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.
Parillo F, Mancuso R, Vullo C, Catone G.This work was undertaken to determine the glycoconjugates secreted by the epithelium of the prostate in the intact stallion and castrated horse using lectin histochemical procedures in conjunction with enzymatic digestion and deglycosylation treatments. Additionally, anti-5 and 13-16-cytokeratin antibodies were used to localize epithelial basal cells. In the stallion, lectin histochemistry showed the following sugar residues in the Golgi zone of the glandular cells: α-Glu/Man, α-Fuc and β-Gal included in both O- and N-linked oligosaccharides as well as β-GalNAc, GlcNAc and α-Gal, which be...
Benhajali H, Richard-Yris MA, Ezzaouia M, Charfi F, Hausberger M.In order to investigate the factors affecting the reproduction efficiency of Arab breeding mares in Tunisia, breeding data corresponding to 2340 mated cycles, over 5 years (from 2000 to 2004), from 555 mares offspring of 50 sires and bred with 17 stallions were analysed using a multivariate logistic regression. We chose logit link function and binomial distribution and we used log-likelihood-ratio (LL) and Wald tests (X(2)Wald) to test the mean values. The factors of variation included in the model were the year, the stallion, the age of the mare at mating, the sire and the category of the mar...
Ortega Ferrusola C, González Fernández L, Morrell JM, Salazar Sandoval C, Macías García B, Rodríguez-Martinez H, Tapia JA, Peña FJ.Lipid peroxidation (LPO) of stallion spermatozoa was assessed in fresh semen and in samples of the same ejaculates after freezing and thawing. Particular attention was paid to individual differences in the susceptibility to LPO and its possible relationship with freezability. Innate levels of LPO were very low in fresh spermatozoa but increased after thawing, a change that was largely stallion-dependent. The level of LPO in fresh spermatozoa was not correlated with that of the thawed spermatozoa. Negative correlations existed between LPO and intact membranes post-thaw (r=-0.789, P<0.001), a...
Koyago M, Nakada K, Tsunoda N, Moriyoshi M, Sawamukai Y.To clarify the physiological changes of sperm morphology in active Thoroughbred stallions during the breeding season, we examined the dismount semen collected from the penile urethra immediately after service. The spermatozoa were analyzed for relationships between the morphology and the stallion's age or the number of services. Seasonal variation was apparent in the rate of the sperm tail abnormalities, spermatozoa with cytoplasmic droplets, appearance of medusa cells, and sperm head length. Area and width of the sperm head correlated negatively with age (P<0.05). The rate of appearance of...
Ponthier J, Franck T, Detilleux J, Mottart E, Serteyn D, Deleuze S.Despite improvement of techniques, semen of 20% of stallions remains unfreezable. Recent studies focused on the impact of reactive oxygen species and oxidant enzymes on semen characteristics. Myeloperoxidase (MPO) is a pro-oxidant enzyme contained in and released by neutrophils during degranulation or after cell lysis. It is responsible for the formation of hypochlorous acid, a strong oxidant agent, which could damage spermatozoa. The aim of this study was to determine the relation between MPO concentration and characteristics of frozen semen from stallions. Thirty-five straws from different s...
Gómez MD, Goyache F, Molina A, Valera M.The mating policy for Spanish Purebred horses encourages the same or closely related stallions to be used for reproduction across studs differing in environments. Stallions may perform differently across studs, and if so, adjustment for the sire x stud (ss) interaction is recommended. However, there are no studies available that analyzed the influence of ss interaction on estimation of genetic parameters in horses. This research is aimed at assessing the implications of including ss interaction in models fitted for the estimation of genetic parameters for traits under selection using 8 body me...
Deleuze S, Goudet G, Caillaud M, Lahuec C, Duchamp G.In vivo techniques, such as intraoviductal oocyte transfer (OT) and intrafollicular oocyte transfer (IFOT), can be considered as alternatives to bypass the lack of efficient superovulation treatments and the inadequacy of conventional in vitro fertilization techniques in the horse. We compared embryo production after transfer of in vivo recovered oocytes (1) into a recipient's oviduct or (2) into her preovulatory follicle either immediately after ovum pick-up or (3) after in vitro maturation (IVM). Recipients were inseminated with fresh semen of a stallion with a known normal fertility. Ten da...
