Stallions are adult male horses that have not been gelded and are often used for breeding purposes. They exhibit distinct behavioral and physiological characteristics compared to mares and geldings. Stallions are known for their strong musculature, prominent neck, and often more pronounced mane and tail. Their behavior can be more aggressive and territorial, especially during the breeding season, as they naturally compete for mating opportunities. This topic explores the anatomy, behavior, and management practices specific to stallions, as well as their role in equine reproduction. The page provides access to peer-reviewed research studies and scholarly articles that investigate various aspects of stallion health, fertility, and behavior, contributing to the understanding and management of these horses in equine science.
Scholtz M, Guthrie AJ, Newton R, Schulman ML.Three bacteria extensively acknowledged as venereal pathogens with the potential to induce endometritis include Taylorella equigenitalis, the causative agent of contagious equine metritis (CEM), specific strains of Pseudomonas aeruginosa, and certain capsule types of Klebsiella pneumoniae. The United Kingdom's Horserace Betting Levy Board recommends pre-breeding screening for these bacteria in their International Codes of Practice and >20 000 samples are tested per annum in the United Kingdom alone. While the pathogenesis and regulatory importance of CEM are well established, an evaluation...
Jung H, Yoon M.Spermatogonial stem cells originate from gonocytes and undergo self-renewal and differentiation to generate mature spermatozoa via spermatogenesis in the seminiferous tubules of the testis in male mammals. Owing to the unique capacity of these cells, the spermatogonial stem cell transplantation technique, which enables the restoration of male fertility by transfer of germlines between donor and recipient males, has been developed. Thus, spermatogonial stem cell transplantation can be used as an important next-generation reproductive and breeding tool in livestock production. However, in large ...
Doyle JL, Egan S, Berry DP.Many sport horse studbooks worldwide use microsatellite markers for parentage verification. However, many have expressed a desire to introduce genomic selection using genome-wide dense single nucleotide polymorphism (SNP) genotypes to complement their current breeding programmes. Hence, it does not make sense to genotype the same animal for both microsatellite markers and SNP markers. Transitioning to SNP-based parentage verification is an obvious solution but one barrier to this transition is the lack of SNP data on parents from which to verify parentage against. Therefore, the objective of t...
Uchida-Fujii E, Kato Y, Ueno T, Numasawa Y, Yusa S, Haga T.Equus caballus papillomavirus 2 (EcPV2) is known to cause genital neoplasms in horses. However, reports on EcPV2 in Japan and Asia are limited. Herein, we present the histopathological and virological findings of the first reported case of an EcPV2-associated penile mass in Japan. The patient was a 22-year-old stallion with a history of breeding in Japan and abroad. Histopathological examination contained RNA in situ hybridization targeting the E6/E7 region and an immunohistochemical approach, and whole-genome sequencing was conducted within the viral examination. Proliferating epidermal cells...
Ing NH, Konganti K, Ghaffar N, Johnson CD, Forrest DW, Love CC, Varner DD.Males of some species, from horses to humans, require medical help for subfertility problems. There is an urgent need for novel molecular assays that reflect spermatozoal function. In the last 25 years, studies examined RNAs in spermatozoa as a window into gene expression during their development and, more recently, for their functions in early embryo development. In clinics, more dense spermatozoa are isolated by density gradient centrifugation before use in artificial insemination to increase pregnancy rates. The objectives of the current study were to discover and quantify the microRNAs i...
Kapusniak A, Nath L, Hebart M, Franklin S.Sudden cardiac death (SCD) is an important cause of exercise-associated fatalities in Thoroughbred racehorses. Equine deaths share similarities with fatalities in human athletes that result from inherited cardiac disease. Whilst genetic causes have been postulated in horses, these have not been confirmed and heritability of SCD has not previously been estimated in Thoroughbred racehorses. Objective: To determine the heritability of SCD in a sample population of Thoroughbred racehorses. Methods: Retrospective case-control study. Methods: Steward and post-mortem reports of Thoroughbred racehorse...
