Spermatogenesis in horses is the process by which spermatozoa are produced in the testes. This complex sequence of events involves the proliferation and differentiation of germ cells, supported by Sertoli cells and influenced by hormonal regulation. Key stages include spermatogonial mitosis, meiosis, and spermiogenesis, resulting in the formation of mature sperm cells. Hormones such as testosterone and follicle-stimulating hormone (FSH) are integral to regulating this process. This topic encompasses research studies and scholarly articles that explore the mechanisms, hormonal influences, and factors affecting spermatogenesis in horses, as well as its implications for equine reproduction and breeding management.
Roser JF, Hughes JP.Seasonal effects on hormonal and seminal parameters in subfertile stallions have not been well documented and could provide information that is needed to understand the underlying endocrine mechanisms associated with testicular dysfunction. Such information may be useful in developing diagnostic tools to identify those stallions who are candidates for treatment. This investigation characterizes and compares the effects of season on endocrine function and seminal quality in fertile and subfertile stallions. Eight fertile and six subfertile stallions between the ages of 5 and 18 years were injec...
Little TV, Holyoak GR.Examination of the stallion's reproductive tract involves assessments of external and internal anatomy. External examinations are performed by visual inspection, palpation, or ultrasonography and include the scrotum, testes, epididymides, penis, and prepuce. Internal examinations may be performed by rectal palpation, transrectal ultrasonography, or endoscopy and include the accessory sex glands, pelvic urethra, and inguinal rings. A fertile stallion must produce, transport, store, and deliver viable spermatozoa to the mare. The physiologic processes involved include neuroendocrine control, spe...
McDonnell SM.In summary, important events of ejaculation include emission of sperm and the accessory gland fluids into the urethra, simultaneous closure of the bladder neck, and forceful ejaculation of the combined semen through the urethra. Emission and bladder neck closure are primarily alpha-adrenergically mediated thoracolumbar sympathetic reflex events with supraspinal modulation. Ejaculation is a sacralspinal reflex mediated by the pudendal nerve. In stallions, the most common ejaculation disorders are emission and ejaculation failure, and urine contamination of semen. Rare disorders are azoospermia ...
Jasko DJ.This article outlines a basic method for conducting a stallion semen evaluation. After the removal of the gel fraction of the ejaculate, semen gel-free volume is determined, and any abnormality in appearance is noted. Concentration of sperm cells in semen can be determined with the use of either a hemacytometer or spectrophotometer after appropriate dilution of raw semen. The percentage of progressively motile sperm is evaluated promptly after collection of semen with the use of a phase-contrast microscope. The total numbers of sperm and progressively motile sperm in the ejaculate are calculat...
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...
Power MM, Gustavsson I, Switoński M, Plöen L.Synaptonemal complex analysis by electron microscopy of a trisomy 28 in a male horse demonstrated a trivalent or a bivalent plus a univalent in primary spermatocytes. Two of the chromosomes making up the trivalent were, most often, completely paired with each other and only partially paired or associated with the third one. Half of the spermatocytes analysed demonstrated heterologous pairing or association between the free axis of the trivalent and the sex bivalent. The pairings remained, to a large extent, into diakinesis-metaphase I. In most pachytene cells one autosomal bivalent showed prox...
Held JP, Prater P, Stettler M.A 9-year-old Arabian stallion with a 3-year history of infertility was evaluated for breeding soundness. Both testes were small. Ultrasonography revealed a small amount of free fluid between the tunics of both testes. Results of cytologic examination of the fluid were unremarkable. On semen examination, progressive motility was 10%, and total number of spermatozoa in the ejaculate was 6.6 x 10(9), of which 92% were abnormal. Predominant abnormalities were head defects (75%): 57% of the heads had single or multiple vacuoles, and 60% also had midpiece swelling or bending.
Hrudka F, Betsch JM, Kenney RM.Anomalies of centriolar derivatives were identified in ejaculates and testicular and tracheal biopsies of a sterile stallion, using light, scanning, and transmission electron microscopy. LM revealed that over half the sperm population had only a vestigial or no tail, while the rest had tails of variable length and shape. The vestigial tail was represented by its anlage, which was implanted on the nucleus and differentiated up to capitulum and collum stage. The stunted tail had an axoneme and its derivatives, but was short in all tail segments. Regardless of the tail length or shape, virtually ...
