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.
Merkt H.The use and techniques of artificial insemination for horses in Germany over the last 30 years is described. Artificial insemination appears to produce pregnancy percentages equal to those from normal breeding methods and its continued availability under veterinary supervision is recommended in conditions where disease, disability or distance debar normal service.
Merkt H.The use and techniques of artificial insemination for horses in Germany over the last 30 years is described. Artificial insemination appears to produce pregnancy percentages equal to those from normal breeding methods and its continued availability under veterinary supervision is recommended in conditions where disease, disability or distance debar normal service.
Dinter Z, Klingeborn B.Six cases of paresis occurred in a Swedish stud with 48 mares and a stallion. Complement-fixation tests revealed a recent infection with EHV-1 in most horses of the stud. Serumneutralisation tests showed rapid antibody-titre increases during the course of the disease. This type of antibody response was interpreted as induced by reinfection or, possibly, recurrent infection. Two diseased mares were sacrificed. No virus could be isolated from their central nervous system (CNS), liver or spleen, but there is a presumptive evidence for the presence of an antigen specific to EHV-1 in the CNS and li...
Stirk SA.A 5 year old Thoroughbred stallion with diarrhoea of unknown aetiology was referred to Davis. Treatment was aimed at terminating diarrhoea and restoring normal fluid status. Laboratory aids were utilised to establish where inbalance and deficits were present. Antibiotics and corticosteroids were used as an adjunct to fluid therapy. The case history and rationale of treatment of fluid disorders resulting from diarrhoea are discussed.
Allen WR, Bowen JM, Frank CJ, Jeffcott LB, Rossdale PD.This short review article describes the various techniques currently available for artificial insemination in the horse. The collection and use of raw and extended semen is discussed together with the more recent developments in freezing semen. The expected conception rates with both fresh and frozen semen are quoted. The possible benefits in disease control and stud management are discussed, as well as the difficulties in controlling the use of A.I. from the Breed Registration Authorities point of view.
van der Mey GJ, Bos H.The study of the literature on a preliminary performance test for saddle horses (stallions) is concerned with European countries. Interest is found to be increasing in the various countries. Performance of the test in the Netherlands (since 1966) is described and the various criteria of evaluation are discussed in detail. The intensity of selection based on this test is referred to. In 1974, it was 78 per cent in the Netherlands. Part of studies on the relationship between some results of testing are reviewed. The traction test shows a very low coefficient of correlation with the other parts o...
Pickett BW, Faulkner LC, Voss JL.Season had a pronounced effect upon seminal pH and refractometer 'protein', total carbohydrate, dry weight, total N2 and lactic acid in seminal plasma of first and second ejaculates. In addition, total seminal volume, spermatozoa per ml and per ejaculate, non-protein sulphhydryl and glycerylphosphorylcholine of second ejaculates were also influenced. There was a season difference in the concentrations of lactic acid in spermatozoa from first and in total N2 from spermatozoa in second ejaculates. The effects of season on seminal plasma were greater than those on spermatozoa. Spermatozoa in firs...
Sullivan JJ, Pickett BW.Approximately 1 week was required to stabilize the extragonadal sperm reserves in stallions ejaculated daily for 10 weeks. The true daily sperm output of a stallion was equal to the mean daily sperm output of seven ejaculates +/- 1-35 X 10(9) spermatozoa. Mean concentrations of spermatozoa/ml and number of spermatozoa/ejaculate were higher (P less than 0-01) for X1 and X3/week ejaculation frequencies than for a X6/week frequency. Sperm output/week was nearly identical for a X6/week frequency. Sperm output/week was nearly identical for the X3 and X6 frequencies and higher (P less than 0-01) tha...