Núñez-Montero K, Leal K, Rojas-Villalta D, Castro M, Larronde C, Wagenknecht L, Contreras MJ.Studies on the bacterial composition of seminal samples have primarily focused on species isolated from semen and their effects on fertility and reproductive health. Culture-independent techniques, such as 16S rRNA gene sequencing and shotgun metagenomics, have revolutionized our ability to identify unculturable bacteria, which comprise >90% of the microbiome. These techniques allow for comprehensive analysis of microbial communities in seminal samples, shedding light on their interactions and roles. In this study, we characterized the taxonomic diversity of seminal microbial communities in he...
Nunes MM, Gurgel JRC, Munhoz ML, de Giuli V, Carneiro GF, Miragaya MH, Gallelli MF, Guimaraes JD.The aim of this study was to assess the effect of lyophilized freezing extenders, which can be stored at room temperature, on stallion post-thaw sperm total motility (TM). Ejaculates of 28 stallions were frozen with four different extenders: two commercial freezing extenders offered worldwide and two novel lyophilized extenders (STAR and MX3), and two different cryopreservation protocols (CP1 with an equilibration period of 20 min. and CP2 with an equilibration period of 60 min.). The TM was assessed after thaw. Mean TM did not show significant differences between cryopreservation protocols wi...
Khorsand F, Hamali H, Qasemi-Panahi B, Tohidkia M.This study evaluated the effects of supplementation of the freezing extender with different concentrations of silymarin on the quality of frozen-thawed Arabian stallion spermatozoa. Semen samples from three stallions (1, 2, and 3) were suspended in the freezing extender without or with silymarin (0, 25 μg/mL, 50 μg/mL, 75 μg/mL, and 100 μg/mL) and cryopreserved in 0.5 mL straws. After 1 month of storage, the frozen semen samples in straws were thawed and evaluated in terms of viability, mitochondrial membrane potential, kinematic parameters, total and progressive motility, plasma membrane ...
Grabatin M, Fux R, Zablotski Y, Goehring LS, Witte TS.Contagious equine metritis (CEM) is caused by Taylorella equigenitalis. It is a venereal disease that is detected in some breeds more than others and can cause temporary infertility with substantial costs for regular testing, sanitation and retesting. There was a perceived increase in T. equigenitalis-positive cases in Icelandic intact males where natural cover is common. Objective: We aimed to investigate the prevalence of T. equigenitalis in Icelandic intact males and compare to draught horse and Haflinger intact males. We hypothesised that prevalence of T. equigenitalis is higher in Iceland...
Asgenbaatar N, Yi M, Wang X, Ulaangerel T, Shen Y, Wen X, Du M, Dong X, Mengkh Y, Dugarjav M, Bou G.The preparation of paraffin sections is an important experimental technique in animal histological research, and key factors that determine the quality of a section include the dehydration time, waxing time, and drying temperature of the paraffin section. Paraffin sections obtained from testis tissue of adult horses exhibited higher quality with clear tissue structure and complete cell morphology after they underwent gradient dehydration for 6 hours, were immersed in wax for 60 minutes, and were dried in a 75-degree oven for 15 minutes. The detailed, optimized procedures that are developed in ...
Hernández-Avilés C, Ramírez-Agámez L, Weintraub ST, Scoggin CF, Davis BW, Raudsepp T, Varner DD, Love CC.Thoroughbred stallions that carry a double-homozygous genotype A/A-A/A for SNPs rs397316122 and rs69101140 in exon 5 of the FKBP6 gene (chr13; EquCab3.0) are uniquely subfertile due to impaired acrosomal exocytosis (IAE). In this study, the sperm proteome in frozen/thawed semen from subfertile Thoroughbred stallions was studied and compared to that of frozen/thawed sperm from fertile Thoroughbred stallions. A total of 2,220 proteins was identified, of which 140 proteins were found to be differentially abundant in sperm from the subfertile stallions compared to that of fertile stallions (83 les...
Peña FJ, Martín-Cano FE, Becerro-Rey L, Ortega-Ferrusola C, Gaitskell-Phillips G, da Silva-Álvarez E, Gil MC.The mammalian ejaculate is very well suited to proteomics studies. As such, research concerning sperm proteomics is offering a huge amount of new information on the biology of spermatozoa. Among domestic animals, horses represent a species of special interest, in which reproductive technologies and a sizeable market of genetic material have grown exponentially in the last decade. Studies using proteomic approaches have been conducted in recent years, showing that proteomics is a potent tool to dig into the biology of the stallion spermatozoa. The aim of this review is to present an overview of...
