Stallions are adult male horses that have not been gelded and are often used for breeding purposes. They exhibit distinct behavioral and physiological characteristics compared to mares and geldings. Stallions are known for their strong musculature, prominent neck, and often more pronounced mane and tail. Their behavior can be more aggressive and territorial, especially during the breeding season, as they naturally compete for mating opportunities. This topic explores the anatomy, behavior, and management practices specific to stallions, as well as their role in equine reproduction. The page provides access to peer-reviewed research studies and scholarly articles that investigate various aspects of stallion health, fertility, and behavior, contributing to the understanding and management of these horses in equine science.
Ball BA.Oxidative stress is an important component of the cytopathology of equine spermatozoa undergoing storage as liquid or frozen semen. Damage to chromatin, membranes and proteins of sperm are important components of oxidative damage to sperm. Similarly, sperm are exposed to a variety of osmotic stresses during storage that result from exposure to hypertonic media or result as a consequence of osmotic changes induced during freezing. A number of changes induced during processing and storage of equine sperm also appear to induce apoptotic-like changes which may adversely affect sperm survival and f...
Chowdhary BP, Paria N, Raudsepp T.Following the recent development of high-resolution gene maps and generation of several basic tools and resources to use them in analyzing traits that are economically important to horse owners, genome analysis in horses is witnessing a shift towards developing an ability to analyze complex traits. The likelihood of this happening in the very near future is great, mainly because of the recent availability of the whole genome sequence in the horse. The latter has triggered the development of novel tools like SNP-chip and expression arrays that will permit rapid genome-wide analysis. While these...
Kareskoski M, Katila T.Seminal plasma is a mixture of secretions produced in the testes, epididymides and accessory sex glands, and ejaculated as several consecutive fluid fractions. The composition of seminal plasma and the effects on sperm longevity vary between fractions and individual stallions. This review focuses on the sequence of ejaculation, constituents of seminal plasma and their potential use as fertility markers as well as the influence of seminal plasma on spermatozoa during storage.
Aurich C.The majority of horse registries approve the use of artificial insemination, and horse breeding has widely taken benefit from the use of cooled-stored semen. New insights into cooled-semen technology open possibilities to reduce problems such as impaired semen quality after cooled-storage in individual stallions. The stallion itself has major impacts on quality and fertility of cooled-stored semen. Dietary supplementation of antioxidants and polyunsaturated fatty acids improves semen quality in a variety of species, but only few studies on this topic exist in the horse. Proper semen collection...
Sostaric E, Aalberts M, Gadella BM, Stout TA.The epididymis is a long, tightly coiled tube within the lumen of which sperm matures. Sperm maturation involves morphological and biochemical changes in the sperm plasma membrane in response to epididymal secretions and their various proteins. Some of these proteins become outer membrane components while others become integral membrane proteins; transfer of some proteins to the sperm plasma membrane may be mediated by epididymosomes. Nevertheless, the molecular pathways by which spermatozoa acquire fertilizing capacity during their transit through the epididymis remain ambiguous. In a recent ...
Brum AM, Sabeur K, Ball BA.The objective was to evaluate apoptotic markers in ejaculated equine spermatozoa after separation by density-gradient centrifugation and after cryopreservation. Subpopulations of percoll-separated equine spermatozoa differed (P<0.05) in the percentage of live, caspase-activated spermatozoa (2.9+/-0.7% vs 14.2+/-6.4%; mean+/-S.E.M.), low mitochondrial membrane potential (MMP; 6.8+/-1.1 vs 23.8+/-3.7), altered plasma membrane permeability (1.3+/-0.2 vs 3.0+/-0.5), DNA fragmentation (2.0+/-1.3 vs 14.3+/-3.6), total motility (81.8+/-3.3 vs 35.1+/-5.4), and progressive motility (66.3+/-4.3 vs 24...
Cavalcanti MC, Rizgalla M, Geyer J, Failing K, Litzke LF, Bergmann M.In eukaryotic cells, the major protein constituents of the chromatin are histones, which can be divided into five classes, identified as H1, H2A, H2B, H3 and H4. During normal spermatogenesis, a testis-specific H1t is expressed in primary spermatocytes and believed to facilitate histone to protamine exchanges during spermiogenesis. In equine testes we detected the H1 protein at 22kDa by western blot analysis while H1t was detected at 29kDa. H1 protein was found to be expressed in all germ cells up to elongating spermatids (Sc) at stage IV. In peripubertal animals, there was a prolonged express...
