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.
Atayde L, Rocha A.It is important to get mares pregnant as early as possible after vernal transition and thus, identification signs of impending 1st ovulation of the year are warranted. To identify clinical indicators of an approaching first ovulation of the year, mares were teased with a stallion for oestrous detection starting January 3 and subjected to ultrasonographic examination. Day of first appearance of uterus oedema, follicular wall invagination, intrafollicular echogenicity, double contour of the follicle wall, increase in granulosa thickness, follicular wall hyperechogenicity and appearance of pear-s...
Han SH, Yang BC, Ko MS, Oh HS, Lee SS.we analyzed the sex chromosome-encoding ZFX-ZFY genes and tested molecular sexing using the amplification patterns of intron 9 of ZFX-ZFY in the horse. Results: the amplification of the ZFX-ZFY produced two distinct patterns, reflecting sexual dimorphism based on a length difference between the X and Y chromosomes. The amplification products from foals showed two distinct bands: one was common to all foals and mares, indicating that this band was amplified from ZFX, while the other was specific to some foals, indicating that it was from ZFY. The result based on the PCR assay was identical to t...
Checura CM, Beg MA, Parrish JJ, Ginther OJ.The effects of FSH, LH or both on follicular growth and intrafollicular free insulin-like growth factor (IGF)-1 and oestradiol were investigated in mares after the beginning of deviation (largest follicle >/= 20 mm; Hour 0). A single treatment with a gonadotropin-releasing hormone antagonist (acyline) was given at Hour 3 to suppress the concentrations of FSH and LH. Five groups (n = 5 mares per group) were evaluated in the present study: (1) control; (2) acyline treated; (3) acyline + recombinant equine (re) FSH treated; (4) acyline + reLH treated; and (5) combined acyline + reFSH + reLH tr...
Bondo T, Jensen SK.This study assessed the effect of a vitamin E supplement given to pregnant mares on immunoglobulins (Ig) levels in foals. In addition, the fatty acid (FA) content and composition of the mares' milk was assessed. Milk α-tocopherol concentrations were compared between pregnant Danish Warmblood mares (n = 17) given a daily oral supplement of 2500 international units (IU) RRR-α-tocopherol in the last 4 weeks of pregnancy and a group of unsupplemented mares (n = 17) receiving 170-320 IU vitamin E daily originating from the feed. Milk α-tocopherol was higher in supplemented mares (36.7, 12.4 and ...
Köllmann M, Rötting A, Heberling A, Sieme H.The diagnostic and therapeutic options for oviduct disorders in the mare are limited. The current best techniques require exploratory surgery under general anaesthesia or flank laparotomy. Objective: The orthograde flushing of the oviduct for diagnostic or therapeutic options is possible using laparoscopic techniques in the standing sedated mare. Methods: Development of a laparoscopic technique for catheterisation of the infundibulum and flushing of the oviduct (sterile methylene blue solution) in the standing sedated mare was examined in 2 experiments. The first involved a transvaginal laparo...
Wnuk M, Lewinska A, Oklejewicz B, Bartosz G, Tischner M, Bugno-Poniewierska M.Antioxidant status of seminal plasma from 23 stallions was evaluated. We found a negative correlation between total antioxidant capacity (ABTS(•+) decolorization assay) and thiol content of seminal plasma, and sperm DNA damage (8-oxoG immunostaining, TUNEL reaction, comet assay). Low seminal redox status was the strongest correlated with 8-oxoG level which may indicate that seminal total antioxidant capacity influences mainly the formation of single strand DNA breaks in sperm cells. Since inter-individual differences in seminal antioxidant status were reported, we postulated that the redox s...
De Lorenzi L, Genualdo V, Iannuzzi A, Di Meo GP, Perucatti A, Mancuso R, Russo M, Di Berardino D, Parma P, Iannuzzi L.A 4-year-old male horse of Friesian breed with normal body conformation, development and libido, and showing an evident ventral penis deviation with hypospadias, underwent both cytogenetic and genetic investigation. Although the karyotype showed normal male arrangement (2n = 64,XY), one telomere of horse (ECA) chromosome 1 was shorter than both the other one and those of a normal horse (control), as revealed by CBA- and RBA-banding, and by Ag-NOR and FISH-mapping techniques using telomere PNA probes. Genetic investigation of the SRY and MAMLD1 coding sequences revealed a normal SRY sequence an...