Johnson L, Varner DD, Tatum ME, Scrutchfield WL.To evaluate the effect of age and season on Sertoli cell number per paired testes, ratio of germ cells per Sertoli cell, and daily sperm production, testes were obtained from 184 adult (4-20 yr) stallions at slaughter throughout one year. Numbers of Sertoli cells or germ cells were derived from nuclear volume density, volume of individual nuclei, and parenchymal volume. Germ cell to Sertoli cell ratios were calculated from cell numbers. Regression analysis was used to detect age-related differences in the breeding season (May-Jul) or throughout the year. A two-way analysis of variance was used...
Monet-Kuntz C, Guillou F, Fontaine I, Combarnous Y.Using a suspension of seminiferous tubule cells, we had previously shown that equine FSH is superactive in the male rat, i.e. that it exhibits a higher biological potency than expected from its binding activity. In this work we investigated equine FSH superactivity in rat, pig and sheep, by comparing in each species the equine FSH with the homologous FSH, both for their binding activities (in a radioreceptor assay using a testicular membrane fraction) and for their in vitro biological potencies (in a plasminogen activator assay using a Sertoli cell-enriched population cultured on plastic). In ...
Johnson L.Spermatocytogenesis plays a pivotal role in regulation of spermatogenesis; however, its details remain relatively obscure in nonrodent species. The equine testis contains approximately 100% more spermatogonia in summer than in winter and appears to be a good model to identify the flexible components of spermatocytogenesis that cause seasonal changes in daily sperm production. Testes were taken from horses in the winter (n = 47) and in summer (n = 43). Tissues were fixed by glutaraldehyde-perfusion and submission in osmium, embedded in Epon or methacrylate, sectioned at 0.5 micron or 5 microns,...
López ML, de Souza W.The presence and distribution of cholesterol in mature and immature epididymal spermatozoa was analyzed using filipin as a cytochemical tool in freeze-fracture replicas and thin section preparations. The polyenic-antibiotic filipin formed complexes with 3, beta -OH sterols, producing characteristic protrusions, or pits, that were heterogeneously distributed in the plasma membrane of stallion spermatozoa, revealing a specific organization in a functionally specialized area of the gamete. The acrosomal region of the sperm head presented a significantly higher density of filipin sterol complexes ...
Johnson L, Varner DD, Thompson DL.To determine the age at which adult values for hormonal and testicular characteristics are established, testes and blood from 123 slaughtered horses, aged 1-5 years, were compared. Serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) and intratesticular testosterone (ITT) were determined by radio-immunoassay. Specimens were obtained in the non-breeding (n = 46) or breeding (n = 43) season in Experiment 1 (Exp. 1) and in the breeding (n = 34) season in Experiment 2 (Exp. 2). Testicular parenchyma was fixed in glutaraldehyde and homogenized to...
Seamans MC, Roser JF, Linford RL, Liu IK, Hughes JP.Six normal stallions of light horse breeds aged 5-17 years were used from fall to winter to investigate the difference between steroid hormone concentrations in testicular and jugular venous blood before and after exogenous GnRH. At 48 h before experimentation, an indwelling cannula was placed surgically in the testicular vein of the stallion. After the stallion recovered from anaesthesia, a catheter was placed percutaneously in the jugular vein. Each stallion was housed in a tie stall to allow simultaneous sampling of jugular or testicular blood. On the first and second sampling days, respect...
Samper JC, Hellander JC, Crabo BG.Studies were designed to investigate whether sperm motility determined with a Hamilton-Thorn HTM-2000 motility analyzer (HTM), or the percentage of spermatozoa that passed through glass wool (GW), Sephadex (S), or glass wool/Sephadex (GWS) filters could be used to predict the fertilizing potential of fresh or frozen semen. In the fresh semen study, 10 randomly selected ejaculates from 4 stallions exclusively used for A.I. breeding were assayed during the season. The 521 mares used were inseminated with 500 x 10(6) motile spermatozoa after gynaecological examination every 2 days. In the frozen ...