Deichsel K, Palm F, Koblischke P, Budik S, Aurich C.Lipid peroxidation contributes to the damage of the sperm plasma membrane. In different species, dietary supplementation with antioxidants has been shown to improve semen quality. Therefore, we tested effects of dietary supplementation with antioxidants and l-carnitin on semen quality in Shetland pony stallions (n=6). Semen was collected twice a week over a time period of 16 weeks. From weeks 5 to 12, a special diet for stallions containing a variety of antioxidants (STALLION, Pavo Pferdenahrung GmbH, Goch, Germany; tocopherol 300 mg/day; ascorbic acid 300 mg/day; l-carnitin 4000 mg/day; folic...
Lu Z, Branscum AJ, Shuck KM, Zhang J, Dubovi EJ, Timoney PJ, Balasuriya UB.Two previously developed TaqMan fluorogenic probe-based 1-tube real-time reverse transcription polymerase chain reaction (real-time RT-PCR) assays (T1 and T2) were compared and validated for the detection of Equine arteritis virus (EAV) nucleic acid in equine semen and tissue culture fluid (TCF). The specificity and sensitivity of these 2 molecular-based assays were compared to traditional virus isolation (VI) in cell culture. The T1 real-time RT-PCR had a higher sensitivity (93.4%) than the T2 real-time RT-PCR (42.6%) for detection of EAV RNA in semen. However, the T1 real-time RT-PCR was les...
Fazio E, Medica P, Aronica V, Grasso L, Ferlazzo A.Since transport evokes physiological adjustments that include endocrine responses, the objective of this study was to examine the responses of circulating beta-endorphin, adrenocorticotrophic hormone (ACTH) and cortisol levels to transport stress in stallions. Methods: Forty-two healthy Thoroughbred and crossbred stallions were studied before and after road transport over distances of 100, 200 and 300 km. Blood samples were collected from the jugular vein: first in a single box immediately before loading (pre-samples), then immediately after transport and unloading on arrival at the breeding s...
Hamann H, Distl O.A data set constituting a total of 310,109 Hanoverian warmblood horses was analyzed to ascertain the genetic variability, coefficients of inbreeding, and gene contributions of foreign populations. The reference population contained all Hanoverian horses born from 1980 to 2000. In addition, Hanoverian stallions born from 1980 to 1995 and Hanoverian breeding mares from the birth years 1980 to 1995 with registered foals were analyzed for the same genetic parameters. The average complete generation equivalent was approximately 8.43 for the reference population. The mean coefficient of inbreeding w...
Crowe CA, Ravenhill PJ, Hepburn RJ, Shepherd CH.Historically, artificial insemination (AI) using frozen semen has been perceived to have poorer success rates and be more labour intensive than using chilled semen. A retrospective study was therefore conducted to compare the conception rate achieved by AI between chilled and frozen semen, using fixed time insemination protocols over 2 breeding seasons. Objective: Artificial insemination using chilled semen produces a higher conception rate than that achieved with frozen semen. Methods: Mares (n = 251) were inseminated with either chilled (n = 112) or frozen (n = 139) semen in the 2006 and 200...
McPartlin LA, Littell J, Mark E, Nelson JL, Travis AJ, Bedford-Guaus SJ.Efficient in vitro capacitation of stallion sperm has not yet been achieved, as suggested by low sperm penetration rates reported in in vitro fertilization (IVF) studies. Our objectives were to evaluate defined incubation conditions that would support changes consistent with capacitation in stallion sperm. Protein tyrosine phosphorylation events and the ability of sperm to undergo acrosomal exocytosis under various incubation conditions were used as end points for capacitation. Sperm incubated 4-6h in modified Whitten's (MW) with the addition of 25 mM NaHCO3 and 7 mg/mL BSA (capacitating mediu...
Ball BA, Conley AJ, Grundy SA, Sabeur K, Liu IK.Anti-Müllerian hormone (AMH) induces regression of Müllerian ducts during male fetal development; in the human male, it is expressed in Sertoli cells during fetal development (and through puberty). The objective was to characterize expression of AMH in the fetal, neonatal, prepubertal, and adult equine testis, as well as in equine cryptorchid testes, in select testicular neoplasms, and in intersex gonads, based upon immunohistochemistry (IHC). Testes were removed from equine fetuses at 5.5, 10, and 11 months of gestation, at 12 months of age, and from adult stallions. In addition, cryptorchi...