Van Grevenhof EM, Ducro BJ, Van Weeren PR, Van Tartwijk JM, Van den Belt AJ, Bijma P.Osteochondrosis (OC) is the most important orthopaedic developmental disorder in horses and may manifest in several different forms. No detailed study on the prevalence and/or interrelation of these forms is available, even though these data are a prerequisite for conclusive genetic studies. Objective: To assess the prevalence of the various manifestations of OC as detected radiographically and to evaluate possible relationships between their occurrence within the same joint and between different joints. Methods: The FP (femoropatellar), TC (tarsocrural) and MCP/MTP (metacarpophalangeal/metata...
Morrell JM, Dalin AM, Rodriguez-Martinez H.A new, simpler, technique of colloidal centrifugation has recently been developed, designated single layer centrifugation (SLC). This technique requires evaluation by comparison with a density gradient for its ability to select the best quality spermatozoa and its practicality of use on studfarms. Objective: To compare the effect of 2 methods of colloidal centrifugation, density gradient centrifugation and single layer centrifugation, on stallion sperm motility, yield and survival, using freshly collected extended stallion semen. Methods: Aliquots of extended stallion semen from 10 stallions (...
Verwilghen D, Busoni V, Gangl M, Franck T, Lejeune JP, Vanderheyden L, Detilleux J, Grulke S, Deberg M, Henrotin Y, Serteyn D.Establishing the osteoarticular status of the horse is often performed by means of radiological screening of the animals. Widespread blood sampling could reveal to be an interesting alternative to this procedure which is time consuming and sometimes technically difficult. The aim of this study was to investigate the relationship between the radiological status of the horses and the levels of biochemical markers of cartilage degradation and synovial inflammation. A specific radiological scoring and classification system was therefore developed and applied on 63 stallions presented for studbook ...
Hebia-Fellah I, Léauté A, Fiéni F, Zientara S, Imbert-Marcille BM, Besse B, Fortier G, Pronost S, Miszczak F, Ferry B, Thorin C, Pellerin JL....In the horse, the risk of excretion of two major equine pathogens (equine herpesvirus types 1 (EHV-1) and 4 (EHV-4)) in semen is unknown. The objective of our study was to assess the possible risks for the horizontal transmission of equine rhinopneumonitis herpesviruses via the semen and the effect of the viruses on stallion fertility. Samples of stallion semen (n=390) were gathered from several different sources. Examination of the semen involved the detection of viral DNA using specific PCR. The mean fertility of the stallions whose sperm tested positive for viral DNA and the mean fertility ...
González-Fernández L, Ortega-Ferrusola C, Macias-Garcia B, Salido GM, Peña FJ, Tapia JA.Protein tyrosine kinases have important roles in spermatozoa; however, little is known about the presence and regulation in these cells of their counterparts in signaling, namely, protein tyrosine phosphatases (PTPs) and dual-specificity phosphatases (DSPs). The objectives of the present study were to identify PTPs and DSPs in boar, stallion, and dog spermatozoa; to characterize their subcellular distribution; and to investigate the roles of tyrosine phosphatases in maintenance of protein tyrosine phosphorylation level and in sperm motility. Using Western blotting with specific antibodies in b...
Giesecke K, Hamann H, Stock KF, Woehlke A, Sieme H, Distl O.Stallion fertility is an economically important trait because the use of artificial insemination is increasing in the horse industry and superior sires are used more intensely. Molecular genetic markers may be useful as early indicators for a stallion's fertility and genetic improvement programmes. The testis-specific SPATA1 protein is involved in shaping the sperm head during spermatogenesis. Thus, the spermatogenesis associated 1 (SPATA1) gene was chosen as candidate for stallion fertility, and we analysed intragenic single nucleotide polymorphisms (SNPs) as genetic markers for the least squ...
McPartlin LA, Suarez SS, Czaya CA, Hinrichs K, Bedford-Guaus SJ.Capacitation is a complex and not well-understood process that encompasses all the molecular changes sperm must undergo to successfully fertilize an oocyte. In vitro fertilization has remained elusive in the horse, as evidenced by low in vitro fertilization (IVF) rates (0%-33%); moreover, only two foals have ever been produced using IVF. Incubation of stallion sperm in modified Whittens supplemented with bovine serum albumin and sodium bicarbonate yielded significant rates of time-dependent protein tyrosine phosphorylation and induced acrosomal exocytosis, consistent with capacitation. The obj...
Hendricks KE, Hansen PJ.Apoptosis is common during spermatogenesis. Here, it was tested whether apoptosis could be induced in sperm after ejaculation. There were several lines of evidence to indicate that sperm are resistant to induction of apoptosis. First, incubation of bull sperm at temperatures characteristic of normothermia (38.5 degrees C) or heat shock (40 and 41 degrees C) for 4h did not increase the proportion of sperm positive for the TUNEL reaction. There was also no reduction in mitochondrial polarity caused by exposure to 40 or 41 degrees C. Incubation at 38.5 degrees C (least-squares mean+/-SEM=4.0+/-1....
