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.
Mateus L, da Costa LL, Cardos JJ, Silva JR.The efficiency of treatments for unobserved oestrus and their effect on the reproductive performance of a dairy cattle herd with low oestrous detection rate till 60 days post-partum (dpp), attributed to the declivous and slippery concrete floor were investigated. The herdsman requested advice in order to improve the mean days open of the herd, but no investments were allowed because a new unit was about to be built. Due to the low oestrus detection rate of the herd, the breeding policy was to inseminate at the first detected post-partum oestrus. Cows were examined at 20-30 dpp to assess uterin...
Ball BA, Vo A.The lipophilic fluorescent probe, 4,4-difluoro-5-(4-phenyl-1 ,3-butadienyl)-4-bora-3a,4a-diaza-s-indacene-3-undecanoic acid (C11-BODIPY581/591) was used to evaluate changes in lipid peroxidation in equine spermatozoa during both short-term exposure to ferrous sulfate and sodium ascorbate in the presence of cumene hydroperoxide as well as during storage of spermatozoa at 5 degrees C for 48 hours. Peroxidation of C11-BODIPY581/591 was accompanied by a shift in fluorescence from red to green, and the relative amount of nonoxidized probe was determined as the ratio of red:(red + green) fluorescenc...
Tanaka Y, Taniyama H, Tsunoda N, Shinbo H, Nagamine N, Nambo Y, Nagata S, Watanabe G, Herath CB, Groome NP, Taya K.Immunolocalization of the inhibin (a) and inhibin/activin (beta3A and betaB) subunit proteins in equine fetal testes was investigated to determine the ability of the fetal testis to produce inhibins at 120, 150, 200, and 250 days of gestation. In addition, concentrations of immunoreactive (ir)-inhibin, inhibin pro-aC, and inhibin A in both the maternal and fetal circulation were measured. It was found that plasma concentrations of ir-inhibin, inhibin pro-alphaC, and inhibin A were much higher (P < .05) in the fetal than in the maternal circulation at any stage of gestation examined. Similar...
Al-Zi'abi MO, Fraser HM, Watson ED.In mares, little information is available on the type of cell death that occurs during natural and induced luteal regression. Corpora lutea were collected from mares in the early luteal phase, days 3-4 (n = 4); mid-luteal phase, day 10 (n = 5); early regression, day 14 (n = 4); late regression, day 17 (n = 4); and 12 and 36 h (n = 3 per group) after PGF2alpha administration on day 10. Histological and ultrastructural sections were examined and TUNEL was used to detect DNA fragmentation. In early luteal regression, there were more pyknotic luteal cells and extracellular round dense bodies compa...
Stout TA, Allen WR.A growing equine conceptus must suppress the cyclical release of PGF(2 alpha) from the endometrium to effect maternal recognition of its presence in the uterus. Paradoxically, the conceptus itself secretes PGF(2 alpha), together with other prostaglandins. In this study, the PGF(2 alpha) and PGE(2) content of, and production in vitro by, day 10-32 equine conceptuses were measured and the influence of pregnancy on the concentrations of these prostaglandins in the uterine lumen was examined. In vitro, the release of both prostaglandins per mg conceptus tissue was very high on day 10 after ovulati...
Inagaki M, Kikuchi M, Orino K, Ohnami Y, Watanabe K.Lactoferrin with a molecular mass of 80 kDa was purified from equine seminal plasma by heparin-Agarose affinity chromatography and Sephacryl S-200 gel filtration. Purified lactoferrin was found to be highly homogeneous on the bases of its migration as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and of the monospecificity of rabbit antibodies to the purified protein in immunoblotting of seminal plasma proteins. A sandwich enzyme-linked immunosorbent assay was developed for quantifying lactoferrin in equine seminal plasma. Seminal plasma lactoferrin concentrations ...