Rho JR, Srygley RB, Choe JC.We investigated mutual grooming by Jeju pony (Equus caballus) foals to determine whether male foals preferentially interact with potential future sexual partners or competitors. We predicted that relative to female foals, male foals would exchange grooming more frequently with young mares and that in general, foals would mutually groom more frequently with the opposite sex rather than the same sex. Observing 53 foals between April and October 1998, we recorded 113 mutual grooming events. Male foals exchanged grooming with yearling mares more frequently than with their mother, while female foal...
Volpe S, Galeati G, Bernardini C, Tamanini C, Mari G, Zambelli D, Seren E, Spinaci M.Heat shock proteins (Hsp)-60, -70 and -90 are important testis chaperones that fulfil several functions during sperm cell maturation. In post-meiotic cells, their expression may change or may be undetectable and in some species it may be evident in mature spermatozoa. The aims of this study were to verify whether Hsp60, -70 and -90 are present in the sperm, and to compare their localization in boar, stallion, cat and dog spermatozoa by immunofluorescence. Hsp-60 immunoreactivity was detected in sperm midpiece in all the species examined. In stallion sperm, Hsp70 signal was localized in the sub...
Moran JA, Lemberger K, Cadoré JL, Lepage OM.An 11-year-old Andalusian stallion developed marked signs of colic associated with an acute small intestine obstruction. Exploratory laparotomy revealed a distal jejunum full-thickness wall induration and multiple small adherent intraluminal masses. Fifteen centimeters of jejunum, including the induration, and several intraluminal masses were resected. Histologic examination revealed an adenocarcinoma and multiple polypoid adenomas. The horse was discharged, and no complications were reported 12 months postoperatively. Colic was considered secondary to partial jejunal lumen obstruction by the ...
Morrell JM, Johannisson A, Dalin AM, Hammar L, Sandebert T, Rodriguez-Martinez H.Artificial insemination is not as widely used in horses as in other domestic species, such as dairy cattle and pigs, partly because of the wide variation in sperm quality between stallion ejaculates and partly due to decreased fertility following the use of cooled transported spermatozoa. Furthermore, predictive tests for sperm fertilising ability are lacking. The objective of the present study was to assess sperm morphology and chromatin integrity in ejaculates obtained from 11 warmblood breeding stallions in Sweden, and to evaluate the relationship of these parameters to pregnancy rates to i...
Wilson AJ, Rambaut A.Horse racing is a multi-million pound industry, in which genetic information is increasingly used to optimize breeding programmes. To maximize the probability of producing a successful offspring, the owner of a mare should mate her with a high-quality stallion. However, stallions with big reputations command higher stud fees and paying these is only a sensible strategy if, (i) there is a genetic variation for success on the racecourse and (ii) stud fees are an honest signal of a stallion's genetic quality. Using data on thoroughbred racehorses, and lifetime earnings from prize money (LE) as a ...
Christensen JW, Malmkvist J, Nielsen BL, Keeling LJ.In fear-eliciting situations, horses tend to show flight reactions that can be dangerous for both horse and man. Finding appropriate methods for reducing fearfulness in horses has important practical implications. Objective: To investigate whether the presence of a calm companion horse influences fear reactions in naive subject horses. Objective: The presence of a habituated (calm) companion horse in a fear-eliciting situation can reduce fear reactions in naive subject horses, compared to subject horses with a nonhabituated companion (control). Methods: Minimally handled (n = 36), 2-year-old s...
Rogers CW, Gee EK, Firth EC.To obtain initial baseline data on the management of Thoroughbred stud farms in the North Island of New Zealand. Methods: Data on the management of Thoroughbred stud farms were collected from a sample of 22 stud farms located in the south Auckland/Waikato region (n=15) and lower North Island (n=7) of New Zealand, using a face-to-face survey. The studmaster provided information on the size, scope and management of the farms during the 2004/2005 breeding season. Analysis was based on the location of the farm and size of the breeding operation (number of resident mares). Results: Effective farm s...
Leeb T.The growing knowledge on physiology, cell biology and biochemistry of the reproductive organs has provided many insights into molecular mechanisms that are required for successful reproduction. Research directed at the investigation of reproduction physiology in domestic animals was hampered in the past by a lack of species-specific genomic information. The genome sequences of dog, cattle and horse have become publicly available in 2005, 2006 and 2007 respectively. Although the gene content of mammalian genomes is generally very similar, genes involved in reproduction tend to be less conserved...
