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.
Scherzer J.Reproductive performance in mares can be enhanced by various techniques. Protocols hastening the onset of follicular development help establish pregnancy in mares and ensure that foals are born early in the year. The time spent breeding mares can be reduced by synchronizing estrus and inducing ovulation. After successful fertilization of the oocyte, the developing embryo can survive in the uterus only if postbreeding endometritis, if present, is treated.
García BM, Fernández LG, Ferrusola CO, Salazar-Sandoval C, Rodríguez AM, Martinez HR, Tapia JA, Morcuende D, Peña FJ.Lipids were extracted from ejaculated spermatozoa from seven individual stallions to distinguish neutral lipids (NL) and polar lipids (PL) and determine their variation among stallions and their relationship with sperm quality and sperm susceptibility to lipid peroxidation. The isolated fatty acids were correlated with sperm quality (membrane integrity, mitochondrial membrane potential (ΔΨm) and expression of active caspases) and the sensitivity of the sperm plasma membrane to LPO. The miristic (C14: 0), palmitic (C16: 0), stearic (C18: 0) and oleic (C18: 1n9) acids were predominant among th...
Bertelsmann H, Keppler S, Höltershinken M, Bollwein H, Behne D, Alber D, Bukalis G, Kyriakopoulos A, Sieme H.The essential trace element selenium is indispensable for male fertility in mammals. Until now, little data existed regarding the relationship between selenium and sperm quality in the stallion. Selenium, or selenium-dependent glutathione peroxidase activity, was determined in red blood cells, semen, seminal plasma and spermatozoa, and the percentages of spermatozoa with progressive motility (PMS), intact membranes (PMI), altered (positive) acrosomal status (PAS) and detectable DNA damage, determined by the sperm chromatin structure assay, were evaluated in 41 healthy stallions (three samples ...
Bailey CS, Macpherson ML, Pozor MA, Troedsson MH, Benson S, Giguere S, Sanchez LC, Leblanc MM, Vickroy TW.The objective was to determine if long-term treatment with trimethoprim sulfamethoxazole (antimicrobial), pentoxifylline (anti-inflammatory/anti-cytokine) and altrenogest (synthetic progestin), would improve pregnancy outcome in mares with experimentally induced placentitis. Seventeen normal, pregnant pony mares were enrolled in the study at 280-295 d of pregnancy. Placentitis was induced in all mares by intra-cervical inoculation of Streptococcus equi subsp. zooepidemicus (10(7) CFU). Five mares served as infected, untreated control animals (Group UNTREAT). Twelve mares (Group TREAT) were inf...
Allen WR.Genus-specific reproductive processes and strategies displayed by equids, camelids and elephantids are compared and contrasted to illustrate the amazing diversity of reproductive physiology between genera and the equally surprising conservation of reproductive processes across a genus in the face of other dramatic phenotypic modifications and adaptation to prosper in the prevailing environment. From intrauterine conceptus mobility and chorionic gonadotrophic secretion by specialised invasive trophoblast cells in equids, through induced ovulation, an asymmetrical uterus and an almost absurdly s...
Bosh KA, Powell D, Neibergs JS, Shelton B, Zent W.There have been no studies reporting the impact of reproductive efficiency and mare financial value on economic returns. Objective: To explore the economic consequences of differences in reproductive efficiency over time in the Thoroughbred mare. Methods: Complete production records for 1176 mares were obtained. Production history and drift in foaling date were calculated. Multiple logistic regression was used to identify factors influencing the probability of producing a registered foal in 2005. The 'net present value' and 'internal rate of return' were calculated for economic scenarios invol...
Bosh KA, Powell D, Shelton B, Zent W.To improve efficiency at the farm level, a better understanding of how farm management factors impact reproductive performance is important. Objective: To assess reproductive efficiency and effectiveness among Thoroughbred mares in central Kentucky. Methods: A cohort of 1011 mares on 13 farms in central Kentucky was followed during the 2004 mating and 2005 foaling season. Information on farm level practices was collected via interviews with farm managers. Reproductive records were collected for each mare mated to obtain information on mare characteristics. The influence of mare age and status ...
