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.
Batellier F, Duchamp G, Vidament M, Arnaud G, Palmer E, Magistrini M.Milk-based semen diluents are known to be practical and effective in protecting equine spermatozoa during storage before artificial insemination. Milk is a biological fluid with a complex composition and contains components which are beneficial or harmful to spermatozoa. The aim of this study was to test the fertility of stallion semen after long-term storage using different milk diluents (INRA 82 or Kenney's diluent) vs one diluent chemically defined (INRA 96), which is composed of efficient milk components and optimized for sperm survival and storage temperature. The milk fraction used was t...
Trimeche A, Yvon JM, Vidament M, Palmer E, Magistrini M.The supplementation of the freezing diluent with 3 amino acids (glutamine, proline and histidine) and 1 amino acid-related compound (betaine) in preserving stallion spermatozoa diluted in INRA82 extender containing 2.5% (v/v) glycerol and 2% (v/v) egg yolk (control extender) during freezing and thawing was studied at 0, 40, 80, 120 and 160 mM in 20 split ejaculates (10 stallions x 2 ejaculates; Experiment 1). Glutamine and proline were studied at 0, 10, 20, 30, 40, 50, 60, 70 and 80 mM in 20 split ejaculates (10 stallions x 2 ejaculates; Experiment 2). In each experiment, spermatozoa were eval...
Brandon CI, Heusner GL, Caudle AB, Fayrer-Hosken RA.The objectives of this study were to 1) identify proteins found in stallion seminal plasma utilizing two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) in conjunction with Western blot analysis; and 2) to determine if any of these individual proteins were correlated with stallion fertility utilizing regression analysis. Fertility was quantified by assigning a breeding score for each stallion. Each score was calculated by dividing the number of conceptions by the number of breedings for each stallion for four successive breeding seasons (1992-1995). Ejaculates from stallions of known ...
Troedsson MH, Liu IK, Crabo BG.After the deposition of semen in the mare's uterus, spermatozoa must be transported to the site of fertilization, be maintained in the female tract until ovulation occurs, and be prepared to fertilize the released ovum. Sperm motility, myometrial contractions, and a spontaneous post-mating uterine inflammation are important factors for the transport and survival of spermatozoa in the mare's reproductive tract. Fertilizable sperm are present in the oviduct within 4 h after insemination. At this time, the uterus is the site of a hostile inflammatory environment. Our data suggest that spermatozoa...
Shore MD, Macpherson ML, Combes GB, Varner DD, Blanchard TL.It has become a common practice in the equine breeding industry to send 2 insemination doses for breeding with transported cooled semen, one to be used for the initial insemination upon arrival, and the other to be held a second insemination the next day. One fertile stallion and 36 fertile mares were used to determine if breeding once with 1 dose of semen cooled for 24 h would improve fertility compared with breeding twice, 1 d apart, with half the dose of semen cooled for 24 h on the first day of breeding and half cooled for 48 h on the second day of breeding. Mares were given two intramuscu...
Liberda J, Tichá M, Zralý Z, Svecová D, Vezník Z.The interaction of seminal plasma proteins, sperms and detergent-released sperm proteins of three species with different types of acidic polysaccharides was studied. Heparin-binding activity of boar, bull and stallion seminal plasma proteins, sperms and sperm proteins was compared with their ability to interact with polysaccharides differing in the presence of the sulfate groups or in their saccharide moiety (chondroitin sulfate, dextran sulfate, fucoidan, hyaluronic acid). Bull seminal plasma proteins were characterized by higher affinity to heparin, fucoidan and dextran sulfate, while signif...
Gahne S, Gånheim A, Malmgren L.Different insemination doses have been used for artificial insemination(AI) in horses. Since the insemination dose can affect the pregnancy rate, it is important to ensure that an adequate dose be used regardless of the type of inseminationprotocol used. The aim of this study was to find out if it is possible to decrease the insemination dose from 500 x 10(6) progressively motile spermatozoa to 300 x 10(6) progressively motile spermatozoa and still maintain an acceptable pregnancy rate when using extended fresh semen. Thirteen stallions of known fertility and a well-defined group of 64 mares w...
