Topic:Equid Semen
Equid semen refers to the reproductive fluid produced by male horses, which contains sperm cells necessary for fertilization. The quality and viability of equid semen are important for successful breeding programs and can be influenced by various factors, including genetics, age, diet, and environmental conditions. Key parameters used to assess semen quality include volume, concentration, motility, and morphology of sperm cells. Techniques for collecting, evaluating, and preserving equid semen, such as cryopreservation, are critical for artificial insemination practices. This page compiles peer-reviewed research studies and scholarly articles that explore the physiology, assessment, and management of equid semen in the context of equine reproduction.
Frozen semen management in equine breeding programs. Success with frozen semen requires attention to detail and a basic understanding of the techniques for properly handling and thawing and inseminating frozen semen. Practitioners should also be familiar with strategies used for managing mares for insemination with thawed semen. This manuscript will review those techniques and also present fertility data collected in a commercial setting. Factors that affect pregnancy rates for mares inseminated with frozen-thawed semen such as timing and frequency of insemination were examined for two separate data sets consisting of 332 and 536 mare cycles col...
Cellular associations and the differential spermiogram: making sense of stallion spermatozoal morphology. Morphologic assessment of spermatozoa is one of the most objective measures in a Breeding Soundness Examination of a stallion. There are different systems for morphologic assessment of spermatozoa. The objectives of this article are to review spermatogenesis, describe clinical sample preparation, discuss previous methods of morphologic classification and explain the use of a differential spermiogram. The advantages of the differential spermiogram method of analysis are discussed, along with its use in delineating intrinsic and extrinsic disturbances in spermatogenesis. Case examples of specifi...
Influence of vedaprofen (Quadrisol) on quality and freezability of stallion semen. The objective of this study was to evaluate the effect of the non-steroidal anti-inflammatory drug (NSAID) vedaprofen (Quadrisol) on quality and freezability of stallion semen. Experiments were performed using 22 Franches Montagnes stallions from the National Stud in Avenches (Switzerland) randomly divided into a control and test group. Vedaprofen was given orally to all stallions of the test group at the recommended therapeutic dose (initial dose of 2mg/kg followed by 1mg/kg body weight every 12h) for 14 days. Control animals received the same amount of carrier substance. During treatment, bl...
Lipid peroxide formation in relation to membrane stability of fresh and frozen thawed stallion spermatozoa. In this study we used a new method to detect reactive oxygen species (ROS) induced damage at the level of the sperm plasma membrane in fresh and frozen-thawed stallion sperm. Lipid peroxidation (LPO) in sperm cells was assessed by a fluorescent assay involving the labeling of stallion sperm with the LPO reporter probe C11-BODIPY(581/591). The peroxidation dependent spectral emission shift of this membrane probe could be localized using inverted spectral confocal microscopy and quantified on living and deteriorated sperm cells using flow cytometry. Mass spectrometric analysis of the main endoge...
Advanced fertility diagnosis in stallion semen using transmission electron microscopy. Routine semen analysis of stallions is based on light microscopy (LM). However, there are still a number of animals that are subfertile or even infertile not being identified with conventional semen analysis. The objective of this study was to investigate the suitability of transmission electron microscopy (TEM) for advanced fertility diagnosis in stallion. We examined ejaculates of 46 stallions with known fertility. Animals were divided into three different groups: group 1, fertile stallions (pregnant mares> or =70%, n=29); group 2, subfertile stallions (pregnant mares 10-69%, n=14); group 3,...
Effect of seminal plasma on the cryopreservation of equine spermatozoa. Seminal plasma is generally removed from equine spermatozoa prior to cryopreservation. Two experiments were designed to determine if adding seminal plasma back to spermatozoa, prior to cryopreservation, would benefit the spermatozoa. Experiment 1 determined if different concentrations of seminal plasma affected post-thaw sperm motility, viability and acrosomal integrity of frozen/thawed stallion spermatozoa. Semen was washed through 15% Percoll to remove seminal plasma and spermatozoa resuspended to 350 x 10(6)sperm/mL in a clear Hepes buffered diluent containing either 0, 5, 10, 20, 40 or 80%...
