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.
Gamboa S, Rodrigues AS, Henriques L, Batista C, Ramalho-Santos J.A group of stallions with different reproductive indexes were used to study seasonal variations in sperm quality (Equus caballus). Semen samples were collected from late September to July and analyzed according to four seasonal periods: late September-December, January-March, late March-May, and June-July. Parameters monitored included sperm concentration, sperm motility, sperm morphology, sperm viability, acrosomal status, plasma membrane stability, and sperm mitochondrial membrane potential. Overall, seminal parameters monitored are affected mostly by time period, followed by animal and last...
Kareskoski AM, Reilas T, Sankari S, Andersson M, Güvenc K, Katila T.Seminal plasma (SP) is a mixture of contents from the testes, epididymides and accessory sex glands. The sperm concentration is highest in the first few jets, or fractions, of the ejaculate, and the composition of SP varies between these fractions because accessory gland secretions are released in a specific order. The aim of this study was to compare the levels of Na, Cl, K, Mg, Ca, inorganic phosphate (Pi) and the enzymes alkaline phosphatase (AP), acid phosphatase (ACP) and β-glucuronidase (BG) in the different fractions of the ejaculate and in different stallions. All semen collections we...
Rojer H, Aurich C.Recently, successful treatment of mares with a history of persistent mating-induced endometritis (PMIE) with dexamethasone has been reported. As systemic treatment of horses with glucocorticoids should be handled with caution, we tested the hypothesis that treatment with the non-steroid anti-inflammatory drug (NSAID) vedaprofen, an inhibitor of cyclooxygenase-2, may have comparative, positive effects on fertility. Barren mares with a history of repeated PMIE were treated with vedaprofen (n = 8; initially 2 mg/kg bodyweight followed by 1 mg/kg orally twice daily) from 1 day before the first ins...
Severa L, Máchal L, Svábová L, Mamica O.This study quantified and evaluated the variability of sperm head shape for 10 different stallions. Sperm head shape characteristics including sperm head length to width ratio, position of the center of gravity, curvature, and degree of roundness were assessed and analysed from images using elliptic Fourier descriptors and inverse Fourier transformation. The first four principal components accounted for 88.46-92.33% of the total variance and provided a good summary of the overall data. In the case of the ejaculate with defective sperm heads the components accounted for 97.35-98.21% of variatio...
Nash DM, Sheldon IM, Herath S, Lane EA.Reproductive efficiency in mares is low and persistent mating-induced endometritis (PMIE) is an important cause of subfertility. Mating-induced endometritis (MIE) an obligate precursor to PMIE, is a ubiquitous, transient inflammatory response to the presence of sperm, seminal components and pathogens. However, the specific inflammatory pathways that derive from MIE and that may also be precursors to PMIE are not clear. The ability to identify and measure robust, repeatable markers of inflammation integral to MIE may be key to understanding the progression to PMIE. The aim of the study was to (...
Minervini F, Lacalandra GM, Filannino A, Nicassio M, Visconti A, Dell'Aquila ME.The purpose of this study was to assess the natural exposure of male horses (Equus caballus) to the mycotoxin zearalenone (ZEA) by using the ELISA test and to evaluate the effects of in vitro exposure of sperm cells to mycotoxin-containing urine extracts on sperm chromatin structure stability. Because of their occurrence in urine samples, ZEA and its derivatives were tested by sperm chromatin structure assay (SCSA) at natural levels detected by ELISA. Thirty-eight urine extracts of Italian (n = 11) and northeastern European (n = 27) horses were tested on frozen-thawed spermatozoa to evaluate t...
Sairanen J, Nivola K, Katila T, Virtala AM, Ojala M.The Finnish mating records of Standardbred trotters (SB; n = 33 679) and Finnhorses (FH; n = 32 731) were analysed to study the effect of the level of inbreeding on foaling rates and to estimate the heritability of foaling rate. A linear mixed model was assumed, with the outcome of the foaling (foal or no foal) as the trait of the study. A restricted maximum likelihood-based method was used to calculate the estimates of the variance components. Predictions of breeding values and estimates of fixed effects were also calculated. The average level of inbreeding was 9.9% in the SB and 3.6% in the ...