Bourzac C, Smith LC, Vincent P, Beauchamp G, Lavoie JP, Laverty S.There is a need to assess and standardise equine bone marrow (BM) mesenchymal stem cell (MSC) isolation protocols in order to permit valid comparisons between therapeutic trials at different sites. Objective: To compare 3 protocols of equine BM MSC isolation: adherence to a plastic culture dish (Classic) and 2 gradient density separation protocols (Percoll and Ficoll). Methods: BM aspirates were harvested from the sternum of 6 mares and MSCs isolated by all 3 protocols. The cell viability after isolation, MSC yield, number of MSCs attained after 14 days of culture and the functional characteri...
Ueno T, Nambo Y, Tajima Y, Umemura T.Broad ligament haemorrhage in peripartum mares is a life-threatening disease and there are few reports on the aetiology and pathogenesis of broad ligament haematoma. Objective: To obtain information regarding the sites for the early diagnosis and pathogenesis of broad ligament haematoma of mares. Methods: Thirty-one mares that died of broad ligament haematoma peripartum were examined pathologically for bleeding sites. The arterial distribution of 5 young mares with several parities served as negative controls. Results: Age and/or multiparity were the predisposing factors for the disease. Arter...
Galvao AM, Ramilo DW, Skarzynski DJ, Lukasik K, Tramontano A, Mollo A, Mateus LM, Ferreira-Dias GM.Proapoptotic factor Fas ligand (FASL) and its cell surface receptor FAS are tumor necrosis factor superfamily members that trigger apoptosis in different cell types. However, their influence on luteal steroidogenesis is not clearly understood. The aim of the present work was to determine (i) the presence of the cytokine FASL and its receptor FAS in the mare's corpus luteum (CL) throughout the luteal phase, as well as (ii) the influence of FASL alone, or together with the cytokines tumor necrosis factor alpha (TNF) and interferon gamma (IFNG), on equine luteal cell production of luteotrophic an...
Atli MO, Kurar E, Kayis SA, Aslan S, Semacan A, Celik S, Guzeloglu A.The aim was to evaluate expression of genes involved in the biosynthesis of prostaglandins (PTG), Prostaglandin H Synthase-1 (PTGS1) and PTGS2, PGF synthase (PTGFS), and PGE synthase (PTGES), PGF receptor (PTGFR), PGE receptors (PTGER2 and PTGER4), prostaglandin transporter (SLCO2A1) and hydroxyprostaglandin dehydrogenase-15 (HPGD). Endometrial biopsies were obtained from mares on day of ovulation (d0, n=4), late diestrus (LD, n=4), early luteolysis (EL, n=4) and after luteolysis (AL, n=4) during the cycle. Stages of the cycle were confirmed by plasma progesterone concentrations measured daily...
Wenzinger B, Kähn W, Bleul U.The aim of this study was to investigate the effect of a GnRH vaccine (Equity) on behavior and gonadal function in horses with unwanted behavior. The reason for the treatment was asked using a questionnaire and the findings of physical examination, rectal palpation as well as rectal ultrasonography, were recorded. The results of these examinations and the behavior of 21 mares and 10 stallions before the first and after the second administration of the GnRH vaccine were compared. In 84 % of all cases a decrease of the unwanted behavior could be observed. In the mares the ovaries were significan...
Cremonesi F, Anderson K, Lange-Consiglio A.TWO METHODS HAVE BEEN DESCRIBED TO RECOVER OOCYTES FROM EQUINE FOLLICLES IN EXCISED OVARIES: aspiration and scraping. Aim of this work was to develop an effective method for collecting equine oocytes using Tuohy needle and comparing this technique to aspiration and scraping, with or without tunica albuginea removal. This hollow hypodermic needle, usually employed for inserting epidural catheters, is designed with a slightly curved tip, shaped similar to a small curette. In unpeeled ovaries, the recovery rates of Tuohy needle group was higher (P < .05) than in the 16 g needle aspiration and ...