Comparison of in vitro laboratory analyses with the fertility of cryopreserved stallion spermatozoa. Assessing the fertilizing potential of a semen sample is important for effective stallion management and for rapid progress in evaluating new cryopreservation technologies. Unfortunately, sperm motility does not estimate fertility well. These experiments established assays to measure cell viability, acrosomal integrity and mitochondrial function for cryopreserved stallion spermatozoa, using flow cytometry, and determined the variability associated with these assays. Correlations between results for these laboratory assays and stallion fertility were also determined. The inter-assay variability...
Sperm motility patterns and metabolism in Catalonian donkey semen. The Sperm-Class Analyzer detected four subpopulations of spermatozoa with different motility characteristics in the ejaculate of the Catalonian donkey. Significant differences (P < 0.001) in the distribution of these subpopulations, as well as in total sperm number and percentage total motility, were seen in the diluted semen of four sampled donkeys. All the ejaculates evaluated showed excellent semen quality characteristics; the sperm they contained was more rapid than horse sperm. Principal components analysis showed sperm l-lactate production to be a good predictor of semen condition. This,...
Relationship of seminal plasma level and extender type to sperm motility and DNA integrity. The relationship between seminal plasma level (0, 10, or 20%) and extender type [Kenney type (EZ-Mixin-CST) or Kenney-modified Tyrodes-KMT] to the susceptibility of sperm DNA to denaturation and sperm motility measures were investigated in cooled (5 degrees C) stallion sperm. Three ejaculates from each of three fertile stallions were collected in an artificial vagina and processed as follows: diluted one part uncentrifuged semen with four parts of extender to a final concentration of 20% seminal plasma in either CST or KMT (20% CST; 20% KMT); diluted to a final concentration of 25 million sper...
High pressure flow cytometric sorting damages sperm. Sexing sperm by high-speed flow cytometry subjects them to high pressure. The routine operating pressure of the MoFlo SX flow cytometer for sperm sorting for commercial production has been 50 pounds/square inch (psi), with a standard 70 microm standard nozzle tip. It was hypothesized that lowering the sorting pressure could reduce sperm damage. Therefore, a series of experiments using semen from six bulls, sorted with three MoFlo SX sorters, was conducted to determine optimal pressure. An additional experiment was done with stallion spermatozoa. In Experiment 1, sorting at 30 psi compared to 5...
Activity of glutathione peroxidase, superoxide dismutase and catalase and lipid peroxidation intensity in stallion semen during storage at 5 degrees C. Sperm cell membranes are susceptible to peroxidative damage by an excess of reactive oxygen species (ROS). Antioxidative defence systems consisting of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) physiologically control the balance between ROS production and neutralization. In the present study the hypothesis was tested that lipid peroxidation occurs during storage of semen at 5 degrees C and that semen extender has positive effects on the antioxidative potential of equine semen. The aim of the study was to determine the activity of GSH-Px, SOD and CAT and the...
Effect of feeding a DHA-enriched nutriceutical on the quality of fresh, cooled and frozen stallion semen. Eight stallions were used in 2 x 2 crossover study to determine if feeding a nutriceutical rich in docosahexaenoic acid (DHA) would improve semen quality. Stallions were randomly assigned to one of two treatment groups (n = 4 per group). Stallions were fed their normal diet (control) or their normal diet top-dressed with 250 g of a DHA-enriched nutriceutical. Feeding trials lasted for 14 week, after which a 14-week washout period was allowed and the treatment groups were reversed for another 14 week feeding trial. Feeding the nutriceutical resulted in a three-fold increase in semen DHA levels ...
Effect of insemination dose and site on uterine inflammatory response of mares. It is unclear whether AI of mares deep into the uterine horn causes more or less inflammation of the endometrium than conventional AI. Thus, we compared uterine inflammatory reactions of mares inseminated with two different doses of frozen-thawed semen into the tip of the uterine horn (UH) ipsilateral to the preovulatory follicle with those of mares inseminated into the uterine body (UB). Thirty-two mares were assigned to one of four groups (eight mares/group): UB20=AI into UB, 20 x 10(6)sperm/0.5 mL; UB200=AI into UB, 200 x 10(6)sperm/0.5 mL; UH20=AI into UH, 20 x 10(6)sperm/0.5 mL; UH200=AI ...