Vasconcelos AB, Santana MA, Santos AM, Santoro MM, Lagares MA.Microscopy has been used in the routine evaluation of sperm metabolism. Nevertheless, it has limited capacity to preview male fertility. As calorimetry may be used to evaluate directly the metabolic activity of a biological system, the aim of this study was to use microcalorimetry as an additive method for sperm metabolism evaluation of cooled equine semen. Two ejaculates of four stallions were collected and motility, viability (eosin 3%) and membrane functional integrity (hyposmotic swelling test) of spermatozoa were evaluated. Sperm samples were processed following different protocols and th...
Raz T, Carley SD, Green JM, Card CE.Reliable methods for regulating oestrus and superovulation in equine embryo transfer (ET) programs are desirable. The objective in this study was to compare two oestrus synchronization methods combined with equine follicle-stimulating hormone (eFSH) treatment in an ET program. In the progesterone and estradiol-17β (P&E) group, mares (n=12) were given progesterone and estradiol-17β, daily for 10 days, followed by prostaglandin (PG)F(2α) on the last day. In the PG group, mares (n=12) were given PGF(2α) 5 days post-ovulation. In both groups donor mares were allocated to eFSH therapy, and were...
Morrell JM, Rodriguez-Martinez H, Johannisson A.This study compared the effect on semen quality of different handling methods used in the preparation of stallion semen doses for artificial insemination. The three methods were (i) extending the ejaculate to 30-50 x 10(6)/ml, (ii) single layer centrifugation (SLC) and (iii) sperm washing (centrifugation without a colloid). An additional treatment was to add seminal plasma (SP) in various proportions to some SLC preparations. The resulting samples were evaluated for sperm motility by computer assisted sperm analysis, membrane integrity using the Nucleocounter SP-100 and chromatin integrity by ...
Clulow JR, Evans G, Maxwell WM, Morris LH.The aim of the present study was to evaluate the potential oocyte binding ability and functional integrity of fresh or frozen-thawed, sex-sorted or non-sorted stallion spermatozoa. In the absence of effective IVF procedures in the horse, a heterologous sperm-binding assay was used as an indicator of fertilising capacity to assess differences in the ability of stallion spermatozoa to bind to bovine oocytes. The functional integrity of four treatment groups was assessed: (1) fresh non-sorted spermatozoa; (2) fresh sex-sorted spermatozoa; (3) frozen-thawed non-sorted spermatozoa; and (4) frozen-t...
Lagares MA, Castanheira PN, Amaral DC, Vasconcelos AB, Veado JC, Arantes RM, Stahlberg R.The aim of the present study was to evaluate the in vitro viability of equine embryos vitrified in three different solutions. Day 6 and 6.5 embryos were measured and morphologically evaluated. Only grade 1 or 2 morulae and early blastocysts were vitrified. Eighteen embryos were distributed in Group 1: 40 percent ethylene glycol in PBS, Group: 2 and 3: 40 percent ethylene glycol, 18 percent Ficoll, 0.3M sucrose or 0.3M trehalose in PBS, respectively. The vitrified embryos were loaded individually into 0.25 ml straws, which were cooled and immersed in liquid nitrogen. After warming at 20 degree ...
Sharma S, Davies Morel MC, Dhaliwal GS.Decreased reproductive performance due to summer stress is a well known phenomenon in farm livestock. Whether this occurs in the mare and specifically how this might affect postpartum reproductive activity and performance, especially at Foal Heat (FH), is unknown. This study, therefore, aims to investigate this and the factors that might affect postpartum reproductive activity. Reproductive records of 228 Thoroughbred mares (694 mare years) bred in subtropical north-western India were retrospectively analysed. Overt oestrous activity occurred within 21 d postpartum in 92.94% (645/694) of mares...
Hoogewijs M, Rijsselaere T, De Vliegher S, Vanhaesebrouck E, De Schauwer C, Govaere J, Thys M, Hoflack G, Van Soom A, de Kruif A.Three experiments were conducted to evaluate the impact of centrifugation on cooled and frozen preservation of equine semen. A standard centrifugation protocol (600 x g for 10 min=CP1) was compared to four protocols with increasing g-force and decreased time period (600 x g, 1200 x g, 1800 x g and 2400 x g for 5 min for CP2, 3, 4, and 5, respectively) and to an uncentrifuged negative control. In experiment 1, the influence of the different CPs on sperm loss was evaluated by calculating the total number of sperm cells in 90% of the supernatant. Moreover, the effect on semen quality following ce...
