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.
In vitro and xenogenous capacitation-like changes of fresh, cooled, and cryopreserved stallion sperm as assessed by a chlortetracycline stain. Like the human female, the mare experiences reproductive tract pathology that may sometimes be circumvented by the use of assisted reproductive technologies (ARTs). One such technology, gamete intrafallopian transfer (GIFT), may be used in mares that exhibit ovulatory, oviductal, or uterine abnormalities that limit the use of common ARTs, such as embryo transfer. Homologous GIFT has been successfully performed in the horse; however, the logistics, costs, and associated risks of surgically transferring gametes to the oviducts of a recipient mare are considerably high. Use of a less costly speci...
Intra- and inter-stallion variation in sperm morphology and their relationship with fertility. Dismount semen samples were collected from Thoroughbred stallions during the breeding season to determine the magnitude and significance of the variation in sperm morphology within (intra-) and among (inter-) stallions. The degree of intra-stallion variation in sperm morphology during the breeding season was substantial (coefficient of variation: 20%; range 8-56%), but did not affect the day-to-day fertility of sperm samples taken from the same stallion (intra-stallion). This variability did not affect the pregnancy rate of the mares with which each stallion was mated. The degree of interstall...
Effect of cryopreservation and oviductal cell conditioned media on Ca2+ flux of equine spermatozoa. Movement of Ca2+ into spermatozoa is a critically important event for capacitation and the acrosome reaction. In the present study, the nature of Ca2+ movement in fresh equine spermatozoa was established and the effects of oviductal cell conditioned medium (OCM) and cryopreservation on Ca2+ flux were investigated. The ability of fresh and cryopreserved stallion spermatozoa to regulate Ca2+ concentration over time was evaluated in Ca2+ -free PBS. Intracellular Ca2+ concentrations were higher in cryopreserved spermatozoa than in fresh spermatozoa. However, extracellular Ca2+ concentrations were ...
Biophysical and 1H magnetic resonance spectroscopy characteristics of fractionated stallion ejaculates. The composition of seminal plasma must be determined to assess the possible roles of sex gland secretions in survival of stallion spermatozoa. In the present study, an automated semen collection device and 1H magnetic resonance spectroscopy were used to analyse and compare the composition of seminal plasma from fractionated and nonfractionated stallion ejaculates. The contribution of each semen component to the ejaculate (sequence of production of component and concentration) was evaluated and its relationship to biophysical parameters was determined. 1H magnetic resonance spectroscopy was use...
Pregnancies produced from fertile and infertile stallions by intracytoplasmic sperm injection (ICSI) of single frozen-thawed spermatozoa into in vivo matured mare oocytes. The use of intracytoplasmic sperm injection (ICSI) for in vitro fertilization of equine oocytes and the developmental potential of these oocytes after transfer to the Fallopian tubes of synchronized mares were examined. Oocytes were aspirated from mature follicles 39 h after injection of a GnRH analogue and transported 190 km at 39 degrees C. Semen from a fertile and an infertile stallion was frozen and prepared for injection. Successfully injected oocytes were transferred surgically into the ampulla of the Fallopian tube either: (i) 4-8 h after semen injection; or (ii) after 24-48 h culture b...
Freezing of stallion semen: interactions among cooling treatments, semen extenders and stallions. In the present study, the interactions among stallions, semen extenders and cooling treatments before stallion semen samples were frozen were studied. In Expt 1, the effects of four cooling treatments and three semen extenders were investigated (11 stallions x four split ejaculates), whereas in Expt 2, the effects of two semen extenders, two egg yolk concentrations and two glycerol concentrations were investigated (six stallions x five split ejaculates). Sperm motility after thawing was evaluated. In Expt 1, the extender x cooling treatment interaction was significant. Centrifugation and addit...
