after collection and again after chilling at ~5 °C for 24 h. The assessment involved evaluating ejaculate volume, sperm concentration, and motility parameters using an iSperm® Equine portable device. After the initial evaluation, a subpopulation of cell...
de Moura TCM, Arruda LCP, Cahú TB, Bezerra RS, Carneiro GF, Guerra MMP.Semen cryopreservation ensures the storage of stallion genetics for an unlimited time. The improvement of extenders with new antioxidant substances can optimize the properties of post-thawed semen. The study aimed to investigate the addition effect of medium-molecular-weight carboxymethylchitosan (CQm) derivates to freezing diluent of stallion sperm after freezinf/thawing. Twice a week, five ejaculates of four stallions were obtained, totalizing 20 ejaculates. Semen was diluted in commercial freezing extender (Botucrio) supplemented with CQm: control (0), 0.75, 1.5, and 3 mg/mL. Samples were ...
Scarlet D, Malama E, Fischer S, Knutti B, Bollwein H.Persistent breeding-induced endometritis (PBIE) is a major cause of subfertility in horses and the susceptibility is increased by several factors. The aim of this study was to determine the effects of clinical uterine findings and PBIE therapies, respectively, on pregnancy rate in mares. The analysis included records from 220 mares (390 cycles) inseminated at an artificial insemination (AI) center in Switzerland. Gynecological examinations were performed repeatedly before and after AI to determine cervical tone, uterine edema, and intrauterine fluid accumulation. Pregnancy rate was lower (p < ...
Silva GF, Cunha R, Carvalho F, Ribeiro M, Rocha A, Amorim I, Guimarães T.A 30-year-old Lusitano stallion presented with an enlarged right epididymis. The ultrasound scan revealed a cyst-like formation and the histopathological examination was compatible with epididymal cyst located at the body/tail transition, epididymal spermatocele and sperm granuloma and epididymitis. However, these conditions did not seem to affect the animal's reproductive performance, nor did the semen parameters analyzed over the 8 years after the diagnosis show significant changes. Nevertheless, since the ejaculate contains mostly sperm cells from the tail of the epididymis, where fertile s...
Ginther OJ.Examples of research discoveries and first reports on mare reproduction by the O.J. Ginther team are (1) determined daily circulating concentrations of four hormones during the estrous cycle, (2) showed that mares can be induced to ovulate and superovulate by hormone treatment during both ovulatory and anovulatory seasons, (3) demonstrated that prostaglandin F2α was the luteolysin in mares, (4) described the mare's elaborate hormonal and biochemical mechanism for selecting the ovulatory follicle from a pool of like follicles, (5) developed the method for diagnosing fetal sex by Day 60 using l...
Tyrnenopoulou P, Fthenakis GC.Antibiotic administration is a standard therapeutic practice for the treatment of reproductive disorders of equids. This might lead to undesirable microbial imbalance and could favour the acquisition of antibiotic resistance. Therefore, it is imperative for clinicians to understand patterns of antibiotic resistance when considering and developing treatment regimes. Continued engagement of clinicians with novel alternative approaches to treat reproductive infections would be essential in order to address this rising threat within the One Health perspective. The objectives of the present review ...
Alim S, Laitaoja M, Pawar SS, Talluri TR, Jänis J, Swamy MJ.Major proteins of the seminal plasma in a variety of mammals such as bovine PDC-109, equine HSP-1/2, and donkey DSP-1 contain fibronectin type-II (FnII) domains and are referred to as FnII family proteins. To further our understanding on these proteins, we carried out detailed studies on DSP-3, another FnII protein of donkey seminal plasma. High-resolution mass-spectrometric studies revealed that DSP-3 contains 106 amino acid residues and is heterogeneously glycosylated with multiple acetylations on the glycans. Interestingly, high homology was observed between DSP-1 and HSP-1 (118 identical r...