Jacobson CC, Choi YH, Hayden SS, Hinrichs K.Oocytes may be collected from live mares from either the stimulated preovulatory follicle or from all visible immature follicles. We evaluated the yield of mature oocytes, and of blastocysts after intracytoplasmic sperm injection (ICSI), for both follicle types. In Experiment 1, mares were assigned to Progesterone (1.2g biorelease progesterone weekly) or Control treatments. Transvaginal aspiration of all follicles was performed every 14 d. Overall, 596 follicles were aspirated, with a 54% oocyte recovery rate. There was no difference between treatments in number of follicles punctured (9.0 to ...
Desantis S, Ventriglia G, Zizza S, Nicassio M, Valentini L, Di Summa A, Lacalandra GM.Stallion sperm from semen collected in Southern Italy during the breeding (June-July) and non-breeding (December-January) periods were analyzed by means of twelve lectins to evaluate the glycoconjugate pattern and to verify whether there are any seasonal differences in the glycosylation pattern of the sperm glycocalyx. The acrosomal cap showed reactivity for Maackia amurensis (MAL II), Sambucus nigra (SNA), Arachis hypogaea (PNA), Glycine max (SBA), Helix pomatia (HPA), Canavalia ensiformis (Con A) Triticum vulgaris (WGA), and Griffonia simplicifolia isolectin II (GSA II) in breeding and non-b...
Wrench N, Pinto CR, Klinefelter GR, Dix DJ, Flowers WL, Farin CE.The objective of this study was to determine the effect of season on sperm quality variables, expression of the fertility-related protein SP22 and selected mRNA transcripts in fresh and cryopreserved stallion sperm. Four stallions were collected in each of the four seasons: summer, fall, winter and spring. Ejaculates were divided and then evaluated for motility, morphology, SP22 staining and expression of selected mRNAs as either fresh semen samples or cryopreserved samples. A significant interaction between season and cryopreservation status was found for total and progressive sperm motility....
Di Meo GP, Neglia G, Perucatti A, Genualdo V, Iannuzzi A, Crocco D, Incarnato D, Romano G, Parma P, Iannuzzi L.Gonadal dysgenesis and heterosexual conditions are often associated with sex chromosome abnormalities. In this study we report on 2 cases of abnormal sex development involving numerical sex chromosome aberrations in both horse and sheep. A 17-month-old Standardbred filly was sent to an equine fertility centre as an embryo donor due to its reduced size, being much smaller than a racehorse filly of the same age, which excluded it from an athletic career. External genitalia were clinically normal but manual palpation of the reproductive tract showed the presence of a small underdeveloped uterus a...
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...
Palmer E, Chavatte-Palmer P.Reproductive technologies aim at improving fertility with the ultimate result of improving genetic selection. In equidae, the respective contribution of different methods of horse management and breeding to genetic progress remain difficult to evaluate as breeding strategies affect the number of offspring per mare or stallion whereas different selection methods (based on pedigree, performance, genomics or progeny's performance) will be applicable at different ages, leading to different accuracy in the estimation of the breeding value. Here, a mathematical model was applied to evaluate theoreti...
Vogelsang MM, Kreider JL, Bowen MJ, Potter GD, Forrest DW, Kraemer DC.A series of experiments was conducted to develop a procedure for consistent, repeatable collection of oocytes from the preovulatory follicle of the mare. In one experiment, in situ follicular aspiration with a needle and syringe was performed on 19 mares. From 37 aspirations, four oocytes were recovered (10% recovery rate). In a second experiment, ovaries were visualized via standing flank laparotomy during which two different aspiration techniques were used. Use of a needle and syringe as in the first experiment resulted in successful oocyte recovery in one of seven (14%) attempts. Aspiration...
Ferrer MS, Miller LMJ.Antisperm antibodies (ASAs) have been associated with infertility in stallions. The objectives of this study were to investigate the frequency of ASA-positive semen samples in satisfactory and non-satisfactory breeder stallions, the association between ASA binding and semen quality, and factors that may affect the diagnosis. Breeding soundness examinations were performed in 21 stallions and the percentage of IgG- and IgA-bound spermatozoa was evaluated using flow cytometry. Median IgG and IgA binding did not differ between the first and second ejaculates. The percentage of IgA-bound spermatozo...
