Reproduction in horses encompasses the biological processes and mechanisms involved in the breeding and development of equine offspring. This includes the study of reproductive anatomy, physiology, and endocrinology in both mares and stallions. Key areas of interest include the estrous cycle, ovulation, conception, gestation, and parturition. Researchers also examine factors influencing fertility, reproductive technologies such as artificial insemination and embryo transfer, and management practices that impact reproductive success. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, genetic, and environmental aspects of equine reproduction.
Aziz DM, Hiss-Pesch S, Mielenz B, Sauerwein H.The study was conducted to determine the baseline concentration of serum haptoglobin (Hp) in jennies during the breeding and nonbreeding season and to evaluate the effects of ovariectomy on serum Hp concentrations in jennies. Eighteen adult jennies were divided in three groups: nine jennies (OVA) were ovariectomized using laparoscopic surgery, six jennies (LAP) were exploratory examined by laparoscopic surgery, and three jennies were used as a control group. Blood samples were collected from the animals at Day -6, -2, -1, 0, 1, 2, 5, 8, 15, 22, 29 and 36 of surgery. Serum samples were analyzed...
Korosue K, Murase H, Sato F, Ishimaru M, Harada T, Watanabe G, Taya K, Nambo Y.The purpose of this study was to demonstrate that a barren parous Thoroughbred mare with lactation induced by hormonal treatment can be introduced to an orphan foal at the same farm and that the mare can become pregnant after the end of the hormonal treatment. An additional purpose was to investigate the changes in the plasma concentrations of prolactin, estradiol-17β, progesterone, follicle-stimulating hormone, and luteinizing hormone before, during, and after hormonal treatment. The difference in body weight between the adopted foal and the control foals, which were at the same farm and rai...
Leme DP, Papa FO, Roser JF.The objective of this study was to investigate reproductive characteristics of stallions at a tropical zone in the breeding and non-breeding seasons. The following parameters were assessed: testicular volume; semen quality; and serum concentrations of LH, FSH, and testosterone; in addition to the percentages of germ cells and proportions of germ cells/Sertoli cells by testicular cytology in stallions. Semen was collected from eight adult stallions twice a week during a 12-week period in both seasons (6 weeks before and 6 weeks after the summer and winter solstices). Jugular blood samples were ...
Tiago G, Júlio C, António R.Pseudomonas aeruginosa may cause venereal disease and infertility in horses. A Pseudomonas aeruginosa - carrier stallion, often unresponsive to artificial vagina collection, was used to naturally breed mares. Semen collected from the same stallion was also used to perform artificial inseminations. Pregnancy rates, embryo quality and incidence of uterine infection were compared between inseminated or naturally-bred mares. Methods: P. aeruginosa was isolated from swabbing of the penis, prepuce and distal urethra of the stallion. Before being bred or inseminated, clitoral/vestibular samples were ...
Harris M, Nolen-Walston R, Ashton W, May M, Jackson K, Boston R.Blood samples banked for up to 1 month are typically used to perform pretransfusion testing in humans and small animals, but this has not been validated using blood from horses. Objective: Compatibility of equine blood samples is repeatable using fresh samples, and reproducible using donor blood samples stored for up to 4 weeks. Methods: Six healthy adult horses. Methods: Randomized, blinded experimental study. Immunologic compatibility of the blood of all horses was assessed using a major and minor saline agglutination and hemolysin crossmatch using blood samples refrigerated for 0-4 weeks an...
Celaya R, Ferreira LM, García U, Rosa García R, Osoro K.As the number of horses is steadily increasing in Cantabrian less-favoured areas, mostly occupied by nutritionally poor heathland communities, the objective of this research was to study and compare diet selection and performance of crossbred horses and beef cattle (Asturiana de los Valles breed) grazing these areas during the summer. A total of 20 cows (seven lactating their calves and thirteen dry) and 20 mares (eight lactating their foals and twelve dry) were managed during 3 years on a heathland area from June to September and October. The proportion of grass (mostly Pseudarrhenatherum lon...
de Andrade AF, Zaffalon FG, Celeghini EC, Nascimento J, Bressan FF, Martins SM, de Arruda RP.The objective was to verify the relationship between equine semen cryopreservation and changes related to increased lipid peroxidation. Also, addition of autologous or homologous seminal plasma from a stallion with a good freezing response to post-thawed sperm was tested to determine whether it would confer protection. Frozen-thawed sperm were evaluated and allocated into three groups: without plasma addition, and supplemented with either homologous or autologous seminal plasma. All groups were evaluated at 0, 60 and 120 min after incubation at 37 °C. Cryopreservation did not increase plasma ...