Johannisson A, Morrell JM, Thorén J, Jönsson M, Dalin AM, Rodriguez-Martinez H.The objective was to investigate the changes in stallion sperm quality (sperm motility, viability, membrane integrity and chromatin integrity) occurring during cool storage, and to study the effect of sperm selection by single layer colloidal centrifugation on these parameters of sperm quality. Spermatozoa from 3 stallions (10 ejaculates, 3-4 per stallion) were selected by centrifugation through a single layer of colloid (SLC). The resulting sperm preparations and the control samples (extended but unselected semen samples) were stored at 5 degrees C for 48h. Assessments of sperm quality, such ...
Brito LF, Kelleman A, Greene LM, Raz T, Barth AD.A 5-year-old Arabian stallion was managed for breeding with fresh/extended semen during a period of 8 months with a resulting per cycle pregnancy rate of 26.3%. The stallion was in good health and no abnormalities of the reproductive tract were observed. Evaluation of several ejaculates revealed that sperm production and semen quality were mostly unchanged during the period of evaluation, that sperm production was normal and that semen quality was extremely poor. The most prevalent sperm defects were abnormal heads and mid-pieces. Most abnormal heads were microcephalic and/or tapered and consi...
Bugno-Poniewierska M, Jabłońska Z, Słota E.Fluorescence in situ hybridization (FISH) is widely used in the study of chromosome structure and organization. Cytogenetic evaluation of chromosomes using FISH technique plays an increasingly important role in diagnosing karyotype changes in both somatic and reproductive cells. The aim of the study was to optimize the conditions of stallion sperm decondensation, which have a significant effect on the results of fluorescence in situ hybridization. Appropriate type and time of decondensation was chosen for the sperm of every stallion. It was found that decondensation performed using a preparati...
Mari G, Rizzato G, Merlo B, Iacono E, Bucci D, Seren E, Tamanini C, Galeati G, Spinaci M.Little information is available on the quality of stallion spermatozoa after sex sorting. The objectives of the present study were to assess the quality of sex-sorted stallion spermatozoa and determine its fertilizing ability after hysteroscopic low dose insemination. Ejaculates from four stallions were collected and sorted by a MoFlo SX flow cytometer/sperm sorter. Before and after sorting, spermatozoa were evaluated for motility by Computer Assisted Sperm Analysis, viability (SYBR 14-propidium iodide), mitochondrial function (JC-1) and acrosomal status (fluorescein isothiocyanate Pisum sativ...
Bucci D, Isani G, Spinaci M, Tamanini C, Mari G, Zambelli D, Galeati G.Spermatozoa, as other eukaryotic cells, need hexoses to produce energy to maintain membrane homeostasis, to move along the female genital tract and to carry the male genome to the female gamete. GLUTs are a family of proteins that permit and improve the passive transport of hexoses inside cells. This study was aimed at investigating the presence and localization of GLUTs 1, 2, 3 and 5 in boar, stallion and dog spermatozoa by both immunofluorescence and western blotting. GLUTs exhibited a peculiar distribution along the sperm cell depending on the isoforms considered, the hexose they transport ...
Corona A, Cherchi R.Bacteriological surveillance is little applied in management of equine frozen semen but it is quite important to verify the microbial contamination in order to find out the chance of transmission of pathology to the mare in AI. Authors describe a qualitative and quantitative analysis for bacterial contamination on long time (3-17 years) equine frozen semen stored in liquid nitrogen. The semen checked, produced in Italy and in another Europe country, was cryopreserved in liquid nitrogen inside sealed plastic straws. One hundred and ten straws were checked out for pathogenic and no pathogenic ba...
Ortega-Ferrusola C, Macías García B, Suárez Rama V, Gallardo-Bolaños JM, González-Fernández L, Tapia JA, Rodríguez-Martinez H, Peña FJ.In an attempt to improve the information obtained after computer-assisted sperm analysis (CASA), data from five stallions (three ejaculates from each) were analysed before (fresh, extended semen) and after cryopreservation using traditional statistics as well as a cluster analysis. The data matrix consisted of 13 987 observations of individual spermatozoa for fresh, extended semen, and 8305 for frozen-thawed samples. As expected, freezing and thawing resulted in a marked decrease of CASA-derived variables of sperm kinematics. All sperm velocities were significantly lower in frozen-thawed sampl...