Górecka-Bruzda A, Jaworska J, Stanley CR.In captivity, intact male horses, due to their sexual drive, are usually socially isolated from other horses. This lifestyle strongly contrasts with that experienced by horses living in free-roaming, feral, or semi-feral conditions, where adult stallions have several roles in their social group, with successful reproduction being their primary drive. Reproductive skew in wild populations is high; many stallions will fail to reproduce at all, while others achieve high levels of reproductive success, siring a large number of foals. Successful stallions are those with particular characteristics a...
Masuda M, Nikadori A, Nikadori E, Uchida N, Takizawa Y, Ishimaru M, Yamamoto T, Yuasa R, Kugai H, Nagahama Y, Takasu M, Tozaki T.The Miyako horse is a native Japanese horse breed. As with other native Japanese horses, the number of Miyako horses decreased due to mechanization and motorization, which reduced their roles, with just 14 in 1980. Although their population had increased to 55 horses by 2021, a further increase in their numbers is required to avoid extinction. Recently, their breeding has involved natural mating during group grazing; therefore, pedigree management has been difficult, and individual identification has been inconclusive. With the aim of formulating an effective breeding plan, this study used mic...
Cortez JV, Hardwicke K, Cuervo-Arango J, Grupen CG.The cloning of horses is a commercial reality, yet the availability of oocytes for cloned embryo production remains a major limitation. Immature oocytes collected from abattoir-sourced ovaries or from live mares by ovum pick-up (OPU) have both been used to generate cloned foals. However, the reported cloning efficiencies are difficult to compare due to the different somatic cell nuclear transfer (SCNT) techniques and conditions used. The objective of this retrospective study was to compare the in vitro and in vivo development of equine SCNT embryos produced using oocytes recovered from abatt...
Jhamb D, Talluri TR, Sharma S, Juneja R, Nirwan SS, Yadav D, Pargi KK, Tanwar A, Kumar P, Kumar R, Mehta SC, Parashar M, Gaur M.Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. One of the reason for this diminished quality is osmotic stress that spermatozoa experiences during freezing and thawing process. The aim of the present study was to evaluate the cryoprotective effect of trehalose on stallion sperm quality and field fertility rates subjected to cooling and freeze-thawing process. Semen samples were collected from six Marwari breed stallions, divided into three different treatments in a final concentration of 150 × 106 sperm/mL by using Lactose based extender containing...
Diel de Amorim M, Dong L, Byron M, Foster RA, Klein C, Saleh M, Saleh T, Card C.Oxytocin is a hormone with functions in: reproduction, maternal bonding, milk ejection, and feeding/social behavior, and is reported to be present in a variety of tissues. Our goal is to characterize oxytocin and leucyl and cystinyl aminopeptidase (LNPEP/oxytocinase), a key regulator of oxytocin in mares. We measured serum and tissue LNPEP by ELISA from ovulation (D0) until D21-22 in non-pregnant (n = 5) and pregnant mares (n = 6); and in periparturient and postpartum mares (n = 18). Placenta (n = 7) and homogenized tissue of diestrus mares (n = 6) were evaluated using prot...
McCue PM, Matthews PM, Prell MJ, Bellone RR, Allen H.Genetic testing is required for the registration of foals of most equine breeds. Objective: To describe two clinical cases of marked delayed embryonic development or delayed fertilisation in pregnancies generated by embryo transfer. Methods: Case report. Methods: Donor mares were inseminated with semen from one stallion during one oestrous cycle and semen from a different stallion on the subsequent oestrous cycle. Embryo(s) were collected 8 days after ovulation during the second oestrous cycle and transferred into synchronised recipient mares. Genetic testing was performed to determine paren...
Gerber V, Kaiser-Thom S, Oesch S.Equine pastern dermatitis (EPD) is a nonspecific cutaneous reaction pattern on the distal extremities, typically in the palmar/plantar area of the pastern. Although EPD is commonly seen in equine practice and can be a debilitating condition, peer-reviewed original studies on many aspects of this multifactorial syndrome are still scarce. This narrative review aims to give an overview of the clinical presentation (forms of EPD and clinical scores and differential diagnoses), risk factors, and therapeutic approaches. The emphasis is on intrinsic and extrinsic risk factors as most of the original ...
