Fertility in horses encompasses the physiological processes and factors influencing reproductive success in equine species. It involves the study of reproductive anatomy, endocrinology, and behavior, as well as the management practices that affect breeding outcomes. Key aspects include the estrous cycle, conception rates, and factors impacting stallion and mare fertility. Reproductive technologies such as artificial insemination, embryo transfer, and hormonal therapies are also explored to enhance breeding efficiency. This page compiles peer-reviewed research studies and scholarly articles that examine the biological mechanisms, management strategies, and technological advancements related to equine fertility.
Bugno-Poniewierska M, Raudsepp T.Clinical cytogenetic studies in horses have been ongoing for over half a century and clearly demonstrate that chromosomal disorders are among the most common non-infectious causes of decreased fertility, infertility, and congenital defects. Large-scale cytogenetic surveys show that almost 30% of horses with reproductive or developmental problems have chromosome aberrations, whereas abnormal karyotypes are found in only 2-5% of the general population. Among the many chromosome abnormalities reported in the horse, most are unique or rare. However, all surveys agree that there are two recurrent c...
Ciani F, Maruccio L, Cocchia N, d'Angelo D, Carotenuto D, Avallone L, Namagerdi AA, Tafuri S.Assisted reproductive technologies (ARTs) are widely used as a tool to improve reproductive performance in both humans and animals. In particular, in the veterinary field, ARTs are used to improve animal genetics, recover endangered animals, and produce offspring in the event of subfertility or infertility in males or females. However, the use of ARTs did not improve the fertilization rate in some animals due to various factors such as the difficulty in reproducing an anatomical and humoral substrate typical of the natural condition or due to the increase in catabolites and their difficult eli...
Ortiz-Rodriguez JM, Nerozzi C, Bucci D, Mislei B, Mari G, Tamanini C, Peña FJ, Spinaci M, Galeati G.Sperm are redox-regulated cells, and deregulation of their redox status is considered to affect male fertility and to reduce their fertilizing ability following biotechnological procedures, such as cryopreservation. Cystine (CysS), after incorporation in sperm via SLC7A11 antiporter, has been demonstrated to increase intracellular GSH content, the most important non enzymatic antioxidant. This study was aimed at investigating the role of SLC7A11 antiporter on frozen-thawed stallion sperm ability to respond to in vitro capacitating environment after post-thaw incubation with CysS and/or Sulfas...
Nielsen JM, Fog P, Bojesen AM.The breeding prognosis for a mare with fungal (yeast or mold) endometritis is generally considered poor. To our knowledge, however, no reports have been published on the expected pregnancy rate for mares diagnosed with a fungal infection. Insemination records from 3,223 mares inseminated at two stud farms were retrospectively examined. Mares diagnosed with fungal endometritis were all treated with uterine lavage using physiological saline, intrauterine deposition of 100 mg Clotrimazole vagitorial tablets and oxytocin (10 i.e., i.m.) for three consecutive days. From mares with signs of endometr...
D'Anza E, Albarella S, Galdiero G, Tafuri S, Del Prete C, Cocchia N, Ciani F, Mastellone V, Pasolini MP, Carotenuto D, Selvaggi M, Ciotola F....The reproductive performances of livestock play an essential role in the economic management of the farm. The improvement of semen quantity and quality through the use of food supplements that lack substances which are forbidden in animal feeding, or that may have detrimental effects, is an important goal. Maca (Lepidium meyenii) is a plant that has been used for centuries in the Andes for nutrition and fertility enhancement in humans and animals. The aim of this study was to evaluate the effects of food supplementation of stallions with maca during the breeding season on spermatozoa parameter...
Catandi GD, Obeidat YM, Broeckling CD, Chen TW, Chicco AJ, Carnevale EM.Advanced maternal age is associated with a decline in fertility and oocyte quality. We used novel metabolic microsensors to assess effects of mare age on single oocyte and embryo metabolic function, which has not yet been similarly investigated in mammalian species. We hypothesized that equine maternal aging affects the metabolic function of oocytes and in vitro-produced early embryos, oocyte mitochondrial DNA (mtDNA) copy number, and relative abundance of metabolites involved in energy metabolism in oocytes and cumulus cells. Samples were collected from preovulatory follicles from young (≤1...
