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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.
Effect of Centrifugation of Stallion Semen Through a Low Density Colloid Prior to Freezing on Sperm Cryosurvival. Sperm quality is adversely affected by cryopreservation due to the increased production of reactive oxygen species, which affects the integrity of sperm membranes, motility, and DNA fragmentation. Three methods for removing seminal plasma, washing (centrifuging extended semen at 800× for 10 min) and Single Layer Centrifugation with high or low density Equicoll, were used to prepare 29 ejaculates from ten stallions for freezing. Sperm quality parameters (kinematics, plasma membrane integrity, superoxide and hydrogen peroxide production, mitochondrial membrane potential, and DNA fragmentation)...
Group housing increases alertness and social interaction compared to traditional single stabling in two-year-old sport horse stallions during pretraining. Horses in training are often stabled individually, but this is increasingly questioned. We have investigated the effects of different stabling systems in Warmblood stallions during a 12-week pretraining programme. Stallions were 24 months old and housed either in a group stable (Group 24, n = 9) or in individual boxes (Box 24, n = 10), or they were 30 months of age and housed in individual boxes (Box 30, n = 10). Cortisol, heart rate, heart rate variability (HRV), body development, injuries and selected behaviour patterns were analysed (1) at transfer from pasture to stable and (2) the...
Catalase in Unexpected Places: Revisiting H2O2 Detoxification Pathways in Stallion Spermatozoa. Oxidative stress plays a critical role in regulating sperm function, yet species-specific antioxidant mechanisms remain poorly understood. This study compared hydrogen peroxide (H2O2) tolerance in horse and human sperm and investigated the roles of catalase and glutathione peroxidase (GPx) in horses. A H2O2 dose-response assay (0-2000 µM) showed that horse sperm were significantly more resistant to oxidative damage, with an IC50 for progressive motility over 14-fold higher than that of human sperm (391.6 µM vs. 27.3 µM). Horse sperm also accumulated more intracellular H2O2 without loss of m...
Sudden death in a Thoroughbred stallion: cardiac tamponade due to transverse aortic rupture with bone metaplasia and calcification. A 17-year-old Thoroughbred stallion died suddenly after grazing. Necropsy revealed massive hemorrhage in the pericardial sac, suggesting cardiac tamponade. Aortic perforation was observed at the aortic origin, and hemorrhage was observed in and around the epicardium. Superficial observation of the aortic lumen revealed a transverse tear of the aortic wall at the bases of the right semilunar valve and septal semilunar valve. Fibro-osseous changes with calcification were histopathologically observed at the site of the rupture. A nodular goiter was observed in the left thyroid gland. The horse di...
Preimplantation genetic testing in horses: biopsy of Piezo-ICSI embryos for sex, coat color, and disease alleles. The introduction of ovum pick-up, Intracytoplasmic Sperm Injection (ICSI) and in vitro embryo production in equine reproduction offers significant advantages, including overcoming infertility, high blastocyst yields, embryo cryopreservation, and preimplantation genetic testing (PGT) by collecting few cells extruded spontaneously during embryo growth using a mouth pipette. PGT enables embryo selection before transfer and is particularly useful in breeds with a preference for specific offspring genders, coat color, and detecting genetic diseases. Here, we present the first large-scale validation...
Seminal vesiculitis and blocked ampullae occurring simultaneously in a stallion. A Gypsy Vanner stallion presented with a history of subfertility and abnormal dense, grey ejaculate. Reproductive examination including ultrasound, cytology, and bacteriology confirmed the diagnosis of seminal vesiculitis. After evaluation of several ejaculates, bilateral blocked ampullae were confirmed by azoospermia and a low level of alkaline phosphatase (30 IU/L) in the filtered fraction. Continuous semen collections, along with oral antibiotics treatment, were performed at the owner's facility for five weeks. After readmission, a successful collection was obtained with a high concentratio...
Stallion spermatozoa express LDH isoforms A, B, and C, with LDHC playing a crucial role in sustaining sperm viability. Three isoforms of lactate dehydrogenase (LDH) - LDHA (cytoplasmic), LDHB (mitochondrial), and LDHC (flagellar) - have been identified and localized in stallion spermatozoa. Functional inhibition assays indicate that these three isoforms constitute a lactate shuttle of crucial importance for sperm function. Unassigned: Stallion spermatozoa use different energy sources; while oxidative phosphorylation predominates, glycolysis and beta-oxidation of fatty acids are also present. Glycolysis depends on the availability of NAD+ as an electron acceptor. During glycolysis, NAD+ is reduced to NADH. To e...