Gray ME.Infanticide by adult males occurs in a variety of species. While infanticidal attacks have been documented in several equid species in captivity, it has never been witnessed in free-roaming feral horses. I report an infanticide attempt by a free-living feral stallion on a recently born female foal. The stallion picked up the foal by the shoulders, tossed it around twice and bit in on the neck several times. The dam of the foal charged the stallion and successfully protected her foal from additional attacks. The foal survived the attack and later weaned successfully. The stallion recently took ...
Janett F, Stump R, Burger D, Thun R.The aim of this study was to evaluate the effects of an anti-GnRH vaccine on testosterone concentration, antibody titer, scrotal width, semen quality and sexual behavior in the stallion. Adverse reactions to the vaccine were also determined. Eight clinically healthy sexually experienced stallions aged between 6 and 15 years from the National Stud in Avenches (Switzerland) were used. Five stallions were immunized 3 times at an interval of 4 and 8 weeks, respectively, with 200 microg of a GnRH-protein conjugate (Equity, CSL Limited, Australia) intramuscularly in the neck and 3 control animals re...
Sleeper MM, McDonnell SM, Ely JJ, Reef VB.Enalapril is an angiotensin converting enzyme (ACE) inhibitor that is frequently used in human, feline and canine patients with cardiac disease. Its use has been associated with impotence in human patients. The purpose of this study was to evaluate if enalapril (0.5mg/kg PO, q24h) is likely to alter behavior in stallions and to assess its effect on ACE activity at the standard dose used in dogs and cats. Twelve pony stallions were evaluated by physical examination and echocardiography followed by treatment with enalapril (n=6) or placebo (n=6) for 2 months. After one month, blood was drawn and...
Goudah A, Abo El-Sooud K, Shim JH, Shin HC, Abd El-Aty AM.The target of the present study was to investigate the plasma disposition kinetics of levofloxacin in stallions (n = 6) following a single intravenous (i.v.) bolus or intramuscular (i.m.) injection at a dose rate of 4 mg/kg bwt, using a two-phase crossover design with 15 days as an interval period. Plasma samples were collected at appropriate times during a 48-h administration interval, and were analyzed using a microbiological assay method. The plasma levofloxacin disposition was best fitted to a two-compartment open model after i.v. dosing. The half-lives of distribution and elimination were...
Cortés-Gutiérrez EI, Crespo F, Serres-Dalmau C, Gutiérrez de las Rozas AL, Dávila-Rodríguez MI, López-Fernández C, Gósalvez J.Sperm DNA fragmentation (sDF) is an important parameter to assessing sperm quality. Information about sperm quality is not available for donkeys, especially in some breeds at risk of extinction. The objectives of this research were to test the four commercial variants of sperm chromatin dispersion test (SCD; sperm Halomax test), originally developed to assess sDF in boars, bulls, rams and stallions, in order to scrutinize their applicability in the study of sDF in a donkey breed at risk of extinction (Zamorano-Leonesa), for which there is no specific test available to analyze sperm at present....
Brito LF, Engiles JB, Turner RM, Getman LM, Ebling A.An 18-year-old Friesian stallion was examined approximately one week after reportedly presenting scrotal swelling due to torsion of the spermatic cords. Upon presentation no scrotal swelling was noted, the testes were normally oriented, and no abnormalities of the spermatic cords were noted. However, both testes were smaller than expected for a mature stallion and deep palpation revealed that the consistency of the testes was nodular. Ultrasonographic evaluation of the testes revealed diffuse heterogeneous parenchyma with multiple hypoechoic nodular areas. Grossly, the testicular parenchyma wa...
Gardiner DW, Teifke JP, Podell BK, Kamstock DA.An 18-year-old Arabian stallion was presented for recent onset of stranguria. Physical examination of the distal portion of the glans penis revealed multiple, smooth, glistening, grayish-pink, variably sized, exophytic, nodular masses circumferentially surrounding the external urethral orifice. Partial penile amputation was performed, and the entire specimen was submitted for histological evaluation. Microscopically, the masses consisted of abundant amounts of loosely arranged fibrovascular stroma with low numbers of spindloid to stellate fibrocytes. The overlying epithelium was mildly to mode...