Price S, Aurich J, Davies-Morel M, Aurich C.This study was undertaken to investigate the effects of storage of stallion semen in a defined milk protein extender at 5 and 15 degrees C under either anaerobic or aerobic conditions, with or without addition of the antibiotic gentamicin. Semen samples were collected from eight fertile stallions and stored for 96 h (day 0-4) and assessed daily for motility, velocity and membrane integrity (viability) using a CASA system. Samples for bacteriology assessment were taken on day 2 of storage. No significant (p > 0.05) differences in motility, velocity or viability were observed between treatmen...
Loomis PR, Graham JK.One of the challenges for those attempting to cryopreserve stallion spermatozoa is dealing with the stallion to stallion variability in the cryosurvival of their semen. In the dairy industry, each bull stud, essentially utilizes a single cryopreservation technique, and bulls that produce sperm that do not cryopreserve well using that technique are replaced by other bulls. However, replacing stallions is unlikely to prove acceptable to the equine industry, where specific genotypes are desired. Instead, to increase the number of stallions that can be effectively utilized for cryopreserved semen ...
Ginel PJ, Zafra R, Lucena R, Bautista MJ.This case report describes a case of multiple follicular cysts in a 4-year-old Spanish purebred stallion. The lesions ranged in size from 0.5 to 3 cm in diameter, and were firm, well circumscribed and nonpruritic. They developed over a 2-year period with a generalized distribution affecting all body regions. Five nodules were removed and histopathologically corresponded to simple epidermal cysts (infundibular and isthmus-catagen) with squamous epithelium and a keratin filled cavity. Lesions were not evident at birth but their number, early age of detection, slow growth and lack of previous tra...
Saragusty J, Gacitua H, Pettit MT, Arav A.Despite its potential impact on the horse industry, sperm cryopreservation is not an established technology throughout the industry, for a number of reasons that include a reduction in pregnancy rate and increased cost per pregnancy. We have evaluated a novel directional freezing technique, based on a multi-thermal gradient (MTG), by comparing it with the conventional, controlled-rate cryopreservation method (CRCM). Ninety-seven ejaculates with > or =50% motility, collected from 31 stallions were each divided into two parts and subsequently frozen by either MTG or CRCM. Frozen samples were ...
López-Fernández C, Crespo F, Arroyo F, Fernández JL, Arana P, Johnston SD, Gosálvez J.The mixed success of equine artificial insemination programs using chilled and frozen-thawed semen is most likely associated with the variable response of the sperm cell to the preservation process and the fact that stallions are not selected on the basis of reproductive performance. We propose that the traditional indicators of sperm viability do not fully account for male factor infertility in the stallion and that knowledge of sperm DNA damage in the original semen sample and during semen processing may provide a more informed explanation of an individual stallion's reproductive potential. ...
Allen WR, Brown L, Wright M, Wilsher S.Previous surveys of reproductive efficiency in British Thoroughbreds included only mares and stallions standing on studfarms in and around Newmarket. The present study was widened to compare Flatrace (FR) (Group A) and National Hunt (NH) (Group B) mares and stallions on studfarms throughout England. Objective: To assess the influences of mare type, status and age, and veterinary manipulations on reproductive efficiency parameters. To compare the inherent fertility of stallions, based on singleton and twin pregnancy rates and pregnancy loss rates, in Groups A and B Thoroughbred breeding stock. ...
Clulow JR, Buss H, Sieme H, Rodger JA, Cawdell-Smith AJ, Evans G, Rath D, Morris LH, Maxwell WM.In the 2004/2005 breeding season, the fertility of sex-sorted (SS) and non-sorted (NS) frozen stallion spermatozoa from two Hannovarian stallions was compared. A hysteroscopic insemination technique [Morris, L.H., Tiplady, C., Allen, W.R., 2003a. Pregnancy rates in mares after a single fixed time hysteroscopic insemination of low numbers of frozen-thawed spermatozoa onto the uterotubal junction. Equine Vet. J. 35, 197-201] was used to deposit low doses (6, 13 or 25 x 10(6) frozen-thawed SS or NS spermatozoa) onto the utero-tubal junction at 32 or 38 h after the administration of Chorulon (2500...
Maitan P, Bromfield EG, Stout TAE, Gadella BM, Leemans B.Conventional in vitro fertilization is not efficacious when working with equine gametes. Although stallion spermatozoa bind to the zona pellucida in vitro, these gametes fail to initiate the acrosome reaction in the vicinity of the oocyte and cannot, therefore, penetrate into the perivitelline space. Failure of sperm penetration most likely relates to the absence of optimized in vitro fertilization media containing molecules essential to support stallion sperm capacitation. In vivo, the female reproductive tract, especially the oviductal lumen, provides an environmental milieu that appropriate...