Khodadadi K, Sumer H, Pashaiasl M, Lim S, Williamson M, Verma PJ.Despite tremendous efforts on isolation of pluripotent equine embryonic stem (ES) cells, to date there are few reports about successful isolation of ESCs and no report of in vivo differentiation of this important companion species. We report the induction of pluripotency in adult equine fibroblasts via retroviral transduction with three transcription factors using OCT4, SOX2, and KLF4 in the absence of c-MYC. The cell lines were maintained beyond 27 passages (more than 11 months) and characterized. The equine iPS (EiPS) cells stained positive for alkaline phosphatase by histochemical staining ...
da Silveira JC, Veeramachaneni DN, Winger QA, Carnevale EM, Bouma GJ.Proper cell communication within the ovarian follicle is critical for the growth and maturation of a healthy oocyte that can be fertilized and develop into an embryo. Cell communication within the follicle involves many signaling molecules and is affected by maternal age. Recent studies indicate that cell communication can be mediated through secretion and uptake of small membrane-enclosed vesicles. The goals of this study were to 1) identify cell-secreted vesicles (microvesicles and exosomes) containing miRNAs and proteins within ovarian follicular fluid and 2) determine if miRNA level differ...
Friedman R.The value of providing equine reproductive services in ambulatory setting is well established. Ambulatory practice has been, and will most likely continue to be, the primary provider of equine reproductive veterinary services. The limitations for performing various reproductive procedures in an ambulatory setting are those imposed by the amount of equipment and supplies that must be brought to the patient, as well as those imposed when procedures require additional assistance. This is analogous to human medical care: the ambulance cannot substitute for a hospital but it can certainly provide s...
Coutinho da Silva MA, Seidel GE, Squires EL, Graham JK, Carnevale EM.The effects of semen extender components on the ability of stallion sperm to bind to the zona pellucida (ZP) and the suitability of using bovine ZP for a ZP-binding assay for stallion sperm were investigated in a series of experiments. In Experiment I, binding of stallion sperm to both bovine and equine ZP was significantly increased when a skim milk-based extender (EZM) was used. In Experiment II, a threefold increase in sperm binding to ZP was observed when sperm were diluted in EZM compared with diluents, which contained no milk (TALP, LAC, and EmCare). In Experiment III, centrifuging the s...
Watts AE, Fubini SL.This report describes a modification of the parainguinal approach for removal of cystic calculi: a ventral midline laparotomy-guided parainguinal laparocystotomy. The ventral midline approach to the abdomen is rapid and routinely used by equine surgeons. With an arm introduced to the abdomen via the ventral midline, the surgeon is able to select the ideal parainguinal laparotomy incision location that allows bladder exteriorisation with the minimum amount of tension. Because the surgeon's hand is introduced via the ventral midline incision, the parainguinal incision can be sized to just allow ...
Canisso IF, Beltaire KA, Bedford-Guaus SJ.Premature luteal demise or luteal insufficiency is not well characterised as a cause of pregnancy loss in domestic species, including horses. In this report, a mare inseminated with cooled-transported semen at our facility returned for a routine pregnancy diagnosis at 15 days post ovulation. Ultrasonography per rectum revealed endometrial oedema and the absence of visual indication of a corpus luteum on either ovary. Nonetheless, an embryonic vesicle small for the gestational age was identified. Daily oral altrenogest treatment was implemented immediately. Serum progesterone concentration was ...
Ginther OJ, Beg MA.Hourly blood sampling in both horses and cattle indicate that the transition between the end of preluteolysis and the beginning of luteolysis occurs within 1 h, as manifested by a change in progesterone concentrations. Each species presents a separate temporality enigma on the relationship between pulses of a prostaglandin (PG) F2α metabolite (PGFM) and the hour of the progesterone transition. In horses, relatively small pulses of PGFM occur during preluteolysis (before transition) and at transition. Oxytocin, but not estradiol, increases and decreases concomitantly with the small PGFM pulse ...