Turner RM, Casas-Dolz R, Schlingmann KL, Hameed S.To determine whether a homologue of A-kinase anchor protein 4 (AKAP4) is present and functional as an AKAP in equine spermatozoa and examine the effect of semen cooling and cryopreservation on binding of equine AKAP4 to the regulatory (RII) subunit of protein kinase-A (PK-A). Methods: Ejaculated semen collected from 2 fertile stallions, 3 bulls, and 3 humans. Methods: Identification of an equine homologue of AKAP4 was investigated via DNA sequencing. Protein was extracted from the spermatozoa of each species for immunoblot analysis to identify AKAP4 and its precursor protein, pro-AKAP4; immuno...
Walbornn SR, Felix M, Schnobrich MR, Bradecamp EA, Scoggin CF, Stefanovski D, Hinrichs K.To determine the effect of stage of estrus cycle (day after ovulation) at the time of transvaginal ultrasound-guided follicle aspiration (TVA) on parameters related to the success of in vitro equine embryo production. 14 healthy mares were used; 11 completed the study and were included for analysis. Mares underwent TVA of all follicles ≥ 5 mm diameter at each of 3 timepoints: 7 days after ovulation, 14 days after ovulation, and S-DSF (subordinate to a dominant stimulated follicle), during estrus at 24 hours after gonadotropin administration. The 3 treatments were assigned to each mare in ran...
Giaretta E, Mislei B, Martínez-Pastor F, Nesci S, Spinaci M, Galeati G, Nerozzi C, Mari G, Tamanini C, Bucci D.Equine spermatozoa highly rely on oxidative phosphorylation for their energy management. The present work aimed to characterize the role of mitochondria on horse sperm motility and ROS production by incubating spermatozoa with specific inhibitors of the different mitochondrial complexes. Equine spermatozoa were incubated 1 h and 3 h at 37 °C with: complex I inhibitor rotenone (5 μM, ROT), complex II inhibitor dimethyl-malonate (10 mM, DMM), complex III inhibitor antimycin A (1.8 μM, ANTI), the uncoupling agent carbonyl cyanide m-chlorophenyl hydrazine (5 μM, CCCP), ATP synthase inhi...
Bucci D, Spinaci M, Mislei B, Gadani B, Rizzato G, Love CC, Tamanini C, Galeati G, Mari G.Stallion semen storage for artificial insemination is mainly based on liquid cooled storage. In many stallions this technique maintains sperm quality for an extended period of time (24-72 hr) at 7°C. While this technique is commonly used in the horse industry, there can be a decline in fertility in some stallions, due to an inability of their sperm to tolerate the cool storage process. The aim of the present work was to evaluate the effect of two natural antioxidants (epigallocatechin-3-gallate (EGCG) at 20, 60 and 120 μm and green tea polyphenols, and p at .001, .01 and .1 mg/ml) on some...
Alghamdi AS, Troedsson MH, Xue JL, Crabo BG.To compare the effect of semen extender and seminal plasma on postthaw motility and filtration through a glass wool-Sephadex (GWS) filter for frozen stallion semen. Methods: 7 stallions from which we collected > or = 3 ejaculates/stallion. Methods: 4 experiments were conducted to evaluate postthaw quality of frozen stallion semen. Kenney extender was compared with glucose-EDTA extender by use of various dilution rates that resulted in differing concentrations of seminal plasma. Stallions known to produce semen with poor postthaw quality were used to investigate whether a particular extender or...
Ing NH, Brinsko SP, Curley KO, Forrest DW, Love CC, Hinrichs K, Vogelsang MM, Varner DD, Welsh TH.Testicular steroidogenesis and spermatogenesis are negatively impacted by stress-related hormones such as glucocorticoids. The effects of two injections of a therapeutic dose of dexamethasone (a synthetic glucocorticoid, 0.1mg/kg; i.v.) given 24h apart to each of three stallions were investigated and compared to three saline-injected control stallions. Dexamethasone decreased circulating concentrations of cortisol by 50% at 24h after the initial injection. Serum testosterone decreased by a maximum of 94% from 4 to 20h after the initial injection of dexamethasone. Semen parameters of the dexame...