Li N, Yu J, Yang F, Shao Y, Wu S, Liu B, Li M, Wang T, Li J, Zeng S.The aim of this study was to evaluate the effects of L-proline on the extender quality of frozen and post-thawed jackass semen. Jackass (n = 6) semen samples were collected and cryopreserved in gradient concentrations (0-80 mM) of L-proline in extenders; post-thawed semen samples were cultured in L-proline medium for 10 hours at 37°C. For cryopreservation experiment I, the motile parameters, mitochondrial membrane potential (MMP), and plasma membrane, acrosome, and chromatin structure integrities of post-thawed semen were assessed. For culture experiment II, additional ROS contents were ana...
Laseca N, Anaya G, Peña Z, Pirosanto Y, Molina A, Demyda Peyrás S.Fertility is one of the key factors in the economic and productive success of the equine industry. Despite this, studies on the genetic causes affecting reproductive performance are scarce, especially in mares, where the genetic architecture of the reproductive traits is extremely complex. Today, with the increasing availability of new genomic methodologies for this species, we are presented with an interesting opportunity to understand the genetic basis of equine reproductive disorders. These include, among others, novel techniques for detecting chromosomal abnormalities, whose association wi...
Kareskoski M, Vakkamäki J, Laukkanen K, Palviainen M, Johannisson A, Katila T.Matrix metalloproteinase (MMP)-2 and MMP-9 are gelatinases that take part in several reproductive processes. The aim of this study was to measure levels of MMP-2 and MMP-9 in fractionated stallion ejaculates, and to evaluate the association between these components and semen quality, and sperm longevity during cooled storage. Semen quality were assessed separately for sperm-rich fractions (HIGH), sperm-poor fractions (LOW), and whole ejaculate samples (WE) from 33 stallions. After cooled storage with SP either present or removed, sperm motility and DFI were determined. The relative activity of...
D'Fonseca NMM, Gibson CME, Hummel I, van Doorn DA, Roelfsema E, Stout TAE, van den Broek J, de Ruijter-Villani M.Obesity has been associated with altered reproductive activity in mares, and may negatively affect fertility. To examine the influence of long-term high-energy (HE) feeding on fertility, Shetland pony mares were fed a diet containing 200% of net energy (NE) requirements during a three-year study. The incidence of hemorrhagic anovulatory follicles (HAF) and annual duration of cyclicity were compared to those in control mares receiving a maintenance diet. Day-7 embryos were flushed and transferred between donor and recipient mares from both groups; the resulting conceptuses were collected 21 day...
Joonè CJ, Gradil CM, Picard JA, Taylor JD, de Tonnerre D, Cavalieri J.The primary aim of this study was to investigate the contraceptive efficacy of a self-assembling uterine device (iUPOD™) in the mare. In addition, the effects of iUPODs on oestrous cyclicity, uterine health and circulating concentrations of cortisol were evaluated. Methods: Domestic mares underwent oestrous monitoring and artificial insemination. After subsequent ovulation, mares underwent either placement (n = 7) or sham placement (n = 7; controls) of an iUPOD device. Devices were left in place for at least 3 months. Pregnancy diagnoses were carried out 14 days post-ovulation, with any pr...
Pasch L, Schmidt A, King W.The use of autologous blood processing tools including platelet-rich plasma (PRP) devices is increasingly widespread in veterinary medicine. In equine reproduction, a number of studies have explored the effects of intrauterine infusion of PRP on persistent mating-induced endometritis. Artificial insemination with thawed frozen semen incites an intrauterine inflammatory response and we sought to extend the applications of intrauterine PRP to normal mares being inseminated with frozen semen. We investigated a subset of our normal breeding population to observe the clinical effects of prebreeding...
Rossetto L, Farcey MF, Bilbao MG, Bartolomé JA, Gallelli MF, Miragaya MH.The stress associated with training may reduce reproductive efficiency in Criollo stallions. The objective of this study was to compare semen quality and hormone concentrations in Criollo stallions under training or under regular field conditions. Criollo breed stallions (n = 18) were evaluated during the spring. The exercise group (n = 9) performed 1 hour of exercise per day and participated in competitions during the experimental period. The control group (n = 9) neither performed exercise nor participated in competitions. Serum and semen samples were obtained every 15 days (two separat...