Ganjam VK, Kenney RM.Total androgens, testosterone and total oestrogens were measured in twenty-one intact, nine unilaterally cryptorchid, three bilaterally cryptorchid stallions and four geldings. Total oestrogens were significantly higher (P less than 0-005) and total androgens significantly lower (P less than 0-05) in the bilateral cryptorchid compared to other groups. There was a significant (P less than 0-025) day and night variation in total androgen levels. Thyroidectomized and intact animals showed a marked decrease in total androgen as well as testosterone levels during the winter period thus showing an e...
Dott HM, Foster GC.Semen from boar, bull, ram, rabbit, reindeer and stallion was diluted in formol citrate or formol saline and stained with eosinnigrosin. The proportion of eosinophilic spermatozoa did not differ from that in fresh semen after storage for 48 hr in the formol diluent at temperatures ranging from 4 degrees C to 40 degrees C. Some samples were kept for periods up to 3 weeks with very little increase in the proportion of eosinophilic spermatozoa.
Pickett BW, Voss JL.Experimental and clinical observations were made to treat abnormal sexual behaviour. The most common cause of abnormality was mismanagement of the animal; over-use and rough treatment at service and too-frequent ejaculation during winter had a detrimental effect on the behaviour of young stallions. Pain due to injury incurred at copulation or when associated with mounting attempts was also a common cause of impotence. Most impotent stallions responded well to re-training and recovery can be achieved without pharmacological treatment in most cases.
van der Holst W.Season was shown to markedly influence semen characteristics of stallions in Holland, including ejaculate volume, sperm motility, total number of spermatozoa/ejaculate and the percentage of spermatozoa showing morphological abnormalities. Maintenance of normal stallions in continuous light during the winter months and administration of a vitamin and mineral supplement to sub-fertile stallions before the start of the breeding season appeared to improve spermatogenesis significantly.
Merkt H, Klug E, Bohm KH, Weiss R.A high incidence of Klebsiella contamination in German 'Warmblut' and Thoroughbred stallions is reported. The organism was recovered from the nostrils, prepuce, pre-ejacultory secretion and, in some cases, on the body surface, in the faeces and on the ground of the covering (mating) yard. Fertility was not affected. However, differences of virulence were observed and Type 5 proved to be the most pathogenic.
Swierstra EE, Gebauer MR, Pickett BW.The relationship between daily sperm productions (DSP) and daily sperm output (DSO) was determined in eleven stallions. The DSO was determined by collecting single ejaculates, with an artificial vagina, at 24-hr intervals. The stallions were killed 24 hr after the last collection and the DSP was determined by quantitative testicular histology. The mean DSP was 8-0 X 10(9) (S.E. +/- 0-4 X 10(9), and the mean DSO was 7-0 X 10(9) (S.E. +/- 0-4 X 10(9)). It was estimated that 87% of the spermatozoa produced by the testes were harvested. The correlation between DSP and DSO was 0-80 (P less than 0-0...
Sinclair CD, Thompson D, Stevenson JS, Rozell T, Jager A, Kouba J.Introducing males to seasonally anestrous females has been shown to increase LH concentrations and hasten the first ovulation in ewes and goat does. Investigation of this sociosexual phenomenon in mares has not been well studied. The objective of this study was to determine if direct or indirect exposure of anestrous mares to a stallion would result in a similar increase in LH and hasten the first ovulation. In late February, mares were stratified by parity and age and assigned randomly to three treatments (n = 7/treatment): (1) DXP (direct exposure; mares housed adjacent to stallion and all...
Dowsett KF, Pattie WA.Semen was collected from 222 stallions of 13 breed or colour types in southern Queensland and northern New South Wales. A total of 648 collection attempts were made, using an artificial vagina, during 4 consecutive breeding seasons (1974/5 to 1977/8). Modifications were made to the techniques used by previous workers because collections were made at commercial studs using minimal animal restraint. Of all collection attempts, 621 (96%) were successful, while at least one semen sample was collected from each of 216 stallions (97%). There were no significant relationships between stallion collect...
