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Topic:Stallion
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.
[A comparison of suturing and non-suturing of scrotal wounds following castration in stallions]. It was found that wound infections may be considerably reduced when castration is carried out under strictly aseptic conditions. In this clinical review, healing of the wound following castration with and without closure of the scrotal wounds is compared. All castrations were performed under similar aseptic conditions, general anaesthesia having been produced in the recumbent stallion. The results do not show that there is a significant difference in the appearance of wound infections in scrotal wounds which are closed and those which are left completely open. On the basis of both papers and t...
[The occurrence and significance of plasma coagulase negative staphylococci from the genital tract of horses]. Classification based on biochemical characteristics of 389 strains of plasma-coagulase-negative (plc-) staphylococci isolated from the genital tract of mares and stallions resulted in the following distribution of species: St. sciuri 130 (33.4%), St. equorum 42 (10.8%), St. xylosus 16 (4.1%), St. epidermidis 35 (9.0%), St. simulans 24 (6.2%), St. haemolyticus 33 (8.5%), St. warneri 18 (4.6%), St. lentus 12 (3.1%), St. hyicus 11 (2.8%). Strains of St. cohnii, St. capitis, St. gallinarum, St. saprophyticus and St. hominis have only been found sporadically (a. 1%). 48 (12.3%) strains could not be...
[Preservation capability of horse semen by the use of two diluents and preservation temperatures]. The effect of a skim milk extender and a glycine-containing extender on sperm motility and acrosome morphology of stallion semen was examined. There was no difference concerning acrosome morphology. After 24 hours of preservation motility of the ejaculates diluted with glycine extender was significantly superior to those handled with skim milk extender. Storage at 5 degrees C in all cases gave better results than storage at room temperature. Skim milk extender is an appropriate diluent when the semen is used for al on the day of its collection, whereas the glycine-containing extender offers th...
Semen selenium content and sperm mitochondrial volume in human and some animal species. Selenium (Se) and glutathione peroxidase (GSH-Px) were determined from the seminal plasma samples and spermatozoa of human and four different animal species. The human sperm Se concentration was 1.8 +/- 0.8 micrograms/g dry weight, which was about half of that in the bull. Abnormal sperm morphology and motility correlated with low sperm Se content. The volume of sperm mitochondrial sheath in human, bull and stallion was measured using transmission electron microscopy. In these species the sperm Se content was highly correlated with the volume of mitochondria. Among the five species studied, th...
Synthesis and aromatization of 19-norandrogens in the stallion testis. The results of the measurement of 19-nortestosterone in the testiscular artery and vein of the stallion, the very low levels of this steroid in the peripheral blood of geldings and the similar patterns of increase in the peripheral levels of 19-nortestosterone and testosterone after hCG stimulation, show that 19-nortestosterone, like testosterone, is essentially synthesized in the testis. This testicular origin was confirmed by the ability of testicular tissue to synthesize 19-norandrogens from [4-14C]androgens in vitro. 19-Nortestosterone was 50% conjugated in the peripheral blood and almost ...
Influences of season and artificial photoperiod on stallions: pituitary and testicular responses to exogenous GnRH. Effects of season and photoperiod on the anterior pituitary gland and testes were studied by responses to exogenous GnRH. Stallions were assigned to one of three treatments: 1) control, exposed to natural day length; 2) S-L, 8 h of light and 16 h dark (8:16) for 20 wk beginning July 16, 1982 then 16:8 from December 2, 1982 until March 5, 1984; or 3) S-S, 8:16 from July 16, 1982 until March 5, 1984. Approximately every 8 wk, stallions were administered GnRH (2 micrograms/kg BW) and blood was sampled at 20-min intervals for 2 h before and 8 h after GnRH administration. Concentrations of LH, FSH ...