Leipold SD, Graham JK, Squires EL, McCue PM, Brinsko SP, Vanderwall DK.Information on the number of motile spermatozoa needed to maximize pregnancy rates for frozen-thawed stallion semen is limited. Furthermore, concentration of spermatozoa per 0.5-mL straw has been shown to affect post-thaw motility (7). The objectives of this study were 1) to compare the effect of increasing the concentration of spermatozoa in 0.5-mL straws from 400 to 1,600 x 10(6) spermatozoa/mL on pregnancy rate of mares, and 2) to determine whether increasing the insemination dose from approximately 320 to 800 million progressively motile spermatozoa after thawing would increase pregnancy r...
Samper JC, Morris CA.Various factors affect the success of AI with frozen-thawed semen in horses. Stallion variability is thought to be one of the major factors, but semen processing and evaluation techniques, thawing protocols, packaging systems and timing of insemination are far from standardized among laboratories. Our objective was to survey current methods for stallion semen cryopreservation used commercially around the world. From the answers to the questions in the survey, we attempted to provide an overview of procedures that are standard as well as those that are used by only few laboratories and to revie...
Troedsson MH, Liu IK, Crabo BG.Following the deposition of semen in the mares uterus, spermatozoa must be transported to the site of fertilization, be maintained in the female tract until ovulation occurs, and be prepared to fertilize the released ovum. Sperm motility, myometrial contractions, and a spontaneous post-mating uterine inflammation are important factors for the transport and survival of spermatozoa in the mares reproductive tract. Fertilizable sperm are present in the oviduct within 4 hours after insemination. At this time, the uterus is the site of a hostile inflammatory environment. Our data suggest that sperm...
Varner DD, Scanlan CM, Thompson JA, Brumbaugh GW, Blanchard TL, Carlton CM, Johnson L.Three experiments were conducted to evaluate the effects of different antibiotics in a milk-glucose semen extender on motility of equine sperm and elimination of bacteria following storage of extended semen in vitro. In Experiment 1, 7 antibiotics were compared: amikacin, gentamicin, streptomycin, potassium penicillin, sodium penicillin, ticarcillin, and polymixin B. In Experiment 2, 3 antibiotic treatments were compared: potassium penicillin G, amikacin, or a combination of potassium penicillin G and amikacin. In Experiment 3, 3 antibiotic treatments were compared: potassium penicillin G-amik...
Merkies K, Buhr MM.Spermatozoal function is affected by the ability to regulate intracellular calcium concentrations ([Ca2+]i), and may be influenced by epididymal maturation as well as environmental components. Regulation of [Ca2+]i in ejaculated and epididymal stallion spermatozoa was monitored over time in various media. Spermatozoa from each of 5 pony stallions (3 ejaculate samples and 1 caput and cauda sample) were labeled with the fluorescent calcium indicator probe Indo-1 in a calcium-free modified Tyrode's buffer. Fluorescent emissions were monitored by a dual wavelength spectrofluorometer over 5 h. Calc...
Paccamonti DL, Buiten AV, Parlevliet JM, Colenbrander B.Breeding soundness evaluation (BSE) of stallions is a routine component of stud farm practice. Guidelines for assessing satisfactory breeding potential have been developed using data derived from stallions of full-size breeds. In view of the increasing popularity of miniature stallions, knowledge of normal semen parameters of these stallions is important. Therefore, testicular measurements and semen parameters from 216 sexually rested miniature stallions were obtained. Semen was collected twice, 1.5 to 3 h apart, using an artificial vagina. Values were averaged over the 2 collections because o...