Jakop U, Hensel B, Czirják GÁ, Quirino M, Schröter F, Jung M, Schulze M.During insemination, bacterial contamination of the ejaculate can lead to reduced sperm quality and transmission of pathogens to the female, thus should be avoided. The semen of a variety of animal taxa possess antimicrobial properties against a wide range of bacterial species through antimicrobial molecules, such as lysozyme, but their variance and the factors influencing it are unknown for most species. In this study, the antibacterial defence (bacterial killing activity (BKA) against Escherichia (E.) coli and Staphylococcus (S.) aureus as well as lysozyme concentration) was studied in semin...
Merkt H.A stallion got fatal injuries by kicks of a maiden mare because a so called "panic hook" untied spontaneously. The use of such hooks to secure mares during mating should therefore not be recommended.
Evans JW, Stanfield J, Hoffman LS, Slaussen C.Testes were obtained from 70 colts and stallions and were pooled according to age (4 months to 23 years) to determine the relationship of age to LH/hCG receptor kinetics. The receptor concentration (Rt) increased from 0.069 x 10(-11) M/mg crude membrane fraction (CMF) for the 4-14-month pools to 0.464 x 10(-11) M for the 2-3-year-old pools. A 10-fold increase in testicular size also occurred, and so the total number of receptors per testis was significantly increased. A further increase to 1.237 x 10(-11) M/mg CMF was observed for stallions older than 5 years. No differences in binding affinit...
Voss JL, Pickett BW.Haemospermia caused infertility in the stallion and frequently results from a urethritis in the area of the ejaculatory ducts. Urethroscopic examination, urethrography, bacterial and viral cultures, biopsy, surgery of the urethra and histocytological examination should be used for diagnosis and it is essential that the exact cause and location of the haemorrhage be known before treatment is initiated. Optimal treatment includes sexual rest and appropriate antibiotics used systemically in conjunction with local medication of the urethra. Cauterization of the urethra with silver nitrate solution...
Collingsworth MG, Fuller Z, Cox JE, Argo CM.Concentrations of gonadotrophins and prolactin were recorded in pony stallions castrated during the early breeding season, to examine the regulatory role of the gonad at a time when testosterone has been postulated to exert positive feedback on LH secretion. Further, gonadotrophin concentrations in geldings are reported to return to values within the normal range of the entire stallion. In an attempt to characterize this species-specific reversal, the gonadotrophin concentrations of 6 male ponies castrated on 25 March were monitored for 4 months, and 4 stallions were used to generate control d...
Ginther OJ, Scraba ST, Nuti LC.Pony mares (n=480) and 16 stallions were assigned to four herds of 60 mares and one stallion (large herds) and to 12 herds of 20 mares and one stallion (small herds). The stallions remained with the herds continuously for all of the large herds and seven of the small herds. In the five remaining small herds the stallion was put into a herd for three hours every two days for 12 observation periods. Pregnancy rates and day of ovulation were estimated by size of embryonal enlargements. Mean pregnancy rates of 51% and 54% were obtained in the small herds and 42% in the large herds during a 48-day ...
Annandale CH, Schulman ML, Kirkpatrick RD.Twelve pony mares were randomly assigned to either a control or a treatment group and inseminated with fresh, raw semen from a single stallion of known fertility in a cross-over trial design. Pregnancy was diagnosed by transrectal ultrasound 12-14 days post-ovulation and then terminated by administration of a luteolytic dose of cloprostenol. Treatment mares received a uterine instillation of 100 ml of electrochemically activated (ECA) saline 4-12 hours post-insemination. Control mares received no treatment post-insemination. Per cycle pregnancy rate was 58.3 % in the control group and 50 % in ...