Allen WR, Wilsher S, Stewart F, Stewart F, Ousey J, Ousey J, Fowden A.Within-breed artificial insemination and between-breed embryo transfer were carried out in small pony (P) and large Thoroughbred (Tb) mares to create 4 types of horse pregnancy in which the fetus experienced spatial and nutritional deprivation (Tb-in-P; n=8), luxury (P-in-Tb; n=7) or normality (Tb-in-Tb; n=7 and P-in-P; n=7) in utero. Measurement of equine chorionic gonadotrophin (eCG), total conjugated oestrogens and progestagen concentrations in serial peripheral serum samples recovered from all the mares throughout gestation showed that the amount of eCG produced during the first half of ge...
Bridges TS, Davidson TR, Chamberlain CS, Geisert RD, Spicer LJ.The objective of the present study was to evaluate changes in equine follicular fluid insulin-like growth factor binding protein (IGFBP) proteolytic activity as well as steroid, IGF, and IGFBP concentrations during follicular development in the mare. Mares (n = 14) were classified as either in the follicular phase (n = 8) or luteal phase (n = 6). Follicles (n = 92) were categorized as small (6 to 15 mm; n = 54), medium (16 to 25 mm; n = 23), or large (> 25 mm; n = 15), and follicular fluid was collected. Estradiol and androstenedione levels in follicular fluid were greater (P < 0.05), an...
Bruemmert JE, Coy RC, Squires EL, Graham JK.Stallion spermatozoa maintain high fertilizing capacity if cooled to 5 degrees C and inseminated within 24 h. However, if spermatozoa are stored for 48 h, fertilizing capacity declines. Therefore, multiple shipments of semen are often required to inseminate mares that remain in estrus for days. Therefore, experiments were designed to determine if adding antioxidants to stallion spermatozoa stored at 5 degrees C for 48 h could maintain motility and fertilizing ability. In the first experiment stallion spermatozoa were incubated in a skim milk (SM) or a skim milk-egg yolk medium in combination w...
Gentry LR, Thompson DL, Stelzer AM.Seventeen seasonally anovulatory light horse mares were treated daily, starting January 5 (d 1), for 28 d with GnRH analog (GnRH-A; 50 ng/kg BW) and(or) thyrotropin-releasing hormone (TRH; 5 microg/kg BW) in a 2 x 2 factorial arrangement of treatments to test the hypothesis that combined treatment may stimulate follicular growth and development. Ovaries were examined via ultrasonography and jugular blood samples were collected every 3 d. Frequent blood samples were collected after treatment injections on d 1, 2, 4, 7, 11, 16, and 22; on d 29, all mares received an i.v. mixture of GnRH, TRH, su...
Morris LH, Allen WR.The findings of a retrospective survey of 1393 Thoroughbred mares visiting 22 studfarms in the Newmarket region of the UK during the 1998 mating season were compared with those of a similar study undertaken in 1983. The effects of mare age and status, stallion, month of mating, application of uterine treatments and other parameters on the rates of singleton and twin conception and subsequent pregnancy losses were analysed. Mare age and status significantly affected the per cycle pregnancy rate and the incidence of pregnancy loss. Overall, the mean number of matings per oestrus was 1.12 and the...
Li ZY, Jiang QS, Zhang YL, Liu XM, Engelhardt JF.In an effort to expand the use of ferrets as models for genetic disease, several experimental parameters that are required for successful genetic manipulation in this species were investigated. Optimum superovulation (19.3 +/- 0.6 oocytes and embryos per female) was achieved after injections of 100 iu equine chorionic gonadotrophin (eCG) and 150 iu human chorionic gonadotrophin (hCG). The ovulation rate achieved by the treatment was more than double that induced by mating. Mating with a male immediately after hCG treatment did not significantly alter the number of oocytes ovulated or the numbe...
Nie GJ, Wenzel JG, Johnson KE.An artificial insemination dose for mares consisting of 500 million progressively motile spermatozoa is considered "standard" by most clinicians. However, little information is available directly comparing pregnancy outcome among methods of evaluating and selecting spermatozoa for insemination. The objective of this study was to determine if the method of spermatozoal evaluation and selection influences fertility as measured by pregnancy outcome. Mares were inseminated with 100 or 500 million spermatozoa that were selected for progressive motility, normal morphology, hypoosmotic swelling or ab...