Fuentes F, Contreras MJ, Arroyo-Salvo C, Cabrera P P, Silva M, Merino O, Arias ME, Felmer R.Although under appropriate laboratory conditions, sperm from different mammalian species can be capacitated in vitro, the optimal conditions for sperm capacitation in the stallion have been elusive. This study evaluated the effect of different capacitating inducers in Whitten and Tyrode media and assessed their impact on capacitation-related factors. Stallion sperm were incubated with different combinations of capacitating inducers at 38.5 °C in an air atmosphere. Sperm quality variables such as motility, mitochondrial membrane potential, and lipid peroxidation were assessed. Membrane fluidi...
Busechian S, Bindi F, Pieramati C, Orvieto S, Pisello L, Cozzi S, Ortolani F, Rueca F.Equine gastric ulcer syndrome (EGUS) is a worldwide disease, and includes two different syndromes, Equine Squamous Gastric Disease (ESGD), affecting the squamous mucosa, and Equine Glandular Gastric Disease (EGGD), affecting the glandular mucosa. These two diseases are present in different categories (different activities, ages, etc.) and breeds of horses. The effect of sex on gastric health is not clear: some studies found a higher prevalence of ESGD in geldings and stallions, while others found no influence of sex on the squamous mucosa. The few studies conducted on glandular diseases failed...
Steensma MJ, Doekes HP, Pook T, Derks MFL, Bakker N, Ducro BJ.In the past, small population sizes and unequal ancestor contributions have resulted in high inbreeding rates (ΔF) in the Friesian horse. Two decades ago, the studbook implemented a mating quota and started publishing individual kinships and reduced ΔF below 1% per generation. However, since then, the breeding population size has decreased and this raises the question whether current breeding strategies are sufficient to keep ΔF below desired rates. The aim of this study was to (1) reflect on past inbreeding trends and their main determinants, using pedigree analysis and (2) evaluate the ef...
Shakeel M, Yoon M.Spermatogonial stem cells (SSCs) are essential for the maintenance of male fertility and survival of species. Environmental conditions, notably heat stress, have been identified as important causes of male infertility and have a negative impact on SSCs. Animals with cryptorchid testes (CT) are optimal models for the study of long-term heat stress-related changes in germ cells. The effect of heat stress on germ cells differs depending on the spermatogenesis stage. Thus, verifying whether the specific phase of spermatogenesis is dependent or independent of heat stress in stallions is important. ...
Gibb Z, Aitken RJ, Sheridan AR, Holt B, Waugh S, Swegen A.The in vitro storage of stallion spermatozoa for use in artificial insemination leads to oxidative stress and imbalances in calcium homeostasis that trigger the formation of the mitochondrial permeability transition pore (mPTP), resulting in premature cell death. However, little is understood about the dynamics and the role of mPTP formation in mammalian spermatozoa. Here, we identify an important role for mPTP in stallion sperm Ca2+ homeostasis. We show that stallion spermatozoa do not exhibit "classical" features of mPTP; specifically, they are resistant to cyclosporin A-mediated inhibition...
Morris L, Harteveld R, Gibb Z.Insemination of mares with frozen-thawed spermatozoa requires intensive management and results in 40%-60% per cycle pregnancy rates. Objective: To determine if satisfactory fertility is possible for frozen-thawed semen after processing it through a microfluidic device, followed by storage at 17°C for up to 24 h before fixed-time insemination. Methods: Uncontrolled field trials. Methods: A pilot study evaluated the motility of frozen-thawed spermatozoa after centrifugation and storage (17°C) in two different media for up to 48 h. Subsequently, the motility of frozen-thawed semen processed...
Shakeel M, Choi Y, Yoon M.Cryptorchidism affects spermatogenesis and testis development, often resulting in stallion subfertility/infertility. This study aims to identify the specific germ cells impacted by cryptorchism in stallions. In a previous study, we found that PGP9.5 and VASA are molecular markers expressed in different germ cells within stallions. Herein, we assessed the heat stress-induced response of spermatogonial stem cells (SSCs) in the seminiferous tubules (ST) of cryptorchid stallion testes (CST) and normal stallion testes (NST). This goal was accomplished by comparing PGP9.5 and VASA expression pattern...
