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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.
Toxic effects induced by mycotoxin fumonisin B1 on equine spermatozoa: assessment of viability, sperm chromatin structure stability, ROS production and motility. Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium species that exerts its toxic effect through interference with the sphingolipid pathway by inhibiting ceramide synthase. A FB1-dependent sperm toxicity was reported in boars. No information on FB1-related reproductive toxicity in stallions, the most sensitive animal species, has been reported. The aim of the present study was to assess the in vitro toxicity of FB1 on fresh and frozen-thawed equine spermatozoa by analyzing sperm viability, chromatin stability (SCSA) and reactive oxygen species (ROS) production by flow cytometry and sperm mo...
Effects of semen storage and separation techniques on sperm DNA fragmentation. To determine the effect of semen storage and separation techniques on sperm DNA fragmentation. Methods: Controlled clinical study. Methods: An assisted reproductive technology laboratory. Methods: Thirty normoozospermic semen samples obtained from patients undergoing infertility evaluation. Methods: One aliquot from each sample was immediately prepared (control) for the sperm chromatin dispersion assay (SCD). Aliquots used to assess storage techniques were treated in the following ways: snap frozen by liquid nitrogen immersion, slow frozen with Tris-yolk buffer and glycerol, kept on ice for 24...
Membrane permeability parameters for freezing of stallion sperm as determined by Fourier transform infrared spectroscopy. Cellular membranes are one of the primary sites of injury during freezing and thawing for cryopreservation of cells. Fourier transform infrared spectroscopy (FTIR) was used to monitor membrane phase behavior and ice formation during freezing of stallion sperm. At high subzero ice nucleation temperatures which result in cellular dehydration, membranes undergo a profound transition to a highly ordered gel phase. By contrast, low subzero nucleation temperatures, that are likely to result in intracellular ice formation, leave membrane lipids in a relatively hydrated fluid state. The extent of free...
Initial occurrence of Taylorella asinigenitalis and its detection in nurse mares, a stallion and donkeys in Kentucky. In 1998, a newly identified bacterium Taylorella asinigenitalis was isolated from the external genitalia and reproductive tracts of nurse mares, a stallion and donkey jacks in Kentucky. An extensive regulatory effort was implemented to contain the outbreak including the tracing and testing of 232 horses and donkeys on 58 premises. T. asinigenitalis was isolated from the reproductive tract of 10 adult equids, including two donkey jacks, one Paint Quarter-horse stallion and seven draft-type breeding mares. None of the infected horses had clinical signs of reproductive tract disease. The odds of ...
Membrane lipids of the stallion spermatozoon in relation to sperm quality and susceptibility to lipid peroxidation. Lipids were extracted from ejaculated spermatozoa from seven individual stallions to distinguish neutral lipids (NL) and polar lipids (PL) and determine their variation among stallions and their relationship with sperm quality and sperm susceptibility to lipid peroxidation. The isolated fatty acids were correlated with sperm quality (membrane integrity, mitochondrial membrane potential (ΔΨm) and expression of active caspases) and the sensitivity of the sperm plasma membrane to LPO. The miristic (C14: 0), palmitic (C16: 0), stearic (C18: 0) and oleic (C18: 1n9) acids were predominant among th...
Selenium in blood, semen, seminal plasma and spermatozoa of stallions and its relationship to sperm quality. The essential trace element selenium is indispensable for male fertility in mammals. Until now, little data existed regarding the relationship between selenium and sperm quality in the stallion. Selenium, or selenium-dependent glutathione peroxidase activity, was determined in red blood cells, semen, seminal plasma and spermatozoa, and the percentages of spermatozoa with progressive motility (PMS), intact membranes (PMI), altered (positive) acrosomal status (PAS) and detectable DNA damage, determined by the sperm chromatin structure assay, were evaluated in 41 healthy stallions (three samples ...
Inhibition of the mitochondrial permeability transition pore reduces “apoptosis like” changes during cryopreservation of stallion spermatozoa. In order to evaluate to what extent the changes that occur during cryopreservation involve the mitochondrial permeability transition pore (PT-pore), a specific inhibitor was used during the cryopreservation process of stallion spermatozoa. Four ejaculates from each of 7 stallions were frozen using a standard protocol. Before freezing, each ejaculate was split into three subsamples. The first was supplemented with 2.5 microM bongkrekic acid (BA) and the second with 5 microM BA. The third subsample served as control. The BA significantly reduced the percentage of spermatozoa depicting active cas...