Gimeno BF, Bariani MV, Laiz-Quiroga L, Martínez-León E, Von-Meyeren M, Rey O, Mutto AÁ, Osycka-Salut CE.Cryopreservation by negatively affecting sperm quality decreases the efficiency of assisted reproduction techniques (ARTs). Thus, we first evaluated sperm motility at different conditions for the manipulation of equine cryopreserved spermatozoa. Higher motility was observed when spermatozoa were incubated for 30 min at 30 × 106/mL compared to lower concentrations (p < 0.05) and when a short centrifugation at 200× g was performed (p < 0.05). Moreover, because sperm suitable for oocyte fertilization is released from oviduct epithelial cells (OECs), in response to the capacitation process, we e...
Papin J, Stuhtmann G, Martinsson G, Sieme H, Lundeheim N, Ntallaris T, Morrell JM.Removal of seminal plasma facilitates stallion sperm survival during storage, but washing may damage sperm chromatin. Therefore, sperm quality was compared in samples following single-layer centrifugation (SLC) or sperm washing and controls (extension only) in two extenders, INRA82 and INRA96. Ejaculates from six stallions were split among six treatments: SLC, sperm washing, and controls, in INRA82 and INRA96. Sperm motility and acrosome status were evaluated at 0, 24, 48, 72 and 96 hours; morphology at 0, 24, 48, 72 hours and chromatin integrity at 0 and 96 hours, with storage at 6°C. Sperm ...
Alves NC, Diniz SA, Viegas RN, Cortes SF, Costa ED, Freitas MM, Martins-Filho OA, Araújo MSS, Lana ÂMQ, Wenceslau RR, Lagares MA.The aim of this study was to improve the quality of frozen-thawed equine sperm by the addition of caffeine to it. Semen from nine stallions was frozen and different concentrations of caffeine (3, 5 and 7.5 mM) were added to frozen-thawed semen. The sperm kinetic parameters, membrane functionality and integrity, and acrosome integrity and spontaneous acrosome reacted sperm were evaluated with a computer-assisted sperm analysis, a hypoosmotic swelling test and epifluorescent microscopy, respectively. Nitrite and hydroperoxide concentrations of frozen-thawed semen were measured using spectrophot...
Ghosh S, Carden CF, Juras R, Mendoza MN, Jevit MJ, Castaneda C, Phelps O, Dube J, Kelley DE, Varner DD, Love CC, Raudsepp T.We report 2 novel autosomal translocations in the horse. In Case 1, a breeding stallion with a balanced t(4p;30) had produced normal foals and those with congenital abnormalities. Of his 9 phenotypically normal offspring, 4 had normal karyotypes, 4 had balanced t(4p;30), and 1 carried an unbalanced translocation with tertiary trisomy of 4p. We argue that unbalanced forms of t(4p;30) are more tolerated and result in viable congenital abnormalities, without causing embryonic death like all other known equine autosomal translocations. In Case 2, two stallions produced by somatic cell nuclear tran...
Diaz-Jimenez M, Rota A, Dorado J, Consuegra C, Pereira B, Camillo F, Panzani D, Fanelli D, Tesi M, Monaco D, Hidalgo M.Sperm vitrification has been recently developed, but fertility trials have not been performed yet in equine species. In this study, a new warming technique for vitrified donkey semen was developed and the uterine inflammatory response and fertility were compared to conventional freezing. In Experiment 1, sperm was vitrified in straws and warmed in 3 ml of extender or in a water bath at: 37 °C/30 s; 43 °C/10 s; and 60 °C/5 s. Sperm motility, plasma and acrosome membranes and DNA integrity were compared between treatments. In Experiment 2, jennies were inseminated twice (500 ...
Mure S, Oishi K, Hirooka H.The objective of the present study was to develop a deterministic simulation model for evaluating the reproductive performance of Thoroughbred mares. As an application, the model was used to estimate the herd level asymptotic foaling percentage (AFP) for evaluating the performance of mares in stabilized mare herds using the convergent method for estimating a steady-state distribution of mares. In this model, it was assumed that the mares were mated only during the breeding season. The effects of early pregnancy loss and fetal loss on reproductive performance were investigated. The sensitivitie...