Watson ED, Nikolakopoulos E, Gilbert C, Goode J.It has been suggested that oxytocin is involved in sperm transport and motility in domestic animals. Immunoreactive oxytocin was measured in seminal fractions (pre-ejaculatory fluid, seminal plasma, gel and sperm) and in extracts of testis and epididymis from stallions. In addition, sections of gonadal tissue from stallions were immunostained for the presence of oxytocin and its neurophysin. Oxytocin was detected in all of the seminal fractions, being highest in the gel. It was also present in washed, lysed sperm and in extracts from the testis and epididymis. Immunostaining for oxytocin was p...
Neild D, Chaves G, Flores M, Mora N, Beconi M, Agüero A.The aim of the study was to evaluate equine sperm membrane integrity using the hypoosmotic swelling (HOS) test and to correlate this test with different sperm parameters in raw and frozen thawed semen. The HOS solutions were made with fructose, sucrose, lactose and sodium citrate each at 300, 150, 100, 50 and 25 mosm. Maximum numbers of swollen spermatozoa were observed in solutions of fructose, sucrose and lactose each at 100, 50 and 25 mosm. Correlations between progressive motility, morphologically normal spermatozoa and the HOS test were r = 0.75 and r = 0.51 in raw semen and r = 0.26 and ...
Lindeberg H, Karjalainen H, Koskinen E, Katila T.A study was performed to test a new semen collection device (Equidame phantom) that fractionates the ejaculate by comparing the quality of semen obtained by the Equidame phantom with that obtained by a Missouri artificial vagina. Semen from 4 Finnhorse stallions was collected 4 times per stallion by both methods. Half of the ejaculate was frozen and the other half extended and loaded into 2 Equitainer transport containers (24- and 48-h samples). Motility parameters were determined by a Hamilton-Thorn motility analyzer after cooled storage for 24 and 48 h and again after freezing/thawing. Raw a...
Bedford SJ, Gowdy HL, Hinrichs K.This study was designed to compare the effects of different media and containers on longevity of motility of spermatozoa during in vitro incubation at 38 degrees C in either air or 5% CO2 atmosphere. Three ejaculates were collected from each of 4 stallions. The media tested were skim milk-glucose, modified Krebs/Ringer and Hank's salts solution for incubation in an air atmosphere, and modified Krebs/Ringer and Brackett and Oliphant (BO) defined medium for incubation in a 5% CO2 atmosphere. All samples were incubated in 5-mL borosilicate glass tubes filled with 3 mL of extended spermatozoa, 5-m...
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...
Gerlach T, Aurich JE.This review considers seasonal reproduction in male animals with emphasis on the stallion, ram and hamster. The pineal hormone melatonin is the common link between photoperiod and reproduction. An increase in the daily diurnal period of melatonin secretion is associated with a decrease in GnRH release in long-day breeders, but an increase in GnRH release in short-day breeders. Melatonin influences GnRH release within or close to the mediobasal hypothalamus in rams; whereas melatonin receptors have not been found in the hypothalamus of horses. Prolactin release is positively correlated with day...
Bedford SJ, McDonnell SM, Tulleners E, King D, Habecker P.A 14-year-old Arabian stallion was examined because of acute hemospermia. The stallion was used in an artificial breeding program and had a 6-year history of low-grade hemospermia and a 4-year history of self-mutilation behavior. During previous examinations, minor irritation of the urethral process was identified as the source of the bleeding. Physical examination revealed a mucosal ulceration in the distal portion of the urethra. Histologic examination of a biopsy specimen from this area revealed low-grade squamous cell carcinoma. The urethral process was excised, and the hemospermia resolve...
Parker NA, Bailey TL, Bowen JM, Ley WB, Purswell BJ, Dascanio JJ.Like the human female, the mare experiences reproductive tract pathology that may sometimes be circumvented by the use of assisted reproductive technologies (ARTs). One such technology, gamete intrafallopian transfer (GIFT), may be used in mares that exhibit ovulatory, oviductal, or uterine abnormalities that limit the use of common ARTs, such as embryo transfer. Homologous GIFT has been successfully performed in the horse; however, the logistics, costs, and associated risks of surgically transferring gametes to the oviducts of a recipient mare are considerably high. Use of a less costly speci...