Aurich C, König N, Budik S.In mares, repeated embryo collection in successive oestrous cycles is necessary if a greater number of foals should be produced. We investigated effects of repeated embryo collection in fertile donor mares on embryo recovery rates. In addition, an influence of the individual mare and season on embryo recovery rates was studied. In nine mares, a total of 153 embryo collections were performed during 30 months (17 ± 2.2 embryo collections per mare). The overall embryo recovery rate was 64% and did not differ among mares. Between successive embryo collection procedures, recovery rate varied signi...
Ramsay JD, Leib SR, Orfe L, Call DR, Tallmadge RL, Fraser DG, Mealey RH.Development of an accurate and efficient molecular-based equine MHC class I typing method would facilitate the study of T lymphocyte immune responses in horses. Here, a DNA microarray was designed to detect expressed classical MHC class I genes comprising serologically defined equine leukocyte antigen (ELA)-A haplotypes represented in a closed Arabian horse breeding herd. Initially, cloning and sequencing of RT-PCR products were used to identify sequences associated with the ELA-A1, A4, and W11 haplotypes, and one undefined haplotype, in six horses. Subsequently, sequence-specific, conserved (...
Hinrichs K.There is currently much interest in assisted reproduction techniques in the horse, however, many aspects of oocyte maturation, fertilization, and embryo development in the horse differ from those in other species. Because of the close attachment of the equine oocyte to the follicle wall, scraping of the follicle is the most effective method for oocyte recovery. A notable feature of equine oocytes is that those with expanded cumuli (Ex oocytes), which originate from atretic follicles, have higher meiotic competence (ability to mature to metaphase II in vitro) than do oocytes with compact cumuli...
Christoffersen M, Baagoe CD, Jacobsen S, Bojesen AM, Petersen MR, Lehn-Jensen H.Infectious infertility in the mare is clinically well described, little is however known about the systemic acute phase reaction (APR) and local immunological responses accompanying equine endometritis. The aim of this study was to monitor selected markers of the APR in the systemic circulation and to correlate them to the local innate immune response in the uterus during infectious endometritis. Six adult standard bred mares received an intrauterine infusion of 10(9)CFU Escherichia coli. Blood samples were obtained before (0 h) and 3, 6, 12, 24, 36, 48, 72, 96 and 120 h post inoculation (pi),...
de Lorenzi L, Molteni L, Zannotti M, Galli C, Parma P.This report concerns the cytogenetic analysis, using both C-banding and fluorescence in situ hybridisation techniques, of a sterile mare. Results obtained revealed a 2n = 65, XXX condition with no sign of mosaicism. The work supports the suggestion that X trisomy, rare in horse, causes infertility in mares and is not associated to other clearly visible phenotypic features.
Ferris RA, McCue PM.Persistent mating induced endometritis is among the most common causes of infertility in the mare. Recently, improved pregnancy rates have been reported when corticosteroids were administered to 'problem mares' specifically, to modulate the post mating inflammatory response; however, the effect of treatment on pituitary and ovarian function requires further study. Objective: To evaluate the effects of prolonged treatment with glucocorticoids on pituitary and ovarian function. Methods: Eighteen cycling Quarter Horse mares in early oestrus were assigned randomly to one of 3 treatment groups: dex...
Samper JC, Plough T.In the last decade, there has been a significant increase in the quality and commercial use of frozen equine semen. The emergence of new reproductive technologies, coupled with the high prices for an insemination dose from some stallions, the increasing costs of import and export and the marketing policies of stallion agents or owners in the sport horse industry has stimulated the fractionation of doses for insemination. Consequently, the sperm number and the volume of an insemination dose are significantly reduced. To deliver lower doses of sperm in lower volumes compared to the standard dose...
LeBlanc MM.Rapid physical uterine clearance is paramount for fertility. Mares that are unable to clear the by-products of insemination or foaling quickly may develop post-mating-induced or acute endometritis. If endometritis is not promptly resolved, the infection can become chronic. Endometritis can be difficult to identify because clinical signs, ultrasonographic and laboratory findings can vary between uterine pathogens. Some micro-organisms are associated with an influx of neutrophils and fluid into the uterine lumen while others are associated with only heavy debris on cytological specimens. Identif...