Cavalero TMS, Segabinazzi LGTM, Scheeren VFDC, Freitas-Dell'Aqua CP, Papa FO.The present study compared the quality of sperm collected by artificial vagina or pharmacologically induced ejaculation from a 10-year-old thoroughbred stallion with seminal vesiculitis. The pharmacological protocol involved intravenous administration of detomidine (0.01 mg/kg) and oxytocin (20 IU) and successfully induced ejaculation in all attempts of semen collection. Sperm motility, plasma membrane and acrosome integrity (PMAI), reactive oxygen species (ROS) levels, polymorphonuclear neutrophil (PMN) percentage, and bacterial profiles of fresh and cooled semen (5°C for 24 hr) were eval...
Rodriguez J, Maserati M, Robilotta T, Augusto G, Alonso MA, Redoan M, Tibary A, Fleury P.Field collection of oocytes in mares using transvaginal follicular aspiration (TVA) for embryo production has the potential to revolutionate the equine industry. Protocols for TVA in specialized laboratory settings have been described in the scientific literature since the early 1980s. The objective of this study was to determine the success rate of TVA oocytes recovery under ambulatory conditions. A secondary goal of this study was to determine if TVA is associated with any health complications when performed by recently trained practitioners in the field. Follicles (n = 296) from 66 adult c...
Vieira LA, Matás C, Torrecillas A, Saez F, Gadea J.Seminal plasma (SP) plays a crucial role in sperm protection and functionality. However, the effect of SP on the sperm cryopreservation is dependent on the stallion and SP composition. The use of epididymal spermatozoa incubated in the presence of SP could help the identification of the components of SP that are able to confer protection upon the spermatozoa during freezing. The aims of this study were (i) to identify SP components involved in the potential protection of epididymal spermatozoa during the freeze-thawing process and (ii) to identify and evaluate the proteins likely related to sp...
Ponthier J, Rigaux G, Parrilla-Hernandez S, Egyptien S, Gatez C, Carrasco Leroy C, Deleuze S.This report describes an option to modulate the testicular function of wild horses and field methods to assess it. Non-surgical castration of a captive wild Przewalski's stallion with anti-gonadotropin-releasing hormone (GnRH) immunization was performed by sub-cutaneous injection of two doses of 450 μg (3 ml) of GnRH conjugated to diphtheria toxin, further repeated every 6 months. Semen quality was assessed after collection by electro-ejaculation under general anesthesia. Endocrine and behavioral consequences were studied during a 2-year follow-up period. The procedure of electro-ejaculation ...
Papas M, Catalán J, Recuero S, Morrell JM, Yeste M, Miró J.This study sought to determine whether single layer centrifugation (SLC) of fresh donkey semen with Equicoll has any impact on sperm quality parameters and on the modulation of endometrial reaction following semen deposition using an in vitro model. Seventeen ejaculates from five jackasses were obtained using an artificial vagina and diluted in a skim-milk extender. Samples were either selected through SLC (Equicoll) or non-treated (control). Two experiments were performed. The first one consisted of incubating selected or non-selected spermatozoa at 38 °C for 180 min. Integrity and lipid dis...
Boakari YL, El-Sheikh Ali H, Schnobrich M, Lofrumento K, Scoggin C, Bradecamp E, Scoggin K, Esteller-Vico A, Claes A, Lawrence L, Ball B.High blood urea nitrogen (BUN) concentration is linked to low fertility in cows and ewes; however, this relationship has not been reported in mares. The study characterized the relationship between BUN and follicular fluid urea nitrogen (FUN) during follicle growth (Experiment 1) and the impact of BUN from embryo donors on the pregnancy outcome of recipient mares (Experiment 2). In experiment one, follicular fluid and blood samples were collected from mares during diestrus with growing follicles and during estrus with pre-ovulatory follicles (n = 16 and 10 mares, respectively). In experiment...