Androgen and oestrogen response to a single injection of hCG in cryptorchid horses. Androgen (testosterone and androstenedione) and oestrogen (oestradiol -17 beta and oestrone) concentrations were measured by radio-immunoassay in the peripheral plasma of two geldings (five-years-old), three bilateral cryptorchids (two, two and a half, and five-years-old) and three normal intact stallions (four, five and five and a half-years-old) before and after a single injection of 10,000 iu human chorionic gonadotrophin (hCG). In the stallions, hCG administration resulted in an immediate sharp increase of conjugated oestrogens and a more gradual increase of unconjugated androgens. In the ...
Down-regulation of testicular aromatization in the horse. A single i.m. injection of testosterone (750 mg of testosterone bexahydrobenzoate) or i.v. injection of human chorionic gonadotrophin (hCG) (10,000 IU) was given to geldings and stallions. Levels of unconjugated and conjugated (after solvolysis) androgens and estrogens were measured in blood and urine samples taken daily from the day of injection (D0) to the tenth day post-injection (D10). In the stallion, both treatments resulted in a sharp increase of plasma estrogens, which peaked one day before the androgen levels. Our results confirmed the testicular localization of a potent aromatase, wh...
Relationship of intratesticular testosterone content of stallions to age, spermatogenesis, Sertoli cell distribution and germ cell-Sertoli cell ratios. Testes were obtained from 47 1-20-year-old stallions during the natural breeding season. Total testicular testosterone and testosterone/g testis increased with age (P less than 0.005), and total testicular testosterone was associated with larger testis size (P less than 0.05). Neither testosterone per gram nor per paired testes were related to total Sertoli cell number (P greater than 0.05), but greater testosterone per paired testes was associated with fewer Sertoli cells per unit of seminiferous tubule length (P less than 0.005) or basement membrane area (P less than 0.02) and with a higher ...
Comparison of partial amino acid sequences of two protamine 2 variants from stallion sperm. Structural evidence that the variants are products of different genes. Protamine 1 and two protamine 2 variants were isolated from stallion sperm and separated by acetic acid-urea gel electrophoresis. After electroblotting onto polyvinyldifluoride filters, their amino-terminal amino acid sequences were determined by pulse-liquid peptide sequencing. The sequences of the two protamine 2 variants are homologous but slightly different in length and amino acid composition and indicate for the first time the existence of two different genes for this protamine species.
Changes in quality of stallion spermatozoa during cryopreservation: Plasma membrane integrity and motion characteristics. Better procedures for freezing and thawing equine sperm are needed since variable fertility is obtained when cryopreserved sperm are used. To evaluate current methods of freezing equine sperm, we examined spermatozoal quality by means of two new techniques. These measured the integrity of plasma-acrosomal membranes by immunofluorescent analyses of binding of an antibody specific to the acrosome and evaluated eight parameters of spermatozoal motion using a fully automated computerized system. Five ejaculates from each of eight stallions were processed for freezing in egg yolk-lactose extender w...
Steroids in equine testes: the identification of endogenous 19-hydroxy and 19-nor neutral steroids by gas chromatography–mass spectrometry. After homogenization of testicular tissue from stallions aged 1, 2 and 5 years, the unconjugated and conjugated steroids were isolated by a combined solvent-solid extraction procedure. The conjugates were further separated into glucuronides and sulphates by chromatography using Sephadex LH-20. After enzyme hydrolysis and solvolysis of the respective conjugate classes, the three extracts, unconjugated steroids, aglycones and solvolysed sulphates, were purified by chromatography using Kieselgel 60H columns. Five fractions were resolved from each extract; an aliquot of each fraction was derivatiz...
Sperm granuloma in a stallion. A 7-year-old stallion with a history of abdominal pain after it fell was examined and found to have a swelling of the right testis and epididymis. Semen evaluation revealed an increase in secondary sperm abnormalities. The stallion was unilaterally castrated. The histologic diagnosis was sperm granuloma, with no evidence of infection. Periductal fibrosis was observed and appeared to have developed before the trauma occurred. The changes seen could be compatible with chronic blockade of efferent ductules, resulting in extravasation of spermatozoa.