Delivery is not easily predictable in horses and the consequences of dystocia can be serious for both the mare and foal. An induction protocol with low doses of oxytocin has been reported as a safe procedure. This study investigates the effect of induced delivery on at-term mares' sympathetic-vagal balance. Fourteen mares were included and divided into two groups, one subjected to spontaneous delivery (SD), and one to induced delivery (ID). In both groups, an ECG was recorded using an elastic belt with integrated smart textile electrodes. The recording started before the delivery (Basal), cont...
Aucamp J, van der Zwan H, Geldenhuys Z, Abera A, Louw R, van der Sluis R.In animal breeding, a species sex can influence the value of the animal. For example, in the horse breeding industry, mares are preferred as polo horses, while in wildlife breeding males with larger horns are more valuable. Therefore, the economic advantages of knowing the unborn fetus' sex are important to successful animal management. Ultrasonography is used to determine the sex of unborn fetuses, but this method places additional stress on the animal and require specialized equipment and expertise. Conversely, molecular-based sexing techniques require less invasive sampling and can determin...
Hensel B, Jakop U, Schmicke M, Schröter F, Jung M, Schulze M.Artificial insemination (AI) is commonly used in the equine industry to enhance the genetic value in breeding programs and to effectively utilize ejaculates. Many stallions are used as breeding stallions as well as in high-level sports competitions to improve their market value. The goal of the present study was to investigate whether this dual use of stallions influences the animals´ stress levels and/or the quality of their ejaculates. For this purpose, 18 stallions were grouped into two categories: breeding stallions with (BSC = breeding stallion competition), and breeding stallions with...
Fedorka CE, Ali HE, Troedsson MHT.Galectins are proteins that bind to glycans in targeted cells and function in cell-to-cell signaling throughout the body. Galectins have been found to be involved in various reproductive processes, including placental dysfunction, but this has not been investigated in the horse. Therefore, the objective of this study was to assess alterations in galectin expression of the abnormal placenta in pregnant mares. Next-generation RNA sequencing was performed on the postpartum chorioallantois of two placental pathologies following clinical cases of ascending placentitis (n = 7) and focal mucoid place...
Ellerbrock M, Wehrend A.In horses, birth is classified as dystocia when the process of parturition threatens to inflict damage onto the mare or the foal, when assistance is required to complete the process of parturition, or when there are temporal deviations in the physiological duration of the first and/or second parturition stages. In this, the duration of the second stage is an important indicator in identifying dystocia, as this phase is easily discernible by the mare's behavior. Equine dystocia is classified as an emergency with life-threatening consequences for mare and foal. A large degree of variation has be...
Hernández-Avilés C, Ramírez-Agámez L, Pearson M, Beckham AMN, Varner DD, Love CC.Analysis of sperm morphology is an important part of the stallion breeding soundness evaluation since it provides an objective measure of a stallion's sperm quality and is one of many factors that estimate a stallion's fertility potential. To describe the effect of sperm quality level on the technique (Differential Interference Contrast - DIC; Phase-contrast - PH; Dip-Quick staining - DQ; and eosin-nigrosin staining - EN; semen samples fixed in buffered-formal saline) and evaluator (three evaluators; using only DIC), stallions were categorized based on sperm quality into three categories: High...
Persistent post-breeding induced endometritis (PPBIE) is considered a major cause of subfertility in mares. It consists of persistent or delayed uterine inflammation in susceptible mares. There are many options for the treatment of PPBIE, but in this study, a novel approach aimed at preventing the onset of PPBIE was investigated. Stallion semen was supplemented with extracellular vesicles derived from amniotic mesenchymal stromal cells (AMSC-EVs) at the time of insemination to prevent or limit the development of PPBIE. Before use in mares, a dose-response curve was produced to evaluate the eff...