Hinrichs K.In vitro embryo production is possible in the horse both clinically and for research applications. Oocytes may be collected from excised ovaries post-mortem, or from either immature follicles or stimulated pre-ovulatory follicles in the live mare. In vitro maturation of immature oocytes typically yields approximately 60% mature oocytes. As standard in vitro fertilization is not yet repeatable in the horse, fertilization is performed by intracytoplasmic sperm injection. Embryo culture requires medium with high glucose, at least during blastocyst development, and rates of blastocyst development ...
Ababneh M, Ababneh H, Shidaifat F.Phospholipase A2 (PLA2) is a key enzyme for biosynthesis of PGF2α. Real-time RT-PCR and immunohistochemistry were used to determine transcription and cellular distribution of cytosolic PLA2 (cPLA2) in the equine endometrium during the oestrous cycle and early pregnancy. Endometrial biopsy and blood samples were collected from cycling mares on days (d) 8, 11, 15 and 18 (oestrus) (Day 0 = Day of ovulation; n = 5 for each day) and from pregnant mares (n = 4) on d15. Except for mares on d18 and some cyclic mares (n = 2) on d15 with low progesterone (P₄) concentrations (< 3.18 nm), P₄ conce...
Menzies-Gow NJ, Stevens KB, Sepulveda MF, Jarvis N, Marr CM.The aim of this study was to evaluate both the repeatability (intraobserver agreement) and reproducibility (interobserver agreement) of Obel grading, the most widely accepted method for describing the severity of equine laminitis. The study comprised two parts. In study A, to test intraobserver agreement, 25 ponies were graded twice by a single blinded experienced equine veterinary surgeon, on the first occasion via clinical examination and on the second occasion via a video recording of the initial clinical examination. In study B, to test interobserver agreement, video recordings of 13 ponie...
Merkl M, Ulbrich SE, Otzdorff C, Herbach N, Wanke R, Wolf E, Handler J, Bauersachs S.Establishment and maintenance of pregnancy in equids is only partially understood. To provide new insights into early events of this process, we performed a systematic analysis of transcriptome changes in the endometrium at Days 8 and 12 of pregnancy. Endometrial biopsy samples from pregnant and nonpregnant stages were taken from the same mares. Composition of the collected biopsy samples was analyzed using quantitative stereological techniques to determine proportions of surface and glandular epithelium and blood vessels. Microarray analysis did not reveal detectable changes in gene expressio...
Das PJ, Paria N, Gustafson-Seabury A, Vishnoi M, Chaki SP, Love CC, Varner DD, Chowdhary BP, Raudsepp T.Sperm mRNA transcriptional profiles can be used to evaluate male fertility, yet differences between species in sperm attributes and packaging require adjustments in sperm RNA isolation protocols. The objective was to optimize RNA isolation methodology for fresh, frozen, and extended ejaculates, and epididymal sperm of stallions. Additionally, a protocol for RNA isolation from testis biopsies was established. Separation of sperm from somatic cells was critical for assuring the isolation of sperm-specific RNA. The highest purity was obtained by centrifuging ejaculates and epididymal sperm at 200...
Morel MC, Newcombe JR, Hayward K.The importance of elucidating factors affecting reproductive performance and efficiency is of paramount concern to the equine industry. Oocyte viability is known to be one of the determinants of reproductive success and evidence suggests that it may be linked to follicle size. The aims of this study were, therefore, to ascertain: i) the average diameter and range of pre-ovulatory follicles in Thoroughbred mares; ii) whether this is affected by either mare age, time within the breeding season, or the presence of multiple pre-ovulatory follicles (MO). One thousand, four hundred and ninety two Th...
Noronha LE, Antczak DF.The horse has proven to be a distinctively informative species in the study of pregnancy immunology for several reasons. First, unique aspects of the anatomy and physiology of the equine conceptus facilitate approaches that are not possible in other model organisms, such as non-surgical recovery of early stage embryos and conceptuses and isolation of pure trophoblast cell populations. Second, pregnant mares make strong cytotoxic antibody responses to paternal major histocompatibility complex class I antigens expressed by the chorionic girdle cells, permitting detailed evaluation of the antigen...