Amann RP, Thompson DL, Squires EL, Pickett BW.Extragonadal reserves totalled 89 X 10(9) spermatozoa for 5--16-year-old sexually rested stallions and 60 X 10(9) for 2--4-year-olds. Regardless of age, the cauda epididymidis contained 62% of the total reserves and the vas deferens, including the ampulla, contained 7% of the total reserves of spermatozoa. The caput plus corpus epididymidis from 5--16-year-old stallions (N = 41) contained 14.9 X 10(9) spermatozoa per side as compared (P less than 0.01) to 8.5 X 10(9) for 2--4-year olds (N = 30). Frequency of ejaculation did not influence the number of spermatozoa found in caput plus corpus epi...
Cox L, Vanderwall DK, Parkinson KC, Sweat A, Isom SC.There is compelling evidence that oocytes from mares >18 years of age have a high incidence of inherent defects that result in early embryonic loss. In women, an age-related decrease in oocyte quality is associated with an increased incidence of aneuploidy and it has recently been determined that the gene expression profile of human oocytes is altered with advancing age. We hypothesised that similar age-related aberrations in gene expression occur in equine oocytes. Therefore, the aim of the present study was to compare gene expression profiles of individual oocytes and cumulus cells from y...
Sharma S, Davies Morel MC, Dhaliwal GS.Decreased reproductive performance due to summer stress is a well known phenomenon in farm livestock. Whether this occurs in the mare and specifically how this might affect postpartum reproductive activity and performance, especially at Foal Heat (FH), is unknown. This study, therefore, aims to investigate this and the factors that might affect postpartum reproductive activity. Reproductive records of 228 Thoroughbred mares (694 mare years) bred in subtropical north-western India were retrospectively analysed. Overt oestrous activity occurred within 21 d postpartum in 92.94% (645/694) of mares...
van Heule M, Verstraete M, Blockx Z, De Blende P, Dini P, Daels P.Cooled storage of semen after thawing can expand the use of frozen semen, providing the possibility of thawing and evaluating the semen at the storage site and subsequently shipping the semen. Our objectives were (1) to examine the motility and viability of frozen-thawed semen after cooled storage and (2) to compare two cooled-storage protocols for frozen-thawed semen. The samples (n = 31) were either placed immediately in a passive cooling box for 8 or 24 hours (CB) or placed in a refrigerator at 4°C for 30 minutes and then transferred to a passive cooling box (REF). Total and progressive ...
Oliveira Neto IV, Canisso IF, Segabinazzi LG, Dell'Aqua CPF, Alvarenga MA, Papa FO, Dell'Aqua JA.This study compared hormone treatments given to mares during anestrus, spring transition, and different stages of the estrous cycle, by assessing uterine features and pregnancy rates after embryo transfer (ET). Embryo recipient mares (n = 160) were equally arranged as follows: G1-spontaneous ovulation (control), G2-anestrus, G3-spring transition, G4-early estrus, G5-estrus, G6-diestrus, G7-early diestrus treated with a dose of dinoprost, and G8-early diestrus treated with two doses of dinoprost. At treatment initiation (Day-4), G2-7 were given dinoprost and estradiol-17β, thereafter, estr...
Diaz-Jimenez M, Dorado J, Ortiz I, Consuegra C, Pereira B, Gonzalez-De Cara CA, Aguilera R, Mari G, Mislei B, Love CC, Hidalgo M.The aim of this study was to evaluate the effect of different concentrations of sucrose combined with bovine serum albumin (BSA), as non-permeable cryoprotectants, on donkey sperm parameters after cryopreservation, in comparison to a control extender containing glycerol. Semen from five Andalusian donkeys (n = 12) were centrifuged and resuspended with a commercial extender for equine sperm (Gent A, Minitube) adding 1% BSA and different concentrations (M, mol/l) of water-diluted sucrose: 0.05, 0.1, 0.25, 0.35 and 0.45. Thereafter, semen (n = 24) were diluted in the same base extender co...
Stich KL, Wendt KM, Blanchard TL, Brinsko SP.Mares treated with subcutaneous deslorelin implants on the first postpartum estrus early in the breeding season had significant reductions in the number of large follicles at early pregnancy examinations and delayed return to estrus (in mares that failed to become pregnant); these adverse effects were attributed to a prolonged release of the drug from the implant. In 2003, an injectable short-term release (<24 h) deslorelin product became available. The objective of this study was to determine if this product would hasten ovulation in early foaling first postpartum estrus mares without reducin...