Leon PM, Campos VF, Thurow HS, Hartwig FP, Selau LP, Dellagostin OA, Neto JB, Deschamps JC, Seixas FK, Collares T.Single nucleotide polymorphisms (SNPs) in the p53 gene have been studied extensively in humans. The aims of this study were to determine the frequency of the Arg/Pro SNP in p53 in Thoroughbred mares on one stud in Brazil and to correlate p53 genotypes with reproductive performance. SNPs were detected by PCR-restriction fragment length polymorphism in blood samples from 105 horses and confirmed by sequencing. The allele frequency in Thoroughbred mares at codon 72 in exon 4 was 73.3% Arg/Pro, 17.1% Arg/Arg and 9.6% Pro/Pro. The presence of Arg/Pro was significantly associated with abortion (P=0....
Betteridge KJ, Waelchli RO, Christie HL, Raeside JI, Quinn BA, Hayes MA.To advance the understanding of early pregnancy and pregnancy failure in horses, this study determined how luteolysis induced by cloprostenol (an analogue of prostaglandin F2α) affects conceptus development. Mares were injected on Days 12, 14, 16 or 18 of pregnancy with either cloprostenol (treatment groups, total n=83 pregnancies) or saline (controls, n=81), and growth of the conceptuses was monitored and compared by daily ultrasonography until they were collected transcervically on Days 15-22, 1-4 days after the injections. The comparisons were extended in the recovered conceptuses by count...
Love CC, Blanchard TL, Varner DD, Brinsko SP, Voge J, Bliss S, Sudderth K, Teague S, LaCaze K.An experiment was conducted to determine whether cooled semen quality could be maintained for a longer interval by conducting daily centrifugation of extended semen, with resuspension of the sperm pellet in fresh extender. Semen treatments included SP10NC and SP50NC which contained 10 and 50% seminal plasma, respectively, were not centrifuged (NC), and were stored at 4 to 7 °C for 96 h. Treatments SP10C and SP50C contained 10 and 50% seminal plasma, respectively, but were centrifuged (C) after 24, 48, and 72 h of cooled storage, with daily resuspension in fresh extender containing 10% seminal...
Morillo Rodriguez A, Balao da Silva C, Macías-García B, Gallardo Bolaños JM, Tapia JA, Aparicio IM, Ortega-Ferrusola C, Peña FJ.A total of 42 ejaculates were used in the experiment; six ejaculates per stallion, obtained from seven Pure Spanish stallions (PRE), were split and frozen in freezing media with different concentrations and combinations of cryoprotectant (CPA): (i) Cáceres (skim milk based extender) containing 2.5% glycerol (2.5GL), (ii) Cáceres containing 1.5% glycerol and 1.5% dimethylformamide (1.5%GL-1.5%DMFA), (iii) Cáceres extender supplemented with 1.5% glycerol and 2.5% dimethylformamide (1.5%GL-2.5%DMFA) and (iv) Cáceres extender supplemented with 4% dimethylformamide (4%DMFA). After at least 4 we...
Gee EK, Dicken M, Archer RM, Herdan CL, Pauwels FE, Drayton BM.A 14-year-old Thoroughbred mare was presented for evaluation of a rapidly enlarging ovary at 73 days gestation. The mare's owner reported behavioural changes in the mare since she returned from stud, notably aggression towards other horses. Results: Transrectal palpation and ultrasonography of the reproductive tract revealed a viable pregnancy, an enlarged, multiloculated right ovary, and a normal-sized left ovary with a corpus luteum present. Concentrations of inhibin and testosterone in serum were 13.8 ng/mL and 1,150 pg/mL, respectively, being markedly higher than reference ranges. Concentr...
Erol E, Sells SF, Williams NM, Kennedy L, Locke SJ, Labeda DP, Donahue JM, Carter CN.Nocardioform placentitis associated with gram positive branching actinomycetes caused a record number of abortions in mares diagnosed by the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) affecting the 2011 foal crop (2011 foal crop: the cohort of foals conceived during the 2010 breeding season). The goal of the present study is to make a comprehensive analysis of this outbreak in terms of frequencies of the bacteria causing nocardioform placentitis mediated abortions and to investigate the ages of fetuses, abortion months and breeding times. In the present study, characterist...
Noronha LE, Huggler KE, de Mestre AM, Miller DC, Antczak DF.To identify equine orthologs of major NK cell marker genes and utilize them to determine whether NK cells are present among the dense infiltration of lymphocytes that surround the endometrial cup structures of the horse placenta during early pregnancy. Methods: PCR primers were developed to detect the equine orthologs of NKP46, CD16, CD56, and CD94; gene expression was detected in RNA isolated from lymphocytes using standard 2-step reverse transcriptase (RT) PCR and products were cloned and sequenced. Absolute real-time RT-PCR was used to quantitate gene expression in total, CD3+, and CD3- per...