Souza SS, Alves BG, Alves KA, Brandão FAS, Brito DCC, Gastal MO, Rodrigues APR, Figueireod JR, Teixeira DIA, Gastal EL.Heterotopic and orthotopic ovarian tissue autotransplantation techniques, currently used in humans, will become promising alternative methods for fertility preservation in domestic and wild animals. Thus, this study describes for the first time the efficiency of a heterotopic ovarian tissue autotransplantation technique in a large livestock species (i.e., horses) after ovarian fragments were exposed or not to a cooling process (4°C/24 h) and/or VEGF before grafting. Ovarian fragments were collected in vivo via an ultrasound-guided biopsy pick-up method and surgically autografted in a subcutan...
Rizzo M, du Preez N, Ducheyne KD, Deelen C, Beitsma MM, Stout TAE, de Ruijter-Villani M.Aneuploidy of meiotic origin is a major contributor to age-related subfertility and an increased risk of miscarriage in women. Although age-related aneuploidy has been studied in rodents, the mare may be a more appropriate animal model to study reproductive aging. Similar to women, aged mares show reduced fertility and an increased incidence of early pregnancy loss; however, it is not known whether aging predisposes to aneuploidy in equine oocytes. We evaluated the effect of advanced mare age on (1) gene expression for cohesin components, (2) incidence of aneuploidy and (3) chromosome centrome...
Crespo F, Wilson R, Díaz-Jimenez M, Consuegra C, Dorado J, Barrado BG, Gosálvez J, Smit RL, Hidalgo M, Johnston S.Horses are long-day seasonal breeding animals, however, with modern stallion reproductive management it is important for collection of semen during periods that are not part of the traditional breeding season. This study was conducted to examine variation in the seminal characteristics of individual stallions in Avila, Spain during 1 year with a particular emphasis on sperm DNA fragmentation. Semen was collected twice per season from a total of 20 stallions. There was a marked seasonal effect on all seminal characteristics, with the greatest on progressive motility, % membrane integrity and le...
Ortiz-Rodríguez JM, Martín-Cano FE, Gaitskell-Phillips G, Silva A, Tapia JA, Gil MC, Redondo E, Masot J, Ortega-Ferrusola C, Peña FJ.Spermatozoa are redox-regulated cells, and stallion spermatozoa, in particular, present an intense mitochondrial activity in which large amounts of reactive oxygen species (ROS) are produced. To maintain the redox potential under physiological conditions, sophisticated mechanisms ought to be present, particularly in the mitochondria. In the present study, we investigated the role of the SLC7A11 antiporter. This antiporter exchanges intracellular glutamate for extracellular cystine. In the spermatozoa, cystine is reduced to cysteine and used for GSH synthesis. The importance of the antiporter f...
Gacem S, Catalán J, Valverde A, Soler C, Miró J.In order to optimize the donkey sperm motility analysis by the CASA (Computer Assisted Sperm Analysis)-Mot system, twelve ejaculates were collected from six jackasses. Capillary loaded chamber (CLC), ISASD4C depths 10 and 20 µm, ISASD4C Leja 20 and drop displacement chamber (DDC), Spermtrack (Spk) depths 10 and 20 µm were used. Sperm kinematic variables were evaluated using each chamber and a high-resolution camera capable of capturing a maximum of 500 frames/second (fps). The optimum frame rate (OFR) (defined according to curvilinear velocity-VCL) was dependent on chamber type. The highest ...
Franciosi F, Goudet G, Tessaro I, Papillier P, Dalbies-Tran R, Reigner F, Deleuze S, Douet C, Miclea I, Lodde V, Luciano AM.Implantation failure and genetic developmental disabilities in mammals are caused by errors in chromosome segregation originating mainly in the oocyte during meiosis I. Some conditions, like maternal ageing or in vitro maturation (IVM), increase the incidence of oocyte aneuploidy. Here oocytes from adult mares were used to investigate oocyte maturation in a monovulatory species. Experiments were conducted to compare: (1) the incidence of aneuploidy, (2) the morphology of the spindle, (3) the acetylation of lysine 16 on histone H4 (H4K16) and (4) the relative amount of histone acetyltransferase...