Wilsher S, Clutton-Brock A, Allen WR.A total of 78 day 10 horse embryos were transferred non-surgically to recipient mares that had ovulated 9, 7, 6, 5, 4, 3, 2 or 1 day after (negative asynchrony), on the same day (synchronous), or 2 or 4 days before (positive asynchrony) the donor (n=6 or 8 mares per group). Pregnancy rates between 100% (6/6) and 63% (5/8) were seen in recipient mares that were between +2 and -6 days asynchronous. Embryo survival to the heartbeat stage declined in recipients that were -7 days asynchronous and no embryos survived in recipients that were -9 days asynchronous. Irrespective of uterine asynchrony, c...
Wilsher S, Lefranc AC, Allen WR.Fillies completely devoid of endometrial glands (uterine gland knockout; UGKO) would make ideal experimental models in which to study the role of endometrial histotroph in embryogenesis and early fetal development in the mare. Objective: Administration of a synthetic progestagen plus oestrogen to newborn filly foals and, thereafter, at regular intervals to age 6 months, would permanently suppress endometrial gland development. Methods: Nine half-sister Thoroughbred filly foals were treated, in 3 groups, with: A) the weakly active progestagen, norgestomet, administered from birth to age 6 month...
Mugnier S, Kervella M, Douet C, Canepa S, Pascal G, Deleuze S, Duchamp G, Monget P, Goudet G.Oviduct epithelial cells (OEC) co-culture promotes in vitro fertilization (IVF) in human, bovine and porcine species, but no data are available from equine species. Yet, despite numerous attempts, equine IVF rates remain low. Our first aim was to verify a beneficial effect of the OEC on equine IVF. In mammals, oviductal proteins have been shown to interact with gametes and play a role in fertilization. Thus, our second aim was to identify the proteins involved in fertilization in the horse. Results: In the first experiment, we co-incubated fresh equine spermatozoa treated with calcium ionophor...
Len JA, Jenkins JA, Eilts BE, Paccamonti DL, Lyle SK, Hosgood G.The objectives of this study were to determine the effects of centrifugation on equine sperm total and progressive motility, viability, and acrosomal integrity. We hypothesized that although high centrifugation forces would be detrimental to equine Equus caballus sperm, recovery rates would increase. Ejaculates from six stallions were collected, extended to a concentration of 25x10(6) cells/mL, and subjected for 10min to (1) no centrifugation (NC) or (2) centrifugation at 400xg, (3) 900xg, or (4) 4500xg. Before and after centrifugation (Day 0), and after 24h of cooling (Day 1), sperm motility ...
Giesecke K, Hamann H, Sieme H, Distl O.Stallion fertility has increasing importance as the artificial insemination is employed in horses more intensely. Molecular genetic markers may be useful tools to evaluate the stallion fertility before breeding. The prolactin receptor gene (PRLR) was chosen as a candidate for stallion fertility because of its influence on testicular and accessory sex gland function. Screening the equine PRLR gene for polymorphisms in Hanoverian stallions revealed two single nucleotide polymorphisms (SNPs). Association and haplotype analyses were performed in 162 Hanoverian warmblood stallions for these intrage...
Lange Consiglio A, Dell'Aquila ME, Fiandanese N, Ambruosi B, Cho YS, Bosi G, Arrighi S, Lacalandra GM, Cremonesi F.The identification of the adipocyte-derived obesity gene product, leptin (Ob), and subsequently its association with reproduction in rodents and humans led to speculations that leptin may be involved in the regulation of oocyte and preimplantation embryo development. In mice and pigs, in vitro leptin addition significantly increased meiotic resumption and promoted preimplantation embryo development in a dose-dependent manner. This study was conducted to determine whether leptin supplementation during in vitro maturation (IVM) to horse oocytes could have effects on their developmental capacity ...