Szóstek AZ, Siemieniuch MJ, Galvão AM, Lukasik K, Zieba D, Ferreira-Dias GM, Skarzynski DJ.Cell cultures are useful for determining the responses of specific cell types to various factors under controlled conditions and for obtaining a better understanding of in vivo physiologic processes. The aims of the present study were (i) to establish methodologies for isolation, culture and cryopreservation of equine endometrial epithelial and stromal cells; and (ii) to determine the effect of passage and cryopreservation on endometrial cell physiology, based on their basal and oxytocin (OT)-stimulated prostaglandin (PG) release. Epithelial and stromal cells were obtained by enzymatic digesti...
Antonello AM, Pivoto FL, Camillo G, Braunig P, Sangioni LA, Pompermayer E, Vogel FS.Neospora spp. is a intracellular protozoan phylogenetically closely related to Toxoplasma gondii and Sarcocystis neurona, and it can infect horses leading to the development of reproductive or neurological diseases. We determined the presence of antibodies to Neospora sp. in mares at their parturition time and determine the frequency of vertical transmission in healthy foals to verify the importance of transplacental transmission. The samples were analyzed by indirect immunofluorescence antibody test, showing that seroprevalence in mares is higher than in foals and seropositive mares are likel...
Kuhnert-Paul Y, Schmäschke R, Daugschies A.Results of parasitological examination of faecal aliquots may vary between diagnostic laboratories. To examine whether inhomogeneous distribution of worm eggs in faecal samples is responsible for this observation, horse faeces provided for routine diagnosis of helminth infection were examined. Distribution of worm eggs was assessed by examining aliquots taken from different locations of the faecal sample by a combined sedimentation-flotation method (KSFV). In addition, it was tested, whether the homogenization of a larger amount (minimum of 40 g) of faeces before performing KSFV improved repro...
Herrera-Luna CV, Budik S, Aurich C.Glucocorticoids (GCs) are important mediators of the stress response and have been implicated in the function and regulation of testicular functions in different species. In many tissues, intracellular glucocorticoid activity is controlled by either or both of the two known isoforms of 11β-hydroxysteroid dehydrogenase (11βHSD) type 1 and 2, which interconvert active and inactive GCs. Little is known about the effects of stress on fertility in the equine species. The main objective of the present study was to investigate the expression of receptors for GCs and adrenocorticotropic hormone [ACT...
Macías García B, Ortega Ferrusola C, Aparicio IM, Miró-Morán A, Morillo Rodriguez A, Gallardo Bolaños JM, González Fernández L....Glycerol is, to date, the most widely used cryoprotectant to freeze stallion spermatozoa at concentrations between 2% and 5%. Cryoprotectant toxicity has been claimed to be the single most limiting factor for the success of cryopreservation. In order to evaluate the toxic effects of the concentrations of glycerol used in practice, stallion spermatozoa were incubated in Biggers Whitten and Whittingham (BWW) media supplemented with 0%, 0.5%, 1.5%, 2.5%, 3.5%, and 5% glycerol. In two additional experiments, a hyposmotic (75 mOsm/kg) and a hyperosmotic (900 mOsm/kg) control media were included. Sp...
Collins CW, Songsasen NS, Vick MM, Wolfe BA, Weiss RB, Keefer CL, Monfort SL.The ex situ population of the Przewalski's horse (Equus ferus przewalskii) is not self-sustaining (20% foaling rate), and the demography is skewed toward aging individuals with low gene diversity. We designed the present study to gain a better understanding of the reproductive biology of the Przewalski's mare and to determine whether age and gene diversity influenced reproductive function. Urine samples were collected 3-7 days/wk from 19 mares from May to September, and ultrasound examinations of follicular structures were performed 3 days/wk for 5 wk from May through July in nine individuals....
Korosue K, Murase H, Sato F, Ishimaru M, Endo Y, Nambo Y.The purpose of this study was to observe the changes in body temperature before parturition using a wireless temperature monitoring device (WTMD) and to evaluate the usefulness of body temperature measurements using a digital rectal thermometer (DRT) and a microchip transponder thermometry device (MTTD) for predicting parturition in mares. The body temperatures using a WTMD at 0 hr and -1 hr were significantly different from those at the same time on Days 1-5 (P<0.01). The temperature differences between the morning of Day 0 and at -3 hr, -2 hr, -1 hr and 0 hr using the DRT and MTTD showed ...