Sampling intensities and replication requirements for detection of treatment effects on testicular function in bulls and stallions: a statistical assessment. Data from testes of 16, 2- to 3-yr-old stallions and 34 yearling beef bulls were utilized in a components of variance approach to calculate the number of observations required per testis and(or) the number of animals required per treatment group to provide experiments of known sensitivity and precision, where treatment was to be assessed by one of several endpoints. The latter included paired testes weight, seminiferous tubular diameter, the number of germ cells per seminiferous tubular cross-section, or the number of elongated spermatids per gram of testicular parenchyma or per testis. For al...
Long-term follow-up of partial limb amputation in 13 horses. Thirteen cases of partial limb amputation in horses were reviewed. Nine horses (69%) survived 18 to 111 months (mean, 41 months). Four unsuccessfully treated horses were euthanatized within 21 days of surgery. The horses' ages at amputation were 4 to 13 years (mean, 7.3 years). There was no predilection for the left or right limb nor for fore or hind limb involvement. Osteomyelitis in six horses (46%) was the most common cause for amputation. Severe, open, comminuted fractures of the third metacarpal bone that were impossible to stabilize by any currently available technique in four horses (31...
Gonadotropin releasing hormone (GnRH) affects precopulatory behavior in testosterone-treated geldings. Twelve pony geldings with (n = 6) and without (n = 6) testosterone replacement (200 micrograms/kg testosterone propionate in oil, SC every 48 hours) received either gonadotropin releasing hormone (GnRH; 25 micrograms SC every 3 hours) or control treatment. Sexual behavior was recorded during 4-minute exposure to an estrous mare, 3 times weekly for 2 weeks before treatment, 3 weeks during treatment, and 3 weeks after treatment had been discontinued. The group receiving testosterone and GnRH (n = 3) exhibited significantly greater flehmen response frequency and attention duration and significant...
[Bilateral rupture of two head flexors with synchondrolysis of the base of the skull in a horse]. Bilateral rupture of the musculus longus capitis from the tuberculum musculare of the os occipitale and of the musculus rectus capitis ventralis from the os occipitale combined with a synchondrolysis of the synchondrosis sphenooccipitalis in a 17 months old thoroughbred stallion is reported.
Cytochemical and ultrastructural characteristics of the stallion epididymis (Equus caballus). The epididymis of stallion castrated during the breeding and non breeding seasons were subdivided into six regions and their ultrastructural and cytochemical characteristics were studied in order to provide a better understanding of the structure-function relationship of this androgen target organ. Even when the stallion has been postulated to be a seasonal breeder, our results do not show significant ultrastructural or cytochemical differences in both seasons. The pseudostratified epithelium is composed mainly of principal and basal cells and intraepithelial lymphocytes. The principal cells s...
Hematochezia attributable to cranial mesenteric arterial aneurysm with connecting tracts to cecum and ileum in a horse. A cranial mesenteric arterial aneurysm with fistulous tracts to the cecum and ileum was discovered in a Missouri Fox Trotter stallion. The principal clinical sign was hematochezia, observed at 7- and 10-day intervals. The lesion may have been attributable to arteritis caused by fourth-stage larvae of Strongylus vulgaris.
An immunochemical demonstration of a pregnancy-specific protein in the horse and its use in the serological detection of early pregnancy. Two-dimensional crossed immunoelectrophoresis of sera from pregnant and non-pregnant horses, using antisera developed against early pregnant mare serum, revealed the presence of two immunologically related proteins one of which appeared to be specific to the pregnant state. This pregnancy-specific protein had beta 2-electrophoretic mobility and was first detectable at Day 6 after successful mating with a stallion. The second protein had gamma 2-electrophoretic mobility and was present in sera from pregnant and non-pregnant horses. The proteins were termed beta 2-horse pregnancy protein and gam...