Pinyopummin A, Mahasawangkul S, Kornkaewrat K, Rattanapirom S, Leartsang W, Kitkha S.The effects of seminal plasma (SP), derived from autologous, homologous and heterologous species (stallion, boar and dog) on chilled Asian elephant sperm quality, were determined. Semen was collected from eight males and samples with ≥30% motile spermatozoa were used in the study. Semen was diluted with Tris-glucose-egg yolk extender, supplemented with different SP types and preserved at 4°C for 48 hr. Experiment 1 (n = 31), showed that the presence of SP (autologous) helped to preserve sperm quality in terms of sperm motility and acrosome integrity (p < .05). Homologous SP did not ...
Schulman ML, Harper CK, Bell E, Nel A, Guthrie AJ.The aim of this study was to establish and validate a method to permit microsatellite analysis of DNA profiles obtained from frozen-thawed stallion sperm cells. This would provide reliable and accurate verification of the identification of a semen donor. Ejaculates from 5 pony stallions were collected, processed and frozen in 0.5 ml plastic straws. Aliquots of 100 microl of the frozen-thawed semen thus obtained were either placed directly, or diluted (1:10; 1:100; and 1:1000) and placed on slides of FTA paper. Similarly, blood samples obtained from each of the stallions were placed onto slides...
Klug E, Brinkhoff D, Flüge A, Scherbarth R, Essich G, Kienzler M.Practical experiences of the phantom method for collection of genital secretions from stallions are reported. Taking a phantom used in the Richard-Götze-Haus Tierärztliche Hochschule Hannover as a prototype two further models slightly modified have been constructed, baring a flat hollow in the right side of the caudal phantom body for manual inserting of the Artificial Vagina. These three models fulfill four important conditions for routine use: (1) sufficient sexual attractivity for the stallions; 80-85% successful collections of presecretions out of a total of 1050 using the dummy and 70% ...
Boyle MS, Skidmore J, Zhang J, Cox JE.The effect of long-term treatment of stallions with a powerful gonadotrophin-releasing hormone (GnRH) analogue was investigated. In the first part of the study, 9 sexually mature pony stallions were allocated to 1 of 3 groups, each of which was treated with 240 micrograms or 60 micrograms Buserelin per day administered by subcutaneously sited osmotic pumps or 30-50 micrograms Buserelin per day via solid, slow-release implants injected subcutaneously. Peripheral blood plasma and serum samples were collected frequently and assayed for follicle-stimulating hormone (FSH) and luteinizing hormone (L...
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...
Gelberg HB, McEntee K.Interstitial cell tumors from nine stallions were described. In all but one horse the tumors were found in undescended testes. Five animals had bilateral tumors. Two animals showed increased aggression. Tumors contained two cell types. The first type were large distinctly bordered eosinophilic cells interpreted to be hyperplastic and hypertrophic interstitial cells. They blended with pleomorphic often spindloid neoplastic cells which had fibrillar, vacuolated cytoplasm and indistinct cell borders. This latter cell population was arranged in nodules or broad sheets as endocrine-like packets or ...
Bartels JE, Beckett SD, Brown BG.Serial arteriography was used to determine the vascular pattern and blood flow in the penis of the pony stallion. Ponies were anesthetized with pentobarbital sodium, and catheters were surgically introduced into the internal pudendal and obturator arteries. The vascular anatomy was visualized by angiography via image-intensified fluoroscopy and was recorded on 70-mm film at 3 frames/s or by direct radiography. Blood flow into the corpus cavernosum penis (CCP) was limited during quiescence because the blood was immediately shunted into the venous system. After vasodilation with mild stimulation...
Soma LR, Uboh CE, You Y, Guan F, McDonnell S.Pennsylvania (PA) State Racing Commissions regulate the endogenous androgenic steroid, testosterone (TES), in racing intact males (RIM) by quantification of TES in post-race samples. Post-race plasma samples (2209) collected between March 2008 and November 2010 were analyzed for TES, nandrolone (NAN), and other anabolic steroids (ABS). Of the 2209 plasma samples, 2098 had quantifiable TES ≥ 25 pg/mL. Plasma (mean ± SD) concentrations of TES and NAN in RIM were 329.2 ± 266.4 and 96.0 ± 67.8 pg/mL, respectively. Only 64.6% of RIM had quantifiable concentration of NAN, and there was no relat...