Advancements in microfluidic and electrophoretic techniques for stallion sperm isolation. Context Equine reproductive technologies are crucial for overcoming challenges in natural fertilisation, particularly in sub-fertile stallions and breeding programs focused on genetic conservation and performance enhancement. Assisted reproductive technologies (ARTs), such as artificial insemination (AI), intracytoplasmic sperm injection (ICSI), and in vitro fertilisation (IVF), improve fertility outcomes and enable breeding across geographical distances. Aims This review examines sperm isolation techniques used in ART, evaluating their efficacy, limitations, and potential to enhance reproduct...
Seroprevalence of Neospora spp. in horses reared in rural and urban areas in southern Brazil. Protozoan Neospora spp. is known to negatively affect horses reared in rural and urban environments, being studied for causing abortion, neonatal mortality and central nervous system disorders in horses. This study aimed to verify the occurrence of anti-Neospora spp. antibodies in horses bred in rural and urban areas from southern Brazil and the risk factors associated with infection. The study consisted of 400 horses, which 241 were bred in rural areas and 159 in urban areas. The detection of serum anti-Neospora spp. antibodies was determined using Immunofluorescence Antibody Test (IFAT). The...
Seminal plasma MicroRNA dynamics in stallion semen due to progressive motility and conception success. This study aims to investigate the expression patterns of miR-34b, miR-122, let-7a in seminal plasma of stallions in relation to progressive motility and conception success, and to evaluate their potential as biomarkers. Fifteen adult stallions were enrolled in study. One ml of seminal plasma was kept at -80 °C, 2 ml of fresh semen was sampled from each stallion for sperm analysis, and the rest were used for artificial insemination only for one mare. Two groups were formed as high progressive motility (HPM; n:8) and low progressive motility (LPM; n:7), based on progressive motility. Besides...
Thermal comfort and seminal traits in stallion reproduction: New methods to understand these relationships. Stallion breeding is mostly based on desirable phenotypic traits, with little consideration for semen quality. Objective: To identify relationships among semen parameters in stallions using a non-invasive, integrative approach across summer and winter seasons. Methods: Twenty-four stallions were evaluated, in which semen collections, testicular thermography, and Doppler velocimetry of the testicular artery by Doppler ultrasonography were performed, in addition to the measurement of physiological, environmental, and heat stress parameters, both in winter (coat weather) and summer (T-shirt weath...
The relationship between post-thaw sperm quality parameters and blastocyst production following Intracytoplasmic Sperm Injection (ICSI) of in vitro-matured equine oocytes. In vitro production of equine embryos by Intracytoplasmic Sperm Injection (ICSI) is commonly utilized to maximize the availability of stallion sperm, particularly from stallions with limited semen supply. The relationship between standard measures of sperm quality in frozen/thawed semen (i.e., sperm motility, normal morphology, DNA quality) and embryo production after ICSI of in vitro-matured equine oocytes has not been thoroughly studied. In this study, frozen/thawed semen from 47 stallions utilized in a commercial ICSI program was analyzed for post-thaw sperm total and progressive motility (...
In vitro embryo production via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) in pure and crossbred Japanese Hokkaido native ponies. This study evaluated the viability of in vitro embryo production using ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) as breeding techniques for pure and crossbred Hokkaido native ponies (n = 9). Oocytes were collected using transvaginal ultrasound-guided follicle aspiration. ICSI was performed on in vitro matured oocytes using frozen semen. Embryonic cultures were monitored using time-lapse cinematography. Blastocysts were cryopreserved and, after thawing, were transferred non-surgically into recipient mares. Over nine OPU sessions, the mean number of aspirated follicles was 2...
Enhanced Reliability of the Evaluation of Fertility Traits in Pura Raza Española Horses Using Single-Step Genomic Best Linear Unbiased Prediction. By simultaneously integrating both genotyped and non-genotyped animals into genetic evaluation, the single-step genomic BLUP method enhanced the accuracy of genetic assessments. This study aimed to compare the increase in prediction reliability (R) between restricted maximum likelihood (REML) and single-step genomic REML (ssGREML) in the Pura Raza Española (PRE) horse breed. The dataset comprised reproductive records for seven fertility traits from 47,502 females, with a total of 57,316 animals represented in the pedigree. A total of 4009 animals were genotyped using the EQUIGENE 90K SNP ar...
Molecular assessment of Coxiella burnetii in horses in Northwestern Iran. Q fever is a frequently occurring illness that is induced by the bacterium ) that can infect humans and various animals. It targets the macrophage cells in the tissues, and circulating monocytes. Unassigned: This study was conducted between 2022 and 2023 in the West Azerbaijan and Ardabil provinces of northwestern Iran to examine the presence infection of . Specimens were obtained by swabbing from 140 mares (70 from each province) and 20 stallions (10 from each province) which were apparently healthy, and their DNA was analyzed using quantitative PCR assay detecting the element of the bacteri...