Effects of glutamine on post-thaw motility of stallion spermatozoa: an approach of the mechanism of action at spermatozoa level. The cryoprotective effect of l-glutamine and an approach of its mechanism of action, in preserving motility of stallion spermatozoa during the freezing-thawing process, were studied. In Experiment 1, thirty-six ejaculates were collected from six stallions (two good, two middle, and two of poor sperm freezability) and were diluted with 10 different freezing media derived from INRA 82 medium supplemented with 20 mM HEPES and 2% (v/v) centrifuged egg yolk (BM). After thawing, sperm motility was evaluated by a computer-assisted semen motility analyser. The effects of glutamine and glycerol at diff...
A Bayesian approach to prediction of stallion daily sperm output. In equine breeding, the number of spermatozoa ejaculated is considered an important factor in fertility. Methods for predicting the number of spermatozoa have been derived from semen collection procedures. A once-daily collection period for 10 days is a standard recommendation to predict long-term daily sperm output (DSO). The first objective of this study was to determine the precision or repeatability of these DSO predictions. Semen was collected and evaluated daily during four periods for 10 days, for 15 different stallions. The analytical methods utilized hierarchal Bayesian modeling as im...
Effect of frozen semen on the uterus of mares with pathological uterine changes. Pregnancy rates after frozen semen inseminations (AI), particularly in older and problem mares, are lower than after fresh semen AI. Uterine contractility and the inflammatory reaction after frozen semen insemination were studied in two groups of mares: the abnormal group comprised of 6 old barren mares categorized in biopsy category IIB or III, and the control group including 6 reproductively normal young maiden mares in biopsy category I or IIA. All 12 mares were inseminated in the first cycle with 2 mL of phosphate-buffered saline (PBS) and in their second cycle with 2 mL of frozen semen co...
Evaluation of alternative cryoprotectants for preserving stallion spermatozoa. Although use of cryopreserved stallion spermatozoa is currently accepted by many breed registries, utilization of this technique remains limited due to poor fertility for some stallions. One reason for these results is osmotic stress that spermatozoa experiences when the cryoprotectant (glycerol) is added to the cells prior to freezing and removal from the cells after thawing. In an effort to minimize osmotic damage, alternative cryoprotectants, having lower molecular weights and greater membrane permeability than glycerol, were evaluated to determine their effectiveness for cryopreserving sta...
Effects of different artificial insemination techniques and sperm doses on fertility of normal mares and mares with abnormal reproductive history. The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto...
[The influence of centrifugation on quality and freezability of stallion semen]. The aim of the present study was to investigate the influence of various centrifugation methods on sperm loss and quality of frozen-thawed semen. From at a total of 8 Warmblood stallions of the National Stud Farm in Avenches, 3 ejaculates each were collected and seminal plasma was removed using 3 different centrifugation regimes. In method I (reference method) centrifugation occurred by a speed of 600 x g during 10 minutes. In method II 1000 x g was used during 2 minutes while in method III centrifugation was performed by 2000 x g during 2 minutes. After centrifugation 90%, of the supernatant ...
Effect of L-carnitine administration on the seminal characteristics of oligoasthenospermic stallions. The effect of orally administered l-carnitine on the quality of semen obtained from stallions with different semen qualities was investigated. Four stallions with proven fertility (high motility group, HM) and with normal seminal characteristics (>50% progressive motility and > 80 x 10(6) spermatozoa/ml), and four questionable breeders (low motility group, LM) with <50% of sperm progressive motility and < 80 x 10(6) spermatozoa/ml, received p.o. 20 g of l-carnitine for 60 days. Blood and semen samples were collected before treatment (T0) and after 30 (T1) and 60 days (T2). Semen ev...
Identification of amino-acids in the alpha-subunit first and third loops that are crucial for the heterospecific follicle-stimulating hormone activity of equid luteinizing hormone/choriogonadotropin. To identify amino-acids in the alpha-subunit important for expression of heterospecific FSH activity of horse (e) LH/choriogonadotropin (CG) (eLH) and donkey (dk) LH/CG (dkLH) (FSH/LH ratio ten times higher for eLH than for dkLH); this FSH activity absolutely requires an equid (donkey or horse) alpha-subunit combined with an equid beta-LH subunit. Methods: Chimeric alpha-subunits possessing the first 63 amino-acids of the porcine (p) and the last 33 amino-acids of the donkey alpha-subunit (alphap-dk) and the inverse (alphadk-p) were constructed. Porcine-specific amino-acids were introduced by ...