Tardif S, Brady HA, Breazeale KR, Bi M, Thompson LD, Bruemmer JE, Bailey LB, Hardy DM.Zonadhesin is a rapidly evolving protein in the sperm acrosome that confers species specificity to sperm-zona pellucida adhesion. Though structural variation in zonadhesin likely contributes to its species-specific function, the protein has not previously been characterized in organisms capable of interbreeding. Here we compared properties of zonadhesin in several animals, including the horse (Equus caballus), donkey (E. asinus), and Grevy's zebra (E. grevyi) to determine if variation in zonadhesin correlates with ability of gametes to cross-fertilize. Zonadhesin localized to the apical acroso...
Cuervo-Arango J, Newcombe JR.The association between use of hormone treatments to induce estrus and ovulation and the incidence of hemorrhagic anovulatory follicles (HAFs) was studied in a mixed population of mares (Equus caballus) during two breeding seasons in a commercial breeding clinic. Mares treated with cloprostenol (CLO) were more likely to develop HAFs than were mares with spontaneous cycles (P0.05) from that of mares with ovulatory cycles (10.5+/-1.5 yr).
Canisso IF, Carvalho GR, Morel MC, Guimarães JD, McDonnell SM.The objectives were to (i) characterize sexual behavior of donkey stallions (jacks; Equus asinus) during on-farm semen collection using estrous horse mares (mares; Equus caballus); (ii) compare behavior of young (less experienced) versus older (more experienced) jacks; (iii) determine whether semen suitable for artificial insemination (AI) could be collected using mares; and (iv) determine the suitability of using mares in field collection of semen from jacks. Six Pêga jacks (3.5 to 16 yr old), previously conditioned to breed mares, were used. Mount mares were confirmed in estrus by a teaser ...
Giesecke K, Sieme H, Distl O.Stallion fertility is of high economic importance for the horse industry. The discovery of molecular mechanisms affecting fertility will be facilitated by the horse genome assembly and the development of novel tools for analysing complex genetic traits. Genetic markers in candidate genes, such as CRISP3, SPATA1 and INHBA, in breeding stallions have been associated with pregnancy rate per oestrus in mares. This paper reviews candidate autosomal, X and Y genes for stallion fertility, including genes encoding hormones and their receptors of the hypothalamic-pituitary axis, proteins of the seminal...
Oliveira CH, Vasconcelos AB, Souza FA, Martins-Filho OA, Silva MX, Varago FC, Lagares MA.Addition of cholesterol to sperm membranes improved equine sperm stability during semen cryopreservation; however, it also reduced in vivo fertility. The objective of the present study was to determine the effects of adding cholesterol to stallion sperm prior to freezing, and subsequently removing it from frozen-thawed sperm. Semen from 12 stallions was subjected to four treatments: (T1) control, semen was diluted with Kenney extender, centrifuged, and resuspended to 100 x 10(6)spermatozoa/mL in INRA 82 freezing extender, packaged into 0.5-mL straws, cooled to 5 degrees C, and cryopreserved in...
Cuervo-Arango J, Clark A.The mare is a seasonally polyestrus breeder. In early spring, the mare enters a "transition period" between the anovulatory season and the first ovulation of the year. This period is characterized by irregular estrus cycles and high incidence of regressing dominant follicles. There is a belief that pregnancy rates resulting from the first ovulation of the season is lower than in subsequent ovulations, however this has never been studied critically. Progestagens are often used as an aid to manage the transition period. The objective of this study was to compare pregnancy rates of mares from the...
Spizziri BE, Fox MH, Bruemmer JE, Squires EL, Graham JK.Irreversible damage occurs to spermatozoal membranes, during the phase transition, when spermatozoa are cooled from room temperature to 5 degrees C. Some of this damage can be ameliorated by adding cholesterol to the membrane, thereby altering membrane lipid composition. Adding cholesterol-loaded cyclodextrins (CLCs) to stallion spermatozoa prior to freezing, increases cell cryosurvival. However, the fertilizing potential of CLC-treated stallion spermatozoa is unknown. To address this, experiments were conducted which evaluated the ability of CLC-treated stallion spermatozoa to capacitate, acr...