Relationship between sperm nuclear protamine free -SH status and susceptibility to DNA denaturation. Data from the sperm chromatin structure assay (SCSA), a flow cytometric measurement of susceptibility of sperm nuclear DNA to denaturation, show strong correlation with the fertility potential of bulls, boars, men and stallions. Previous studies showed a strong relationship between stallion spermatozoa with denatured DNA and the presence of DNA strand breaks. In the present study, the relationship between stallion sperm DNA denaturation and the redox status of -SH groups on the cysteine residues of sperm nuclear protamines that are thought to stabilize chromatin was investigated. Semen samples...
Motility, morphology and triple stain analysis of fresh, cooled and frozen-thawed stallion spermatozoa. The aim of the present study was to determine whether there are characteristics of fresh, cooled and frozen-thawed semen samples that can be used to predict the suitability of stallion semen for preservation by cooling or freezing. Each of three ejaculates obtained from 12 stallions was divided into aliquots to be analysed for sperm motility, morphology and membrane integrity as fresh, cooled and frozen-thawed samples. The percentage of morphologically normal spermatozoa was similar in fresh and cooled samples and both were greater than in the frozen samples. There were no strong linear relati...
Indirect determination of stallion sperm capacitation based on esterase release from spermatozoa challenged with lysophosphatidylcholine. A spectrophotometric assay was developed to measure the amount of esterase released from stallion spermatozoa. This assay was used to determine the percentages of capacitated stallion spermatozoa, determined by the ability of spermatozoa to undergo an acrosome reaction and release esterase in response to a lysophosphatidylcholine challenge, for spermatozoa incubated under conditions to increase intracellular calcium and cAMP. Incubation with 100 nmol calcium ionophore A23187 l(-1) induced 66% of stallion spermatozoa to capacitate after 60 min of incubation at 37 degrees C. Subsequent experimen...
Preservation of stallion sperm quality by native phosphocaseinate: a direct or indirect effect? Milk-based diluents are generally considered efficient for survival of stallion spermatozoa in vitro. However, milk is a complex and variable medium and native phosphocaseinate is a milk component that is more efficient for preservation of sperm motility and fertility, although the mechanisms involved in this protection have not yet been elucidated. The aim of the present study was to characterize the interactions between native phosphocaseinate and equine spermatozoa. No binding between sperm membranes and native phosphocaseinate was observed using indirect immunofluorescent staining or elect...
Possible role of autoimmunity to spermatozoa in idiopathic infertility of stallions. Testicular degeneration is a major cause of subfertility in stallions, although an aetiological diagnosis cannot be made in most cases. In the present study, autoimmune testicular degeneration was induced and evaluated in stallions by immunizing stallions with their own spermatozoa mixed with an adjuvant. The factors evaluated included changes in semen quality and testicular histology. A large decrease in sperm number and quality was observed in response to sperm autoantigens. An ELISA test specific for antisperm antibodies was developed which enabled antibody titres in serum, seminal plasma a...
Measurements of reproductive function in stallions treated with trimethoprim-sulfamethoxazole and pyrimethamine. To evaluate the effects of trimethoprim-sulfamethoxazole and pyrimethamine treatment on various measures of reproductive function in healthy pony stallions. Methods: Randomized complete block study. Methods: 12 healthy, mature pony stallions. Methods: Stallions were assigned to treatment and control groups balanced for age and various characteristics of reproductive function. The treated group received trimethoprim-sulfamethoxazole and pyrimethamine for 90 days during summer and fall; the control group was not treated. Semen characteristics, sexual behavior, testicular volume, and sperm produc...
Secular sperm trends in stallions between 1981 and 1996. Several reports have suggested that human semen quality has declined throughout the world over the last few decades. Chemicals in the environment acting as endocrine disrupters have been implicated as a possible cause. If this is indeed the case, then similar effects may be observed in animals. We analyzed 1489 ejaculates collected from 390 Breton draught stallions between 1981 and 1996. Semen was collected from all the stallions at a single center, according to standardized semen collection protocols and laboratory methods. Semen volume decreased slightly but significantly and there was an in...