Li N, Yu J, Yang F, Shao Y, Wu S, Liu B, Li M, Wang T, Li J, Zeng S.The aim of this study was to evaluate the effects of L-proline on the extender quality of frozen and post-thawed jackass semen. Jackass (n = 6) semen samples were collected and cryopreserved in gradient concentrations (0-80 mM) of L-proline in extenders; post-thawed semen samples were cultured in L-proline medium for 10 hours at 37°C. For cryopreservation experiment I, the motile parameters, mitochondrial membrane potential (MMP), and plasma membrane, acrosome, and chromatin structure integrities of post-thawed semen were assessed. For culture experiment II, additional ROS contents were ana...
González-Fernández L, Sánchez-Calabuig MJ, Calle-Guisado V, García-Marín LJ, Bragado MJ, Fernández-Hernández P, Gutiérrez-Adán A....A repeatable protocol for equine in vitro fertilization (IVF) has remained elusive. This is likely, in part, due to suboptimal composition of capacitation or IVF media that are currently in use. Hence, we aimed to analyse the metabolome of equine oviductal fluid (OF) at the pre- (PRE) and immediate post-ovulatory (PST) stages using proton magnetic resonance spectroscopy (H NMR). Oviductal fluid from eight PRE and six PST mares were used to prepare a total of five samples per group. A total of 18 metabolites were identified. The five metabolites with the highest concentrations in the OF sample...
Prasinou P, De Amicis I, Fusaro I, Bucci R, Cavallini D, Parrillo S, Caputo M, Gramenzi A, Carluccio A.Fatty acid-based lipidomic analysis has been widely used to evaluate health status in human medicine as well as in the veterinary field. In equine species, there has been a developing interest in fertility and sperm quality. Fatty acids, being the principal components of the membranes, play an active role in the regulation of the metabolic activities, and their role on spermiogenesis seems to be of great importance for the resulting quality of the sperm and, thus, fertility. With the application of widely used lipidomic techniques, the aim of this study was to evaluate: (a) the fatty acid cont...
Zong E, Fan G.Generally speaking, the majority of F1 hybrids between the horse and donkey are sterile and do conform to the hypothesis of gametogenic breakdown. The results of our own research, nevertheless, lead us to conclude that there is variability in degree of sterility and fertility for both F1 and B1 individuals, with a gradual advance from sterility to fertility being seen. This is the subject we will discuss from the point of view of oestrus, ovulation, mating, pregnancy, spermatogenesis, endocrine activity, isozymes and karyotypic analysis in this paper.
Varner DD.The conventional approach to evaluation of stallion semen dates back several decades, and includes evaluation of spermatozoal concentration, semen volume, spermatozoon morphological characteristics, and spermatozoal motility patterns initially and following in-vitro storage. While an analysis performed in this manner does have predictive value, incorporation of some more newly developed techniques may improve the predictive value of the examination. This communication addresses some newer tests that can be applied today for evaluation of semen, as well some tests that may be available in the c...
Campbell ML.Embryo transfer (ET) is an accepted and successful technique for obtaining foals from mares without interrupting their competition careers. Recent research, however, suggests that the potential of factors including heat, exercise, repeated embryo flushing and repeated manipulation of the reproductive cycle using exogenous hormones to have a negative impact on fertility may have been underestimated. This paper reviews the evidence base for involvement of these factors in repeated failures to recover embryos from nongeriatric competition mares without obvious clinical or pathological indications...
Gacem S, Catalán J, Yánez-Ortiz I, Soler C, Miró J.The evaluation of the male fertility potential is based on the analysis of the basic spermatic characteristics of concentration, motility and morphology. Thus, the study of sperm morphology is a fundamental element in the seminal analysis, but its real meaning has been biased by the techniques used for its evaluation. These techniques involve dehydration phases and subsequent staining, which involves the production of artifacts. The aim of the study is to compare two methods for equid semen morphology evaluation, Trumorph using living sperm vs. eosin-nigrosine stain. A total of 49 ejaculates f...
Card C.Endometritis has been reported to be the third most common medical condition of horses. Timely diagnosis and treatment of endometritis in mares increases the chance of pregnancy. Exfoliative endometrial cytology is often used as a clinical tool to evaluate endometrial inflammation through detection of neutrophils. There is a lack of information on the time frame for changes in endometrial cytologic parameters following breeding. The main objectives of this article are to use current information to describe systematic analysis of endometrial cytology using standardized methods for sample collec...