LeBlanc MM, Causey RC.Endometritis, a major cause of mare infertility arising from failure to remove bacteria, spermatozoa and inflammatory exudate post-breeding, is often undiagnosed. Defects in genital anatomy, myometrial contractions, lymphatic drainage, mucociliary clearance, cervical function, plus vascular degeneration and inflamm-ageing underlie susceptibility to endometritis. Diagnosis is made through detecting uterine fluid, vaginitis, vaginal discharge, short inter-oestrous intervals, inflammatory uterine cytology and positive uterine culture. However, these signs may be absent in subclinical cases. Hyper...
Ortega-Ferrusola C, González-Fernández L, Muriel A, Macías-García B, Rodríguez-Martínez H, Tapia JA, Alonso JM, Peña FJ.In an attempt to evaluate the possible relationship between the microbial flora in the stallion ejaculate and its ability to freeze,three ejaculates from five stallions were frozen using a standard protocol. Before freezing, an aliquot was removed for bacteriological analysis. Bacterial growth was observed in all the ejaculates studied. The isolated microorganisms were:Staphylococcus spp. and Micrococcus spp. (in all the stallions), beta-haemolytic Streptococcus (in stallions 3 and 4), Corynebacterium spp. (in stallions 1, 3-5), Rhodococcus spp. (in stallion number 2), Pseudomonas spp. (in sta...
Cuervo-Arango J, Newcombe JR.Prostaglandin F(2α) and its analogues (PGF) are widely used in equine reproductive practice. The interval from PGF treatment to ovulation (ITO) varies greatly with a range from 2 to 16 days. Clinical observation suggests that mares mated and ovulated soon after PGF treatment may have poor fertility. Reproductive records of 329 cyclic Thoroughbred mares were analysed retrospectively. The following parameters were analysed: (i) use of cloprostenol; (ii) ITO and (iii) number of ovulations per cycle. According to these parameters, mares were classified into four groups. (i) mares with spontaneous...
Bugno M, Słota E, Pieńkowska-Schelling A, Schelling C.Fluorescent in situ hybridisation (FISH) using a panel of molecular probes for all chromosome pairs obtained by chromosome microdissection of the domestic horse ( Equus caballus ) was used to diagnose karyotype abnormalities in 35 horses (32 mares, 2 stallions and 1 intersex), which were selected for the study due to infertility (23 horses), reduced fertility (10 horses) and developmental anomalies (2 horses). The use of the FISH technique with probes for each horse chromosome pair enabled the diagnosis of many different chromosome aberrations in this population. Among the horses analysed, 21 ...
Ortega Ferrusola C, González Fernández L, Macías García B, Salazar-Sandoval C, Morillo Rodríguez A, Rodríguez Martinez H, Tapia JA, Peña FJ.The ability of stallion spermatozoa to produce nitric oxide (NO) before (fresh) and after freezing and thawing (FT) was evaluated by means of flow cytometry after loading the sperm suspension with the probe, 4,5-diaminofluorescenin diacetate. The presence of NO synthase (NOS) was investigated by Western blotting using anti-NOS1, anti-NOS3, or anti-universal NOS antibodies (Abs). While NO was detected both in fresh and FT sperm suspensions, its production increased after cryopreservation only when egg yolk was removed from the extender. Anti-NOS1 Ab intensively labeled a single band with an app...
Morrell JM, Johannisson A, Dalin AM, Rodriguez-Martinez H.The objective of the current study was to optimize the volumes of Androcoll-E and sperm sample used in various sizes of centrifuge tube to scale up single-layer centrifugation (SLC) for routine use in the field. Although sperm suspensions of equivalent quality were produced using Androcoll-E in small and large tubes, the sperm yield was much lower in the latter (P<0.001). In contrast, in 200-mL tubes (XL), the yields were approximately 25% higher than those for the small tubes. An increased volume (4.5 mL) of extended ejaculate in small tubes (SLC-Inc) or 15 to 18 mL extended ejaculate on 1...