Torres-Boggino F, Sato K, Oka A, Kanno Y, Hochi S, Oguri N, Braun J.Seminal characteristics, fertility and the response to semen preservation (liquid storage and cryopreservation) were evaluated in 4 Draft stallions (Percheron 2, Breton 2). Seminal characteristics (gel-free volume, sperm concentration, sperm morphology, percentage of motile spermatozoa) were assessed in 5 ejaculates from each of the 4 stallions. The fertility of the stallions was calculated retrospectively as the accumulated pregnancy rate over 3 breeding seasons. Five ejaculates from each of the stallions were subjected to liquid storage at 5 degrees C. The percentage of motile spermatozoa (P...
Ferrer MS, Canisso IF, Podico G, Ellerbrock RE, Hurley DJ, Palomares R.Different stallions exhibit a high level of variation in the ability of their sperm to survive cryopreservation. A large fraction of stallions show poor post-thaw sperm motility, and their semen is not suitable for commercial freezing. In this study, we hypothesized that the presence of sperm-bound antisperm antibodies (ASAs) was associated with poor cryosurvival of stallion sperm. Our objective was to assess the level of ASA binding to stallion sperm, and determine if it was associated with good or poor sperm cryosurvival. In Experiment 1, cooled shipped semen from 27 stallions was frozen usi...
Hackett ES, Bruemmer J, Hendrickson DA, McCue PM.Description-An 11-year-old Quarter Horse stallion was admitted for intermittent hemospermia of 4 years' duration. Results: A linear vertical defect had been detected endoscopically following multiple episodes of hemospermia on the caudodorsal convex surface of the urethra at the level of the ischial arch. Results: When sexual rest alone did not result in complete healing of the urethral defect, a subischial urethrotomy and buccal mucosal urethroplasty were performed. The surgical site healed without complication. Four months of sexual rest was recommended after surgery. Repeat endoscopy at 4 m...
Pruett HE, Thompson DL, Cartmill JA, Williams CC, Gentry LR.Light horse mares, stallions, and geldings were used to 1) extend our observations on the thyrotropin releasing hormone (TRH) inhibition of GH secretion in response to physiologic stimuli and 2) test the hypothesis that stimulation of endogenous TRH would decrease the normal rate of GH secretion. In Exp. 1 and 2, pretreatment of mares with TRH (10 microg/kg BW) decreased (P < 0.001) the GH response to exercise and aspartate infusion. Time analysis in Exp. 3 indicated that the TRH inhibition lasted at least 60 min but was absent by 120 min. Administration of a single injection of TRH to stal...
Braun J, Torres-Boggino F, Hochi S, Oguri N.The objective of this experiment was to examine the effect of seminal plasma on motion characteristics of epididymal and ejaculated equine spermatozoa during storage at 5 degrees C. Epididymal spermatozoa were flushed with either seminal plasma or a skim milk-glucose extender. Ejaculated spermatozoa were collected with extender added 10 minutes after semen collection and addition of extender during ejaculation by placing 50 ml extender in the collection bottle. Semen samples were centrifuged and resuspended with a skim milk-glucose extender containing seminal plasma (0, 5 and 25%; v/v), prepar...
Motton DD, Roser JF.Recent evidence in our laboratory suggests that the cause of idiopathic subfertility/infertility in breeding stallions may originate in the testes at the luteinizing hormone (LH) receptor or postreceptor level. The objective of this research was to determine if LH receptor binding activity is altered in subfertile and infertile stallions. Six fertile, three subfertile, and three infertile stallions, ages 11-23 years, were classified according to normal semen parameters and pregnancy rates and then castrated in the breeding season. Blood was collected prior to castration, and plasma was stored ...