Fouchécourt S, Charpigny G, Reinaud P, Dumont P, Dacheux JL.Prostaglandin D2 synthase (PGDS) is a major epididymal secretory protein in several species. We quantified PGDS in ram and bull semen using a specific antiserum. Strong variations in PGDS concentration existed between animals. In the bull, the highest concentrations were found preferentially in animals with normal or high fertility, as was previously suggested. However, low concentrations were found in males with all ranges of fertility, suggesting that the function of PGDS either is not necessary for male fertility or can be assumed by other proteins when its concentration is low. In the ram ...
Machida N, Tanaka Y, Taya K, Nakamura T.A case of congenital ovarian interstitial cell hamartoma in a thoroughbred foal that died of apparent nutritional myopathy (white-muscle disease) 14 h after birth is described. An incidental finding at necropsy was a pale brown, mushroom-shaped, pedunculated mass (6 x 4 x 3 cm) attached to the left ovary. On the cut surface, the mass had a peripheral rim of dense parenchyma (3-5 mm wide), surrounding a pale gelatinous core. Histologically, the mass consisted of a peripheral zone of densely packed large cells that were quite similar, morphologically, to fetal ovarian interstitial cells, and a c...
Linfor JJ, Meyers SA.Single-cell gel electrophoresis (SCGE), or comet assay, has the ability to detect damage at the single cell level and has not been reported for equine sperm. The ability to detect nuclear damage at the single cell level could aid in the advancement of protocols for optimal semen preservation. The goals of these experiments were to adapt this assay for use with equine sperm and to utilize the assay for determining the integrity of equine sperm DNA following treatments with storage at various decreased temperatures (-20 degrees C and 5 degrees C). Results from experiments in which sperm were fro...
Tozaki T, Kakoi H, Mashima S, Hirota K, Hasegawa T, Ishida N, Miura N, Choi-Miura NH, Tomita M.Microsatellite 15 TKY System was characterized for parentage verification of horse registry. The Microsatellite 15 TKY System was constructed by using 15 microsatellites, TKY279, TKY287, TKY294, TKY297, TKY301, TKY312, TKY321, TKY325, TKY333, TKY337, TKY341, TKY343, TKY344, TKY374, and TKY394, to provide stringent PCR-based microsatellite typing specifically optimized for multicolor fluorescence detection. The Microsatellite 15 TKY System showed good resolutions for 250 unrelated Thoroughbred horses, and the probability of exclusion (PE) at each microsatellite ranged from 0.437 to 0.621, resul...
Devireddy RV, Swanlund DJ, Olin T, Vincente W, Troedsson MH, Bischof JC, Roberts KP.Optimization of equine sperm cryopreservation protocols requires an understanding of the water permeability characteristics and volumetric shrinkage response during freezing. A cell-shape-independent differential scanning calorimeter (DSC) technique was used to measure the volumetric shrinkage during freezing of equine sperm suspensions at cooling rates of 5 degrees C/min and 20 degrees C/min in the presence and absence of cryoprotective agents (CPAs), i.e., in the Kenney extender and in the lactose-EDTA extender, respectively. The equine sperm was modeled as a cylinder of length 36.5 microm a...
Carnevale EM, Maclellan LJ, Coutinho da Silva MA, Checura CM, Scoggin CF, Squires EL.Insemination of recipients for oocyte transfer and gamete intrafallopian transfer (GIFT) in five experiments were reviewed, and factors that affected pregnancy rates were ascertained. Oocytes were transferred into recipients that were (1) cyclic and ovulated at the approximate time of oocyte transfer, (2) cyclic with aspiration of the preovulatory follicle, and (3) noncyclic and treated with hormones. Recipients were inseminated before, after, or before and after transfer. Intrauterine and intraoviductal inseminations were done. Pregnancy rates were not different between cyclic and noncyclic r...
Batellier F, Vidament M, Fauquant J, Duchamp G, Arnaud G, Yvon JM, Magistrini M.In the horse industry, milk or milk-based extenders are used routinely for dilution and storage of semen cooled to 4-8 degrees C. Although artificial insemination (AI) with chilled and transported semen has been in use for several years, pregnancy rates are still low and variable related to variable semen quality of stallions. Over the years, a variety of extenders have been proposed for cooling, storage and transport of stallion semen. Fractionation of milk by microfiltration, ultrafiltration, diafiltration and freeze-drying techniques has allowed preparation of purified milk fractions in ord...