Heise A, Kähn W, Volkmann DH, Thompson PN, Gerber D.The use of epididymal stallion spermatozoa for routine artificial insemination can secure easy future use of valuable genetics after unforeseen death or injury of a valuable stallion. The aims of this study were to (1) directly compare pregnancy rates for fresh and frozen-thawed stallion epididymal and ejaculated spermatozoa after conventional artificial insemination and (2) to investigate the effect of seminal plasma on the fertility of epididymal spermatozoa after insemination. Twenty-one mares were randomly assigned to three stallions. Mares were inseminated at five consecutive oestrous per...
Mugnier S, Dell'Aquila ME, Pelaez J, Douet C, Ambruosi B, De Santis T, Lacalandra GM, Lebos C, Sizaret PY, Delaleu B, Monget P, Mermillod P....The mechanism of fertilization remains largely enigmatic in mammals. Most studies exploring the molecular mechanism underlying fertilization have been restricted to a single species, generally the mouse, without a comparative approach. However, the identification of divergences between species could allow us to highlight key components in the mechanism of fertilization. In the pig, in vitro fertilization (IVF) and polyspermy rates are high, and spermatozoa penetrate easily through the zona pellucida (ZP). In contrast, IVF rates are low in the horse, and polyspermy is scarce. Our objective was ...
Scherzer J, Fayrer-Hosken RA, Aceves M, Hurley DJ, Ray LE, Jones L, Heusner GL.We evaluated combinations of two commercial semen extenders and three concentrations of glycerol to determine the combination that yielded the highest post-thaw sperm motility. Methods: A randomised 2 x 3 block design was used. Methods: Semen was collected from four stallions (6 collections per stallion). The sample was diluted with either a dried skim-milk glucose extender (EZ Mixin Original Formula) or a chemically defined, milk-free diluent (INRA 96), and each was used in combination with 2%, 3% or 4% glycerol in standard commercial freezing medium. Sperm motility was assessed by microscopy...
Pieńkowska-Schelling A, Kaul A, Schelling C.Abnormalities of chromosomes are an important and well documented cause of disorders of sexual development, fertility problems and congenital anomalies in mammals. Detection of low-level 63,X/64,XX mosaicism during routine cytogenetic evaluation is a challenge because its clinical significance is not yet fully clear. This study describes the prevalence and levels of 63,X mosaicism for a cohort of fertile mares and compares the results with eight problem mares for which no clinical cause of sub-fertility was found. The study design allowed for the analysis of micronuclei which are biomarkers of...
Tshewang U, Dowsett KF, Knott LM, Trigg TE.To investigate the effects of two doses (200 and 400 mg) of a water-soluble gonadotrophin-releasing hormone vaccine on the ovarian activity of 2-year-old fillies. Methods: A controlled vaccination dose rate experiment. Methods: Six 2-year-old Australian Stock Horse fillies were randomly allocated to three treatment groups; unvaccinated controls, those receiving 200 mg of the vaccine and those receiving 400 mg of the vaccine. Results: Ovarian activity of the treated fillies was suppressed at the peak of breeding season while that of untreated controls continued normally. The control fillies dis...
Brink P, Schumacher J, Schumacher J.There is a need for study of a method for restoring a ventrally positioned uterus to a horizontal position involving fertility of mares with delayed uterine clearance. Objective: A ventrally-angled uterus can be elevated to a horizontal position using a laparoscopic technique. Objective: To develop a laparoscopic technique of imbricating the mesometria to elevate the uterus to a horizontal position. Methods: The right and left mesometria of 5 pluriparous mares, all barren for 1-8 years (mean 3.8 years), with a pendulous, ventrally-angled uterus were shortened laparoscopically, by imbrication, ...
Al-Jaru A, Goodwin W, Skidmore J, Khazanehdari K.Advances in molecular cytogenetics have provided the opportunity to study events during prophase I of meiosis. Immunofluorescent localization of different meiotic protein components were used to characterize the early stages of the first meiotic division in horse spermatocytes. The frequency and distribution of recombination events during prophase I were investigated using the mutL homolog 1 (MLH1) protein that is known to be associated with these events. The frequency and distribution of MLH1 foci were investigated in pachytene nuclei of 6 fertile stallions, and the average relative synaptone...