Donadeu FX, Ginther OJ.Follicular waves and associated circulating hormone concentrations were studied during the anovulatory season in pony mares (n=8). Follicles were monitored by ultrasonography and a blood sample was taken daily from 29 January until ovulation (mean, 28 April). A mid-anovulatory period (largest follicle, 16.0+/-0.5 mm in diameter) and transitional period (largest follicle, 22.4+/-0.5 mm) were distinctive in each mare. The two periods were delineated by an increase in the diameter of the largest follicle to >/=21.0 mm. Follicular waves, identified by significant increases in the mean diameter ...
Rubessa M, Feugang JM, Kandel ME, Schreiber S, Hessee J, Salerno F, Meyers S, Chu I, Popescu G, Wheeler MB.The capacity for microscopic evaluation of sperm is useful for assisted reproductive technologies (ART), because this can allow for specific selection of sperm cells for in vitro fertilization (IVF). The objective of this study was to analyze the same sperm samples using two high-resolution methods: spatial light interference microscopy (SLIM) and atomic force microscopy (AFM) to determine if with one method there was more timely and different information obtained than the other. To address this objective, there was evaluation of sperm populations from boars and stallions. To the best of our k...
Lewis N, Hinrichs K, Leese HJ, McGregor Argo C, Brison DR, Sturmey RG.The use of in vitro embryo production in the horse is increasing in clinical and research settings; however, protocols are yet to be optimised. Notably, the two most commonly used base media for in vitro maturation (IVM) supply glucose at markedly different concentrations: physiological (5.6 mM, M199) or supraphysiological (17 mM, DMEM/F-12). Exposure to high glucose has detrimental effects on oocytes and early embryos in many mammalian species, but the impact has not yet been examined in the horse. To address this, we compared the energy metabolism of equine COCs matured in M199-based maturat...
Todhunter KH, Muscatello G, Blishen AJ, Chicken C, Perkins NR, Gilkerson JR, Begg AP.A series of unusual abortions occurred in Thoroughbred and Quarterhorse mares in the Hunter Valley region of New South Wales from mid-March to November 2004. The initial link between early cases was the microbiological culture of atypical environmental coryneforms from the stomach contents and/or lungs of fetuses aborted on different properties. Methods: The unique pathologic lesions were described with a case definition and the term 'equine amnionitis and fetal loss' (EAFL) was established. Results: The causal factor was the ingestion of the processionary caterpillar (Ochrogaster lunifer). Ba...
Choi I, Collante WR, Simmen RC, Simmen FA.Pig blastocysts exhibit a transient period of estrogen production at periimplantation, with a second, more sustained period of estrogen synthesis occurring in endometrium and placenta at later pregnancy. Previously we reported the isolation of cDNA clones encoding a novel isoform of cytochrome P450 aromatase (the terminal enzyme in the estrogen biosynthetic pathway) from porcine periimplantation blastocysts. The present study investigated pregnancy-associated expression, in blastocysts and maternal reproductive tract tissues of this and an additional mRNA transcript encoding a distinct P450 ar...
Dobrinski I, Thomas PG, Ball BA.Two bioassays were used to evaluate the interaction of fresh and cryopreserved equine semen with oviductal epithelial cells (OEC) and with the zona pellucida (ZP). Split ejaculates were either stored at room temperature or frozen and thawed. In experiment 1, progressive motility and membrane integrity were evaluated for each treatment. Fluorescent labeled spermatozoa were cocultured with monolayers of OEC for 30 minutes, and the number of sperm attached to OEC was counted by fluorescence microscopy and analysis of digitized images. Motility of spermatozoa attached to OEC was observed at 0.5, 3...
Loux SC, Macías-Garcia B, González-Fernández L, Canesin HD, Varner DD, Hinrichs K.Equine in vitro fertilization is not yet successful because equine sperm do not effectively capacitate in vitro. Results of previous studies suggest that this may be due to failure of induction of hyperactivated motility in equine sperm under standard capacitating conditions. To evaluate factors directly affecting axonemal motility in equine sperm, we developed a demembranated sperm model and analyzed motility parameters in this model under different conditions using computer-assisted sperm analysis. Treatment of ejaculated equine sperm with 0.02% Triton X-100 for 30 sec maximized both permeab...