Metcalf ES.Despite the numerous benefits of having the capability to transport semen internationally, there are serious potential ramifications if that semen is contaminated with a communicable disease. Bacteria: Many commensal bacteria colonize the exterior of the stallion penis and are not regarded as pathogenic. They may be cultured from an ejaculate. Alterations of the normal bacterial flora on the exterior genitalia may cause the growth of opportunistic bacteria such as Klebsiella pneumonia, Pseudomonas aeruginosa, Streptococcus zooepidemicus, which, if inseminated, may cause infertility in suscepti...
Gadella BM, Rathi R, Brouwers JF, Stout TA, Colenbrander B.During sexual reproduction, the sperm and oocyte must fuse before the production of a diploid zygote can proceed. In mammals such as equids, fusion depends critically on complex changes in the plasma membrane of the sperm and, not surprisingly, this membrane differs markedly from that of somatic cells. After leaving the testes, sperm cease to synthesize plasma membrane lipids or proteins, and vesicle-mediated transport stops. When the sperm reaches the female reproductive tract, it is activated by so-called capacitation factors that initiate a delicate reorientation and modification of molecul...
Lindsey AC, Bruemmer JE, Squires EL.Mares are generally inseminated with 500 million progressively motile fresh sperm and approximately 1 billion total sperms that have been cooled or frozen. Development of techniques for low dose insemination would allow one to increase the number of mares that could be bred, utilize stallions with poor semen quality, extend the use of frozen semen, breed mares with sexed semen and perhaps reduce the incidence of post-breeding endometritis. Three low dose insemination techniques that have been reported include: surgical oviductal insemination, deep uterine insemination and hysteroscopic insemin...
Troedsson MH, Loset K, Alghamdi AM, Dahms B, Crabo BG.Insemination of mares with bacteria-free equine spermatozoa results in an influx of polymorphonuclear neutrophils (PMNs) into the uterine lumen. In vitro studies have demonstrated that equine spermatozoa activate complement, resulting in cleavage of factors C5a and C3b. Since uterine secretion is rich in complement, it is likely that an interaction between spermatozoa and uterine secretion results in C5a-mediated chemotaxis and migration of PMNs into the uterine lumen. Once in the uterine lumen, the PMNs phagocytize bacteria and spermatozoa, which is an important part of sperm elimination from...
Love CC, Love LB, Varner DD, Hinrichs K.The relationship of holding time in media at room temperature (approximately 22 degrees C) to initial chromatin configuration and rate of in vitro maturation (IVM) of equine oocytes was determined. Only oocytes having a complete, compact cumulus were used in this study. Oocytes were removed from ovaries 3.5-8 h after slaughter and were put into one of four treatment groups: (1) immediate/fix (IF) = immediate fixation following removal from the ovary; (2) delay/fix (DF) = fixation after oocytes were held 1-4 h in medium at room temperature; (3) immediate/mature (IM) = immediate placement into m...
Bergqvist AS, Johannisson A, Bäckgren L, Dalin AM, Rodriguez-Martinez H, Morrell JM.This study was designed to evaluate the effect of single layer centrifugation (SLC) and subsequent cold storage on stallion sperm capacitation-like status and acrosome reaction. Three stallions were included in the study, with three ejaculates per stallion. The samples were examined 4, 24 and 72 h after collection, extension and SLC, with storage at 6°C. Sperm capacitation-like status was investigated using the fluorescent dye chlortetracycline (CTC). There was no difference in capacitation-like status between colloid-selected and non-selected spermatozoa. Sperm motility decreased significant...
Love LB, Choi YH, Love CC, Varner DD, Hinrichs K.Two experiments were conducted to determine the effects of storage on equine ovaries or isolated oocytes. Ovaries were collected at an abattoir and were maintained at room temperature during collection and transport (3-9h total). After arrival at the laboratory, ovaries were divided into three groups: immediate oocyte collection (control), storage at room temperature overnight (15-18 h) before oocyte collection, or storage at 4 degrees C overnight before oocyte collection. Collected oocytes were cultured in maturation medium for 24h. There was a significant increase in the proportion of oocyte...