In vitro interactions of cryopreserved stallion spermatozoa and oviduct (uterine tube) epithelial cells or their secretory products. Formation of a spermatozoa ('sperm') reservoir in the mare is thought to occur through lectin-mediated sperm attachment to the oviductal epithelium. Once attached, prefertilization sperm survival is supported by oviductal factors. Cryopreservation of stallion sperm decreases the number of sperm attaching to oviduct epithelial cells (OEC) and the length of time these sperm survive. Quantification of in vitro interactions between sperm and OEC in a co-culture system may provide an assay for functional integrity of cryopreserved or fresh sperm samples. Additionally, superior additives for in vitr...
Detection of equine arteritis virus in semen by reverse transcriptase polymerase chain reaction-ELISA. The reverse transcriptase polymerase chain reaction (RT-PCR) assay was used to detect Equine Arteritis Virus (EAV) in the semen of 88 horses and 2 donkeys, with neutralising antibodies against EAV, on the basis of the amplification of a 279 bp long fragment located in the viral polymerase gene. The RT-PCR assay revealed the virus at 4 TCID50/ml in cell culture and showed a greater sensitivity (54.4%) than cell culture isolation (33.3%). Moreover, the two samples of donkey semen were found positive. The cDNAs obtained from 14 samples of horse and 2 of donkey semen were sequenced. Comparing the ...
Freezing of stallion semen with addition of glycine betaine. The effect of addition of glycine betaine to a lactose-EDTA freezing medium on the post-thaw motility of stallion semen was determined. The first three semen-rich fractions of nine stallions were collected with an open-end Krakow artificial vagina on consecutive weekdays. Semen was frozen using the Hannover method with freezing media containing glycine betaine in various concentrations from 0 to 5%. After thawing, sperm motility was analysed both by a light microscope and by a Hamilton-Thorn Motility Analyser. Total and progressive post-thaw motilities of semen containing 0.25-3% glycine betai...
Effects of bovine serum albumin on function of cryopreserved stallion spermatozoa during medium culture and uterine tube epithelial cell coculture. To compare function of cultured cryopreserved stallion spermatozoa in a modified Tyrode's medium (TM), with or without bovine serum albumin (BSA), or in uterine tube (oviduct) epithelial cell (OEC) coculture in TM, with or without BSA. Methods: Cryopreserved spermatozoa from 6 proven stallions and OEC from bovine reproductive tracts in follicular phase. Methods: Thawed spermatozoa were cultured in TM, with or without BSA, or cocultured with OEC monolayers in TM, with or without BSA. Percentages of capacitated and acrosome-reacted spermatozoa were measured at 5 hours for TM cultures. Spermatozo...
Occurrence of prostasome-like membrane vesicles in equine seminal plasma. Equine seminal plasma was shown to contain membrane vesicles that are similar to the well characterized prostasomes in human seminal plasma. Determination of nucleoside and nucleotide concentrations of these particles have shown that ATP, ADP and adenosine are the main components of the nucleotidic pool. 5' nucleotidase, endopeptidase and dipeptidyl peptidase i.v. activities have been found on the surface of the particles. The interaction between these prostasome-like vesicles and spermatozoa was demonstrated by electron micrograph scans which revealed the steps of a fusion-like process leadin...
Glutathione-independent prostaglandin D2 synthase in ram and stallion epididymal fluids: origin and regulation. Microsequencing after two-dimensional electrophoresis revealed a major protein, glutathione-independent prostaglandin D2 synthase (PGDS) in the anterior epididymal region fluid of the ram and stallion. In this epididymal region, PGDS was a polymorphic compound with a molecular mass around 30 kDa and a range of pI from 4 to 7. PGDS represented 15% and 8% of the total luminal proteins present in this region in the ram and stallion, respectively. The secretion of the protein as judged by in vitro biosynthesis, and the presence of its mRNA as studied by Northern blot analysis, were limited to the ...
Serologic and molecular characterization of an abortigenic strain of equine arteritis virus isolated from infective frozen semen and an aborted equine fetus. A virus isolated from an aborted equine fetus was determined to be antigenically distinct from several other strains of equine arteritis virus (EAV) by use of a neutralization assay with a large panel of neutralizing monoclonal antibodies. The virus was readily neutralized by polyclonal equine anti-EAV serum. Comparative nucleotide and amino acid sequence analyses indicated that the virus (WA97) isolated from the aborted fetus was virtually identical to a virus (S1971) isolated from imported semen used to inseminate another mare on the farm. Phylogenetic analysis indicated that the WA97/S1971 ...