Sayasith K, Bouchard N, Doré M, Sirois J.The progressive rise in gonadotropins prior to ovulation triggers a marked increase in intrafollicular levels of prostaglandin F(2alpha)(PGF(2alpha)), which is known to interact with PGF(2alpha) receptor (FP). Little is known about the regulation of FP during ovulation. This study was undertaken to characterize the equine FP and its gonadotropin-dependent regulation in preovulatory follicles prior to ovulation. The full-length equine FP encodes a 366-amino acid protein that is 82-93% homologous to other species. Using semi-quantitative RT-PCR/Southern blot, we showed that FP mRNA expression wa...
Amit T, Dibner C, Barkey RJ.The present study was undertaken to identify and characterize the diversity and species distribution of soluble prolactin binding-protein (PRL-BP) and growth hormone-binding protein (PRL-BP) in mammalian milk. We previously divided mammalian serum GH-BP into four main groups and identified a GH-BP with shared lactogenic/somatogenic properties in rabbit, horse, dog, pig and cat (Type III species). Here we describe PRL-BP in milk of Type III species and show it is relatively conserved within the group, having similar characteristics in terms of binding affinity for hGH (0.74-5.5 x 10(10) M(-1)),...
Calvete JJ, Reinert M, Sanz L, Töpfer-Petersen E.Boar and stallion seminal plasmas were fractionated using affinity chromatography on heparin-Sepharose. In both species, among other proteins, the heparin-binding (H+) and non-heparin-binding (H-) fractions each contained glycoforms of either porcine PSP-I or equine HSP-1 and HSP-2. However, porcine H+/PSP-I eluted as a monomeric protein, whereas H-/PSP-I formed a heterodimer with PSP-II, another major seminal plasma protein. On the other hand, the stallion proteins H+/HSP-1 and H+/HSP-2 eluted together as an aggregate of relative molecular mass (M(r)) 90,000, whereas H-/HSP-1 and H-/HSP-2 elu...
Turner RM, Zeng W.Studies in laboratory rodents are shedding light on the pathophysiology of testicular ageing and now suggest a complicated basis for age-related declines in testicular function. A highly significant contributor to infertility may involve failure of specific and complex testicular microenvironments (niches) comprised of a variety of cellular and molecular components. Our laboratory has applied testis tissue xenografting to the study of testicular ageing in the stallion. Using this technique, we have confirmed that the disease is tissue autologous. As would be expected from a tissue autologous d...
Pirhonen A, Linnala-Kankkunen A, Mënpää PH.P1 protamines isolated from ejaculated human, stallion, bull, boar and ram spermatozoa and P2 protamines from human and stallion spermatozoa were subjected, after alkaline phosphatase treatment, to in vitro phosphorylation reactions using cAMP-dependent protein kinase (PKA) and protein kinase C (PKC). All P1 protamines were phosphorylated by PKA, whereas P2 protamines were phosphorylated only by PKC. In addition, human, stallion and boar, but not bull and ram, P1 protamines were phosphorylated by PKC. After phosphoamino acid analysis, the protamines showing positive signals for phosphoserine (...
Yánez-Ortiz I, Catalán J, Delgado-Bermúdez A, Carluccio A, Miró J, Yeste M.In donkeys, the use of frozen-thawed sperm for artificial insemination (AI) leads to low fertility rates. Furthermore, donkey sperm produce a large amount of reactive oxygen species (ROS), and post-AI inflammation induces the formation of neutrophil extracellular traps (NETosis), which further generates many more ROS. These high ROS levels may induce lipid peroxidation in the sperm plasma membrane, thus affecting its integrity. Enzymatic and non-enzymatic antioxidants, mainly found in the seminal plasma (SP), are responsible for maintaining the redox balance. However, this fluid is removed pri...
Aurich JE, Kranski S, Parvizi N, Aurich C.This study investigated the regulation of growth hormone (GH) release in stallions and tested the hypothesis that the somatotrophic axis influences testicular function. Basal plasma GH concentrations, effects of an experimental decrease of GH release on testicular function and an opioidergic regulation of GH release were investigated in Shetland stallions (n=6). No seasonal variations in plasma GH concentrations were found over a 12-month period. Treatment with the somatostatin analogue octreotid (100mg twice daily over 10 days) caused a decrease in semen motility from 38.7+/-8.4% progressivel...