Administration of perioperative penicillin reduces postoperative serum amyloid A response in horses being castrated standing. To compare postoperative inflammatory responses in horses administered perioperative procaine penicillin and those not administered penicillin using acute phase protein serum amyloid A (SAA) as a marker of inflammation. Methods: Randomized clinical trial. Methods: Stallions (n=50) castrated under field conditions. Methods: SAA concentrations were determined on days 0, 3, and 8. Six horses were subsequently excluded because of elevated SAA concentrations on day 0. Of the remaining 50 horses, 26 were administered nonsteroidal anti-inflammatory drug (NSAID) therapy and 24 were administered NSAID ...
Post-anaesthetic myelopathy in a 3-year-old Friesian gelding. A 3-year-old Friesian stallion was referred to the Department of Equine Sciences at Utrecht University with signs of colic. Laparotomy was performed and the stallion was castrated bilaterally because of an incarcerated inguinal hernia. Intestinal resection was not performed. Eight days postoperatively, the horse showed signs of severe colic and was admitted for re-laparotomy. After resection of 1.5 m of strangulated jejunum and severe intraoperative hypotension, bradycardia, and electrolyte disorders, the horse showed problems during recovery with signs of hindquarter paralysis. There was no p...
Seasonal variation of plasminogen activator activity in spermatozoa and seminal plasma of boar, buck, bull and stallion. Plasminogen activators (PA) are proteolytic enzymes present in the spermatozoa and seminal plasma of various species. They play a role in the binding of the spermatozoon and its penetration through the layers surrounding the oocyte. Plasminogen activator activity (PAA) is modulated by hormones that have a seasonal variation, such as testosterone and melatonin. The present study investigates the seasonal variation of PA activity in sperm extracts and seminal plasma of four farm animal species: boar, buck, bull and stallion. Semen samples were collected every second week during a 12-month period...
Imaging diagnosis–Medullary tibial infarction in a horse. An Andalusian Stallion with left hind limb lameness had a radiolucent lesion in the medullary cavity of distal tibial metaphysis. After euthanasia for other disease, the tibia was examined with magnetic resonance (MR). The MR imaging sequences were characterized by a double line sign, although showing quite different lesion area intensities. Histologically, the lesion was compatible with medullary infarction being characterized by normal spongy bone, areas of abundant fibrous tissue and numerous necrotic adipocytes in various stages of destruction.
An investigation into the suitability of a commercial real-time PCR assay to screen for Taylorella equigenitalis in routine prebreeding equine genital swabs. Standard bacteriological methods for identifying Taylorella equigenitalis in cervical smears are time consuming. Therefore, a more rapid real-time PCR assay was evaluated for its suitability in screening swabs. Objective: To compare the results of a commercially available real-time PCR assay with routine microbiological culture for the identification of T. equigenitalis, the causative organism of contagious equine metritis, in equine genital swab samples, under 'field trial' conditions. Methods: Routine prebreeding genital swabs (n=2072) collected from Thoroughbred mares and stallions during 2...
Reproductive performance measures among Thoroughbred mares in central Kentucky, during the 2004 mating season. To improve efficiency at the farm level, a better understanding of how farm management factors impact reproductive performance is important. Objective: To assess reproductive efficiency and effectiveness among Thoroughbred mares in central Kentucky. Methods: A cohort of 1011 mares on 13 farms in central Kentucky was followed during the 2004 mating and 2005 foaling season. Information on farm level practices was collected via interviews with farm managers. Reproductive records were collected for each mare mated to obtain information on mare characteristics. The influence of mare age and status ...
Metabolic evaluation of cooled equine spermatozoa. Microscopy has been used in the routine evaluation of sperm metabolism. Nevertheless, it has limited capacity to preview male fertility. As calorimetry may be used to evaluate directly the metabolic activity of a biological system, the aim of this study was to use microcalorimetry as an additive method for sperm metabolism evaluation of cooled equine semen. Two ejaculates of four stallions were collected and motility, viability (eosin 3%) and membrane functional integrity (hyposmotic swelling test) of spermatozoa were evaluated. Sperm samples were processed following different protocols and th...