Koyago M, Nakada K, Tsunoda N, Moriyoshi M, Sawamukai Y.The morphology of spermatozoa of modern Thoroughbred stallions in Japan was investigated during the breeding season. A total of 299 semen samples were collected from the penises of 16 stallions immediately after service. The rate of abnormalities in sperm heads and tails, spermatozoa with cytoplasmic droplets and slides with medusa cells to total observed slides in each stallion were 3.9 +/- 2.1%, 11.5 +/- 5.9%, 2.4 +/- 2.6% and 20.1%, respectively. The values for the area, length, width and aspect ratio of the stallion sperm head were 12.54 +/- 1.34 microm(2), 5.93 +/- 0.40 microm, 2.69 +/- 0...
Balao da Silva C, Macías-García B, Morillo Rodriguez A, Gallardo Bolaños JM, Tapia JA, Aparicio IM, Morrell JM, Rodriguez-Martínez H....The only known means of effectively separating populations of X and Y bearing sperms is the Beltsville sexing technology. The technology implies that each individual sperm is interrogated for DNA content, measuring the intensity of the fluorescence after staining the spermatozoa with Hoechst 33342. Because there are no data regarding the effect of the staining on stallion sperm, ejaculates were incubated up to 90 min in presence of 0, 4.5, 9, 22.5, 31.5, 45, 54, 67.5, 76.5 and 90 μM of Hoechst 33342, in two media, KMT or INRA-Tyrodes. After 40 and 90 min of incubation, motility (CASA) and mem...
Ewert M, Lüders I, Böröcz J, Uphaus H, Distl O, Sieme H.The aim of the present study was to analyze the effects of stallion and mare, their ages, and maternal lineage on the gestation length (GL) in Thoroughbreds. In addition, additive genetic effects of the dam, stallion and fetus were analyzed. Data were taken from 1993 through 2009, and included 16,226 pregnancies from 5959 Th oroughbred mares mated with 290 different stallions. All analyses were performed using linear mixed models. The GL ranged from 306 to 390 days, with a mean length of 347.0 ± 14.4 days. Mating of mares with stallions aged 17 years and older resulted in a significantly ...
Driessen B, Zarucco L, Kalir B, Bertolotti L.Current use of acepromazine in the anaesthetic management of male horses and ponies and associated risks are largely unknown. Objective: To explore anaesthetic acepromazine use and related adverse effects in the male horse. Methods: Of 8533 anaesthetised horses and ponies medical records of male animals treated perianaesthetically with acepromazine were reviewed. Demographic data, time and dose of acepromazine administration, co-administered drugs, quality of induction and recovery from anaesthesia, arterial blood pressures, and occurrence of penile dysfunction were recorded. Practising ACVA a...
Sousa AS, Jesus IIC, Araújo Oliveira CA, Costa RB, de Godoi FN.The aim of this study was to evaluate the morphometric measurements of stallion and mares show-winning and nonwinning Campolina breed with batida and picada gaits. A total of 167 horses (74 stallions and 93 mares), consisting of 102 batida and 65 picada gait animals, were used. Among these horses, 96 were awarded and 71 were not. Twenty linear, seven angular, and 11 girth measurements were taken. Results from the judging sessions were collected, and awards were observed in both sexes and both gaits. A descriptive statistical analysis and an analysis of variance were performed using the MEANS s...
Brinsko SP, Rowan KR, Varner DD, Blanchard TL.This study was conducted to compare the cooling rates and storage temperatures within equine semen transport containers exposed to different ambient temperatures, and to evaluate the ability of these containers to preserve spermatozoal motility following 24 h of storage under these conditions. In Experiment 1, nonfat dried milk solids, glucose, sucrose, equine semen extender was divided into seven 40-mL aliquots and loaded into seven different semen transport containers: Equitainer I, Equitainer II, Equitainer III, ExpectaFoal, Bio-Flite, Lane STS, and Equine Express. After containers were loa...
Varner DD, Blanchard TL, Meyers PJ, Meyers SA.A breeding trial was conducted to evaluate the effect of in vitro storage time and temperature on fertilizing capacity of equine spermatozoa. Semen obtained from one stallion and diluted with skim milk-glucose extender was used to artificially inseminate 45 estrussynchronized mares. The mares were assigned to one of three treatment groups (15 mares per group): 1) insemination with fresh semen (collected within 0.5 h of use), 2) insemination with semen stored for 24 h at 20 degrees C or 3) insemination with semen stored for 24 h at 5 degrees C. The mares were inseminated daily during estrus, fr...