Turner JW, Liu IK, Flanagan DR, Bynum KS, Rutberg AT.Porcine zona pellucida (PZP) immunocontraception was investigated for possible use in free-roaming wild horses in the western USA. A protocol of two injections (3-4 weeks apart) of vaccine lasting 1 year was first used and a single-injection controlled-release vaccine of 1 year duration was developed and tested in the field. Studies of a presumptive vaccine of 2 year duration were initiated. The parameters of anti-PZP antibody titre response, pregnancy testing and offspring production were used, and PZP vaccine was found to provide up to 94% infertility in free-roaming wild mares. In addition,...
Benhajali H, Richard-Yris MA, Ezzaouia M, Charfi F, Hausberger M.In order to investigate the factors affecting the reproduction efficiency of Arab breeding mares in Tunisia, breeding data corresponding to 2340 mated cycles, over 5 years (from 2000 to 2004), from 555 mares offspring of 50 sires and bred with 17 stallions were analysed using a multivariate logistic regression. We chose logit link function and binomial distribution and we used log-likelihood-ratio (LL) and Wald tests (X(2)Wald) to test the mean values. The factors of variation included in the model were the year, the stallion, the age of the mare at mating, the sire and the category of the mar...
Hernández-Avilés C, Ramírez-Agámez L, Varner DD, Love CC.The current study determined the effect of the egg-yolk (phospholipid source) level (egg yolk [20% EY] vs. skim-milk + egg yolk [SM + 2% EY]), cryoprotectant (glycerol [Gly] vs. glycerol + methylformamide [Gly + MF]), and pre-freeze cooling rate (-0.1 vs. -1 vs. -5 °C/min) on post-thaw stallion sperm quality. In Experiment 1, ejaculates (n = 27) from 9 stallions (3 ejaculates each) with varied sperm quality (High, Average, or Low) were frozen in EY-Gly, SMEY-Gly, EY-Gly + MF, or SMEY-Gly + MF extenders. Sperm in each group were cooled from 22° to 5°C using either -0.1 °C/min or -1 ...
Sevinga M, Hesselink JW, Barkema HW.Because the incidence of retained placenta in Friesian mares is estimated to be high, and no reports have been published on the reproductive performance of Friesian mares after retained placenta, we studied postpartum reproductive performance in Friesian brood mares with (n = 54) and without (n = 50) retained placenta. We defined a retained placenta as the failure to expel all fetal membranes within 3 h after the delivery of a foal. We subdivided the group of mares with retained placenta into mares in which the placenta had been removed manually (n = 30) and mares in which it had not (n = 24)....
Güvenc K, Reilas T, Katila T.Pregnancy rates after frozen semen inseminations (AI), particularly in older and problem mares, are lower than after fresh semen AI. Uterine contractility and the inflammatory reaction after frozen semen insemination were studied in two groups of mares: the abnormal group comprised of 6 old barren mares categorized in biopsy category IIB or III, and the control group including 6 reproductively normal young maiden mares in biopsy category I or IIA. All 12 mares were inseminated in the first cycle with 2 mL of phosphate-buffered saline (PBS) and in their second cycle with 2 mL of frozen semen co...
Huber D, Amsler E, Vidondo B, Kaeser R, Wespi B, Sieme H, Burger D.There exist differences in the reproductive behavior of stallions and mares under free-running and domestic in-hand breeding conditions. Contrary to artificial insemination programs, a stallion mates a mare multiple times per estrus under natural conditions. The objective of this study was to determine if multiple periovulatory artificial inseminations (MI), four times in two different time intervals instead of two, would result in increased pregnancy outcome or higher incidences of breeding induced endometritis. Methods: Eighty-two estrous mares were allocated randomly to one of three experim...
Vieira LA, Gadea J, García-Vázquez FA, Avilés-López K, Matás C.After injury or death of a valuable male, recovery of epididymal spermatozoa may be the last chance to ensure preservation of its genetic material. The objective of this research was to study the effect of sperm storage, at 4°C up to 96h, in the epididymides obtained from castrated horses and its effect on different functional sperm parameters. Aims were to study the effect of (1) sperm storage on viability and chromatin condensation; (2) pre-incubation of recovered epididymal sperm in the freezing extender, prior cryopreservation, on viability and chromatin condensation; and (3) freezing-tha...