Rueca F, Conti MB, Porciello F, Spaterna A, Antognoni MT, Mangili V, Fruganti G, Avellini G.The purpose of this study was to assess the possible relationship between maximal running speed, serum isoenzyme patterns of creatine kinase (CK) and lactate dehydrogenase (LDH) and echocardiographic indices of left ventricular function. A group of 15 healthy, 3-year-old Maremmano stallions were given a 100 day training programme. At the end of this the animals carried out a maximum speed test and were divided into 2 groups (A and B) according to whether or not they had attained a speed of 15 m/s. Venous blood samples were taken from each horse before exercise (T0), 2 min (T1) and 24 h (T2) af...
Hoekstra KE, Nielsen BD, Orth MW, Rosenstein DS, Schott HC, Shelle JE.Sixteen Arabian yearlings were assigned randomly to 2 groups, confined to stall and pastured, to investigate the effects of confinement vs. pasture-rearing on bone mineral content and biochemical markers of bone metabolism over a 140 day period. Following an 84 day pretraining period, 6 horses from each group were selected randomly to complete a 56 day training period. Serum osteocalcin concentrations were determined from blood samples collected every 14 days. Urinary deoxypyridinoline concentrations and mineral content of the third metacarpus, as determined by lateral and medial radiographic ...
Berry S.Hemangiosarcoma in the spinal canal was diagnosed in a 25-year-old stallion showing progressive and symmetrical 4-limb ataxia, proprioceptive deficits, and weakness. On necropsy, an extradural mass consisting of spindle-shaped cells and numerous free erythrocytes was found at the level of C7-T1. Immunohistochemical staining confirmed a neoplasm of endothelial origin.
Kostiuk D.A 4-year-old Morgan stallion was presented with a 9-week history of diarrhea. Biopsy of nodules in the rectal mucosa yielded a diagnosis of eosinophilic enterocolitis. Treatment with steroids was instituted and the feces firmed within 2 days. Continued treatment with oral prednisone kept the feces at a normal consistency for 4 months.
Love CC, Varner DD, Thompson JA.Dismount semen samples were collected from Thoroughbred stallions during the breeding season to determine the magnitude and significance of the variation in sperm morphology within (intra-) and among (inter-) stallions. The degree of intra-stallion variation in sperm morphology during the breeding season was substantial (coefficient of variation: 20%; range 8-56%), but did not affect the day-to-day fertility of sperm samples taken from the same stallion (intra-stallion). This variability did not affect the pregnancy rate of the mares with which each stallion was mated. The degree of interstall...
Roser JF, Tarleton M, Belanger JM.Recent studies in our laboratory investigating plasma gonadotrophin concentrations before and after castration indicate that the hypothalamic-pituitary axis is not the original site of dysfunction in stallions with idiopathic infertility. In the present study, fertile, subfertile and infertile stallions were subjected to replacement therapy with oestradiol and testosterone 1 year after castration to investigate hypothalamic-pituitary axis function further. Fertile (n=5), subfertile (n=3) and infertile (n=2) castrated stallions of Light horse breeds, aged 11-23 years, were given either oestradi...
Blanchard T, Varner D, Johnson L, Roser J, Hill J, Miller C.The scrota of three Pony stallions and one miniature horse were insulated for 36 h. Plasma testosterone concentrations decreased gradually and were significantly (P < 0.05) lower than pretreatment values at 16, 24, 30, 38 and 44 h after onset of scrotal insulation. Plasma LH and oestradiol concentrations were significantly (P < 0.05) decreased 18 h, and 24 and 26 h, after onset of scrotal insulation, respectively. Plasma FSH concentrations were significantly (P < 0.05) decreased 4 days after the insulation was removed. Decreases in the potential daily sperm output per Pony for early p...