Molecular assessment of Coxiella burnetii in horses in Northwestern Iran. Q fever is a frequently occurring illness that is induced by the bacterium ) that can infect humans and various animals. It targets the macrophage cells in the tissues, and circulating monocytes. Unassigned: This study was conducted between 2022 and 2023 in the West Azerbaijan and Ardabil provinces of northwestern Iran to examine the presence infection of . Specimens were obtained by swabbing from 140 mares (70 from each province) and 20 stallions (10 from each province) which were apparently healthy, and their DNA was analyzed using quantitative PCR assay detecting the element of the bacteri...
Sperm Vitrification in Horse and Donkey. Sperm vitrification is a novel-assisted reproductive technique that is increasingly gaining relevance in the last years. This technique allows to cryopreserve sperm from valuable stallions and donkeys without the exposure to permeable cryoprotectants, particularly toxic for the gametes of these species.This chapter aims to describe the current range of methodologies available that are key to ensure sperm quality after vitrification and warming of stallion and donkey sperm.
Cryopreservation of Horse Sperm. Cryopreservation is currently the only strategy for long-term conservation of equine sperm. To get optimal post-thaw sperm survival, carefully following each step of the freezing protocol is crucial. First, one needs to obtain and exhaustively analyze an ejaculate of good sperm quality. Then, the seminal plasma is removed by centrifugation, and the resulting pellet is resuspended in a certain volume of the freezing medium to reach the right sperm concentration. Finally, sperm samples are packaged into 0.5-mL straws, cooled, and frozen using an automatic, controlled-rate freezer. Once the tempe...
Effect of pre-freeze sperm concentration, freezing extender, and epididymal flushing technique on post-thaw quality of cryopreserved epididymal stallion sperm. Cryopreservation of stallion epididymal sperm has become a common clinical procedure after routine castration, euthanasia, or acute death. Unique features of epididymal sperm compared to ejaculated sperm include the requirement to remove sperm from the cauda epididymis, lack of exposure to seminal plasma, and potential recovery of large sperm numbers. In this study, the effect of the flushing technique (Extender (INRA) vs. AIR), freezing extender (LE, CMLE, MFR5, CFR5, or BOTU), and the concentration at which sperm are cryopreserved (200, 400, or 800 × 10 sperm/mL) on post-thaw epididymal s...
Sperm Motility Evaluation in Stallion Fresh, Cooled and Frozen Semen Using a Portable Computer-Assisted Sperm Analysis System. Semen analysis is an important laboratory diagnostic test for stallions. Evaluation of sperm motility is integral to basic semen analysis and results are important for breeding management and clinical practice. Computer-assisted sperm analysis (CASA) allows objective sperm motility evaluation and increases analytical precision. The objective of the present study was to validate a portable CASA system (AndroScope). Fresh/cooled semen samples (33 ejaculates, 18 stallions) and frozen semen (40 ejaculates and one epididymal flush, 27 stallions) were evaluated using the AndroScope and the IVOS II C...
Cryoprotective effect of zinc and gold nanoparticles during cooling and freeze-thawing on Marwari stallion sperm parameters and reactive oxygen species production. Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. Objective: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. Methods: A total of 20 ejaculates from four Marwari ...
Concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in blood, hair and semen of stallions in Finland. Heavy metal contamination poses significant environmental and health risks to both humans and animals. This study investigates the concentrations of arsenic (As), cadmium (Cd), and lead (Pb) in blood, hair, and semen samples collected from 16 breeding stallions in Western Finland to assess whether concentrations in hair and serum samples represent concentrations in semen. The analysis was conducted using an inductively coupled plasma mass spectrometry (ICP-MS) system. Results showed that hair samples exhibited the highest concentrations of heavy metals, particularly Pb and As, while semen show...
Equine in vitro fertilization with frozen-thawed semen is associated with shortened pre-incubation time and modified capacitation-related changes. We recently reported successful equine IVF using fresh semen pre-incubated for a prolonged period (22 h) before co-culture with oocytes. In this study, we evaluated the feasibility of equine IVF with frozen-thawed sperm and evaluated capacitation-related changes in these sperm over the pre-incubation period. Sperm selected via a commercial sperm separation device (SSD) yielded significantly higher fertilization than did sperm selected by swim-up or by colloid centrifugation. Using the SSD method, fertilization rates with sperm pre-incubated for 15 min, 3 h, 6 h, and 9 h were 7.1, 22.2, 38...