Blue BJ, Pickett BW, Squires EL, McKinnon AO, Nett TM, Amann RP, Shiner KA.Gonadotrophin-releasing hormone (GnRH) was administered subcutaneously to reproductively normal stallions, either in a pulsatile manner (10 micrograms GnRH/2 h; n = 6) or as a continuous infusion (10 micrograms GnRH/2 h; n = 6), and in a pulsatile manner to 9 reproductively abnormal stallions, from February to July, 1988. Hormonal secretion patterns, testicular parameters and semen characteristics were monitored before and during treatment. In general, pulsatile GnRH caused a significant increase (P less than 0.05) in luteinizing hormone (LH) concentrations in the peripheral blood of normal st...
Freidman R, Scott M, Heath SE, Hughes JP, Daels PF, Tran TQ.Stallions can experience an increase in testicular temperature from bouts of fever or from injury to the testes. In species other than the horse, increased temperature models have been used to study testicular degeneration. This study was undertaken to examine the effects of increased testicular temperature on spermatogenesis in the stallion as measured by semen evaluation. The results of this investigation demonstrate that increased testicular temperature is associated with significant transitory alterations in the routine semen evaluation of the stallion. The duration of increased testicular...
Dowsett KF, Pattie WA, Knott LM, Jackson AE, Hoskinson RM, Rigby RP, Moss BA.This study tested the effectiveness of a conjugated GnRH vaccine for stimulating antibody production, suppressing testosterone secretion and depressing testicular development in yearling colts. Two colts were allocated to each of three groups, (1) control, (2) subcutaneous and (3) intramuscular vaccinations. Two injections of the vaccine were given 11 weeks apart. Liveweight gain was not affected by vaccination but plasma testosterone concentrations in the treated colts were suppressed and their antibody titres to GnRH were greater than 1:1000. Testicular development in the treated colts also ...
Boyle MS, Skidmore J, Zhang J, Cox JE.The effect of long-term treatment of stallions with a powerful gonadotrophin-releasing hormone (GnRH) analogue was investigated. In the first part of the study, 9 sexually mature pony stallions were allocated to 1 of 3 groups, each of which was treated with 240 micrograms or 60 micrograms Buserelin per day administered by subcutaneously sited osmotic pumps or 30-50 micrograms Buserelin per day via solid, slow-release implants injected subcutaneously. Peripheral blood plasma and serum samples were collected frequently and assayed for follicle-stimulating hormone (FSH) and luteinizing hormone (L...
López ML, Olea N, Retamal CA.Freeze-fracture replicas of stallion spermatozoa, collected from the proximal caput, corpus and cauda epididymides regions, were analyzed by electron microscopy to explore the distribution and density of intramembrane particles (IMP). Conspicuous differences in density and arrangement of the IMP were observed in the different topographical domains of mature and immature spermatozoa. A reduction of IMP, especially remarkable in the post-acrosomal domain, was observed in mature epididymal spermatozoa when compared with samples collected from ductuli efferentes. Some structural species-specific d...
Guimarães T, Lopes G, Ferreira P, Leal I, Rocha A.Cryopreservation of epididymal spermatozoa is a useful tool to preserve genetic material of valuable stallions after emergency castration or unexpected death. For that, testicles and epididymides are generally sent refrigerated to the laboratory. Collection of epididymal spermatozoa is a simple procedure that reduces the volume of the material to be shipped, and may improve the quality of the chilled epididymal sperm cells. In the present study we compared the characteristics of frozen/thawed epididymal spermatozoa after refrigeration of the epididymis or after direct refrigeration of the exte...
Bugno-Poniewierska M, Kij-Mitka B, Podstawski Z, Długosz B, Lasek O, Mrowiec P, Tischner M.The use of frozen semen lowers the risk of disease transmission, eliminates geographical limitations and supports the implementation of genetic resource protection programs. However, due to the very rare use of frozen semen from Hutsul stallions, their genetic material is not secured in sperm banks, and very little information is available about their semen, including its suitability for cryopreservation, and sperm survival rates after thawing. The aim of this study was to analyse basic parameters such as sperm motility, vitality and morphology in diluted-stored and post-thawed Hutsul semen, u...