Müller V, Moraes BDSS, Carvalho IR, Wendt CG, Patten RD, Nogueira CEW.The aim of this study was to estimate the genetic parameters for the morphometric measurements of withers height (WH), thoracic circumference (TC) and cannon bone circumference (CBC) of Criollo horses, stratified for maternal and paternal effects. Statistical genetic design of factor crossings was used to evaluate the offspring of full siblings and half-siblings. Fifty stallions were selected (n = 50) who had been crossed with six mares each (n = 6), to provide 300 parental pairings in which two offspring were born per mare (n = 600). WH in females and TC in males were highly influenced ...
Rodríguez H, Torres C, Valdés X, Guerra H, Pastor LM, Maccallini G, Bustos-Obregón E.In the female genital tract, spermatozoa must undergo capacitation and acrosome reaction prior to fertilization. A number of factors may induce physiological acrosome reaction assayed in vitro. The aims of this study are to determine the inductive effect of the preovulatory follicular fluid on the sperm acrosomal status in the equine, once some characteristics of the follicular fluid during folliculogenesis had been evaluated. The spermatozoa were obtained from cauda epididymes of adult stallion. Follicular fluid was taken from mare ovarian follicles classified according to their diameter. In ...
Rigby S, Hill J, Miller C, Thompson J, Varner D, Blanchard T.It is probable that reduced pregnancy rates in mares bred to subfertile stallions is attributable, in part, to the reduced number of normal spermatozoa that colonize the oviduct. Administration of oxytocin stimulates both uterine and oviductal contractility. The hypothesis that oxytocin may enhance sperm transport to/into the oviducts, and thereby increase pregnancy rates, was tested in 2 trials. For both trials, fertile estrous mares with follicles > or = 35 mm in diameter were inseminated once at 24 h after administration of 1500 to 2000 U hCG. The inseminate dose was limited to 100 milli...
Mennella MR, Jones MR.The activity of 5'-nucleotidase (EC 1.3.5), cyclic nucleotide phosphodiesterase (EC 2.1.4.17), non-specific phosphodiesterase (EC 3.1.4.1) and ribonuclease (EC 1.7.7.16)has been investigated in the seminal plasma of whole semen and in the secretions of the seminal vesicle, prostate and epididymis of the bull, boar, ram, stallion, jackass, rabbit and man. Bull seminal plasma showed the highest activity for 5'-nucleotidase, cyclic nucleotide phosphodiesterase and ribonuclease; in contrast, stallion and jackass semen were very poor in these enzymes. Ram, rabbit and boar seminal plasma showed inte...
Werner HW.Prepurchase examination provides a significant opportunity for veterinarians to offer an important professional service to the equine industry. When the service is performed competently and ethically, prospective buyers and sellers will recommend the examining veterinarian to fellow horse owners and professionals. To become comfortable with and skilled at performing prepurchase examinations, a veterinarian must understand the operational challenges associated with this service-and master them. Veterinarians performing prepurchase examinations should address the needs and manage the expectation...
Scott CJ, de Mestre AM, Verheyen KL, Arango-Sabogal JC.The overall aim of this work was to identify the potential impact of misclassification errors associated with routine screening and diagnostic testing for endometritis in mares. Using Bayesian latent class models (BLCM), specific objectives were to: 1) estimate the diagnostic accuracy of cytology and culture of endometrial swab samples to detect endometritis in mares; 2) assess the impact of different cytology thresholds on test accuracy and misclassification costs; and 3) assess the sensitivity (Se) and specificity (Sp) of a diagnostic strategy including both tests interpreted in series and p...