Goetting-Minesky MP, Makova KD.In mammals, males undergo a greater number of germline cell divisions compared with females. Thus, the male germline accumulates more DNA replication errors, which result in male mutation bias-a higher mutation rate for males than for females. The phenomenon of male mutation bias has been investigated mostly for rodents and primates, however, it has not been studied in detail for other mammalian orders. Here we sequenced and analyzed five introns of three genes (DBX/DBY, UTX/UTY, and ZFX/ZFY) homologous between X and Y chromosomes in several species of perissodactyls (horses and rhinos) and of...
Stothart MR, Greuel RJ, Gavriliuc S, Henry A, Wilson AJ, McLoughlin PD, Poissant J.Studies of microbiome variation in wildlife often emphasize host physiology and diet as proximate selective pressures acting on host-associated microbiota. In contrast, microbial dispersal and ecological drift are more rarely considered. Using amplicon sequencing, we characterized the bacterial microbiome of adult female (n = 86) Sable Island horses (Nova Scotia, Canada) as part of a detailed individual-based study of this feral population. Using data on sampling date, horse location, age, parental status, and local habitat variables, we contrasted the ability of spatiotemporal, life history...
Petersen MR, Skive B, Christoffersen M, Lu K, Nielsen JM, Troedsson MH, Bojesen AM.Endometritis in horses caused by Streptococcus equi subspecies zooepidemicus (S. zooepidemicus) may be underdiagnosed due to traditional diagnostic methods lacking sensitivity and specificity. We serendipitously identified a bacterial growth medium (bActivate) that appeared capable of inducing growth of dormant S. zooepidemicus, which subsequently allowed detection by standard diagnostics. To assess the effect of bActivate we compared its ability to activate dormant S. zooepidemicus in a group of potentially infected subfertile mares with phosphate-buffered saline (PBS). All mares had to test ...
Morris GJ, Faszer K, Green JE, Draper D, Grout BW, Fonseca F.The cellular damage that spermatozoa encounter at rapid rates of cooling has often been attributed to the formation of intracellular ice. However, no direct evidence of intracellular ice has been presented. An alternative mechanism has been proposed by Morris (2006) that cell damage is a result of an osmotic imbalance encountered during thawing. This paper examines whether intracellular ice forms during rapid cooling or if an alternative mechanism is present. Horse spermatozoa were cooled at a range of cooling rates from 0.3 to 3,000 degrees C/min in the presence of a cryoprotectant. The ultra...
Klein C.Maintenance of pregnancy is dependent on the exchange of signals between the conceptus and the endometrium. The objective of this study was to use next-generation sequencing to determine transcriptome blueprints of the conceptus and endometrium 16 days after ovulation in the horse. There were 7760 and 10 182 genes expressed in the conceptus and endometrium, respectively, of which 7029 were present in both. Genes related to developmental processes were enriched among conceptus-specific transcripts, whereas many endometrium-specific genes had known roles in cell communication, cell adhesion and ...
Raudsepp T, Durkin K, Lear TL, Das PJ, Avila F, Kachroo P, Chowdhary BP.Male-to-female 64,XY sex reversal is a frequently reported chromosome abnormality in horses. Despite this, the molecular causes of the condition are as yet poorly understood. This is partially because only limited molecular information is available for the horse Y chromosome (ECAY). Here, we used the recently developed ECAY map and carried out the first comprehensive study of the Y chromosome in XY mares (n=18). The integrity of the ECAY in XY females was studied by FISH and PCR using markers evenly distributed along the euchromatic region. The results showed that the XY sex reversal condition...
Bressan FF, Bassanezze V, de Figueiredo Pessôa LV, Sacramento CB, Malta TM, Kashima S, Fantinato Neto P, Strefezzi RF, Pieri NCG, Krieger JE....Induced pluripotent stem cells (iPSCs) have enormous potential in developmental biology studies and in cellular therapies. Although extensively studied and characterized in human and murine models, iPSCs from animals other than mice lack reproducible results. Herein, we describe the generation of robust iPSCs from equine and bovine cells through lentiviral transduction of murine or human transcription factors Oct4, Sox2, Klf4, and c-Myc and from human and murine cells using similar protocols, even when different supplementations were used. The iPSCs were analyzed regarding morphology, gene and...