Bartoš L, Bartošová J, Pluháček J.In a previous study, we suggested that the common practice of transporting a mare for mating and then bringing her back to an environment that also contains males that did not sire the fetus may be a major cause of high percentages of pregnancy disruption in domestic horses. In this study, we tested whether disruption of pregnancies induced by AI occurs as frequently as after mating with a strange stallion away from home and is affected by the same factors in the home social environment. Based on 77 records, the probability of pregnancy disruption after AI depended on the social environment in...
Da Silva-Álvarez E, Gaitskell-Phillips G, Ortiz-Rodríguez JM, Serres C, García-Rodríguez B, Gutiérrez-Cepeda L, Martín-Cano FE, Echegaray A....This study aimed to assess if Ecotext, a new software for evaluation of testicular echotexture, is a good method for diagnosis of stallions with testicular dysfunction (TD). Relationships between Ecotext parameters and sperm motility and production, testicular volume, and testicular blood flow were also studied. Ecotext provides a total of six echotexture parameters: Ecotext 1 (black pixels), 2 (white pixels) and 3 (grey pixels), and another 3 parameters related to hypoechogenic areas: Ecotext tubular density (ETD), Ecotext tubular diameter (ETd), and Ecotext tubular area (ETA). Stallions (n ...
Madill S, Troedsson MH, Alexander SL, Shand N, Santschi EM, Irvine CH.The aim of this study was to investigate the effect of different breeding stimuli on uterine contractility and pituitary oxytocin release in five oestrous mares, in order to design better treatments for mares with defective physical uterine clearance mechanisms. Electrodes and strain gauges were implanted surgically on the uterine myometrium and myometrial activity was monitored with a Grass polygraph. A catheter was placed non-surgically in the intercavernous sinus of each oestrous mare to sample pituitary venous blood and a second catheter was placed in the jugular vein. Continuous sampling ...
Ohnesorge B, Deegen E, Miesner K, Geldermann H.Laryngoscopic examination during sedation was performed on 24 stallions and on their offspring (240 foals and 474 adult horses). Additionally the dams (n = 308) of 35 foals and 216 horses were examined. With the bilateral comparison of the arytaenoid movements the function of the abductory and adductory laryngeal muscles were evaluated and the left abductory dysfunction (idiopathic laryngeal hemiplegia, ILH) was divided into six degrees. The incidence and degree of ILH depended on age and the occurrence of the same dysfunction in the parents. Foals suffered in significantly lower number (24.7 ...
Delerue M, Breuil MF, Duquesne F, Bayon-Auboyer MH, Amenna-Bernard N, Petry S.Taylorella equigenitalis can be transmitted during artificial insemination. This report describes clinical T. equigenitalis transmission by cryopreserved stallion semen. T. equigenitalis isolates from a mare's vaginal discharge and semen from the same batch of the cryopreserved semen used for the insemination gave identical API ZYM, antibiotic susceptibility, and multilocus sequence typing results (ST-46); furthermore, the multilocus sequence typing lineage ST-46 is known to circulate in the country of semen collection. These results support the need for strict contagious equine metritis scre...
Thomas PG, Ball BA, Miller PG, Brinsko SP, Southwood L.Attachment of spermatozoa to oviductal epithelial cells (OEC) may be a prefertilization event in some species. We tested the hypothesis that spermatozoa that attach to equine OEC monolayers are a selected subpopulation of the initial inseminate, containing a higher proportion of morphologically normal, motile cells than the inseminate. Washed stallion spermatozoa were cocultured with monolayers of OEC or monolayers of Vero cells, and controls were incubated in wells coated with basement membrane extract (Matrigel [Mgel]) or in plastic (uncoated) wells. Unattached spermatozoa were removed by ri...
Al-Jaru A, Goodwin W, Skidmore J, Khazanehdari K.Advances in molecular cytogenetics have provided the opportunity to study events during prophase I of meiosis. Immunofluorescent localization of different meiotic protein components were used to characterize the early stages of the first meiotic division in horse spermatocytes. The frequency and distribution of recombination events during prophase I were investigated using the mutL homolog 1 (MLH1) protein that is known to be associated with these events. The frequency and distribution of MLH1 foci were investigated in pachytene nuclei of 6 fertile stallions, and the average relative synaptone...