Clulow JR, Maxwell WM, Evans G, Morris LH.Duck and chicken egg yolk were compared for their protective effects against cold shock during the cryopreservation of stallion sperm in a lactose-EDTA-glycerol cryodiluent. Methods: A completely randomised design was used. Procedure Ejaculates from five stallions (n = 14 ejaculates) were split and diluted to either 20 or 200 x 10(6) sperm/mL in a lactose-EDTA extender containing either duck or chicken egg yolk. The extended semen was then frozen in liquid nitrogen. The percentage of sperm total motility and forward progressive motility were assessed before freezing and at 0 and 1 hr after tha...
Daels PF, Hughes JP.The purpose of this study was to develop a contraceptive method for feral horses. The feral horse population has increased significantly in recent years despite attempts to control numbers. As in most wild animal population control programs, contraceptive methods must be easy to apply, cause minimal disruption to the social structure and be fully reversible. In the present study, we tested the effectiveness of an intrauterine device (IUD) for fertility control in mares. Six mares were fitted with a silastic O-ring-shaped IUD on July 1 of Year 1. The IUD-treated mares were turned out with 12 no...
Michel TH, Rossdale PD, Cash RS.Plasma progesterone levels were measured daily to determine the accuracy of diagnosing ovulation by rectal palpation carried out every other day; 81.5 per cent mares injected with human chorionic gonadotrophin showed increases of progesterone more than 1 ng/ml by 72 h after injection compared with 65 per cent of mares injected with gonadotrophin releasing hormone (GnRH) or saline. Mating at ovulation achieved a 74 per cent pregnancy rate in mares given hCG compared with 50 per cent given GnRH and 45 per cent controls. Diagnosis of ovulation per rectum on the basis of a pit in the ovarian surfa...
Meyers-Brown GA, Loud MC, Hyland JC, Roser JF.The most common equine breeding practice to decrease the time to the first ovulation of the year is to use artificial lights starting December 1 in the Northern Hemisphere. It can take 60-90 d for this lighting regimen to induce a fertile ovulation. The success rate for pharmaceutical compounds to carry out the same process has been variable. One compound that did induce an early ovulation was recombinant equine follicle stimulating hormone (reFSH), but neither pregnancy nor cyclicity was established in that study. Starting on December 1, 20 deep-anestrous mares of light horse breeds (4-15 y...
Lefranc A-, Allen WR.The diffuse noninvasive epitheliochorial equine placenta develops an intimate and complex interdigitation with the maternal endometrium throughout gestation to maximise surface contact and, consequently, optimise nutritional and gaseous maternofetal exchanges. A significant reduction occurs in the surface density of microcotyledons on the placentae of Welsh Pony vs. Thoroughbred mares that may relate to a difference in either the number or density of endometrial glands between these breeds. Objective: To examine this hypothesis and to determine the influence of the oestrous cycle upon the deve...
Oxender WD, Noden PA, Hafs HD.The luteolytic effect of PGF2alpha, administered by intrauterine infusion or subcutaneous injection during early dioestrus, was observed in mares of mixed breeds. An infusion of 10 mg on Days 7 to 9 after ovulation caused a sharp fall in plasma progesterone levels and induced oestrus and ovulation. Oestrus was significantly longer than in the natural cycle but the time of ovulation in relation to the end of oestrus was normal. The time of return to oestrus following luteolysis was not dependent on the amount of PGF2alpha within the range of doses given. Luteolysis could be induced as early as ...
Roach J, Schnobrich M, Ellerbrock R, Feijo L, Bradecamp E, Alvarenga MA, Kline K, Canisso I.This study compares two methods for seminal plasma removal by evaluating sperm recovery rates, and motility and morphology of cooled-stored semen. Ejaculates were divided into three groups: control, filtration and cushioned centrifugation. Semen was extended to 25 million sperm/ml using a skim-milk-based extender and stored at 5°C for all groups. Sperm motility (total motility (%TM) and progressive motility (%PM)) was determined at 0, 24, 48 and 72 hours by a computer-assisted sperm analyser. Sperm morphology was assessed using differential interference microscopy. Overall, %TM of the cen...