Mathias S, Allen WR.The incidence of recurrent spontaneous abortion within the human population in the Western world is low (2-5%) but significant, and a proportion of these pregnancy losses are thought to have an underlying immunological cause. Immunization of women who have a history of recurrent spontaneous abortion with lymphocytes isolated from their husband or a third party donor is one of several forms of immunotherapy used to treat the problem. Early pregnancy loss in Thoroughbred mares is also significant and, as in women, a small number of mares undergo repeated pregnancy losses. Two trials have been pe...
Yoshimura S, Barber SM, Tucker ML, Bracamonte JL, Mund SJK, Thomas KL.To describe a new technique to repair a sinocutaneous fistula with a masseter muscle transposition flap. Methods: Case report. Methods: One 13-year-old thoroughbred stallion. Methods: One 13-year-old stallion with a 3.5 × 6-cm sinocutaneous fistula over the right caudal maxillary sinus was treated with a transpositional masseter muscle flap. This repair consisted of a commercial wound matrix dressing placed directly over the hole in the maxilla and secured with suture material; a cancellous bone graft collected from the right tuber coxa placed on the dressing; and a portion of the superfi...
Larsen LE, Storgaard T, Holm E.The study describes for the first time the phylogenetic relationship between equine arteritis virus (EAV) isolated from asymptomatic virus-shedding stallions and fatal cases of equine viral arteritis (EVA) in an European country. EAV was isolated from three dead foals and an aborted foetus during three different outbreaks of EVA. From these fatalities, the complete open reading frame 5, encoding the EAV G(L) protein, was amplified by reverse transcription-polymerase chain reaction and subjected to nucleotide sequence analysis. Furthermore, DNA sequences were obtained from virus isolated from s...
MacDonald MH, Richardson DW, Morse CC.A 23-year-old Thoroughbred stallion was admitted to the hospital for treatment of acute esophageal obstruction. Clinical examination and contrast radiography confirmed the presence of an esophageal obstruction. The horse was euthanatized, and examination revealed a bolus of feed material occluding the esophageal lumen 6 cm caudal to the thoracic inlet, with underlying necrosis of the esophageal mucosa. A large pulsion diverticulum was identified in the caudocervical portion of the esophagus. Apparently, the phytobezoar was formed within the esophageal diverticulum and subsequently became dislo...
Bornstein S.Two intersex horses were characterized externally by vulva and “enlarged clitoris-hypoplastic penis” and internally by uterus and testicles. Both had a normal female karyotype 64/XX. One of the horses whose body measurements were in accordance with mares of the same breed, showed a distinct stallion behaviour.
Graham JK.Methodologies to capacitate bovine spermatozoa, induce the acrosome reaction, and fertilize bovine oocytes in vitro have been established. The capability to do the same with stallion spermatozoa, however, is not available. Several different methods have been used to capacitate stallion spermatozoa with variable results. More basic research needs to be done to establish in vitro conditions necessary to capacitate and induce an acrosome reaction in stallion spermatozoa. Although much progress can be expected in this area, it is unlikely that the general practitioner will use these technologies i...
Koskinen E, Marttila P, Katila T.The long-term effects of the anabolic steroid 19-norandrostenololylaurate on semen characteristics of Finnhorse colts were studied in 3 experiments. Semen was collected initially at 24 months of age and then twice a year. In experiment I, 500 mg or 100 mg of steroid per animal was given every 3rd week from 12 or 16 months to 24 months of age. In colts treated with 500 mg of anabolic steroid every 3rd week, azoospermia was observed in 3 out of 5 colts in the first semen collections, immediately after the end of treatment. The other 2 colts had low sperm numbers and a high percentage of proximal...