Adler DMT, Østergaard S, Jørgensen E, Jacobsen S.Castration of the stallion is one of the most frequently performed surgical procedures in the horse. Recently barbed suture materials for surgical wound closure were introduced to the market with manufacturers claiming that these sutures enhance speed and security as they eliminate the need to tie knots. Recently, it has been suggested that this type of suture may increase postoperative complications. This study aimed at investigating and comparing a bidirectional absorbable knotless barbed suture (KBS) to a conventional smooth suture (SS) for wound closure of inguinal castrations in the horse...
Clulow JR, Maxwell WM, Evans G, Morris LH.Duck and chicken egg yolk were compared for their protective effects against cold shock during the cryopreservation of stallion sperm in a lactose-EDTA-glycerol cryodiluent. Methods: A completely randomised design was used. Procedure Ejaculates from five stallions (n = 14 ejaculates) were split and diluted to either 20 or 200 x 10(6) sperm/mL in a lactose-EDTA extender containing either duck or chicken egg yolk. The extended semen was then frozen in liquid nitrogen. The percentage of sperm total motility and forward progressive motility were assessed before freezing and at 0 and 1 hr after tha...
Ponthier J, Teague SR, Franck TY, de la Rebière G, Serteyn DD, Brinsko SP, Love CC, Blanchard TL, Varner DD, Deleuze SC.Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after lysis. Post-thaw semen contains MPO and its concentration is associated with decreased sperm motility. Recently, MPO concentration in post-thaw semen was shown to be associated with the presence of non-sperm cells (NSC). The objective of this study was to evaluate the effect of a single-layer colloidal centrifugation before cryopreservation on NSC and MPO concentrations in equine semen. The experimental design consisted of freezing semen with or without previous centrifugation t...
Clark-Price SC, Posner LP, Gleed RD.To assess whether recovery from general anesthesia, in an illuminated or a darkened stall, has an effect on time to first movement, time to standing, and recovery score. Methods: Prospective randomized clinical study. Methods: Twenty-nine healthy, 2- to 5-year-old horses undergoing surgical correction of dorsal displacement of the soft palate. Methods: Each horse was assigned randomly to recover in either an illuminated (n = 15) or a darkened stall (n = 14). For pre-anesthetic medication, all horses received intravenous (IV) xylazine (0.4 mg kg(-1)) and butorphanol (0.02 mg kg(-1)). Anesthesia...
Roach J, Schnobrich M, Ellerbrock R, Feijo L, Bradecamp E, Alvarenga MA, Kline K, Canisso I.This study compares two methods for seminal plasma removal by evaluating sperm recovery rates, and motility and morphology of cooled-stored semen. Ejaculates were divided into three groups: control, filtration and cushioned centrifugation. Semen was extended to 25 million sperm/ml using a skim-milk-based extender and stored at 5°C for all groups. Sperm motility (total motility (%TM) and progressive motility (%PM)) was determined at 0, 24, 48 and 72 hours by a computer-assisted sperm analyser. Sperm morphology was assessed using differential interference microscopy. Overall, %TM of the cen...
Moine S, Flammer SA, de Jesus Maia-Nussbaumer P, Klopfenstein Bregger MD, Gerber V.This study attempted to determine: (1) if degree of dental malocclusion assigned prior to dental treatment was associated with equine rideability, assessed using a standardized score and (2) if performance dentistry improved this score. Methods: Thirty-eight Franches-Montagnes stallions. Methods: All horses were examined and assigned a dental malocclusion score by a veterinary dentist and randomized into two groups: sham treatment (Group S) and performance dentistry including occlusal equilibration (Group D). The horses were ridden twice before and three times after treatment by a professional...
Jaworska J, Jaworski Z, McDonnell SM, Górecka-Bruzda A.Infanticide, related to a stallion's aggression toward a foal sired by another stallion, and feticide related to a new stallion's aggression and/or pheromonal influence (the Bruce effect) inducing loss of a fetus sired by another stallion, a female's counteraction to infanticide, have been proposed for domestic horses (Equus caballus) in human-managed conditions. The aim of the present study was, in conditions close to natural, to investigate the influence of the natural succession of a harem stallion on the mares' subsequent reproductive performance. In a population of semi-feral Konik polski...