Yang YJ, Cho GJ.A total of 384 Thoroughbred mares were investigated to determine and evaluate the features of early embryonic death at nine equine farms on Jeju Island, South Korea, from 2001 to 2003. Overall, 771 matings for 384 mares resulted in 376 pregnancies 15 days after ovulation. Subsequently, 12.2% (46/376) of these early conceptuses were lost within 45 days after ovulation. Furthermore, about three quarters of the 46 embryonic deaths occurred between 16 and 25 days after ovulation. The incidence of embryonic death was highest in the barren (17.2%), more than 15 years old (15.4%), and more than 10 pa...
Chavatte-Palmer P, Arnaud G, Duvaux-Ponter C, Brosse L, Bougel S, Daels P, Guillaume D, Clément F, Palmer E.The induction of lactation is performed in ruminants by steroidogenic impregnation, followed by drugs intended to increase prolactin secretion. The aim of this study was to induce lactation in barren mares and to evaluate milk production. Five treated and 5 control mares were used in June and September in year 1, and 12 mares were used in year 2. Mares were administered a vaginal pessary (500 mg altrenogest and 50 mg estradiol benzoate) for 1 week. The 2nd week, another sponge with 100 mg estradiol benzoate was administered, together with 50 mg/100 kg body weight (BW) sulpiride in oil (IM q12h...
Rideout MI, Burns SJ, Simpson RB.Sterile filtrates were prepared from equine isolates of Klebsiella pneumoniae (genitalium), Proteus mirabilis, Pseudomonas aeruginosa, Escherichia coli, Streptococcus zooepidemicus, Streptococcus equisimilis, Actinobacillus equuli, and Corynebacterium equi and mixed individually with extended stallion semen. When diluted in the extended semen the filtrates represented bacterial populations of 0.5 x 10(6), 1 x 10(6), 2 x 10(6) and 4 x 10(6) cells/ml. pH values were recorded for each filtrate. Specimens were monitored for percentage motile spermatozoa at 30-min intervals until they reached 10% o...
Consuegra C, Crespo F, Dorado J, Diaz-Jimenez M, Pereira B, Sánchez-Calabuig MJ, Beltrán-Breña P, Pérez-Cerezales S, Rizos D, Hidalgo M.The aim of this study was to evaluate the fertilizing capacity of frozen or vitrified stallion sperm after assessing different warming procedures. In Experiment 1, different warming procedures were compared after sperm vitrification: immersion in extender at 43 °C (C), or in a water bath at 37 °C/30 s (W37), 43 °C/10 s (W43) or 60 °C/5 s (W60). With the W60 treatment, there were greater values (P < 0.05) for VCL (83.93 ± 3.6 μm/s) and ALH (3.00 ± 0.2 μm) than freezing and with the C group, and greater values (P < 0.001) for PM (35.33 ± 2.5 %) than with the W43 treatment. In Experiment...
Besognet B, Hansen BS, Daels PF.We have previously demonstrated that daily administration of the dopamine D2 antagonist, sulpiride, during seasonal anoestrus, effectively advances the mean time of onset of the breeding season in mares. The purpose of this study was to examine the effect of sulpiride administration on pulsatile FSH and LH secretion in seasonally anoestrous mares, follicular development, time of first ovulation and the fertility at the first ovulation. Fourteen anoestrous mares were selected based on progesterone concentrations < 1 ng ml-1 for 3 weeks and largest follicle diameter < 20 mm. Starting 30 Ja...
Cuervo-Arango J, Newcombe JR.The most common pathological anovulatory condition that occurs spontaneously during the breeding season in the mare is the haemorrhagic anovulatory follicle (HAF). A relatively high proportion of mares, soon after ovulation, develop a corpus haemorrhagicum (CH) with a central lacuna. This type of corpora lutea may resemble an HAF, which may complicate the accurate diagnosis of ovulation. The main objective of this study was to compare the ultrasound data of mares examined frequently with HAFs and CHs to elucidate whether it is possible to distinguish them from each other. A total of 135 ovulat...
Kölle S, Dubois CS, Caillaud M, Lahuec C, Sinowatz F, Goudet G.In the equine, the zona pellucida (ZP) is the major barrier to successful in vitro fertilization. Therefore the aim of our studies was to analyze species-specific features of the equine ZP in regard to structure and glycoprotein ZPB and ZPC expression sites during oocyte development and embryogenesis. The equine ZP revealed high immunological cross-reactivity to porcine ZPB and ZPC. In the ovary, the distribution of ZPB and ZPC was co-localized and correlated with the developmental stage of the follicle. ZPB and ZPC expression started in the oocyte of the late primordial and primary follicle. ...