LaPolt PS, Tilly JL, Aihara T, Nishimori K, Hsueh AJ.The actions of gonadotropins on ovarian differentiation are associated with dynamic changes in gonadotropin receptor content, presumably due to modulation of receptor gene expression. The present studies used a reverse transcription-polymerase chain reaction to obtain a rat FSH receptor cDNA fragment, followed by synthesis of a labeled cRNA probe to examine the regulation of FSH receptor mRNA levels during follicular maturation, ovulation, and luteinization. Northern blot analysis of ovarian RNA with the FSH receptor probe revealed two predominant hybridization signals of 7.0 and 2.5 kilobases...
Ferris RA, McCue PM, Borlee GI, Glapa KE, Martin KH, Mangalea MR, Hennet ML, Wolfe LM, Broeckling CD, Borlee BR.Bacteria in a biofilm community have increased tolerance to antimicrobial therapy. To characterize the role of biofilms in equine endometritis, six mares were inoculated with -engineered strains isolated from equine uterine infections. Following establishment of infection, the horses were euthanized and the endometrial surfaces were imaged for luminescence to localize adherent -labeled bacteria. Samples from the endometrium were collected for cytology, histopathology, carbohydrate analysis, and expression of inflammatory cytokine genes. Tissue-adherent bacteria were present in focal areas bet...
Szóstek-Mioduchowska AZ, Baclawska A, Okuda K, Skarzynski DJ.Equine endometrosis (endometrial fibrosis) is a degenerative chronic process that occurs in the uterus of the mare and disturbs proper endometrial function. Fibrosis is attributed to excessive deposition of extracellular matrix (ECM) components. The turnover of ECM is mediated by matrix metallopeptidases (MMP). Previously, it was shown that cytokines modulate MMP expression in other tissues and may regulate fibrosis indirectly by attracting inflammatory cells to the site of inflammation and directly on various tissues. However, the regulation of MMP expression in equine endometrosis is still r...
Donadeu FX, Schauer SN.Relatively little is known about the physiological roles of microRNAs (miRNAs) during follicular development. Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to gain insight on the involvement of these miRNAs during follicle maturation. Follicular fluid was aspirated from dominant follicles (>32 mm) during the ovulatory season (July to October) and the anovulatory season (January to M...
Clérico G, Taminelli G, Veronesi JC, Polola J, Pagura N, Pinto C, Sansinena M.Oocyte vitrification is considered experimental in the horse with only three live foals reported. The oxidative conditions induced by vitrification could in part explain the poor results and melatonin, a powerful antioxidant, could stimulate ROS metabolization and restore mitochondrial function in these oocytes. Our objective was to determine the oxidative status of vitrified equine oocytes and to analyze the effect of melatonin on mitochondrial-specific ROS (mROS), oocyte maturation, ICSI embryo development and viability. Immature, abattoir-derived oocytes were held for 15 h and vitrified in...
Neves ES, Chiarini-Garcia H, França LR.The mule (Equus mulus mulus) is a sterile hybrid domestic animal that results from the breeding of a male donkey (Equus asinus) to a female horse (Equus caballus). Usually, spermatogenesis in mules does not advance beyond spermatocytes. In the present study, we performed a comparative and more accurate morphometric and functional investigation of the testis in donkeys and mules. Due to the smaller testis size, lower seminiferous tubule volume density, and fewer germ cells, the total length of seminiferous tubules in mules was significantly smaller than in donkeys. However, the percentage of se...
Smits K, De Coninck DI, Van Nieuwerburgh F, Govaere J, Van Poucke M, Peelman L, Deforce D, Van Soom A.Although the equine oviduct clearly affects early embryo development and the selective transport of equine embryos through the oviduct indicates a reciprocal interaction, the influence of the embryo on gene expression in the oviduct remains to be determined in the horse. The aim of this study was to examine this by means of RNA sequencing. Four days after ovulation, epithelial cells ipsilateral and contralateral to the ovulation side from five cyclic and five pregnant mares were collected from the oviduct. RNA was extracted, samples were sequenced, and data analysis was performed to determine ...