Gil MC, Ferrusola CO, Anel-López L, Ortiz-Rodriguez JM, Alvarez M, de Paz P, Anel L, Peña FJ.Spermatozoa undergo apoptotic changes during the cryopreservation process. These changes, recently termed spermptosis, resemble the cryopreservation induced delayed onset of cell death observed after thawing of somatic cells. Due to its importance in cryobiology, methods to easily identify spermptotic cells are warranted. In this study, a well-validated method for identification of spermatozoa with caspase 3 activity was compared with use of the combination of Hoechst 33342 (H-42) and ethidium homodimer (Eth-1). Live, dead and apoptotic spermatozoa assessed with each method were compared using...
Dodman NH, Normile JA, Shuster L, Rand W.Owners who believed they had a horse with self-mutilating behavior were asked to complete a questionnaire to obtain information on the signalment, clinical history, clinical signs, management, and treatment of the condition. Fifty-two owners of 59 horses responded; 2 cases were omitted because an organic cause was determined. Owners also were asked to complete information for unaffected horses on the same farm. Various breeds were affected, and of the 57 horses, 20 were stallions, 31 were geldings, and 6 were mares. Affected horses tended to develop the condition prior to sexual maturity. Clin...
Kędzierski W.Leptin is a tissue-derivative adipokine that regulates appetite, food intake and energy expenditure. It is still not clear how exercise affects plasma leptin concentration in horses. The aim of this study was to evaluate the influence of exercise intensity and duration on plasma leptin levels in working horses. A total of 38 horses were prospectively included in the study and grouped according to the type of exercise they performed: dressage (six stallions, group D), jumping (12 stallions, group J), race (12 Thoroughbred horses, six stallions and six mares, group R) and harness (10 light draft...
Gottschalk M, Sieme H, Martinsson G, Distl O.A high quality of stallion semen is of particular importance for maximum reproductive efficiency. In the present study, we estimated the relationships among estimated breeding values (EBVs) of semen traits and EBVs for the paternal component of the pregnancy rate per estrus cycle (EBV-PAT) for 100 German Warmblood stallions using correlation and general linear model analyses. The most highly correlated sperm quality trait was total number of progressively motile sperm (r = 0.36). EBV-PAT was considered in three classes with stallions 1 SD below (<80), around (80-120), and above (>120) the popu...
Aitken RJ, Lambourne S, Medica AJ.A capacity to predict the likelihood of pregnancy following natural matings would be of considerable benefit to the Thoroughbred horse breeding industry. In this article, we describe a strategy for achieving this outcome through the analysis of dismount samples, that achieved an overall accuracy of 94.6%. The purpose of this study was to determine whether the analysis of dismount semen samples from Thoroughbred stallions could be used to predict whether a given mating would result in a pregnancy. The analysis was based on 143 matings of 141 mares by a cohort of 7 Thoroughbred stallions over a ...
Pires DA, Coelho EG, Melo JB, Oliveira DA, Ribeiro MN, Gus Cothran E, Juras R.Knowledge of genetic diversity and relationships between breeds is very important for conservation programs. Hair samples were collected from 393 individual Nordestino horses and genotyped using 14 microsatellite markers in order to investigate the genetic relationship between this breed and 66 international horse breeds. There was high allelic diversity and inbreeding coefficient within population values were not significant, which was probably due to crossbreeding. Despite the Nordestino horse population being in Hardy-Weinberg equilibrium, a global deficit of heterozygotes was observed. Thi...
Rivero JL, Serrano AL, Diz AM, Morales JL.The right and left gluteus medius muscles of 4 mature Andalusian stallions were examined by repeated needle biopsy over a specific area and depth, as well as at different depths, to determine whether the cross-sectional area and capillary supply of the various fiber types are homogeneous throughout the muscle. The muscle biopsy specimens were histochemically analyzed for fiber types (myofibrillar adenosine triphosphatase) and capillaries (amylase-periodic acid-Schiff method). Differences between contralateral sites were not identifiable for any of the analyzed variables. Differences between sa...
Kunanusont N, Taesuji M, Kulthonggate U, Rattanamas K, Mamom T, Thongsri K, Phannithi T, Ruenphet S.African horse sickness (AHS) has become a newly emerging disease after an outbreak in northeastern Thailand in March 2020. Mass vaccination in horses with live-attenuated AHS virus (AHSV) vaccine is essential for AHS control and prevention. This study aimed to monitor the longitudinal humoral immune response before and after a single vaccination using a live-attenuated vaccine against AHS in stallions, mares, and pregnant mares, including maternal immunity in foals born from pregnant mares during the outbreak in Thailand. Unassigned: A total of 13 stallions and 23 non-pregnant and 21 pregnant ...