Artificial insemination with cooled-shipped semen is the primary method used in the equine breeding industry; yet, sperm quality and fertility can be suboptimal for some stallions when standard techniques are used. Therefore, there is a critical need to develop alternative approaches for these stallions. Objective: To assess sperm quality parameters and fertility of cooled-stored stallion semen processed by SpermFilter® or centrifugation and resuspended in three extenders. Methods: Controlled and field study. Methods: In Experiment 1, semen was collected from 21 stallions classified as having...
Mai Z, Fu H, Miao R, Lu C, Zhang X, Yuan Z, Ji P, Hua Y, Wang C, Ma Y, Deng H, Wei Y.Salmonella enterica subspecies enterica serovar abortus equi (S. abortus equi) is one of the main pathogens that causes abortion in pregnant horses and donkeys, which was highly infectious and greatly restricts the healthy development of the horse industry. Objective: In order to investigate the prevalence and biological characteristics of S. abortus equi in different regions and breeds of horses in Xinjiang. Methods: This study conducted ELISA detection of S. abortus equi antibodies on serum samples of 971 horses collected from three large-scale horse farms and five free-range horse farms in ...
Peña FJ, Martín-Cano FE, Becerro-Rey L, Ortega-Ferrusola C, Gaitskell-Phillips G, da Silva-Álvarez E, Gil MC.We are currently experiencing a period of rapid advancement in various areas of science and technology. The integration of high throughput 'omics' techniques with advanced biostatistics, and the help of artificial intelligence, is significantly impacting our understanding of sperm biology. These advances will have an appreciable impact on the practice of reproductive medicine in horses. This article provides a brief overview of recent advances in the field of spermatology and how they are changing assessment of sperm quality. This article is written from the authors' perspective, using the sta...
Malaluang P, Niazi A, Guo Y, Nagel C, Guimaraes T, Rocha A, Aurich C, Morrell JM.The microbiome plays a significant role in shaping the health and functioning of the systems it inhabits. The seminal microbiome of stallions has implications for the health of the reproductive tract, sperm quality during preservation and antibiotic use in semen extenders. Diverse bacteria are present on the external genital tract and a mix of commensal microorganisms populates various parts of the reproductive tract, influencing the seminal bacterial content. Other sources of bacteria include the environment, semen collection equipment, and personnel. The bacterial load can adversely affect s...
Al-Kass Z, Morrell JM.Artificial insemination (AI) is used frequently in the breeding of sport horses, apart from Thoroughbreds. Most AIs are carried out with cooled semen rather than frozen semen because of the difficulties in identifying a protocol that is suitable for freezing most ejaculates and the necessity to inseminate close to ovulation because of the short life of the thawed spermatozoa. More widespread use of frozen semen would improve biosecurity, allow greater choice of stallions, and offer more flexibility when managing deliveries of semen to the stud. It would even decrease the amount of antibiotics ...
Uhlmannsiek L, Shen H, Eylers H, Martinsson G, Sieme H, Wolkers WF, Oldenhof H.Cryopreserved semen is routinely shipped in liquid nitrogen. Dry ice could serve as an alternative coolant, however, frozen storage above liquid nitrogen temperatures (LN2, -196 °C) may negatively affect shelf-life and cryosurvival. In this study, we determined critical temperatures for storage of cryopreserved stallion sperm. We evaluated: (i) effects of cooling samples to different subzero temperatures (-10 °C to -80 °C) prior to storing in LN2, (ii) stability at different storage temperatures (i.e., in LN2, dry ice, -80 °C and -20 °C freezers, 5 °C refrigerator), and (iii) sperm...
Nooroozian A, Goodarzi N, Tafti RD.The present work was designed for a thorough investigation into the sperm morphology and morphometry of Kurdish stallions. The semen samples were collected from 10 Kurdish stallions. Three preparations from each ejaculate were stained with eosin-nigrosin (EN), Diff-Quik (DQ) and Rose Bengal (RB). The area, perimeter, length and width of the sperm head as well as tail length and total sperm length were measured. The parameters ellipticity, elongation, roughness and regularity were calculated. The morphology of sperm was also investigated under scanning and transmission electron microscopes. DQ ...