Mawyer JD, Cavinder CA, Vogelsang MM, Sigler DH, Love CC, Brinsko SP, Blanchard TL, Varner DD, Arnold CE, Teague S, Gordon RK.Stallions (n = 8) were implanted with a thermal sensory device in the muscle of the neck and the subcutaneous tissue of the scrotum and then assigned to either a nonexercise (Non-EX; n = 4) or exercise (EX; n = 4) group. A motorized equine exerciser was used to work EX stallions 30 min/d for 4 d/wk during a 12-wk period from July through October 2010. Temperatures (subcutaneous scrotal, intramuscular neck, and rectal) were recorded at 0, 22, and 30 min after the start of exercise, as well as 60 and 120 min post-exercise. Hourly ambient temperature and relative humidity data were also obtained....
Moura TCM, Arruda LCP, Araújo Silva RAJ, Silva RPF, Oliveira AS, Tobal LFM, Batista AM, Carneiro GF, Guerra MMP.The aim of this study was to investigate the effects of sucrose on post-thawed equine semen quality. Semen samples (n = 24) were collected from six stallions. They were diluted (200 × 10 sperm/mL) in a freezing medium based on skimmed milk, egg yolk, dimethylformamide, and supplemented with sucrose at concentrations of 0 (Control), 25, 50, and 100 mM and in a commercial extender (BotuCrio). Subsequently, they were filled in straws (0.5 mL) and subjected to freezing and storage (-196°C). Immediately after thawing (37°C, 30 seconds), semen samples were evaluated for kinetics (CASA), plasm...
Marr CM, Reef VB.Colour flow Doppler echocardiographic examinations were performed on 15 horses; 10 Thoroughbreds and 5 Standardbreds; 9 mares, 5 geldings and 1 stallion; mean +/- s.d. 3.4 +/- 1.1 years. Cardiac murmurs were audible in 12 horses (80%), but these had characteristics consistent with functional murmurs in all horses. A standardised two-dimensional (2-D) and M-mode echocardiographic examination was unremarkable in all horses except that aortic valve prolapse was identified in 3 horses, tricuspid valve prolapse in 2 horses and mitral valve prolapse was present in one horse. Colour flow Doppler echo...
Guillaume D, Moussu C, de Geoffroy F, Chesneau D, Keller M.Stallions show decreased sexual responses and activities during short days in winter. To evaluate the importance of sexual olfactory communication in horses, we tested whether sexual responses could be stimulated through various sexual olfactory stimulations in winter. To this end, we presented stallions with various olfactory stimulations (urine from mares at different stages of the reproductive cycle, urine from stallions or geldings, or chemically defined synthetic odorant) during the non-breeding season and measured their behavioral responses through (1) a test of olfactory investigation (...
Johannisson A, Lundgren A, Humblot P, Morrell JM.The decrease in foaling rates after artificial insemination with cooled semen warrants the search for new predictors of fertility. The objectives were to investigate levels of naturally occurring reactive oxygen species (ROS) in cooled, stored stallion semen doses for artificial insemination (AI), and their relationship with parameters of semen quality and with pregnancy rate. Semen was collected from warmblood stallions (n=15) and used to prepare commercial semen doses for AI. Sperm quality was evaluated after cooled transport to the laboratory overnight. The results were correlated with obse...
Heckenbichler S, Deichsel K, Peters P, Aurich C.Stallion semen processing is far from standardized and differs substantially between AI centers. Suboptimal pregnancy rates in equine AI may primarily result from breeding with low quality semen not adequately processed for shipment. It was the aim of the study to evaluate quality and fertility of cooled-shipped equine semen provided for breeding of client mares by commercial semen collection centers in Europe. Cooled shipped semen (n = 201 doses) from 67 stallions and 36 different EU-approved semen collection centers was evaluated. At arrival, semen temperature was 9.8 ± 0.2 °C, mean sperm ...
Manning AW, Rajkumar K, Bristol F, Flood PF, Murphy BD.The variation in the quantity of circulating chorionic gonadotrophin (CG) and its follicle-stimulating hormone (FSH) and luteinizing hormone (LH) activity in rodent bioassay systems was investigated. A portion of the variability in total CG could be attributed to the stallion that sired the pregnancy and it was possible to select sires and mares to increase CG production. It was further demonstrated that FSH activity per unit of CG was greater at Days 71 and 104 of gestation than at Day 39. LH activity per unit of CG varied with the sire, but no effect of day of gestation could be shown. It wa...
Clay CM, Clay JN.The seasonal reproductive cycle of stallions is characterized by an annual regression and recrudescence in testicular function and concentrations of LH, FSH, and testosterone in serum. Maximum reproductive capacity occurs during the increasing day lengths of spring and summer. The annual cycle in LH secretion may reflect a seasonally associated and photosensitive reduction and replenishment in pituitary content of LH. Similar to other seasonal breeders, it appears that stallions may possess an endogenous circannual rhythm in reproductive function that is subject to manipulation by altering the...