A cross-sectional survey of biosecurity practices on Thoroughbred stud farms in New Zealand. To examine the on-farm biosecurity practices of a group of commercial Thoroughbred stud farms in the North Island of New Zealand, in the absence of an exotic disease outbreak. Methods: A cross-sectional survey of biosecurity practices was conducted during the 2006/2007 Thoroughbred breeding season, and consisted of data from commercial Thoroughbred farms in the North Island of New Zealand standing a stallion. Data were collected on-farm by a single interviewer, using 17 open, closed and multiple-choice questions examining general farm/operation size and features, general animal health and bios...
Single layer centrifugation of stallion spermatozoa improves sperm quality compared with sperm washing. This study compared the effect on semen quality of different handling methods used in the preparation of stallion semen doses for artificial insemination. The three methods were (i) extending the ejaculate to 30-50 x 10(6)/ml, (ii) single layer centrifugation (SLC) and (iii) sperm washing (centrifugation without a colloid). An additional treatment was to add seminal plasma (SP) in various proportions to some SLC preparations. The resulting samples were evaluated for sperm motility by computer assisted sperm analysis, membrane integrity using the Nucleocounter SP-100 and chromatin integrity by ...
Multiple osteochondral autografts for treatment of a medial trochlear ridge subchondral cystic lesion in the equine tarsus. To adapt the multiple osteochondral autograft technique for treatment of a subchondral cystic lesion (SCL) of the proximal medial trochlear ridge (MTR) of the equine talus and assess long term outcome. Methods: Case report. Methods: Quarter horse stallion with SCL of the proximal MTR of the talus. Methods: Osteochondral autograft techniques used in dogs and humans were adapted and optimized in equine cadavers. A horse with a SCL of the MTR of the talus was treated by osteochondral autografting. Three osteochondral autografts were harvested from the distal lateral trochlear ridge of the talus i...
Influence of different centrifugation protocols on equine semen preservation. Three experiments were conducted to evaluate the impact of centrifugation on cooled and frozen preservation of equine semen. A standard centrifugation protocol (600 x g for 10 min=CP1) was compared to four protocols with increasing g-force and decreased time period (600 x g, 1200 x g, 1800 x g and 2400 x g for 5 min for CP2, 3, 4, and 5, respectively) and to an uncentrifuged negative control. In experiment 1, the influence of the different CPs on sperm loss was evaluated by calculating the total number of sperm cells in 90% of the supernatant. Moreover, the effect on semen quality following ce...
Curing of HeLa cells persistently infected with equine arteritis virus by a peptide-conjugated morpholino oligomer. A significant consequence of equine arteritis virus (EAV) infection of horses is persistence of the virus in a variable percentage of infected stallions. We recently established an in vitro model of EAV persistence in cell culture for the purpose of furthering our understanding of EAV biology in general and viral persistence in the stallion in particular. In this study we investigated whether persistently infected HeLa cells could be cured of EAV infection by treatment with an antisense peptide-conjugated phosphorodiamidate morpholino oligomer (PPMO) designed to target the 5'-terminal region o...
Lectin-binding sites on ejaculated stallion sperm during breeding and non-breeding periods. Stallion sperm from semen collected in Southern Italy during the breeding (June-July) and non-breeding (December-January) periods were analyzed by means of twelve lectins to evaluate the glycoconjugate pattern and to verify whether there are any seasonal differences in the glycosylation pattern of the sperm glycocalyx. The acrosomal cap showed reactivity for Maackia amurensis (MAL II), Sambucus nigra (SNA), Arachis hypogaea (PNA), Glycine max (SBA), Helix pomatia (HPA), Canavalia ensiformis (Con A) Triticum vulgaris (WGA), and Griffonia simplicifolia isolectin II (GSA II) in breeding and non-b...
Effect of season on fresh and cryopreserved stallion semen. The objective of this study was to determine the effect of season on sperm quality variables, expression of the fertility-related protein SP22 and selected mRNA transcripts in fresh and cryopreserved stallion sperm. Four stallions were collected in each of the four seasons: summer, fall, winter and spring. Ejaculates were divided and then evaluated for motility, morphology, SP22 staining and expression of selected mRNAs as either fresh semen samples or cryopreserved samples. A significant interaction between season and cryopreservation status was found for total and progressive sperm motility....
Shared Y chromosome repetitive DNA sequences in stallion and donkey as visualized using whole-genomic comparative hybridization. The genome of stallion (Spanish breed) and donkey (Spanish endemic Zamorano-Leonés) were compared using whole comparative genomic in situ hybridization (W-CGH) technique, with special reference to the variability observed in the Y chromosome. Results show that these diverging genomes still share some highly repetitive DNA families localized in pericentromeric regions and, in the particular case of the Y chromosome, a sub-family of highly repeated DNA sequences, greatly expanded in the donkey genome, accounts for a large part of the chromatin in the stallion Y chromosome.