Castaneda C, Ruiz AJ, Tibary A, Raudsepp T.We present a detailed molecular cytogenetic analysis of a reciprocal translocation between horse (ECA) chromosomes Y and 13 in a Friesian stallion with complete meiotic arrest and azoospermia. We use dual-color fluorescence in situ hybridization with select ECAY and ECA13 markers and show that the translocation breakpoint in ECAY is in the multicopy region and in ECA13, at the centromere. One resulting derivative chromosome, Y;13p, comprises of ECAY heterochromatin (ETSTY7 array), a small single copy and partial Y multicopy region, and ECA13p. Another derivative chromosome 13q;Y comprises of E...
Clay CM, Squires EL, Amann RP, Nett TM.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 ...
Frerichs WM.The effect of imidocarb dipropionate [3, 3' bis-(2-imidazolin-2-yl) carbanilide dipropionate] on spermatogenesis in 3 pony stallions was studied. The drug alone had no deleterious effect on spermatogenesis when given intramuscularly 4 times at a dosage level of 4 mg/kg at 72-hour intervals. Hemicastration, with or without subsequent drug treatment, caused almost complete cessation of spermatogenesis 30 days after the operation.
Papa FO, Alvarenga MA, Lopes MD, Campos Filho EP.THE immunogenicity of mammalian sperm has been recognised since the beginning of this century. In 1909, Adler induced autoantibodies in the serum of guinea pigs by injecting them with their own spermatozoa. Nowadays, the concept of
immunologically privileged sites is well understood and any disruption which allows antigenic contact with the immune system may give rise to an immune response. For example, failure
of the blood/testes barrier following infection, trauma or surgery can lead to the production of antisperm antibodies as a result of spermatozoa coming in contact with the immune syst...
Ganjam VK.Changes in the daily secretory patterns of testosterone and other 17 beta-hydroxyandrogen, total oestrogens and total corticoids were investigated in 7 stallions. Pulsatile fluctuations in plasma hormone levels were found in the serial blood samples collected hourly for 24 h in all animals. The plasma profiles indicated that corticoids, oestrogens and androgens were secreted episodically at all times in stallions. A significant correlation was observed between the precursor and products of delta 4-ene and delta 5-ene pathways and in inverse correlation (r = -0.68; P less than 0.01) was observe...
McDonnell SM, Garcia MC, Kenney RM.Series of experiments and clinical trials were conducted to evaluate the effects of psychoneurotropic agents on sexual behaviour of stallions. The benzodiazepine derivative, diazepam (Valium), effectively reversed experimentally suppressed precopulatory arousal and response. Diazepam treatment also blocked the negative effect of novel environment on sexual response. The dibenzazepines imipramine and clomipramine induced erection, masturbation, and ejaculation in the absence of a sexual stimulus.
Holley DC, Evans JW.Total and ultrafilterable calcium (Ca) and magnesium (Mg) values were determined for Shetland pony stallions, stallions, and pregnant and diestrous mares, using a simple, inexpensive, quick procedure to obtain an ultrafiltrate of serum. There was no significant difference between horses and ponies, between stallions and mares, or between pregnant and nonpregnant mares. The percentage of total serum Ca that was ultrafilterable was 63.4+/-1.7 for horses and 64.8+/-2.2 for ponies. The percentage of total serum Mg that was ultrafilterable was 75.6+/-1.5 for horses and 77.0+/-1.7 for ponies. Total ...
Baird AN, Frelier PF.A Quarter Horse stallion developed an abscess over the left gluteal region after an IM injection of antihistamine. The wound healed with considerable fibrous scarring and some persistent granulation tissue. The lesion was static for 2 years before the granulation tissue went through a 6-month period of progressive enlargement. At that time, histopathologic diagnosis of squamous cell carcinoma was made from excisional biopsy. Six months after diagnosis, the horse had lost body weight and the lesional diameter had further increased, so the horse was euthanatized.