Pompermayer E, Ysebaert MP, Vinardell T, Oikawa MA, Jonhson JP, Fernandes T, David F.A two-year-old Arabian horse presented for abnormal external genitalia and dangerous stallion-like behavior was diagnosed with disorder of sexual development (DSD), also known as intersex/hermaphroditism. Standing 1-stage surgical procedure performed under sedation, and local anesthesia to concurrently eliminate stallion-like behavior, risk of neoplastic transformation of intraabdominal gonads, and to replace ambiguous external genital with a functional, and cosmetically more acceptable anatomy. Step-1) Laparoscopic abdominal exploration and gonadectomy; Step-2) Rudimentary penis resection and...
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...
Couroucé A, Normand C, Tessier C, Pomares R, Thévenot J, Marcillaud-Pitel C, Legrand L, Pitel PH, Pronost S, Lupo C.A total of 752 horses were involved in the CES Valencia Spring Tour 2021. Due to an equine herpesvirus-1 (EHV-1) outbreak, the competition was cancelled and the site was locked down. The objective of this study was to describe epidemiological, clinical, diagnostic, and outcome data of the 160 horses remaining in Valencia. Clinical and quantitative polymerase chain reaction (qPCR) data were analysed for 60 horses in a retrospective case-control observational study. The risk of developing clinical manifestations was explored using a logistic regression approach. EHV-1 was detected by qPCR, genot...
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...
Morrell JM, Johannisson A, Dalin AM, Hammar L, Sandebert T, Rodriguez-Martinez H.Artificial insemination is not as widely used in horses as in other domestic species, such as dairy cattle and pigs, partly because of the wide variation in sperm quality between stallion ejaculates and partly due to decreased fertility following the use of cooled transported spermatozoa. Furthermore, predictive tests for sperm fertilising ability are lacking. The objective of the present study was to assess sperm morphology and chromatin integrity in ejaculates obtained from 11 warmblood breeding stallions in Sweden, and to evaluate the relationship of these parameters to pregnancy rates to i...
Wutke S, Sandoval-Castellanos E, Benecke N, Döhle HJ, Friederich S, Gonzalez J, Hofreiter M, Lõugas L, Magnell O, Malaspinas AS, Morales-Muñiz A....Present-day domestic horses are immensely diverse in their maternally inherited mitochondrial DNA, yet they show very little variation on their paternally inherited Y chromosome. Although it has recently been shown that Y chromosomal diversity in domestic horses was higher at least until the Iron Age, when and why this diversity disappeared remain controversial questions. We genotyped 16 recently discovered Y chromosomal single-nucleotide polymorphisms in 96 ancient Eurasian stallions spanning the early domestication stages (Copper and Bronze Age) to the Middle Ages. Using this Y chromosomal t...
Cocchia N, Pasolini MP, Mancini R, Petrazzuolo O, Cristofaro I, Rosapane I, Sica A, Tortora G, Lorizio R, Paraggio G, Mancini A.New studies are underway to find new methods for supporting longer storage of cooled stallion semen. It is known that high concentrations of reactive oxygen species (ROS) cause sperm pathology. The metalloprotein superoxide dismutase (SOD) is responsible for H(2)O(2) and O(2) production, by dismutation of superoxide radicals. The aim of this study is to assess the quality of chilled stallion semen processed with extenders containing SOD at different concentrations as antioxidant additives. A total of 80 ejaculates collected from 5 standardbred stallions was divided into 5 aliquots treated as: ...
Kim JY, Jung HJ, Yoon MJ.Expression of the protein DDX4/MVH, or VASA, has been reported in germ cells of several species. The main objectives of this study were to (i) investigate VASA expression patterns in testicular cells of stallions at two different reproductive stages (pre-pubertal and post-pubertal) and (ii) evaluate the use of VASA antibody as a molecular marker for single germ cells from stallions. Testicular tissues were obtained from stallions and categorized as pre-pubertal and post-pubertal based on the formation of lumen and status of spermatogenesis on the cross section of seminiferous tubules. The resu...