Hoffmann N, Oldenhof H, Morandini C, Rohn K, Sieme H.Cryopreserved stallion sperm displays a high degree of male-to-male variability with respect to cell viability after thawing. Animals that have semen with low viability after cryopreservation are classified as 'poor' freezers, and when post-thaw viability is high they are designated as 'good' freezers. Cryoprotective agents that are used for cryopreserving stallion sperm include glycerol, ethylene glycol, methyl formamide, and dimethylformamide, and are typically used in concentrations ranging from 1% to 4%. The aim of this study was to evaluate the osmotic stresses that stallion sperm is expo...
Catalán J, Papas M, Gacem S, Mateo-Otero Y, Rodríguez-Gil JE, Miró J, Yeste M.Previous studies in other mammalian species have shown that stimulation of semen with red-light increases sperm motility, mitochondrial activity, and fertilizing capacity. This study sought to determine whether red-light stimulation using a light emitting diode (LED) at 620-630 nm affects sperm motility and structure of motile subpopulations, sperm viability, mitochondrial activity, intracellular ATP levels, rate of O consumption and DNA integrity of horse spermatozoa. For this purpose, nine ejaculates were collected from nine different adult stallions. Upon collection, semen was diluted in Ke...
Cabrera T, Ramires-Neto C, Belaz KRA, Freitas-Dell'aqua CP, Zampieri D, Tata A, Eberlin MN, Alvarenga MA, Souza FF.The membrane of spermatozoa, which contributes to cellular cryoresistance, contains numerous lipids with a composition that directly affects membrane fluidity and the fertilization process. In light of variations in the degree of sensitivity in equine seminal freezing, this study aimed to correlate equine semen lipids with post-thawing characteristics of spermatozoa. We used ejaculates from 34 stallions, which were evaluated (total motility ≥ 60%), frozen and thawed and reevaluated for motility of spermatozoa, membrane integrity and lipid peroxidation. Lipid extraction of the fresh semen s...
Amann RP.Apparent fertility of a male or group of females is considered frequently by veterinarians or animal scientists. Unfortunately, concepts of experimental design and statistics impacting validity and interpretation of values for average pregnancy rate frequently are ignored. The magnitude of this problem was documented by examination of published papers; 51 of 67 (76%) were considered flawed for one or more reasons. The discussion considers why: (a) conclusions from most published fertility studies reporting no significant difference due to treatment(s) are suspect, because too few males and/or ...
Voß K, Blaj I, Tetens JL, Thaller G, Becker D.Since domestication, a wide variety of phenotypes including coat color variation has developed in livestock. This variation is mostly based on selective breeding. During the beginning of selective breeding, potential negative consequences did not become immediately evident due to low frequencies of homozygous animals and have been occasionally neglected. However, numerous studies of coat color genetics have been carried out over more than a century and, meanwhile, pleiotropic effects for several coat color genes, including disorders of even lethal impact, were described. Similar coat color phe...
Hidalgo M, Consuegra C, Dorado J, Diaz-Jimenez M, Ortiz I, Pereira B, Sanchez R, Crespo F.Vitrification is based on rapid freezing by direct exposure of sperm to liquid nitrogen (LN). This study evaluated the effect of non-permeable CPAs and equilibration temperature on stallion sperm quality after vitrification. In Experiment 1, different concentrations of sucrose (20, 50, 100 mM; mmol/L) and bovine serum albumin (BSA 1%, 5%, 10%) were compared including different temperatures for the equilibration (≈22 °C or 5 °C). Vitrification was performed dropping 30 μl sperm suspension directly into LN In Experiment 2, conventional sperm freezing using 2.2% of glycerol in 0.5 ...
Ricketts SW, Alonso S.Paired endometrial biopsy samples were taken from 530 subfertile mares, before and after treatment (where indicated) and a period of sexual rest. Prognoses were made after each biopsy (Categories 1A-4A before treatment and Categories 1B-4B after treatment), using histopathological criteria similar to those described by Kenney and Doig (1986). Eighty-seven per cent of the mares were assigned to first biopsy prognosis Category 3A. The second biopsy prognosis produced a more even population distribution (10, 47, 40 and 3 per cent respectively for Category 1B, 2B, 3B and 4B mares). First biopsy Ca...