Seasonal functional relevance of sperm characteristics in equine spermatozoa. A group of stallions with different reproductive indexes were used to study seasonal variations in sperm quality (Equus caballus). Semen samples were collected from late September to July and analyzed according to four seasonal periods: late September-December, January-March, late March-May, and June-July. Parameters monitored included sperm concentration, sperm motility, sperm morphology, sperm viability, acrosomal status, plasma membrane stability, and sperm mitochondrial membrane potential. Overall, seminal parameters monitored are affected mostly by time period, followed by animal and last...
Alkaline and acid phosphatase, β-glucuronidase and electrolyte levels in fractionated stallion ejaculates. Seminal plasma (SP) is a mixture of contents from the testes, epididymides and accessory sex glands. The sperm concentration is highest in the first few jets, or fractions, of the ejaculate, and the composition of SP varies between these fractions because accessory gland secretions are released in a specific order. The aim of this study was to compare the levels of Na, Cl, K, Mg, Ca, inorganic phosphate (Pi) and the enzymes alkaline phosphatase (AP), acid phosphatase (ACP) and β-glucuronidase (BG) in the different fractions of the ejaculate and in different stallions. All semen collections we...
[The case of the nematode Setaria equina found in the vaginal sac of the stallion’s scrotum]. The nematode Setaria equina usually reside in body cavities and do not cause clinical symptoms. From time to time, however, these parasites can be located in the scrotum and spermatic cord inflicting pain and edema in these body parts. The aim of the study was to describe the case of the nematode Setaria equina found in the vaginal sac of the stallion's scrotum. During the study, thorough examination of 50 isolated testicles of 25 stallions was conducted. The horses were obtained post-slaughter from the local slaughterhouse near Krakow. In one of examined stallions, two females of Setaria equi...
Oxytocin, vasopressin, prostaglandin F(2alpha), luteinizing hormone, testosterone, estrone sulfate, and cortisol plasma concentrations after sexual stimulation in stallions. This experiment was designed to determine the effects of sexual stimulation on plasma concentrations of oxytocin (OT), vasopressin (VP), 15-ketodihydro-PGF(2alpha) (PG-metabolite), luteinizing hormone (LH), testosterone (T), estrone sulfate (ES), and cortisol (C) in stallions. Semen samples were collected from 14 light horse stallions (Equus caballus) of proven fertility using a Missouri model artificial vagina. Blood samples were collected at 15, 12, 9, 6, and 3 min before estrous mare exposure, at erection, at ejaculation, and at 3, 6, and 9 min after ejaculation. Afterwards, blood sampling ...
Evaluation of shape variability of stallion sperm heads by means of image analysis and Fourier descriptors. This study quantified and evaluated the variability of sperm head shape for 10 different stallions. Sperm head shape characteristics including sperm head length to width ratio, position of the center of gravity, curvature, and degree of roundness were assessed and analysed from images using elliptic Fourier descriptors and inverse Fourier transformation. The first four principal components accounted for 88.46-92.33% of the total variance and provided a good summary of the overall data. In the case of the ejaculate with defective sperm heads the components accounted for 97.35-98.21% of variatio...
Effects of inbreeding and other genetic components on equine fertility. The Finnish mating records of Standardbred trotters (SB; n = 33 679) and Finnhorses (FH; n = 32 731) were analysed to study the effect of the level of inbreeding on foaling rates and to estimate the heritability of foaling rate. A linear mixed model was assumed, with the outcome of the foaling (foal or no foal) as the trait of the study. A restricted maximum likelihood-based method was used to calculate the estimates of the variance components. Predictions of breeding values and estimates of fixed effects were also calculated. The average level of inbreeding was 9.9% in the SB and 3.6% in the ...
Effect of a feed/fast protocol on pH in the proximal equine stomach. Risk factors for the development of gastric squamous ulcers include various management procedures, such as intermittent feed deprivation that can occur during weight management regimens or stall and dry lot confinement. Objective: To investigate the effect of intermittent feed deprivation relative to continuous feed intake on proximal intragastric pH, specifically in the region of the squamous mucosa of the lesser curvature. Methods: In 6 horses, pH electrodes were placed just inside of the oesophageal sphincter in the stomach for each of two 72 h protocols (A and B) in a randomised, cross-ove...