Malaluang P, Niazi A, Guo Y, Nagel C, Guimaraes T, Rocha A, Aurich C, Morrell JM.The microbiome plays a significant role in shaping the health and functioning of the systems it inhabits. The seminal microbiome of stallions has implications for the health of the reproductive tract, sperm quality during preservation and antibiotic use in semen extenders. Diverse bacteria are present on the external genital tract and a mix of commensal microorganisms populates various parts of the reproductive tract, influencing the seminal bacterial content. Other sources of bacteria include the environment, semen collection equipment, and personnel. The bacterial load can adversely affect s...
Hernández-Avilés C, Ramírez-Agámez L, Weintraub ST, Scoggin CF, Davis BW, Raudsepp T, Varner DD, Love CC.Thoroughbred stallions that carry a double-homozygous genotype A/A-A/A for SNPs rs397316122 and rs69101140 in exon 5 of the FKBP6 gene (chr13; EquCab3.0) are uniquely subfertile due to impaired acrosomal exocytosis (IAE). In this study, the sperm proteome in frozen/thawed semen from subfertile Thoroughbred stallions was studied and compared to that of frozen/thawed sperm from fertile Thoroughbred stallions. A total of 2,220 proteins was identified, of which 140 proteins were found to be differentially abundant in sperm from the subfertile stallions compared to that of fertile stallions (83 les...
Busechian S, Bindi F, Pieramati C, Orvieto S, Pisello L, Cozzi S, Ortolani F, Rueca F.Equine gastric ulcer syndrome (EGUS) is a worldwide disease, and includes two different syndromes, Equine Squamous Gastric Disease (ESGD), affecting the squamous mucosa, and Equine Glandular Gastric Disease (EGGD), affecting the glandular mucosa. These two diseases are present in different categories (different activities, ages, etc.) and breeds of horses. The effect of sex on gastric health is not clear: some studies found a higher prevalence of ESGD in geldings and stallions, while others found no influence of sex on the squamous mucosa. The few studies conducted on glandular diseases failed...
Ortiz-Rodriguez JM, Bucci D, Tovar-Pascual L, Granata S, Spinaci M, Nesci S.Sperm metabolism consists of a sophisticated network of biochemical reactions and varies between species, resulting in different metabolic strategies for ATP production to maintain sperm functionality. ATP can be produced through glycolysis or in the mitochondria by oxidative phosphorylation (OXPHOS). Since OXPHOS is the predominant metabolic pathway in horses spermatozoa, various assessments of mitochondrial activity are used to evaluate fertility, utilizing techniques such as fluorescent probes analysed via microscopy or flow cytometry, and polarographic electrode assays to measure current f...
Lu Z, Wen M, Yao X, Meng J, Wang J, Zeng Y, Li L, Ren W.The reproductive performance of horses is closely associated with testicular development, which involves a complex network of gene regulation. The molecular mechanisms underlying the reproductive traits of Kazakh horses are yet to be fully understood. In this study, transcriptomic analysis was performed on testicular tissues from Kazakh horses at different developmental stages using whole-transcriptome sequencing, aiming to investigate differential gene expression and regulatory mechanisms during testicular development. The results revealed significant differential expression of 7678 mRNAs, in...
Peña FJ, Martín-Cano FE, Becerro-Rey L, da Silva-Álvarez E, Gaitskell-Phillips G, Ortega-Ferrusola C, Aparicio IM, Gil MC.Although stallion spermatozoa are now recognized as highly dependent on oxidative phosphorylation for ATP production in the mitochondria, most extenders in use contain supraphysiological concentrations of glucose as the main energy source. While the toxicity of cryoprotectants has been well documented in the literature, the potential toxicity of excessive glucose in extenders is largely ignored. However, the toxicity of excess glucose, known as "carbotoxicity", is well-established in many areas of medicine. In this paper, we review the basic aspects of stallion spermatozoa metabolism, focusing...
Valdez H, Taylor TS, McLaughlin SA, Martin MT.Removal of abdominal testes was accomplished in 32 horses ranging in age from 6 to 72 months. Twenty were unilateral and 12 were bilateral abdominal cryptorchids. An incision was made over the superficial inguinal ring, and the extension of the gubernaculum testis was identified and grasped with forceps. Traction was applied to this structure until the vaginal process was everted beyond the superficial inguinal ring. The vaginal process was incised and the protruding structure, usually the epididymis, was grasped. The testis was drawn out by gentle traction on the epididymis, and castration wa...