Gonzalez-Castro RA, Carnevale EM.Limited clinical information is available regarding sperm population parameters that are important for use with equine intracytoplasmic sperm injection (ICSI). Therefore, the appropriateness of a sample of sperm is typically not known before ICSI. The aim of our study was to determine which sperm population characteristics were predictive of ICSI outcome. Frozen-thawed sperm samples (n = 114) from 37 stallions in a clinical program were analyzed after ICSI for percentages of normal morphology (MORPH+), live as assessed by eosin/nigrosin stain (LIVE+), membrane intact as assessed by hypoosmot...
Podico G, Ellerbrock RE, Curcio BR, Cheong SH, Lima FS, Canisso IF.Urospermia is a major ejaculatory dysfunction affecting stallions. It has been thought that urine-contaminated semen should not be cryopreserved; however, on select cases, urine contamination of semen cannot be avoided. A recent study suggested that urospermic semen can be cryopreserved after cushion centrifugation and extension. Thus, this study aimed to assess the use of single-layer colloid centrifugation (SLC) to process frozen-thawed urine-contaminated stallion semen. Raw ejaculates (n = 55) from eight stallions were split into three groups: no urine, low (20%), or high (50%) urine conta...
Vigolo V, Gautier C, Falomo ME, Aurich C.The use of microfluidic technology is increasing in artificial reproduction technologies: With a small amount of semen, it allows for the selection of sperm with the best characteristics of kinetics, morphology and chromatin integrity. The ZyMot Multi (850 μl) is the most popular device of ZyMot Fertility Inc. To date, it was proven to be a valid instrument for sperm selection for in vitro fertilization and intracytoplasmic sperm injection in men. The aim of this study was to test the efficacy of the ZyMot Multi (850 μl) for stallion semen. Frozen-thawed semen from 15 stallions that were...
Jantosovicová J, Jantosovic J.To study the vascularization of the testis of stallions we used 96 testes. We examined its topography and anatomy by roentgenography, stereoroentgenography, by the corosive method, and by means of gel and China ink injections. To make the roentgeno-arteriograms we used minimum emulsified in glycerine as contrast medium. The branching off of the Aa. testiculares from the Aorta abdominalis is variable in stallions. We observed also a peculiar age-dependent arrangement of the loops of the convolution. In the adult stallion, the shape of the convolution is either cylindrical or conical, spindle-sh...
Dobrinski I, Ignotz GG, Fagnan MS, Yudin SI, Ball BA.The periacrosomal plasma membrane of spermatozoa is involved in sperm binding to oviductal epithelial cells and to the zona pellucida. A protein of 68-70 kD molecular mass was purified biochemically from the isolated periacrosomal plasma membrane of equine spermatozoa as a possible receptor for adhesion of spermatozoa to oviductal epithelial cells. A polyclonal antibody raised in rabbits against the purified equine sperm membrane protein recognized the 70 kD and an antigenically related to 32 kD protein in preparations of isolated periacrosomal sperm plasma membrane and in detergent extracted ...
Murase H, Saito S, Amaya T, Sato F, Ball BA, Nambo Y.Anti-Müllerian hormone (AMH), a glycoprotein secreted from the fetal testis, is responsible for regression of the Müllerian duct in the male fetus. The aim of this study was to evaluate the usefulness of serum AMH as a biomarker for diagnosis of cryptorchidism in horses. Serum AMH concentrations were measured in intact stallions, hemi-castrated unilateral cryptorchid stallions, and geldings. In addition, expression of AMH was characterized in cryptorchid testes by immunohistochemistry. Serum AMH was detected in intact stallions (n=11, 13.3 ± 1.8 ng/ml) and in hemi-castrated cryptorchid stal...
Gutiérrez-Cepeda L, Crespo F, Blazquez JC, Serres C.The Purebred Spanish Horse, according to our clinical experience, is characterized by having a high number of stallions that do not meet the international commercial recommendations for equine-sperm cryopreservation. This means that artificial insemination with frozen semen from these stallions is less widespread than in other breeds. In this study, we investigated if the incorporation of single-layer colloidal centrifugation prior to cryopreservation in clinical conditions could increase the number of ejaculates of Purebred Spanish stallions suitable for this processing, observing the influen...