Cappelli K, Brachelente C, Passamonti F, Flati A, Silvestrelli M, Capomaccio S.Epitheliogenesis imperfecta in horses was first recognized at the beginning of the 20th century when it was proposed that the disease could have a genetic cause and an autosomal recessive inheritance pattern. Electron microscopy studies confirmed that the lesions were characterized by a defect in the lamina propria and the disease was therefore reclassified as epidermolysis bullosa. Molecular studies targeted two mutations affecting genes involved in dermal-epidermal junction: an insertion in LAMC2 in Belgians and other draft breeds and one large deletion in LAMA3 in American Saddlebred. Metho...
Dufour P, Courtois J, Seynaeve Y, Peeters S, Le Goff C, Cavalier E, Ponthier J.Steroid concentrations in serum are fluctuating during pregnancy of many mammal species. The current knowledge about endocrinology of gestation is mainly based on immunoassays. However, the lack of specificity of these assays hampers the reliability of the results. In the present work, we developed and validated a methodology associating liquid chromatography (LC) and mass spectrometry (MS) to simultaneously quantify, with high specificity and accuracy, estrone-3-sulfate (E3S), progesterone (PRO), estrone (E1) and estradiol (E2) in serum of two different mammal species. The sample preparation ...
Jaeger LH, Moreno LZ, Kremer FS, Dellagostin OA, Moreno AM, Lilenbaum W.The genome of a Brazilian strain of Leptospira kirschneri serogroup Grippotyphosa isolated from a mare post-abortion was sequenced and analyzed. High symmetrical identity and few structural differences were found when compared with a European strain of the same serogroup, L. kirschneri serovar Valbuzzi strain 200702274. Genes associated with virulence and antimicrobial resistance were found. Knowledge of the virulence evolution of Leptospira remains limited, especially in diseases of the reproductive sphere. We highlight the importance of virulence studies in the sphere of genital leptospirosi...
Kavak A, Johannisson A, Lundeheim N, Rodriguez-Martinez H, Aidnik M, Einarsson S.Methods to evaluate the quality of frozen-thawed stallion semen are still needed, particularly those considering the sperm function. The present study evaluated sperm motility, membrane and acrosome integrity and the capacitation status of frozen-thawed spermatozoa from seven Tori and six Estonian breed stallions by way of computer assisted sperm analysis (CASA), a triple fluorophore stain combination and Merocyanine 540, respectively, the latter ones using flow cytometry. Two ejaculates from each stallion were cryopreserved using the Hannover method in 0.5 ml plastic straws. Two straws per ej...
Henry M, McDonnell SM, Lodi LD, Gastal EL.The mating behaviour of 2 jacks, each with 21 non-pregnant jennies, was studied when the jennies were in natural oestrus and simultaneously induced oestrus. The main observations were: efficient pasture breeding at natural and induced oestrus, a territorial sociosexual structure, prolonged pre-copulatory interaction, gradual increase of mating activity up to 2 days before ovulation, a copulatory sequence similar to that of horses, vocalization of the jack as a conspicuous behaviour initiating pre-copulatory interaction, frequent heterotypical behaviour of jennies and active involvement of jenn...
Ellenberger C, Müller K, Schoon HA, Wilsher S, Allen WR.Anovulatory haemorrhagic follicles (AHFs) are often the reason for ovulation failure in the mare. As the underlying factors that lead to AHF development are not well understood, it was of interest to investigate the vascularization of AHFs compared with normal follicles and corpora lutea (controls). In the present study, the ovarian cell populations investigated immunohistochemically included granulosa and luteal cells as well as various vascular structures. None of these cell types showed differences in the expression of vascular endothelial growth factor A (VEGF-A) between control ovaries co...
Hepperger C, Mayer A, Merz J, Vanderwall DK, Dietzel S.Whether chromosome sets inherited from father and mother occupy separate spaces in the cell nucleus is a question first asked over 110 years ago. Recently, the nuclear organization of the genome has come increasingly into focus as an important level of epigenetic regulation. In this context, it is indispensable to know whether or not parental genomes are spatially separated. Genome separation had been demonstrated for plant hybrids and for the early mammalian embryo. Conclusive studies for somatic mammalian cell nuclei are lacking because homologous chromosomes from the two parents cannot be d...
Nie GJ, Wenzel JG.Hypoosmotic swelling (HOS) is used for assessing plasma membrane function and fertilizing capacity of human spermatozoa. However, HOS solutions and methodologies have not been evaluated specifically for assessing stallion spermatozoa. The objective of this study was to identify a HOS solution and assay conditions specifically for stallions that would maximize spermatozoal plasma membrane swelling. The HOS solutions and assay conditions, including incubation time (15 to 180 min), temperature (25 degrees vs 37 degrees C), and total number of cells examined (100, 200 or 500) were evaluated. Assay...