Alghamdi AS, Funnell BJ, Bird SL, Lamb GC, Rendahl AK, Taube PC, Foster DN.We performed a series of comparative studies of bull and stallion seminal plasma (SP) and its role on sperm-neutrophil binding as well as the interaction between semen extender and seminal DNase. Because of contrasting roles of SP on sperm-neutrophil binding between horses and cattle, it was suspected there were some species-specific differences on sperm interaction with SP proteins due to the variations in the natural location of semen deposition (uterus compared to vagina). Bull frozen-thawed sperm removed from egg yolk extender showed similar results to fresh sperm, but this also caused ext...
Seabaugh KA, Goodrich LR, Bohn AA, Morley PS, Hendrickson DA.The objective of this study was to determine the effect of bilateral laparoscopic ovariectomy on peritoneal fluid values in mares and compare how this effect was modified by the method of ovarian vessel hemostasis used. Ten mares undergoing standing bilateral laparoscopic ovariectomy were used in a randomized clinical study. During surgery, blood vessels within the mesovarium were either: (1) sealed and transected with a vessel sealing and dividing device (VSDD), or (2) ligated using two loops placed proximal to each ovary and then the mesovarium transected using laparoscopic scissors. The ova...
Nambo Y, Oikawa M, Yoshihara T, Kuwano A, Katayama Y.To investigate the morphological changes of uterine wall arteries associated with the progression of age in Thoroughbred broodmares, uterine wall arteries from 13 mares, aged 2 to 31 years, were studied by routine histomorphometry. The ratio of intimal thickness to external diameter increased due to hyperplasia of elastic fibers and was significantly correlated with age (r = 0.95, P < 0.001). The ratio of medial thickness to external diameter decreased and was also significantly correlated with age (r = -0.84, P < 0.001). Using electron microscopy, it was determined that the cross-sectional ar...
Pascoe JR, Meagher DM, Wheat JD.Uterine torsion was diagnosed in 26 mares of various breeds. The mean duration of gestation was 9.6 months. The most common clinical history was intermittent unresponsive colic of varying duration. Diagnosis of uterine torsion was confirmed by rectal palpation, and surgical correction was achieved in most cases by standing flank laparotomy and manual repositioning of the gravid uterus. Recumbent laparotomy was used only if the mare was intractable, the uterus was ruptured, or hysterotomy was indicated. Of 20 foals determined to be alive during surgery, 14 (70%) were subsequently born alive.
Nieto JE, Aleman M.Anesthetic-induced malignant hyperthermia has been documented in Quarter Horses and is caused by a single-point mutation in the ryanodine receptor 1 gene at nucleotide C7360G generating a R2454G amino acid substitution. An accurate, faster molecular test that is less prone to contamination would facilitate screening for the mutation in horses intended for breeding, in those undergoing surgical procedures, and in those with clinical signs compatible with malignant hyperthermia. Objective: To report a rapid and accurate method for the detection of the ryanodine receptor 1 C7360G mutation. Method...
Curtin DJ.An aggressive mare, presented for prebreeding examination, was found to have a significantly enlarged ovary (soccer ball size). A granulosa thecal cell tumor was initially suspected. Following laboratory and repeated clinical examination, the mare was diagnosed with an ovarian hematoma, which regressed with treatment.
Bielański W, Kaczmarski F.Semen samples were collected from 3 fertile stallions by means of an 'open' artificial vagina and examined under scanning and transmission electron microscopy. The stallion spermatozoon has many features in common with that of other mammals but differs specifically in that it has an asymmetric head, an abaxial position of the tail and an acrosome of small volume. The presence of microtubules in the neck is also a characteristic of stallion spermatozoa.
Wichtel JJ, Reinertson EL, Clark TL.Nonsurgical correction of uterine torsion was performed in 7 mares, and 6 foals were subsequently born alive. Uterine rupture necessitated euthanasia in 1 mare. Correction was achieved by rolling of the mares after general anesthesia had been induced. Previously, this technique was believed to be associated with a high prevalence of fetal and maternal mortality. Nonsurgical correction may be a satisfactory alternative to abdominal surgery in treating uterine torsion in mares.