Hinojosa AM, Bloeser JR, Thomson SR, Watson ED.Relatively little is known about endocrine control of reproduction in the stallion, but gonadotropins are thought to be central in regulating spermatogenesis and libido. The ability to effectively antagonise GnRH, and thereby gonadotropins, is therefore important both in further investigations of hormonal control of reproduction in stallions, and for clinical applications. In the present study four pony stallions were treated with a potent GnRH antagonist, Antarelix. Their libido, seminal parameters, and hormonal profiles were compared with those recorded before administration of the antagonis...
Kosiniak K.The use of an 'open' artificial vagina made it possible to separate the individual jets in the ejaculate of the stallion. A total of 132 jets were collected in this way from twenty-one ejaculates. After macro- and microscopic examination and sperm counting, glycerylphosphorylcholine (GPC), ergothioneine and fructose levels were determined for every jet. The values obtained for the first three jets were similar and accounted for about 76% of all spermatozoa, and 70% of GPC. These jets also contained the highest concentration of ergothioneine and fructose.
Lowe JE, Baldwin BH, Foote RH, Hillman RB, Kallfelz FA.Surgical thyroidectomies (Thx) were per-formed in 6 yearling grade horse colts, (3 males, 3 females). Five control colts (3 males, 2 females) were included and comparative studies were carried out for 67 weeks. The comparative measurements included rectal temperature, heart rate, feed consumption, packed cell volume, serum cholesterol, serum calcium, serum phosphorus, serum TO height, heart girth, body weight, epiphyseal plate closure and tooth eruption times. A thyroprotein supplement was fed to the Thx males during weeks 46 to 53. The Thx animals failed to grow in height, were sensi-tive to ...
Swerczek TW.Small but significant numbers of primary and secondary spermatocytes and spermatids have been observed in the semen of some Thoroughbred stallions. Extensive histological examination of the testes of affected animals has not been undertaken but in one young stallion which died as the result of a leg injury, the premature dehiscence of these cells seemed to be related to segmental defects within the seminiferous tubules. The causes of lesions leading to premature shedding of germ cells are discussed.
Stewart KA, Genetzky RM.Weight loss, poor growth and dysphagia occurred in a young stallion with some teeth missing, and soft, discolored and/or deformed deciduous incisors, premolars and molars. At necropsy, permanent teeth sites were filled with yellow, gelatinous material. Clinical signs suggested fluorosis but laboratory findings did not confirm the diagnosis.
Maurice KT.An 8-year-old mare showed stallion-like behavior and aggressiveness. A granulosa-theca cell tumor was tentatively diagnosed based on history, transrectal palpation, and ultrasonography, and surgically removed. Serological levels of testosterone and inhibin were elevated. Histopathological examination confirmed the diagnosis. The mare recovered and by day 45 could be turned out with other horses. Une jument de 8 ans a manifesté un comportement et de l’agressivité semblables à ceux d’un étalon. Une tumeur de cellule de la granulosa-theca a été provisoirement diagnostiquée, en se fond...
Arighi M, Miller CR, Pennock PW.Scapulohumeral arthrodesis was performed successfully as treatment for severe degenerative arthritis in a 62-kg miniature horse. Using an approach similar to that used for a dog, this horse's scapulohumeral joint was opened, the cartilage was removed, and the site was stabilized, using an 11-hole narrow dynamic compression plate. Fusion was uncomplicated. The stallion became a successful pasture-breeding animal.
Hazard GH, Hughes KL, Penson PJ.Contagious equine metritis (CEM) was first diagnosed in Australia in August 1977 and it has since been found on 6 farms in 3 states, having been isolated from about 24 mares and 2 stallions. Details are given of the epidemiology and control procedures used to combat CEM on one farm. Difficulty was experience in successfully treating one infected stallion; this was thought to be associated with inadequate cleaning and treating of the diverticulum of the urethral fossa. Introduction of the disease has had far-reaching consequences and may well result in the adoption of routine bacteriological te...