Duval LH, Rechsteiner SMF, Gastal GDA, Gastal MO, Mattos RC, Gastal EL.After having been brought to America 400 years ago, the Criollo horse reproduced freely for centuries in the southern part of the American continent. Roughness, resistance, and endurance are typical characteristics of this breed of horses. Although the natural selection that occurred over the centuries may have positively influenced the fertility and longevity of this breed, information regarding ovarian function and other reproductive aspects of Criollo breed mares under natural or controlled management conditions is scarce. The objectives of the present study were to (1) characterize the fol...
Uhlenbruck F, Sinowatz F, Amselgruber W, Kirchhoff C, Ivell R.cDNA probes derived from genes expressed specifically in the human epididymis were used to examine gene expression in the epididymides of boar, bull and stallion by Northern hybridization. Two probes for the HE1 and HE4 gene products were found to recognize tissue-specific transcripts in all three species, with a regionally differential distribution within the epididymis. Additionally, antibodies recognizing the HE4 protein were shown to react specifically in the epididymis of the boar and bull. An extensive study of the boar showed that, whereas mRNA for the HE1-homologue was up-regulated mar...
de Vries C, Vanhaesebrouck E, Govaere J, Hoogewijs M, Bosseler L, Chiers K, Ducatelle R.A premature dead equine fetus with excessive fluctuating distension of the abdomen was delivered by extraction. Post-mortem examination revealed ascites and a solitary, irregular, bulging, multinodular, firm, yellow mass of 25 cm in diameter in the right liver lobe. Extensive peritoneal implantation metastases were present. The masses were composed of polygonal embryonal cells arranged in sheets and nests. Based on the immunohistochemical expression of Ki67, low molecular weight cytokeratin and alpha-1 fetoprotein, a diagnosis of hepatoblastoma with peritoneal implantation metastases was made....
Monteiro de Barros MR, Davies-Morel MCG, Mur LAJ, Creevey CJ, Alison RH, Nash DM.Persistent mating-induced endometritis is a major cause of poor fertility rates in the mare. Endometritis can be investigated using an ex vivo equine endometrial explant system which measures uterine inflammation using prostaglandin F2α as a biomarker. However, this model has yet to undergo a wide-ranging assessment through transcriptomics. In this study, we assessed the transcriptomes of cultured endometrial explants and the optimal temporal window for their use. Endometrium harvested immediately post-mortem from native pony mares (n = 8) were sampled (0 h) and tissue explants were cultured ...
Heiskanen ML, Pirhonen A, Koskinen E, Mäenpää PH.The role of various environmental conditions on sperm motility and ATP content was investigated by incubating raw and washed spermatozoa collected with an open-ended artificial vagina from 10 stallions in various biological and artificial media under different atmospheric conditions. Spermatozoa did not survive for more than 12 h when kept unextended in the original seminal fluid in any circumstances. The most favourable media tested for long-term sperm survival were Kenney's medium or Kenney's medium supplemented with 10 mM-theophylline and 10 mM-Hepes, pH 7.2. Centrifugation and slow cooling...
Spoormakers TJ, Graat EA, ter Braake F, Stout TA, Bergman HJ.Previous surveys have reported that mare and foal survival after correction of uterine torsion (UT) varies from 60 to 84% and from 30 to 54%, respectively. Furthermore, resolution via a standing flank laparotomy (SFL) has been associated with better foal, but not mare, survival. Objective: To compare the success of SFL with other correction methods (e.g. midline or flank laparotomy under general anaesthesia; correction per vaginam). Methods: Retrospective analysis of clinical records. Methods: Data on correction technique, stage of gestation, degree of rotation, survival and subsequent fertili...