Pukazhenthi BS, Johnson A, Guthrie HD, Songsasen N, Padilla LR, Wolfe BA, Coutinho da Silva M, Alvarenga MA, Wildt DE.Two studies were conducted to understand sperm cryosensitivity in an endangered equid, the Przewalski's horse (Equus ferus przewalski), while testing the cryoprotectant ability of formamides. The first assessed the toxicity of permeating cryoprotectants (glycerol, methylformamide [MF] and dimethylformamide [DMF]) to Przewalski's horse spermatozoa during liquid storage at 4°C. The second examined the comparative influence of three diluents (with or without formamides) on cryosurvival of sperm from the Przewalski's versus domestic horse. When Przewalski's horse spermatozoa were incubated at 4°...
Kandiel MMM, El Khawagah ARM.Egypt is anticipated to be potentially influenced by the global climate warming. Therefore, the current study aimed to evaluate the influence of age on the fertility potential of Arabian stallions during summer breeding months. Arabian horses grouped according to their age into three groups, each involved six stallions: young (5-6 years), middle (11-12 years) and old (15-20 years) age groups, were weekly sampled during the months of July-August. Ejaculates were collected using artificial vagina, Missouri model, and examined for pH, volume, concentration, motility, livability and morphological ...
Romero-Aguirregomezcorta J, Sugrue E, Martínez-Fresneda L, Newport D, Fair S.The journey of spermatozoa through the female genital tract is facilitated by rheotaxis, or the cell's preference to swim against a flow, as well as thigmotaxis, the wall tracking behaviour, which guides them to the site of fertilisation. The aim of this study was to characterise the rheotactic and thigmotactic response of stallion sperm within a microfluidic channel. Stallion sperm rheotaxis was assessed within the microfluidic channel with regard to: (i) A range of flow velocities, (ii) Varying media viscosity and (iii) Sperm hyperactivation. Sperm distribution across the microfluidic channe...
Al-Kass Z, Eriksson E, Bagge E, Wallgren M, Morrell JM.Stallion semen is known to contain environmental bacteria and normal commensals, and in some cases may contain opportunistic pathogens. These bacteria may negatively influence sperm quality during storage before artificial insemination. The bacteria isolated depend on the culture conditions and method of identification; therefore, the aim of this study was to identify as many of the bacteria present in stallion semen as possible by culturing aliquots of semen under a variety of conditions. Eleven semen samples were available: five extended semen samples from one stud together with a sample of ...
Li B, He X, Zhao Y, Bai D, Li D, Zhou Z, Manglai D.Numerous studies have shown that microRNAs (miRNAs) are essential for testicular development and spermatogenesis. In order to further characterise these physiological processes, three immature and three mature testes of the Mongolian horse were collected and six libraries were established. Using small RNA sequencing technology, 531 mature miRNAs were identified, including 46 novel miRNAs without previously ascribed functions. Among the 531 miRNAs, 421 were expressed in both immature and mature libraries, 65 miRNAs were found solely in immature testis libraries and 45 miRNAs were found solely i...
Hernández-Avilés C, Love CC, Serafini R, Ramírez-Agámez L, Friedrich M, Ghosh S, Teague SR, LaCaze KA, Brinsko SP, Varner DD.In Experiment 1, the effects of glucose concentration in extender (0 mM, 67 mM, 147 mM, 270 mM; G0, G67, G147, and G270, respectively) and storage temperature of extended semen (5, 10, 15 and 20 °C) were evaluated after storage for up to 5 days (T0h to T120h). For all time points tested, mean total (TMOT) and progressive (PMOT) sperm motility were lower in G0 than all other treatment groups (P < 0.05). Mean curvilinear velocity (VCL) was lower in G0 than other treatment groups at all time points tested except T0h (P 0.05). Mean TMOT and PMOT, were lower for semen stored at 20 °...
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...
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...
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...
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...
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...