Ortiz-Rodriguez JM, Anel-Lopez L, Martín-Muñoz P, Álvarez M, Gaitskell-Phillips G, Anel L, Rodríguez-Medina P, Peña FJ, Ortega Ferrusola C.Testicular function is particularly susceptible to vascular insult, resulting in a negative impact on sperm production and quality of the ejaculate. A prompt diagnosis of testicular dysfunction enables implementation of appropriate treatment, hence improving fertility forecasts for stallions. The present research aims to: (1) assess if Doppler ultrasonography is a good tool to diagnose stallions with testicular dysfunction; (2) to study the relationship between Doppler parameters of the testicular artery and those of sperm quality assessed by flow cytometry and (3) to establish cut off values ...
Murray MJ, Eichorn ES.To determine the effect of decreasing gastric acidity in a feed-deprivation protocol on induction of gastric ulcers, and to determine whether stall confinement may be a factor contributing to gastric ulceration in horses. Methods: 8 adult horses, 4 geldings and 4 mares, 3 to 8 years old, and 7 adult horses, 5 geldings and 2 mares, 4 to 11 years old. Methods: Gastric ulceration was induced in horses by alternating 24-hour periods of feed deprivation and ad libitum access to hay, for a total of 96 hours' feed deprivation. This protocol was repeated with the horses receiving the histamine type-2 ...
Sieme H, Harrison RA, Petrunkina AM.Success in cryopreserving stallion semen has been very variable. Several different freezing regimes have been published. However, because extenders and procedures used in each regime have differed, direct comparison of these techniques has been very difficult, and controlled studies comparing different techniques have not been reported. A number of different factors affect sperm cryosurvival. In this article we review briefly current cryopreservation procedures for stallion semen, and then in more detail cryobiological determinants of sperm function, and mechanisms of cryoinjury and cryoprotec...
Suh TK, Schenk JL, Seidel GE.Sexing sperm by high-speed flow cytometry subjects them to high pressure. The routine operating pressure of the MoFlo SX flow cytometer for sperm sorting for commercial production has been 50 pounds/square inch (psi), with a standard 70 microm standard nozzle tip. It was hypothesized that lowering the sorting pressure could reduce sperm damage. Therefore, a series of experiments using semen from six bulls, sorted with three MoFlo SX sorters, was conducted to determine optimal pressure. An additional experiment was done with stallion spermatozoa. In Experiment 1, sorting at 30 psi compared to 5...
Oldenhof H, Gojowsky M, Wang S, Henke S, Yu C, Rohn K, Wolkers WF, Sieme H.The aim of this study was to determine how different membrane-permeable and -impermeable cryoprotective agents modulate tolerance of stallion sperm to osmotic stress and stabilize membranes during cryopreservation. Special emphasis was on hydroxyl ethylene starch (HES), which exposes cells to minimal osmotic stress due to its large molecular weight. Percentages of motile sperm post-thaw were found to be similar when glycerol, sucrose, and HES were used at their optimal concentrations. Percentages of plasma membrane intact sperm after return to isotonic medium were highest for HES. Fourier tran...
Gottschalk M, Metzger J, Martinsson G, Sieme H, Distl O.We performed a genome-wide association study for semen quality traits in 139 German Warmblood stallions. Stallions were genotyped using the Illumina equine SNP50 Beadchip. Traits analysed were de-regressed estimated breeding values (EBVs) for gel-free volume, sperm concentration, total number of sperm, progressive motility and the total number of progressively motile sperm. The GWAS revealed 29 SNPs on 12 different chromosomes as genome-wide significantly associated with semen quality traits. For ten genomic regions we could retrieve candidate genes influencing stallion fertility. Among the ca...
Loomis PR.Clinical reproduction in the horse more closely parallels human clinical reproduction than in other domestic farm animals. Horse breeders rarely include fertility as a selection criterion when making mating decisions; in most breeds, there is no licensing or approval of stallions. This has led to a significant number of stallions in the breeding pool that possess desirable performance traits but are subfertile for a variety of reasons, some of them genetically transmitted between generations. Therefore, semen characteristics can vary greatly among stallions within the breeding population. A ch...