Lindeberg H, Kurtén A, Koskinen E, Katila T.The effect of addition of glycine betaine to a lactose-EDTA freezing medium on the post-thaw motility of stallion semen was determined. The first three semen-rich fractions of nine stallions were collected with an open-end Krakow artificial vagina on consecutive weekdays. Semen was frozen using the Hannover method with freezing media containing glycine betaine in various concentrations from 0 to 5%. After thawing, sperm motility was analysed both by a light microscope and by a Hamilton-Thorn Motility Analyser. Total and progressive post-thaw motilities of semen containing 0.25-3% glycine betai...
Lemasson A, Remeuf K, Hausberger M.Animal calls are commonly considered indicators of a sudden change in their arousal state. However, reports evidencing associated internal physiological changes are rare. By homology with human "emotional" vocal productions (e.g., laughter and crying), we predicted that animal vocal productions may result in relaxing tenseness or excitement. In this study, 15 stallions equipped with a heart rate monitor were presented a mare at some distance so as to prevent contact, thereby increasing the males' arousal. Stallions' heart rates increased just before whinnying but returned to baseline rates whi...
Cox JE.The false rig is a castrated horse which shows masculine behaviour of one sort or another. The behaviour patterns reported to the author by owners of such animals and the possible causes are discussed here. Some such horses can show all the behaviour patterns of the entire, including erection and intromission. Evidence is presented that the behaviour is not hormonally induced or hormone dependent. The thesis is put forward that the behaviour shown is part of the normal social interaction between horses and possible treatments are discussed in the light of this possibility.
Battelli G, Galuppi R, Pietrobelli M, Tampieri MP.Fecal examinations of horses (Equus caballus) from studs in the province of Udine (Friuli Venezia Giulia region, east-northern Italy), carried out during two periods of the year 1993, revealed coccidian oocysts in six foals, two stallions and one mare. The species was identified as Eimeria leuckarti. This species was reported only once in Italy, more than 20 years ago (1972). For this reason, the prevalence of the parasite and the description of immature and sporulated oocysts are given.
Tischner M, Kosiniak K, Bielański W.The emission of stallion semen was studied with the aid of
an `open' Krak\l=o'\w-72Model artificial vagina. The pattern of mating
behaviour was constant in all copulations observed : a mean number of
seven intravaginal thrusts was required to elicit ejaculation. The
pressure within the vestibule of the artificial vagina averaged 66 mmHg
at the beginning of copulation, 142 mmHg just before ejaculation, and
70 mmHg during the emission of semen. Emission appeared to be a more
variable process. Five to ten jets were observed; the mean number was
eight. The early jets occurred under high pr...
Pattie WA, Dowsett KF.Fifteen seminal characteristics were measured in ejaculates from 4 laboratory stallions and from 164 commercial stud stallions. Complete field and laboratory data were available from 536 and 531 ejaculates, respectively. These were obtained over 4 breeding seasons (1974/75-1977/78) and 9 breeds were represented. Stallions at commercial studs produced 1-13 ejaculates at intervals of approximately 4 weeks and ranging from 1 h to 1 year apart. Intra-class correlations or 'repeatability' of each seminal characteristic were calculated. Significant between-stallion variation occurred in all characte...
Müller Z.Semen of 16 stallions collected by the fractionated method and frozen in liquid nitrogen was used to inseminate 175 mares of different ages and in various reproductive conditions. Pregnancy was recorded in 91 mares of which 72 delivered a foal. Pregnancy followed by resorption occurred in another 10 mares and 9 aborted. The best results were obtained in the young primiparous and in older mares inseminated in the oestrous cycle that followed the post-partum oestrus. Overall, 64% of mares became pregnant and 56% gave birth to a living foal. The highest occurrence of fetal death and resorption we...
Dodman NH, Shuster L, Court MH, Patel J.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.