Giese A, Jude R, Kuiper H, Raudsepp T, Piumi F, Schambony A, Guérin G, Chowdhary BP, Distl O, Töpfer-Petersen E, Leeb T.The cysteine-rich secretory protein (CRISP) family consists of three members called acidic epididymal glycoprotein 1 (AEG1), AEG2, and testis-specific protein 1 (TPX1), which share 16 conserved cysteine residues at their C-termini. The CRISP proteins are primarily expressed in different sections of the male genital tract and are thought to mediate cell-cell interactions of male germ cells with other cells during sperm maturation or during fertilization. Therefore, their genes are of interest as candidate genes for inherited male fertility dysfunctions and as putative quantitative trait loci fo...
Jaworska J, Jaworski Z, McDonnell SM, Górecka-Bruzda A.Infanticide, related to a stallion's aggression toward a foal sired by another stallion, and feticide related to a new stallion's aggression and/or pheromonal influence (the Bruce effect) inducing loss of a fetus sired by another stallion, a female's counteraction to infanticide, have been proposed for domestic horses (Equus caballus) in human-managed conditions. The aim of the present study was, in conditions close to natural, to investigate the influence of the natural succession of a harem stallion on the mares' subsequent reproductive performance. In a population of semi-feral Konik polski...
Gil MC, Ferrusola CO, Anel-López L, Ortiz-Rodriguez JM, Alvarez M, de Paz P, Anel L, Peña FJ.Spermatozoa undergo apoptotic changes during the cryopreservation process. These changes, recently termed spermptosis, resemble the cryopreservation induced delayed onset of cell death observed after thawing of somatic cells. Due to its importance in cryobiology, methods to easily identify spermptotic cells are warranted. In this study, a well-validated method for identification of spermatozoa with caspase 3 activity was compared with use of the combination of Hoechst 33342 (H-42) and ethidium homodimer (Eth-1). Live, dead and apoptotic spermatozoa assessed with each method were compared using...
Gottschalk M, Sieme H, Martinsson G, Distl O.A high quality of stallion semen is of particular importance for maximum reproductive efficiency. In the present study, we estimated the relationships among estimated breeding values (EBVs) of semen traits and EBVs for the paternal component of the pregnancy rate per estrus cycle (EBV-PAT) for 100 German Warmblood stallions using correlation and general linear model analyses. The most highly correlated sperm quality trait was total number of progressively motile sperm (r = 0.36). EBV-PAT was considered in three classes with stallions 1 SD below (<80), around (80-120), and above (>120) the popu...
Aitken RJ, Lambourne S, Medica AJ.A capacity to predict the likelihood of pregnancy following natural matings would be of considerable benefit to the Thoroughbred horse breeding industry. In this article, we describe a strategy for achieving this outcome through the analysis of dismount samples, that achieved an overall accuracy of 94.6%. The purpose of this study was to determine whether the analysis of dismount semen samples from Thoroughbred stallions could be used to predict whether a given mating would result in a pregnancy. The analysis was based on 143 matings of 141 mares by a cohort of 7 Thoroughbred stallions over a ...
Kastelic JP, Adams GP, Ginther OJ.Luteal progesterone was removed by an injection of prostaglandin F2alpha or bilateral ovariectomy on Day 12 of pregnancy in pony mares. The embryonic vesicle remained mobile in the uterus until loss occurred on Days 13, 13, 15, or 19 in four prostaglandin-treated mares and Days 15, 17, 19, or 26 in four ovariectomized mares. Exogenous progesterone given daily, starting on Day 12, maintained pregnancy until Day 40 in five of five prostaglandin-treated and three of four ovariectomized mares. During two-hour mobility trials on Day 14, embryonic vesicles in mares without luteal or exogenous proges...
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...
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...
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...
Le Breton A, Lewis N.Assisted reproductive technologies (ARTs) are performed worldwide in the equine industry to produce genetically valuable foals. Among them, ovum pick up (OPU) combined with intra-cytoplasmic sperm injection (ICSI) can now be more efficient than embryo transfer (ET) under optimal conditions. However, OPU is not a benign procedure for the mare and the process is costly. Improved efficiency is therefore in the interest of everyone, maximizing mare welfare and optimizing economics for the client. One of the key factors of success is the antral follicle count (AFC) at the time of OPU and subsequent...