Aerobic bacterial flora of semen and stallion reproductive tract and its relation to fertility under field conditions. This study was initiated in order to investigate the bacterial flora of the stallion genital tract by taking consecutive samples from normal stallions in regular use. The objective was to determine whether any growth of potential pathogens, particularly P. aeruginosa and K. pneumoniae, in fresh semen and urethra was associated with the presence of inflammatory cells in the semen and whether bacterial growth had any effect on sperm morphology and pregnancy results. Sixteen stallions, only used for A.I., housed at 3 different commercial stud farms, were used. A wide variety of microorganisms was...
Prostasome-like particles in stallion semen. Human semen contains membranous vesicles called prostasomes. They are secreted by the prostate gland and contain large amounts of cholesterol, sphingomyelin, and Ca2+. Prostasomes enhance the motility of ejaculated spermatozoa and are involved in a number of additional biological functions. No prostasome-like vesicles have been described in horse semen up to now. We have demonstrated the presence of prostasome-like vesicles in the equine semen and characterized them as to size, morphology, and lipid composition; we have found that they are similar to human prostasomes in many respects. We prop...
Endometritis, salpingitis and fertilisation rates after mating mares with a history of intrauterine lumenal fluid accumulation. The occurrence of uterine and oviductal inflammation, and fertilisation rates, were measured on Day 3 post ovulation in inseminated mares that had either exhibited intrauterine lumenal fluid during a previous dioestrus (Experiment 1) or had acute endometritis induced by intrauterine infusion of 1% glycogen (Experiment 2). Endometritis was assessed by uterine cytology and histology whereas oviductal inflammation was measured histologically. Fertilisation rates were calculated from the percentage of cleaved ova recovered by retrograde flushing of the oviducts. Mares with or without pre-existing ...
[Clinical aspects of fertility in stallions]. The studies described in this thesis investigated the factors that can affect the fertility of stallions. The introduction describes the male gamete and the processes that occur during maturation of sperm and fertilization. Methods to evaluate the quality of sperm and ova are then discussed. Fertility can be expressed in various ways and is also affected by many factors such as the stallion, the mare and management factors. The fertility of stallions is usually assessed a good year after they have served mares, because then the number of foals is known. However, it would be preferable to be ab...
Detection of equine arteritis virus in the semen of carrier stallions by using a sensitive nested PCR assay. A nested PCR, developed for the detection of equine arteritis virus (EAV) in semen, detected less than 2.5 PFU of EAV per ml of naturally infected seminal plasma. Based on results from testing 88 semen samples from 70 stallions, the sensitivity and specificity of the test were 100 and 97%, respectively.
[Separation techniques ro achieve vital and reproduction competent equine spermatozoa populations–a survey]. Equine ejaculates are significantly characterized by widely varying parameters especially in those of practical relevance for equine Al. Therefore it is of interest for practical purposes to get subpopulations of concentrated, vital, and competent spermatozoa from the origin ejaculates. Special preparation of the donor stallions will stabilize sperm output. Fractionated semen collection from stallions supplies sperm enriched seminal fractions very useful to work with further in semen preservation. Most important to achieve a concentrated sperm subpopulation are semen manipulations post ejacula...
Effect of milk fractions on survival of equine spermatozoa. Milk-based semen diluents are known to be practical and effective in protecting equine spermatozoa during storage. Due to complex composition of milk, the components which are beneficial or harmful to spermatozoa are unknown. To address these unknowns the effect of various milk fractions on motility of stallion spermatozoa was evaluated. The fractions tested were native phosphocaseinate (NPPC), beta-casein, whey protein concentrate (WPC), alpha-lactalbumin, beta-lactoglobulin, microfiltrate, and ultrafiltrate. The standard reference diluents were INRA 82, commercial skim milk, and Hank's salts...