Luthersson N, Ýr Þorgrímsdóttir Ú, Harris PA, Parkins T, Bennet ED.To investigate equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD) in Icelandic horses moving from pasture into training. 81 horses (median age, 3 years; interquartile range, 1 year) from 10 farms representing 4 different Icelandic regions. Initial gastroscopy was undertaken within 2 weeks of moving from pasture into a training establishment. A total of 71 horses underwent endoscopic examination again 8 weeks later. Various management and behavioral factors were assessed through face-to-face questionnaires with the owners or trainers. Multivariable logistic regre...
de Vasconcelos Franco JS, Faheem M, Chaveiro A, Moreira da Silva F.The effects of supplementation of α-tocopherol and different freezing rates (FRs) on the ability of stallion sperm to fertilize bovine oocytes with intact zona pellucida were investigated, in an attempt to develop a model to assess cryopreserved sperm function. Semen was obtained from four purebred Lusitano stallions (n = 4). Each ejaculate was subjected to cryopreservation with a commercial extender (Ghent, Minitub Iberia, Spain), without any supplementation (control) or supplemented with 2-mM α-tocopherol. The semen was exposed to two different FRs between 5 °C and -15 °C: slow (5 °C...
Trumble TN, Hendrickson DA.Standing laparoscopy in the horse was used initially as a diagnostic tool to assist in the diagnosis of a cryptorchid testicle. Now, this technique is also used for treatment of cryptorchid testicles. The focus of this article is the standing laparoscopic cryptorchidectomy, the most common laparoscopic procedure performed on the male equine urogenital tract. Advantages, disadvantages, instrumentation, and general procedure are discussed.
Terada M, Momozawa Y, Komano M, Kusunose R, Sato F, Saito TR. The physiological indexes of the copulatory behavior of the stallion have not been investigated in detail and may differ from those of other species, such as humans and rats. In order to understand the breeding capability of various stallions, their behavior during copulation was observed, and heart rate (HR) and the plasma concentrations of norepinephrine (NA) and epinephrine (Ad) were measured sequentially for a total of 13 copulations carried out during 2 days. The mean HR at rest was 35.3 ± 0.9 beats per minute (b.p.m.) and it peaked during mounting (162.1 ± 5.4 b.p.m.). The HR a...
Sairanen J, Katila T, Virtala AM, Ojala M.Racing and fertility are connected with each other in many ways. Stress and increased body temperature induced by racing may have negative effects on fertility, but on the other hand, high quality nutrition and management of racing horses may have positive effects. Fertility may also be genetically associated with racing performance. The analysed data consisted of Finnish mating records of Standardbreds (n=33,679) and Finnhorses (n=32,731), from 1991 to 2005, and the harness racing records of both mares and stallions. Fertility was measured by foaling outcome, and racing performance was measur...
Johannisson A, Figueiredo MI, Al-Kass Z, Morrell JM.An improved fertility prediction for stallions is of importance for equine breeding. Here, we investigate the potential of a combined staining of stallion spermatozoa for superoxide and mitochondrial membrane potential (MMP) for this purpose. Semen samples were analysed immediately after arrival at the laboratory, as well as after 24 h. Superoxide was measured by MitoSOXRed, while MMP was measured with JC-1. Menadione was used to stimulate superoxide production. In addition, other parameters of sperm quality, namely motility, membrane integrity, chromatin integrity, sperm kinematics and Hoec...
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...
Al-Khaldi K, Yimer N, Al-Bulushi S, Haron AW, Hiew M, Babji AS.The aim of this study was to evaluate the effects of adding different concentrations of edible bird's nest (EBN) which is secreted by swiftlet birds (), into EquiPlus® and E-Z Mixin® extenders on the quality of chilled Arabian stallion semen at various storage times (0, 24 and 48 h). Ten ejaculates were collected from five stallions, and diluted using the two extenders containing 0% (control), 0.12%, 0.24% and 0.24% of EBN + seminal plasma (SP). All the diluted semen samples were then cooled and stored at 5 °C, and examined at 0, 24 and 48 h. Sperm kinetic parameters were assessed using com...
Palmer E, Chavatte-Palmer P.Reproductive technologies aim at improving fertility with the ultimate result of improving genetic selection. In equidae, the respective contribution of different methods of horse management and breeding to genetic progress remain difficult to evaluate as breeding strategies affect the number of offspring per mare or stallion whereas different selection methods (based on pedigree, performance, genomics or progeny's performance) will be applicable at different ages, leading to different accuracy in the estimation of the breeding value. Here, a mathematical model was applied to evaluate theoreti...