Risk Factors and Long-Term Outcomes in Horses After the 2021 Outbreak of Equine Herpesvirus 1 Myeloencephalopathy, Valencia, Spain. Equine herpesvirus myeloencephalopathy (EHM) is a persistent threat to horses, with unclear risk factors and disease severity. Objective: To evaluate risk factors, effective reproduction rate (Rt), and long-term athletic outcomes of an EHM outbreak. Methods: Retrospective study of the 2021 EHM outbreak in Valencia, Spain, examining associations between risk factors (sex, age, breed, country of origin, and vaccination status) and case fatality rate, EHM development, and odds of returning to competition using odds ratios [95% CI] and Rt via the Robert Kochs Institute method. Results: Among 191 h...
Results of the “test-freeze” approach in a commercial program of stallion sperm cryopreservation and the relationship between pre-freeze sperm quality and “freezability.”. In the current study, we report the effect of different commercially available semen freezing extenders utilized for the "test-freeze" procedure for 13 years (2010-2023) as part of a commercial program of stallion sperm cryopreservation. Ejaculates obtained from sexually active and healthy stallions (n = 124) were cryopreserved using up to five commercially available semen freezing extenders (Lactose-EDTA [LE], MFR5, CryoMax LE [CMLE], CryoMax MFR5 [CMMFR5] or BotuCrio [BC]). Post-thaw sperm motility (total motility - TM [%]; progressive motility - PM [%]; and curvilinear velocity - VCL [μm...
Strategic approaches to improve equine breeding and stud farm outcomes. This review explores advanced strategies for enhancing fertility and optimizing reproductive outcomes in equine breeding programs. Horses, being seasonal breeders, present unique reproductive challenges influenced by environmental and physiological factors such as photoperiods, hormone cycles, and aging. Key approaches discussed include hormonal therapies, artificial light manipulation, and nutritional supplementation to improve ovulation and conception rates during the breeding season. Specific hormones such as gonadotropin-releasing hormone analogs, equine follicle-stimulating hormone, and p...
Gait kinematics at trot before and after repeated ridden exercise tests in young Friesian stallions during a fatiguing 10-week training program. Appropriate training is essential for equine athletes to improve fitness and ensure welfare. Young Friesian stallions must complete a 10-week training program for acceptance as breeding stallions. Earlier, this training program was demonstrated to induce overtraining. Unassigned: To evaluate how this training program affects stallions' trot locomotion variables in relation to fatigue. Unassigned: Prospective analytical study. Unassigned: 3 or 4 years-old (n = 16) Friesian stallions performed three ridden indoor standardized exercise tests (SETs) in week-1 (SET-I; n = 15), week-6 (SET...
The inability of spectral Doppler ultrasonography to identify stallions with testicular dysfunction. This retrospective study aimed to validate the usefulness of spectral Doppler ultrasonography in diagnosing testicular dysfunction in stallions. The first part of the study included a pony stallion with age-related testicular degeneration (18 - 21 yrs. old). Testicular dimensions, spectral Doppler parameters of testicular blood flow, and semen parameters were obtained numerous times from this pony over four consecutive years. While testicular volume decreased dramatically, and the stallion became azoospermic, there were no changes in any of the spectral Doppler parameters of testicular blood f...
Laparoscopic Inguinal Hernioplasty with a Polyether Ether Ketone Anchoring Device in Intact Male Horses Does Not Compromise Testicular Perfusion, Sperm Production or Motility Characteristics. A new surgical technique using a polyether ether ketone (PEEK) anchoring device for testicle-sparing laparoscopic inguinal hernioplasty in stallions was described in 2023 and is known as the PEEK harpoon technique (PHT). In breeding stallions, it is essential that the surgery is effective in preventing inguinal hernia but also that it does not impair the testicular function. This study aims to evaluate whether the PHT may affect testicular function. To achieve that, changes in the testicular blood flow, sperm production and motility characteristics were assessed 28 days after use of the PHT. S...
Clinical findings of candidate stallions presented for licensing at all German Warmblood horse-breeding associations in 2018-2020. There is very little information available about the health status of young stallions from the German Warmblood population that will, once licensed, shape the future of equestrian sport and horse breeding. Objective: To evaluate the prevalence of clinical findings at licensing examinations of candidate stallions and the influences of season of birth, age at licensing, year of licensing, and the evaluator on the distribution of recorded findings. Methods: Retrospective observational study. Methods: Clinical records of 1655 candidate stallions presented for licensing in 2018-2020 were reviewed. ...