Lange-Consiglio A, Corradetti B, Perrini C, Bizzaro D, Cremonesi F.In human and swine, leptin (OB) has been identified in seminal plasma and leptin receptors (OB-R) on the cell surface of spermatozoa, indicating that spermatozoa are a target for OB. This hormone has also been detected in follicular fluid (FF) in women and mares, although its role requires further study. The aims of this study were to investigate the immunolocalisation and the expression of OB and OB-R in equine spermatozoa and to evaluate the involvement of OB in equine in vitro fertilisation (IVF). Since progesterone (P) and OB are both found in FF, the individual and combined effects of the...
Herrera-Luna CV, Budik S, Helmreich M, Walter I, Aurich C.Glucocorticoids (GCs) as mediators of the stress response may affect Leydig cell function by inhibiting either luteinizing hormone receptor expression or testosterone biosynthesis. The isozymes 11β-hydroxysteroid dehydrogenase (11βHSD) 1 and 11βHSD2 control the intracellular cortisol levels. Little is known about the effects of stress on fertility in the equine. The objective of the present study was to determine the presence and cellular localization of glucocorticoid receptors (GCR) and glucocorticoid-metabolizing enzymes (11βHSD1 and 11βHSD2) in equine epididymal and testicular tissue ...
Bollwein H, Kolberg B, Stolla R.In recent years, a positive relationship between genital perfusion and fertility has been established; in species other than horses, uterine and ovarian perfusion was improved by exogenous estrogen but impaired by exogenous progestin. The goal of the present study was to investigate the effect of exogenous estrogen and progestin on uterine and ovarian blood flow in cycling mares. Five Trotter mares were examined daily during three estrous cycles. Mares were given no treatment, altrenogest (0.044 mg/kg BW) orally from Day 0 (ovulation) to Day 14 and estradiol benzoate (5mg i.m.) on Days 0, 5, a...
Arriola J, Foote RH.Because microfloral content of stallion semen tends to be high, and strains may be resistant to commonly used antibiotics, amikacin was tested with stallion semen and compared with bull semen. Nine ejaculates to stallion semen were incubated at 37 C in egg yolk-tris extender for 0, 2, 4, 6, 8 and 10 h in the presence of amikacin concentrations of 0, 50, 100, 250, 500, 1,000 and 10,000 microgram/ml, with penicillin and penicillin-streptomycin as controls. Averaged over all incubations, spermatozoal motility was 44, 48, 49, 46, 45, 45 and 19%, for increasing concentrations of amikacin, compared ...
Handler J, Schönlieb S, Hoppen HO, Aurich C.To investigate seasonal effects on the efficacy of estrus synchronization in mares, we administered a progesterone-releasing device (PRID) intravaginally to eight Haflinger mares for 11 days. In January 3 of 8 mares responded to the treatment with estrus and ovulation, in March 7 with estrus and 6 of 7 mares with ovulation, in June 6 of 7 and in October 7 of 8 mares with estrus and ovulation. Follicle distribution patterns at PRID insertion were different between January/October, March/June and June/October (P<0.05). Number of follicles decreased during PRID treatment in January, March and ...
Maitan P, Bromfield EG, Stout TAE, Gadella BM, Leemans B.Conventional in vitro fertilization is not efficacious when working with equine gametes. Although stallion spermatozoa bind to the zona pellucida in vitro, these gametes fail to initiate the acrosome reaction in the vicinity of the oocyte and cannot, therefore, penetrate into the perivitelline space. Failure of sperm penetration most likely relates to the absence of optimized in vitro fertilization media containing molecules essential to support stallion sperm capacitation. In vivo, the female reproductive tract, especially the oviductal lumen, provides an environmental milieu that appropriate...
Da Silva-Álvarez E, Gaitskell-Phillips G, Ortiz-Rodríguez JM, Serres C, García-Rodríguez B, Gutiérrez-Cepeda L, Martín-Cano FE, Echegaray A....This study aimed to assess if Ecotext, a new software for evaluation of testicular echotexture, is a good method for diagnosis of stallions with testicular dysfunction (TD). Relationships between Ecotext parameters and sperm motility and production, testicular volume, and testicular blood flow were also studied. Ecotext provides a total of six echotexture parameters: Ecotext 1 (black pixels), 2 (white pixels) and 3 (grey pixels), and another 3 parameters related to hypoechogenic areas: Ecotext tubular density (ETD), Ecotext tubular diameter (ETd), and Ecotext tubular area (ETA). Stallions (n ...