Beckelmann J, Budik S, Bartel C, Aurich C.Until now, sex determination in equine embryos has been performed by detection of Y-chromosome-specific sequences only. In the present study, expression of a Barr-body-specific marker, the X-inactivated-specific transcript (Xist) gene, whose gene product consists of RNA which coats and thereby inactivates one of the X chromosomes, was investigated in equine embryos produced in vivo. Preattachment embryos at different times after ovulation (Day 8: n = 9; Day 10: n = 12; Day 12: n = 15) were analyzed for Xist RNA expression using quantitative and qualitative reverse transcription-polymerase chai...
Thorson JF, Karren BJ, Bauer ML, Cavinder CA, Coverdale JA, Hammer CJ.To investigate the maternal plane of nutrition and role of Se yeast on foaling variables and passive transfer of IgG, 28 Quarter Horse mares were used in a study with a randomized complete block design. Mares were blocked by expected foaling date and assigned randomly within block to dietary treatments. Dietary treatments were arranged as a 2 x 2 factorial with 2 planes of nutrition, pasture or pasture + grain mix (fed at 0.75% of BW on an as-fed basis) and 2 concentrations of Se yeast (0 or 0.3 mg/kg of DMI). This resulted in 4 treatments: pasture (PA), pasture + Se (PS), pasture + grain mix ...
Galvão AM, Szóstek AZ, Skarzynski DJ, Ferreira-Dias GM.Normal reproductive function involves the expression of inflammatory mediators. Regarding the corpus luteum (CL), cytokines promote the cross-talk between immune, vascular and steroidogenic cells, among others. Moreover, TNF, IFNG and FASL were shown to regulate equine CL establishment and regression. We hypothesized that cytokines action on equine CL may be mediated by nitric oxide (NO), through the regulation of endothelial NO synthase (eNOS) expression. TNF increased eNOS mRNA level and NO metabolite (nitrite) production during CL growth. Cytokines combined action (TNF+IFNG+FASL) promoted e...
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...
Santos MM, Maia LL, Nobre DM, Oliveira Neto JF, Garcia TR, Lage MC, de Melo MI, Viana WS, Palhares MS, da Silva Filho JM, Santos RL, Valle GR.The aim of this study was to determine the influence of parental age on the sex ratio of offspring in horses. Two trials were performed. In the first trial, the data from a randomly obtained population with a 1:1 sex ratio of 59,950 Mangalarga Marchador horses born in Brazil from 1990 to 2011 were analyzed. The sex ratios of the offspring were compared among groups according to the mare and the stallion ages (from 3 to 25 years). In the first step of the analysis, the mares and stallions were grouped according to age in 5-year intervals. In the second step, the groups were based on the parenta...
Mantovani R, Sartori C, Pigozzi G.This study investigated some aspects of breeding management in the Italian Heavy Draught Horse breed, aiming at improving its efficiency at stud farm level. A first aim was to evaluate the risk of unsuccessful reproduction in mares after an early (3 years) or normal (4 years) age at first foaling, in interaction with different stud rearing systems. A second objective was the examination of the mean time length in which young 2-year-old stallions maintain a genetic superiority on older proven stallions, identifying a 'genetic lifespan' in which young stallions can be safely used for reducing th...
Uzans AJ, Lucas Z, McLeod BA, Frasier TR.For small, isolated populations 2 common conservation concerns relate to genetic threats: inbreeding and negative consequences associated with loss of genetic diversity due to drift. Mitigating these threats often involves conservation actions that can be controversial, such as translocations or captive breeding programs. Although such actions have been successful in some situations, in others they have had undesirable outcomes. Here, we estimated the effective population size (N e ) of the Sable Island horses to assess the risk to this population of these genetic threats. We found surprising ...
Sessions-Bresnahan DR, Carnevale EM.Age-related changes in follicle paracrine signalling are not defined, and follicular gene transcript abundance could predict oocyte viability. Granulosa cells from preovulatory follicles of mares considered Young (n=12; 4-14 years), Mid-aged (n=9; 15-19 years) and Old (n=14; 20-27 years) were evaluated for transcript abundance related to systemic and follicle-specific pathways. Gene transcript abundance for receptors of insulin, adiponectin and peroxisome proliferating factor-γ were higher or tended to be higher in Mid-aged or Old than Young mares. Transcript abundance for interleukin (IL)-6 ...