Pommer AC, Linfor JJ, Meyers SA.Preserved stallion semen often has decreased spermatozoal motility and fertility that can vary significantly between individual stallions. It is not known whether the medium used for extending equine sperm contributes to these decreases by inducing premature capacitation during storage. If spermatozoa undergo capacitation or acrosome reaction prior to insemination, this could result in a diminished capacity to penetrate the cumulus mass and fertilize the egg. We hypothesized that skim milk-based semen extenders, similar to those used in cooled storage, stabilize sperm membranes and prolong spe...
The Journal of hereditySeptember 1, 1984
Volume 75, Issue 5 413-414 doi: 10.1093/oxfordjournals.jhered.a109968
Sponenberg DP, Harper HT, Harper AL.A bay roan Brabant Belgian stallion (ERn/ ern) was bred to eight chestnut American Belgian mares (ern/ ern), producing 57 foals. Thirty foals were bay roan, 25 were chestnut, one was bay, and one was chestnut roan. The recombination rate was 0.035 +/- 0.024, indicating fairly close linkage between the roan (Rn) and extension (E) loci.
Jhamb D, Talluri TR, Sharma S, Juneja R, Nirwan SS, Yadav D, Pargi KK, Tanwar A, Kumar P, Kumar R, Mehta SC, Parashar M, Gaur M.Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. One of the reason for this diminished quality is osmotic stress that spermatozoa experiences during freezing and thawing process. The aim of the present study was to evaluate the cryoprotective effect of trehalose on stallion sperm quality and field fertility rates subjected to cooling and freeze-thawing process. Semen samples were collected from six Marwari breed stallions, divided into three different treatments in a final concentration of 150 × 106 sperm/mL by using Lactose based extender containing...
Allen WRT, Wilsher S.Early embryo transfer in equids was undertaken simultaneously in the early 1970s in Cambridge, England, and Kyoto, Japan. Both groups achieved limited success when flushing the uterine horn ipsilateral to the side of ovulation but the rates improved markedly when the whole uterus was flushed on realization of the continued movement of the embryo throughout the uterine lumen after day 6. Initial transfers of embryos to recipient mares were carried out surgically, but nonsurgical transfer via the cervix has been used subsequently with increasing success, culminating in pregnancy rates of 75%-90%...
van Niekerk CH, Morgenthal JC.The depressing effect on plasma progestagen levels of pregnant mares subjected to specific stressful conditions such as severe pain, infectious diseases, emotional disturbances and exogenous corticosteroids are described. It is concluded that the detrimental effect of stress, evident from its negative influence on plasma progestagen concentrations, could play a major role in the occurrence of pregnancy failure in the Thoroughbred mare.
Acosta TJ, Beg MA, Ginther OJ.Color Doppler transrectal ultrasound was used to evaluate blood flow area in the wall of dominant anovulatory follicles versus ovulatory follicles in mares during the transition between anovulatory and ovulatory seasons. Daily examinations were done in 11 control mares toward the end of the anovulatory season. In 13 separate mares, follicular fluid was collected from 30-mm follicles, and blood flow areas from control mares were used as a basis for designating the sampled follicle as either anovulatory or ovulatory. Blood flow area in the controls ranged from 0.18 to 0.35 cm(2) in six mares on ...
Ginther OJ.One of the most profound theriogenology applications of transrectal diagnostic ultrasonography in mares involves the imaging of ovarian follicles and corpora lutea. The resolving capabilities (frequency) and quality of the scanner directly affect the minimal size of a structure that can be imaged and the quality of the image. High-frequency scanners (5 or 7.5 MHz) of good quality can image a 2-mm follicle and the corpus luteum throughout its functional life. A low-frequency scanner (3 or 3.5 MHz) can image a 6-mm follicle and the corpus luteum for several days after ovulation. Equine follicles...