Use of a monoclonal antibody to evaluate integrity of the plasma membrane of stallion sperm. Transmission electron microscopy was used to confirm that a monoclonal antibody (F79.3E2; class IgG1 kappa) was specifically localized to an antigen in the acrosomal ground substance of stallion sperm. This antibody was used to develop and validate an indirect immunofluorescent procedure to evaluate integrity of the plasma-acrosomal membranes of stallion sperm. The concept was that primary monoclonal antibody would be "shielded" from its acrosomal antigen by an intact plasma membrane. Conversely, sperm with damaged plasma-acrosomal membranes would exhibit green acrosomal fluorescence when view...
Management of a severely comminuted fracture of the third metacarpal bone in a horse. A 4-year-old Standardbred stallion sustained a severely comminuted fracture involving the second, third, and fourth metacarpal bones. The fracture was repaired using two 14-hole broad dynamic compression plates positioned at 90 degrees to one another, allowing one plate to protect the other in the bending mode. An autologous cancellous bone graft obtained from the tuber coxae was added at the site of the defect in the mid- to upper third of the third metacarpal bone. Complications associated with the fixation included a Staphylococcus aureus infection 5 months after surgery, laminitis that dev...
The effect of artificial photoperiod at the end of the breeding season on plasma testosterone concentrations in stallions. Testosterone concentrations in stallions showed a seasonal trend with peak concentrations in the spring (April and May in Britain) and lowest concentrations in the period from December to February. The effect on this pattern of changing the length of the photoperiod at the end of the normal breeding season (mid-summer's day) was studied in 2 experiments. In the first experiment artificial illumination was organised from 21 June to mimic the effect of transfer to a southern hemisphere spring and summer, that is short days becoming longer. The stallions had low concentrations of testosterone in ...
[Growth course of young warm-blooded stallions as the basis for the derivation of energy and protein requirement standards]. The live weight development of young warm-blooded stallions at the age of 0 to 30 months of life was investigated in order to derive their energy and protein requirement. The aim of the studies was the derivation of a standard curve for the course of growth. Choice of the best suited model and the corresponding calculations were one of the main investigation objects. The mathematical function developed by Janoschek provided a relatively good description of the material.
Use of a narcotic antagonist (nalmefene) to suppress self-mutilative behavior in a stallion. Nalmefene, an opioid antagonist, caused a decrease in self-mutilative behavior in a 500-kg stallion. Self-mutilative attempts were counted during a control period and on 4 subsequent occasions after the IM administration of 100 mg, 200 mg, 400 mg, or 800 mg of nalmefene. The frequency of self-mutilation decreased with increasing doses of nalmefene and was virtually abolished with the 800-mg dose.
The pathogenesis and treatment of osteomyelitis and laminitis in a stallion after the prolonged topical application of formalin to the distal phalanx. A 12-year-old Quarterhorse stallion was presented with a severe lameness in the left forefoot. There was a 3 cm diameter cavity in the sole that extended to the solar surface of the distal phalanx. Radiographs revealed an osteomyelitis and a sequestrum which probably developed following the prolonged topical application of 10 percent formalin. The sequestrum was removed and the infected bone curetted under general anaesthesia. The horse was shod with heart bar shoes on both front feet 7 days after the surgery. Eight months later, radiographs showed marked rotation of the distal phalanx despite...
Studies of stallion sperm survival: preservation of progressive motility of stallion spermatozoa by low ionic strength media. Preservation of stallion sperm forward motility was studied using a video recording system in semen diluted with media of different ionic strength and sodium content. After 8 hr of incubation at room temperature, semen diluted in a low ionic strength media containing sucrose displayed 65 +/- 9% motility with 68 +/- 3% of the motile sperm showing forward motility (diameter of head trajectory greater than or equal to 80 microns). In contrast, sperm populations diluted and incubated with a normal ionic strength media containing sodium had 56 +/- 7% motile sperm of which only 36 +/- 7% displayed f...