Hurtgen JP.Inflammatory conditions of the uterus, collectively known as endometritis, can be classified as acute, chronic, active, or subclinical. This condition causes substantial reductions in mare fertility. To diagnose and treat mares with endometrial inflammation, it is imperative to identify predisposing factors and challenges to the reproductive tract of the mare in a chronological order; these factors change from those of the young maiden filly to the older, multiparous broodmare. This paper addresses predisposing factors, diagnostic procedures and therapy strategies for different mare groups.
Troedsson MH.Endometritis is a common cause of infertility in broodmares. In the past, the condition was believed to be exclusively the result of bacterial contamination of the uterus. Treatment strategies were focused on preventing bacteria from entering the uterus and on treating mares with signs of endometritis with antibiotics. More recent research on uterine defense mechanisms has increased our understanding of the pathophysiology of equine endometritis. Additional causative agents have been identified, and we have learned to separate uterine infections and a physiologic breeding-induced endometritis ...
Aurich C, Spergser J.This study investigated effects of bacteria from the genital tract of horses and the effect of gentamicin in semen extender on spermatozoal function in cooled-stored stallion semen. Semen was collected from healthy stallions and processed with a milk-based extender with or without gentamicin (1g/l). Pseudomonas (Ps.) aeruginosa, Staphylococcus (St.) aureus, Streptococcus (Sc.) equi subsp. equi (Sc. equi), Sc. equi subsp. zooepidemicus (Sc. zooepidemicus), Sc. dysgalactiae subsp. equisimilis (Sc. equisimilis) or culture medium alone (control) were added. Immediately after addition of bacteria a...
Sartori Blanc N, Senn A, Leforestier A, Livolant F, Dubochet J.In human and other mammal sperm nuclei, DNA is packed in a highly condensed state, the structure of which remains unsolved. Cryoelectron microscopy of vitrified sections provides a first direct view of the local arrangement of the nucleoprotamine filament. DNA aligns in parallel in layers and its orientation rotates along a single-twist direction as in a cholesteric liquid crystal. The structure contains numerous defects, which introduce locally double-twist configurations. Destruction of the SS bonds with dithiotrehitol relaxes the twist and favors the extension of the hexagonal close packing...
Berger J.Much evidence now suggests that the postnatal killing of young in primates and carnivores, and induced abortions in some rodents, are evolved traits exerting strong selective pressures on adult male and female behaviour. Among ungulates it is perplexing that either no species have developed convergent tactics or that these behaviours are not reported, especially as ungulates have social systems similar to those of members of the above groups. Only in captive horses (Equus caballus) has infant killing been reported. It has been estimated that 40,000 wild horses live in remote areas of the Great...
Timoney PJ, McCollum WH, Murphy TW, Roberts AW, Willard JG, Carswell GD.The carrier state has been confirmed virologically in Thoroughbred and non-Thoroughbred stallions naturally infected with equine arteritis virus (EAV). Short-term or convalescent and long-term carriers occur. The frequency rate of the long-term carrier state in Thoroughbreds was high, averaging 33.9% among the three groups of stallions under study. While the convalescent carrier state only lasted a few weeks after clinical recovery, the long-term carrier state could persist for years. There was evidence, however, that not all such carriers might remain persistently infected for life. Carrier s...
Dobrinski I, Smith TT, Suarez SS, Ball BA.Interaction of equine spermatozoa with oviductal epithelial cells (OEC) prolongs sperm viability and maintains low intracellular calcium concentration ([Ca2+]i) in spermatozoa. Experiments were designed to investigate 1) whether release of spermatozoa from OEC in vitro is associated with elevated [Ca2+]i and 2) whether soluble products from OEC or direct membrane contact between spermatozoa and OEC mediates the effects of OEC on sperm [Ca2+]i. In the first experiment, changes in [Ca2+]i in spermatozoa loaded with indo-1 acetoxymethylester were determined in motile spermatozoa released from OEC...