Frazer GS, Bucci DM.The aims of this project were to document the protein profile of equine seminal plasma and determine the variability between stallions in the relative composition of proteins in the ejaculate. A single ejaculate was obtained from 14 stallions of varying breed and age. The gel fraction was removed by an in-line filter. The semen was centrifuged and the supernatant seminal plasma aspirated without disturbing the sperm pellet. The seminal plasma was recentrifuged and stored in cryovials at -70 degrees C. Samples were thawed, recentrifuged, assayed for protein concentration (BCA protein assay), di...
Miszczak F, Pronost S, Vabret A.Equine arteritis virus (EAV) is the causative agent of equine viral arteritis, a disease observed only in equids. EAV is the prototype of the family Arteriviridæ within the order Nidovirales. EAV is an enveloped, positive-sense, single-stranded RNA virus with a considerable variation in the genome as observed in other RNA viruses. During natural infections, EAV may cause abortion and persistent subclinical infections in stallions which can shed the virus in the semen for years, or even lifetime. Chronically infected stallions represent the natural reservoir of the virus. They ensure the persi...
Parlevliet JM.The studies described in this thesis investigated the factors that can affect the fertility of stallions. The introduction describes the male gamete and the processes that occur during maturation of sperm and fertilization. Methods to evaluate the quality of sperm and ova are then discussed. Fertility can be expressed in various ways and is also affected by many factors such as the stallion, the mare and management factors. The fertility of stallions is usually assessed a good year after they have served mares, because then the number of foals is known. However, it would be preferable to be ab...
Houghton E, Copsey J, Dumasia MC, Haywood PE, Moss MS, Teale P.As part of a continuing research program associated with the detection of anabolic steroid residues in horse urine, normal samples from entire male horses have now been investigated. Isomers of three C-18 neutral steroids; 4-estren-17-ol-3-one (1), estrane-3,17-diol (2) and an unsaturated estranediol having a possible structure (3), have been identified in urine samples from two male horses aged 8 and 14 years. Of these three steroids, compound (2) was not detected in the urine of a 2.5 yr old entire male nor in the majority of post-race urine samples from entire male horses average age 3.8 yr...
Sales FA, Ferreira-Silva JC, Vieira JI, Chaves MS, Caldas EL, Filho JP, Freitas VJ, Oliveira MA.Addition of extenders to thawed semen could improve fertility. Objective: To determine the efficiency of extenders to increase viability of thawed semen, measured by sperm parameters in vitro and pregnancy rates after artificial insemination (AI). Methods: Sperm motility and acrosin activity were measured during a thermoresistance test (TRT). Results: Progressive motility decreased (P<0.05) after 30 min in thawing semen treated with saline solution (SS) and only after 60 min with Tyrode's solution (TS) or freezing diluent (FD). The total motility decreased (P<0.05) after 60 min in thawed semen...
Bugno-Poniewierska M, Dardzińska A, Pawlina K, Słota E.A normal course of meiosis and the associated course of spermatogenesis in males are very significant from the viewpoint of animal breeding, in particular animal reproduction. This takes on special significance when studying late-maturing animals such as horses. The aim of the study was to analyse meiotic cells, with particular consideration of synaptonemal complexes obtained from the testes of young stallions and cryptorchids, based on observations of the X-Y bivalent. The analysis was performed in successive stages of meiotic division using the FISH technique. The greatest diversity and most...
Starick E.A reverse transcription-polymerase chain reaction (RT-PCR) assay using four different primer pairs for the detection of equine arteritis virus (EAV) RNA in semen and tissue samples was evaluated. A fragment encoding the leader sequence of the EAV genome was most successfully amplified. The specificity and sensitivity of RT-PCR was assessed by virus isolation in cell culture, restriction analysis, dot blot hybridisation and nested PCR. To this end, 23 semen samples from seropositive stallions and 11 tissue samples from 4 aborted foals were tested. Compared to the virus isolation test in cell cu...