Satué K, Fazio E, Ferlazzo A, Medica P.The hypothesis that a local serotonergic network might also exist in the follicle of mares remains poorly documented, with exception for humans and laboratory species. For this reason, the aim of the present study was to clarify this possibility, investigating intrafollicular serotonin concentrations of the cycling mare at ovulation time. Sixty ovaries collected from 30 clinically healthy mares of slaughterhouse meat production with clinically normal reproductive tracts after slaughtering were evaluated. Blood samples were taken prior to sacrifice. Follicles were classified in three categories...
Deichsel K, Pasing S, Erber R, Ille N, Palme R, Aurich J, Aurich C.The use of breeding stallions for equestrian competitions requires that fertility is not negatively affected by competition or transport to the competition site. In this study, effects of cortisol release induced by road transport (600 km), adrenocorticotropic hormone (ACTH) administration (3 × 0.5 mg synthetic ACTH) and placebo treatment on semen quality and testosterone release were investigated in Shetland stallions (N = 13) using a crossover design. Saliva for cortisol and blood for testosterone analysis were collected for 10 weeks after treatments. Semen was collected daily for 5 days di...
Mitchell D, Allen WR.Reproductive performance was studied in 137 yearling mares run with stallions in small groups for 3 months between June and August in 1968 to 1971 (four breeding seasons). Pregnancy diagnosis by repeated rectal palpation and qualitative tests for PMSG, showed that ninety-five mares conceived of which forty-four aborted spontaneously between Days 30 and 160 of gestation. Laboratory examination of twenty-one aborted fetuses failed to show any infectious agents. Serial quantitative and qualitative tests for PMSG in aborting animals gave results similar to those observed in mares with normal pregn...
Trommershausen-Smith A, Hughes JP, Neely DP.Gonadal dysgenesis in the mare is associated with several different karyotypes, including sex chromosome aneuploidy (63,X; 63,X/64,XX; 63,X/64,XY or 65,XXX), the normal male complement (64,XY) and autosomal deletion (64,XX?del2q-). The 63,X is the most common karyotype found in gonadal dysgenesis. Aneuploid cases probably represent spontaneous chromosome non-disjunction during oogenesis, spermatogenesis or early embryonic development. Cases with XY or autosomal deletion may be inherited defects or of spontaneous origin.
Hershman L, Douglas RH.Two experiments were performed to deterine the critical time at which the equine blastocyst must be present within the uterus of the mare to prevent regression of the corpus luteum, and thus establish the critical time for the maternal recognition of pregnancy. A non-surgical blastocyst collection technique was developed to study this relationship between the blastocyst and the maternal ovary. Results from these experiments demonstrated that the cyclic life-span of the corpus luteum is not affected by the presence of the blastocyst within the mare's uterus until after Day 14 after ovulation. L...
Handler J, Königshofer M, Kindahl H, Schams D, Aurich C.We conducted the present study to establish a standardized method for cervical stimulation without affecting the endometrium, and to investigate the effect on estrous cycle pattern and concentrations of progesterone, oxytocin and PGF2alpha-metabolite of cervical dilatation in the mare. Six healthy Haflinger mares underwent three different treatments (control, insertion, dilatation) on Days 5 and 7 of the cycles in different orders according to a Latin square design. During dilatation, the balloon of the catheter was inflated stepwise every 30s with warm physiological saline to a maximum of 50 ...
Herrera M, Herrera JM, Cantatore S, Aguilar J, Felipe A, Fumuso E.Uterine acute post-breeding inflammation is a physiological tissue response to the entry of exogenous elements, with persistent endometritis being the main pathology responsible for subfertility in the mare (Equus ferus caballus; Linnaeus, 1758). Mares can be classified as susceptible or resistant to endometritis according to their ability to remove intrauterine fluid within 48 hr after experimental inoculation. Endometrial biopsy is a technique that is commonly used to establish the degree of lesions that can affect the fertility of the mare. Endometrial histomorphometry is an objective and ...
Khalil AM, Murakami N.For the past 12 years, a study was conducted in the Misaki area (southern Kyushu Island, Japan) to investigate young males form new harems, how they acquire the mares and the factors affecting the process of new harem formation. Young males formed new harems between the ages of 3.8 and 7.6 yr, and 93% of these new harem groups were formed at the beginning of the breeding season. The most common way (87%) for young males to form a new harem was by acquiring wandering mares which had separated from their groups, whereas 13% stole unstable mares from established bands. The fact that all young mal...