Irvine CH, Alexander SL.To study the mechanisms responsible for the unusually slow decline of the ovulatory LH surge in mares, secretion patterns of GnRH, LH and FSH were monitored in pituitary venous blood collected every 2 or 5 min for 10.5-18.0 h from five mares on the third (n = 4) or fifth day after ovulation (first sampling period). To determine the effectiveness of progesterone negative feedback, mares were then given a luteolytic dose of a prostaglandin analogue (PGF2 alpha) and pituitary venous sampling (every 2 or 5 min for 16 h) recommenced 20-22 h later (second sampling period). During the declining arm o...
Turner JW, Rutberg AT.There are only two nonlethal approaches with which to manage wildlife populations: remove excess individuals or decrease reproductive rates. In the case of wild horse management, the latter has already been shown to be a more humane and less costly approach. Contraception has been known for many years to be effective in wild horses with regard to both fertility and population alteration. Field testing under real-world management situations is a critical aspect of wildlife contraception assessment. Field testing also requires documentation to justify eventual large-scale use of fertility contro...
Douglas-Hamilton DH, Osol R, Osol G, Driscoll D, Noble H.A field trial of artificial insemination in horses with transproted, chilled semen was conducted using a specially designed container which permitted a controlled, slow initial rate of cooling (-0.3 degrees C/min) and maintenance of a final temperature of 4 degrees -6 degrees C for more than 36 hrs. Forty-six mares in 23 states were inseminated with semen from three German Warmblood stallions standing at stud in Hamilton, Massachusetts. A third-cycle conception rate of 91% was obtained.
Cook NL, Masterson KR, Battaglia D, Beck R, Metcalf ES.Numerous variables affect invitro blastocyst development following intracytoplasmic sperm injection (ICSI). The paternal factor is affected by initial semen quality, processing techniques and final selection of individual spermatozoon for injection. This study investigated whether there was an effect of sperm cryoprotectant agent (CPA) on equine invitro blastocyst production, and reviews recent developments examining how processing equine semen affects ICSI outcomes. Single ejaculates from five stallions were collected and processed in a freezing extender containing either 1M dimethyl sulfoxid...
Bos H, van der Meij GJ, Dik KJ.Bone structure, nutrient canals, form and definition, and a total evaluation of both fore navicular bones were radiologically evaluated in 169 three- and four-year-old Dutch warmblood mares divided into eleven daughter (half sister) groups. On the basis of the 'total evaluation', differences between the three- and four-year-old horses were detectable. Using the 'total evaluation', significant differences were found between daughter groups consisting of three-year-old mares. These differences support the theory that podotrochleosis may be (partly) due to the presence of genetic factors. The pos...
Hartig W, Houe H, Andersen PH.The plentiful data on Danish horses are currently neither organized nor easily accessible, impeding register-based epidemiological studies on Danish horses. A common database could be beneficial. In principle, databases can contain a wealth of information, but no single database can serve every purpose. Hence the establishment of a Danish equine health database should be preceded by careful consideration of its purpose and content, and stakeholder attitudes should be investigated. The objectives of the present study were to identify stakeholder attitudes to the importance, purpose, research ar...
Villani M, Cairoli F, Kindahl H, Galeati G, Faustini M, Carluccio A, Veronesi MC.Very little information is available regarding the physiological mechanisms involved in the normal sexual activity in the stallion and, in particular, the endocrine control of reproduction is still not clearly understood. This experiment was designed to determine the short-term effect of sexual stimulation on plasma concentrations of testosterone, cortisol, oestrone sulphate and 15-ketodihydro-PGF(2alpha) in stallions. Semen samples were collected from 10 lighthorse stallions of proven fertility using a Missouri model artificial vagina. At the same time, blood samples were collected from the j...
Jung H, Yoon M.The production of donor-derived sperm using spermatogonial stem cell transplantation has been studied in various animals including mice, rats, goats, boar, dogs, sheep, and monkeys. However, germ cell transplantation has not been applied in stallions. The objective of this study was to produce donor germ cell-derived sperm using germ cell transplantation in stallions. Donor germ cells were transplanted into the parenchyma of 3 recipient stallions that had been treated with busulfan IV injections of 15 mg/kg body weight. For the preparation of donor single germ cells, tissue (20 g) from each te...