Roser JF.It is well established in many mammalian species, including the horse that normal testicular function is dependent upon a functional hypothalamic-pituitary-testicular (HPT) axis, which involves classic feedback mechanisms. The major HPT hormones involved in the stallion are gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone (T), estrogens (Es) and inhibin (INH). Although prolactin (PRL) fluctuates with season in the stallion and both PRL and thyroid hormone (TH) affect reproduction in other male species, their effects on stallion r...
Gonzales DS, Jones JM, Pinyopummintr T, Carnevale EM, Ginther OJ, Shapiro SS, Bavister BD.The behaviour of bovine, equine and human blastocysts was studied in vitro by time-lapse videomicrography and computer imaging. This study revealed that cytoplasmic extensions of the trophectoderm ['trophectoderm projections' (TEP)] were expressed by embryos of all three species, prior to or during zona escape. Bovine and human blastocysts escaped their zonae with a combination of blastocoele expansion, collapse and re-expansion coupled with the penetration of the zona pellucida by TEP. In equine embryos, after several cycles of blastocoele expansion and collapse, trophectoderm ruptured the zo...
Li B, He X, Zhao Y, Bai D, Du M, Song L, Liu Z, Yin Z, Manglai D.Horse testis development and spermatogenesis are complex physiological processes. To study these processes, three immature and three mature testes were collected from the Mongolian horse, and six libraries were established using high-throughput RNA sequencing technology (RNA-Seq) to screen for genes related to testis development and spermatogenesis. A total of 16,237 upregulated genes and 8,641 downregulated genes were detected in the testis of the Mongolian horse. These genes play important roles in different developmental stages of spermatogenesis and testicular development. Five genes with ...
Morrell JM, Johannisson A, Dalin AM, Rodriguez-Martinez H.The objective was to investigate whether it is possible to improve the quality of stallion semen, with respect to sperm morphology and chromatin integrity, both of which have been linked to fertility, using either density gradient centrifugation (DGC) or a new method, hereby named single layer centrifugation (SLC). The two methods of colloidal centrifugation were evaluated using 38 ejaculates from 10 stallions. Sperm morphology, subjective motility and sperm chromatin integrity were compared in uncentrifuged samples and in centrifuged sperm preparations. The proportion of morphologically norma...
Stout TA, Allen WR.A growing equine conceptus must suppress the cyclical release of PGF(2 alpha) from the endometrium to effect maternal recognition of its presence in the uterus. Paradoxically, the conceptus itself secretes PGF(2 alpha), together with other prostaglandins. In this study, the PGF(2 alpha) and PGE(2) content of, and production in vitro by, day 10-32 equine conceptuses were measured and the influence of pregnancy on the concentrations of these prostaglandins in the uterine lumen was examined. In vitro, the release of both prostaglandins per mg conceptus tissue was very high on day 10 after ovulati...
Manteca Vilanova X, De Briyne N, Beaver B, Turner PV.Collection of blood from pregnant mares for extraction of equine chorionic gonadotropin (eCG) is a critical but relatively unknown and poorly regulated practice in the countries in which it occurs. Equine chorionic gonadotropin is a hormone that is widely used to enhance reproductive performance and management of dairy and beef cattle, sheep, goats, and pigs kept under intensive housing systems. eCG is extracted from the blood of brood mares between days 40-120 of gestation. Although alternatives have been sought, there is currently no efficacious replacement, natural or synthetic, for eCG. Re...
Burnaugh L, Sabeur K, Ball BA.Low-level production of the superoxide anion (O2*-) is an important signal transduction event in sperm function including capacitation; however, excessive production of O2*- can be detrimental to sperm function. The objective of this study was to assess dihydroethidium (DHE) as a probe for O2*- in equine spermatozoa. Ejaculated spermatozoa were separated by centrifugation over a Percoll gradient (40:80), and loaded with DHE (2.0 microM) as well as with calcein-acetoxymethylester (CAM, 7.8 nM) to determine cell viability. In Experiment 1, cells were incubated with the xanthine-xanthine oxidase ...