Varner DD, Ward CR, Storey BT, Kenney RM.Equine spermatozoa were incubated in a chemically defined medium for 8 hours. The medium preserved spermatozoal viability, as assessed by total spermatozoal motility, progressive spermatozoal motility, and spermatozoal exclusion of eosin stain. Effects of time and divalent cation ionophore, A23187, on the occurrence and character of the spermatozoal acrosome reaction were determined. Two light microscopic assays, a triple-stain technique and a chlortetracycline fluorescence assay, were calibrated with transmission electron microscopy for detection of the acrosome reaction. Incubation time and ...
Schams D, Papkoff H.Highly purified pregnant mare serum gonadotropin (PMSG) can be prepared from crude commercial preparations of PMSG by chromatography on sulfoethyl-Sephadex C-50 and gel filtration on Sephadex G-100. The preparation was examined by disc electrophoresis and gel filtration and found to be of high purity. Amino acid analysis shows similarities to pituitary gonadotropins. The PMSG contains a high content of proline and cystine and low amounts of the aromatic amino acids. Phenylalanine is the major amino terminal amino acid. The carbohydrate content totals 45% of which 10% is the content of sialic a...
Orsolini MF, Meyers SA, Dini P.As the use of assisted reproductive technologies (ART) and in vitro embryo production (IVP) expand in the equine industry, it has become necessary to further our understanding of semen physiology as it applies to overall fertility. This segment of our two-section review will focus on normal sperm parameters, beginning with development and extending through the basic morphology of mature spermatozoa, as well as common issues with male factor infertility in IVP. Ultimately, the relevance of sperm parameters to overall male factor fertility in equine IVP will be assessed.
Carluccio A, De Amicis I, Panzani S, Tosi U, Faustini M, Veronesi MC.No knowledge regarding the peripartum changes in mammary secretions in the jenny are presently available in literature. In the mare, instead, several studies report the role of these changes as indicators of foetal readiness for birth and impending parturition. This experiment was designed to determine calcium, sodium, potassium concentrations, and the value of sodium/potassium ratio in mammary fluids during prepartum in the jenny. Samples were daily collected by hand milking, after mammary gland size increased noticeably, from 17 Martina Franca jennies. Prepartum mammary secretions were analy...
Rader K, Choi YH, Hinrichs K.Intracytoplasmic sperm injection is becoming a common clinical procedure in the horse, but little information is available on techniques for its performance. Each laboratory uses different procedures and different media for the steps involved with in vitro embryo production. This article outlines the procedures used in the Clinical Equine Intracytoplasmic Sperm Injection Program at Texas A&M University for in vitro blastocyst production during the past 3 years.
Hamond C, Martins G, Bremont S, Medeiros MA, Bourhy P, Lilenbaum W.The purpose of the present study was to detect the presence of DNA of pathogenic Leptospira sp. in vaginal fluids of mares regarding a possible role of the sexual transmission. A total of 134 breeding mares from four troops were studied and sampling was conducted from vaginal fluids and urine for culture and PCR; and blood for serology. From the 134 serum samples tested, 59 (44%) were seroreactive, and serovar Bratislava was the most frequent (54.2%). None positive culture was obtained, but leptospiral DNA was detected by PCR (lipL32 gene) in 45 (33.5%) urine samples and 43 (32%) vaginal fluid...
Ousey JC, Palmer L, Cash RS, Grimes KJ, Fletcher AP, Barrelet A, Foote AK, Manning FM, Ricketts SW.Standard bacteriological methods for identifying Taylorella equigenitalis in cervical smears are time consuming. Therefore, a more rapid real-time PCR assay was evaluated for its suitability in screening swabs. Objective: To compare the results of a commercially available real-time PCR assay with routine microbiological culture for the identification of T. equigenitalis, the causative organism of contagious equine metritis, in equine genital swab samples, under 'field trial' conditions. Methods: Routine prebreeding genital swabs (n=2072) collected from Thoroughbred mares and stallions during 2...