Meyers S, Bulkeley E, Foutouhi A.The biological nature of age-related declines in fertility in males of any species, including stallions, has been elusive. In horses, the economic costs to the breeding industry are frequently extensive. Mitochondrial function in ejaculated sperm, which is essential for sperm motility, is reflected by adenosine triphosphate production, mitochondrial oxidative efficiency and production of reactive oxygen species, and that this balance may become compromised in ageing stallions and during the process of cryopreservation. This presentation will focus on mitochondrial integrity and function as an ...
Gibb Z, Butler TJ, Morris LH, Maxwell WM, Grupen CG.Excessive reactive oxygen species generation during sex sorting and cryopreservation of stallion sperm leads to DNA fragmentation, lipid peroxidation, and motility loss. In this study we investigated whether antioxidant supplementation during sex sorting and cryopreservation could ameliorate the effects of reactive oxygen species on stallion sperm. In experiment 1, the postthaw characteristics of stallion sperm (N = 9) cryopreserved in the presence or absence of catalase (200 U/mL), cysteine (0.2 mg/mL), or quercetin (0.15 mM) was examined. Motility and acrosome integrity were assessed at 0, 1...
Stradaioli G, Sylla L, Zelli R, Chiodi P, Monaci M.The effect of orally administered l-carnitine on the quality of semen obtained from stallions with different semen qualities was investigated. Four stallions with proven fertility (high motility group, HM) and with normal seminal characteristics (>50% progressive motility and > 80 x 10(6) spermatozoa/ml), and four questionable breeders (low motility group, LM) with <50% of sperm progressive motility and < 80 x 10(6) spermatozoa/ml, received p.o. 20 g of l-carnitine for 60 days. Blood and semen samples were collected before treatment (T0) and after 30 (T1) and 60 days (T2). Semen ev...
Batellier F, Vidament M, Fauquant J, Duchamp G, Arnaud G, Yvon JM, Magistrini M.In the horse industry, milk or milk-based extenders are used routinely for dilution and storage of semen cooled to 4-8 degrees C. Although artificial insemination (AI) with chilled and transported semen has been in use for several years, pregnancy rates are still low and variable related to variable semen quality of stallions. Over the years, a variety of extenders have been proposed for cooling, storage and transport of stallion semen. Fractionation of milk by microfiltration, ultrafiltration, diafiltration and freeze-drying techniques has allowed preparation of purified milk fractions in ord...
Giaretta E, Munerato M, Yeste M, Galeati G, Spinaci M, Tamanini C, Mari G, Bucci D.Setting an open-access computer assisted sperm analysis (CASA) may benefit the evaluation of motility in mammalian sperm, especially when economic constraints do not allow the use of a commercial system. There have been successful attempts to develop such a device in Zebra fish sperm and the system has been used in very few studies on mammalian spermatozoa. Against this background, the present study aimed at developing an open-access CASA system for mammalian sperm using the horse as a model and based upon the Image J software previously established for Zebra fish sperm. Along with determining...
Morrell JM, Klein C, Lundeheim N, Erol E, Troedsson MH.Bacteria (environmental contaminants and occasionally potential pathogens) are found in most stallion ejaculates and may negatively affect sperm quality during storage. Since the use of antibiotics can lead to the development of resistance, an alternative means of microbial control is desirable. The removal of bacteria from stallion semen using Single Layer Centrifugation through Androcoll-E was investigated. Known doses of cultured bacteria were added to freshly collected ejaculates (15mL aliquots) before processing by Single Layer Centrifugation. The resulting sperm pellets and controls (not...
Carossino M, Dini P, Kalbfleisch TS, Loynachan AT, Canisso IF, Cook RF, Timoney PJ, Balasuriya UBR.Equine arteritis virus (EAV) has the unique ability to establish long-term persistent infection in the reproductive tract of stallions and be sexually transmitted. Previous studies showed that long-term persistent infection is associated with a specific allele of the CXCL16 gene (CXCL16S) and that persistence is maintained despite the presence of local inflammatory and humoral and mucosal antibody responses. Here, we performed transcriptomic analysis of the ampullae, the primary site of EAV persistence in long-term EAV carrier stallions, to understand the molecular signatures of viral persiste...