Ortiz-Rodriguez JM, Bucci D, Tovar-Pascual L, Granata S, Spinaci M, Nesci S.Sperm metabolism consists of a sophisticated network of biochemical reactions and varies between species, resulting in different metabolic strategies for ATP production to maintain sperm functionality. ATP can be produced through glycolysis or in the mitochondria by oxidative phosphorylation (OXPHOS). Since OXPHOS is the predominant metabolic pathway in horses spermatozoa, various assessments of mitochondrial activity are used to evaluate fertility, utilizing techniques such as fluorescent probes analysed via microscopy or flow cytometry, and polarographic electrode assays to measure current f...
Sievers J, Distl O.The Rhenish German draught horse is an endangered German horse breed, originally used as working horse in agriculture. Therefore, the objective of this study was to evaluate the breed's genetic diversity using pedigree and genomic data in order to analyze classical and ancestral pedigree-based inbreeding, runs of homozygosity, ROH islands, and consensus ROH. Methods: We studied the genome-wide genotype data of 675 Rhenish German draught horses and collated pedigree-based inbreeding coefficients for these horses. The final dataset contained 64,737 autosomal SNPs. Results: The average number of ...
Peña FJ, Martín-Cano FE, Becerro-Rey L, da Silva-Álvarez E, Gaitskell-Phillips G, Ortega-Ferrusola C, Aparicio IM, Gil MC.Although stallion spermatozoa are now recognized as highly dependent on oxidative phosphorylation for ATP production in the mitochondria, most extenders in use contain supraphysiological concentrations of glucose as the main energy source. While the toxicity of cryoprotectants has been well documented in the literature, the potential toxicity of excessive glucose in extenders is largely ignored. However, the toxicity of excess glucose, known as "carbotoxicity", is well-established in many areas of medicine. In this paper, we review the basic aspects of stallion spermatozoa metabolism, focusing...
Pezo F, Contreras MJ, Zambrano F, Uribe P, Risopatron J, Andrade AFC, Yeste M, Sánchez R.In recent decades, there has been a growing interest in optimizing the protocols intended to sperm cryopreservation in domestic animals. These protocols include initial cooling, freezing, and thawing. While different attempts have been devised to improve sperm cryopreservation, the efficiency of this reproductive biotechnology is still far from being optimal. Furthermore, while much attention in improving cooling/freezing, less emphasis has been made in how thawing can be ameliorated. Despite this, the conditions through which, upon thawing, sperm return to physiological temperatures are much ...
The Journal of heredityJanuary 1, 1964
Volume 55 31-38 doi: 10.1093/oxfordjournals.jhered.a107283
BENIRSCHKE K, LOW RJ, SULLIVAN MM, CARTER RM.This study is oriented towards explaining the usual infertility observed in mule and hinny species through a detailed investigation of their chromosomal structures, with a special emphasis on the instances […]
Jones R.A protein-carbohydrate recognition system is thought to be involved in the early stages of fertilization in mammals. In this investigation carbohydrate-binding proteins have been identified in extracts of human, bull, boar, ram, stallion and hamster spermatozoa using [125I]fucoidin and [125I]neoglycoproteins (BSA-fucose and BSA-mannose) to probe Western blots. Results show that proacrosin is the major protein species recognized in extracts of human, bull, boar and ram spermatozoa. In hamster and stallion spermatozoa, carbohydrate-binding activity was associated with several low molecular weigh...
Merkt H, Jacobs KO, Klug E, Aukes E.An evaluation of the foaling rate achieved in the Hannoverian breed in Germany between 1815 and 1973 showed that during this period no improvement of the reproductive rate was achieved. The decennial foaling percentage remained within 50--60% except for those decades which included the two World Wars and their aftermaths. The annual foaling percentage remained maximal until the number of mares covered/stallion rose above 80 and it also remained high throughout the reproductive life of the stallion. Only in the oldest stallion (32 years) was there a significant lowering of fertility.