Characterization and localization of membrane vesicles in ejaculate fractions from the ram, boar and stallion. Membrane vesicles, separated by differential centrifugation from the seminal plasma, were detected in the sperm-rich ejaculate fractions of four boars and three stallions, and in the whole ejaculates of seven rams. The volume and percentage of vesicles, determined by a stereological technique, were higher in the sperm-rich than in the post-sperm-rich fractions of the boar and stallion ejaculates, and no vesicles were detected in the pre sperm-rich fractions. Vesicles were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). For boar, stallion and ram semen...
Studies on motility and fertility of cooled stallion spermatozoa. This study on extended, cooled stallion spermatozoa aimed to compare the ability of three extenders to maintain sperm motility during 24 h of preservation, and to describe pregnancy and foaling rates after artificial insemination (AI) of stallion spermatozoa stored and transported in the extender chosen from the in vitro study. After 6 and 24 h of preservation, motility, both subjective and evaluated by the motility analyzer (total, progressive and rapid), was lower in non-fat, dried skim milk-glucose than in both other extenders: dried skim milk-glucose added to 2% centrifuged egg yolk, and u...
Pregnancy rates of mares inseminated with semen cooled for 18 hours and then frozen. The ability to ship cooled stallion sperm for subsequent freezing at a facility specializing in cryopreservation would be beneficial to the equine industry. Stallion sperm has been centrifuged, cooled to 5 degrees C for 12 h, and frozen without a detrimental effect on motility in a previous study; however, no fertility data were available. Experiment 1 compared the post-thaw motility of sperm cooled for 18 h at 15 or 5 degrees C at either 400 or 200 x 10(6) sperm/mL and then frozen. Storage temperature, sperm concentration, or the interaction of temperature and concentration had no effect on t...
The first isolation of equine arteritis virus in Argentina. This paper describes the first isolation of equine arteritis virus (EAV) in Argentina. The virus was isolated from the semen of an imported seropositive stallion held in isolation at a breeding farm in Tandil in the Buenos Aires Province. In addition, viral nucleic acid was detected in seminal plasma using the reverse-transcription polymerase chain reaction. The isolated virus was propagated in cell cultures and confirmed as EAV by indirect immunofluorescence and virus neutralisation, using a serum specific for the reference Bucyrus strain of EAV. As far as the authors are aware, this is the f...
A comparison of electroejaculation and epididymal sperm collection techniques in stallions. The purpose of this study was to evaluate 2 methods of semen collection that could be used as terminal procedures in stallions with irreparable conditions, such as fractures or colic. Electroejaculation was attempted under general anesthesia. Forty-eight hours later, the ponies were castrated and 2 different epididymal sperm collection techniques were attempted by using a flushing or floating method. Additionally, the effect of supplemental seminal plasma was evaluated. Experimentally, electroejaculation was found to be a safe but ineffective method of terminal semen collection. Viable sperm c...
Interaction of fibronectin type II proteins with membranes: the stallion seminal plasma protein SP-1/2. Seminal plasma of mammalians contains, among others, proteins that are characterized by the fibronectin (Fn) type II module. Our knowledge about the structure and the physiological function of seminal Fn type II proteins mainly originates from studies on PDC-109, the bovine representative of this protein family. The present work focuses on the equine protein SP-1/2 (also named HSP-1/2) with particular emphasis on its interaction with lipid membranes by employing the intrinsic protein fluorescence and a number of spin-labeled and fluorescent lipid analogues. The results indicate that the intera...
Effect of semen collection practices on sperm characteristics before and after storage and on fertility of stallions. This study analyzed effects of different methods and intervals of semen collection on the quantity and quality of fresh, cool-stored, and frozen-thawed sperm and fertility of AI stallions. In Experiment 1, ejaculates were obtained from six stallions (72 ejaculates per stallion) using fractionated versus non-fractionated semen collection techniques. Initial sperm quality of the first three jets of the ejaculate was not different from that of total ejaculates. Centrifugation of sperm-rich fractions before freezing improved post-thaw motility and sperm membrane integrity when compared to non-cent...