Georgopoulos SP, Parkin TD.OBJECTIVE To identify risk factors associated with fatal injuries in Thoroughbred racehorses in the United States and Canada. DESIGN Retrospective study. ANIMALS 1,891,483 race starts by 154,527 Thoroughbred racehorses at 89 racetracks in the United States and Canada from 2009 to 2013. PROCEDURES Data were extracted from the Equine Injury Database, which contained information for 93.9% of all official flat racing events in the United States and Canada during the 5-year observation period. Forty-four possible risk factors were evaluated by univariate then multivariable logistic regression to id...
Ortega-Ferrusola C, García BM, Gallardo-Bolaños JM, González-Fernández L, Rodríguez-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 ...
Mshelia ES, Adamu L, Wakil Y, Turaki UA, Gulani IA, Musa J.The equine gut harbours complex microbial populations which influence physiology, metabolism, nutrition and immune functions, while disruption to the gut microbiota has been linked with conditions such as lameness, diabetes and obesity. Therefore, the present study was conducted to determine the association between microbial dysbiosis, sex, age and body condition scores (BCS) of horses (Equus equus caballus) in Maiduguri and its environs. Forty horses were assessed by convenient sampling, while faecal samples were collected and analyzed to determine the microbiomes in the various age groups wi...
Crowell-Davis SL, Houpt KA.In colts and fillies observed from birth to 24 weeks old, coprophagy occurred from Weeks 1 to 19. Its frequency was greatest during the first two months. Coprophagy was rarely observed in mares and stallions. Foals usually ate the faeces of their mother but were observed to eat their own and those of a stallion and another unrelated mare. Urination by the foal occurred before, during or after 26 per cent of the coprophagy incidents. It is hypothesised that foals may consume faeces in response to a maternal pheromone which signals the presence of deoxycholic acid or other acids which the foal m...
Lane EA, Bijnen ML, Osborne M, More SJ, Henderson IS, Duffy P, Crowe MA.To evaluate factors contributing to fertility of thoroughbred mares, data from 3743 oestrous periods of 2385 mares were collected on a large thoroughbred farm in Ireland. Fourteen stallions (mean age 8.3 years; range 4-15 years) had bred 2385 mares (mean age 9.4 years; range 3-24 years). Maiden mares accounted for 12%, mares with a foal at foot for 64%, and barren, slipped or rested mares for 24% of the total. The mean pregnancy rate per cycle was 67.8% (68.6% in year 1 and 66.9% in year 2). Backward stepwise multivariable logistic regression analysis was utilized to develop two models to eval...
Janett F, Stump R, Burger D, Thun R.The aim of this study was to evaluate the effects of an anti-GnRH vaccine on testosterone concentration, antibody titer, scrotal width, semen quality and sexual behavior in the stallion. Adverse reactions to the vaccine were also determined. Eight clinically healthy sexually experienced stallions aged between 6 and 15 years from the National Stud in Avenches (Switzerland) were used. Five stallions were immunized 3 times at an interval of 4 and 8 weeks, respectively, with 200 microg of a GnRH-protein conjugate (Equity, CSL Limited, Australia) intramuscularly in the neck and 3 control animals re...
Yoon MJ, Berger T, Roser JF.The insulin-like growth factor-I (IGF-I) is a key regulator of reproductive functions. IGF-I actions are primarily mediated by IGF-IR. The main objective of this research was to evaluate the presence of IGF-I and IGF-I Receptor (IGF-IR) in stallion testicular tissue. The hypotheses of this study were (i) IGF-I and IGF-IR are present in stallion testicular cells including Leydig, Sertoli, and developing germ cells, and (ii) the immunolabelling of IGF-I and IGF-IR varies with age. Testicular tissues from groups of 4 stallions in different developmental ages were used. Rabbit anti-human polyclona...
Pommer AC, Rutllant J, Meyers SA.Phosphorylation of tyrosine residues on sperm proteins is one important intracellular mechanism regulating sperm function that may be a meaningful indicator of capacitation. There is substantial evidence that cryopreservation promotes the capacitation of sperm and this cryocapacitation is frequently cited as one factor associated with the reduced longevity of cryopreserved sperm in the female reproductive tract. This study was designed to determine whether stallion sperm express different levels of tyrosine phosphorylation after in vitro capacitation and whether thawed sperm display similar ph...