Jung H, Kim N, Yoon M.The main objective of this study was to evaluate the efficacy of an additional cryoprotectant in 10% dimethyl sulfoxide (DMSO) on cryopreserving germ cells from stallions at different reproductive stages. Testicular samples were obtained from pre-pubertal (1-1.5 yr, n=6) and post-pubertal (3-7 yr, n=5) stallions. Germ cells were isolated using a two-enzyme digestion procedure and cryopreserved in minimal essential medium alpha containing 10% fetal bovine serum and 10% DMSO with or without addition of trehalose (50, 100, or 200mM) or polyethylene glycol (PEG, 2.5, 5, or 10%). Viability, cell po...
Ha TY, Kim HS, Shin T.The expression of three isoforms of nitric oxide synthase (NOS) were examined in the testis and epididymis of a thoroughbred horse. Immunohistochemical studies demonstrated the presence of eNOS immunostaining in some germ cells in the seminiferous tubules and in vascular endothelial cells in the interstitial tissues. Interstitial cells, most likely Leydig cells, were also intensely immunopositive for eNOS. The pattern of immunostaining for nNOS was similar to that for eNOS in the testis. Weak expression of iNOS was detected in the seminiferous tubules of the testis, but intense expression was ...
Thomson CH, Thompson DL, Kincaid LA, Nadal MR.To test the hypothesis that prolactin mediates the increase in seminal volumes induced by sexual stimulation in stallions, semen was collected from six stallions every other day for 26 d. The last eight collection days were treatment days. For each stallion, four treatments were randomly assigned to the first four of the eight treatment collection days, and then repeated in reverse order on the last four collection days; 1) CONTROL: semen collected per normal procedures; 2) Sexually stimulated: stallions were presented to mares in a chute for 10 min before collection; 3) Bromocriptine (dopamin...
Weber JA, Geary RT, Woods GL.Ultrasonographic images of the accessory sex glands of 8 stallions were recorded immediately prior to sexual preparation, immediately after sexual preparation, and immediately after ejaculation. Relative size changes, determined by measurements of ultrasonograms of accessory sex gland, were contrasted. Length and width of the bulbourethral glands increased significantly (P less than 0.05) after sexual preparation and decreased significantly (P less than 0.05) after ejaculation. The increase in bulbourethral gland volume following sexual preparation was correlated significantly (P less than 0.0...
Scully CM, Lee RL, Pielstick L, Medlock J, Patton KM, Collins GH, Kutzler MA.Free-roaming horse (Equus caballus) management is a complex issue incorporating social, economic, emotional, political, and environmental factors. Currently, few proven field techniques exist for managing free-roaming horse population growth, which can reach 20-25% annually. Although there are several strategies available for sterilizing mares when managing free-roaming horse populations, surgical vasectomy is the only method used in the field for stallions. Some managers believe that surgically vasectomizing dominant stallions would have significant effects on reducing horse populations. Howe...
Rodriguez H, Bustos Obregon E.The fertilizing ability of stallion semen was analyzed using fresh and frozen samples, obtained before (June-July) or during (October-November) the breeding season. Thirty ejaculates obtained from 4 stallions were used. The analysis comprises routine seminogram; ATP concentration (Comhaire et al., 1983); subjective and objective motility and sperm velocity (Makler, 1980). Freezing was done following the technique of Martin et al. (1979). Sperm velocity, ATP content and objective motility in ejaculates of subjective motility >50% show values of 14.0 + or - 0.84 mu m s(-1); 4.8 + or - 2.7x10(...
Novello G, Segabinazzi LGTM, Lisboa FP, Canuto LE, Freitas-Dell'Aqua CP, Dell'Aqua JA, Canisso IF.This study compared the postthaw semen parameters of stallions with high and low body condition score (BCS) and evaluated associations between body morphometric parameters and postthaw semen parameters. Twenty stallions were split into Low BCS (BCS<7, n = 11) and High BCS (BCS ≥7, n = 9) groups, and underwent a complete morphometric analysis (e.g., neck scores and circumference, crest neck height, body weight, and height), and subcutaneous body fat thickness (SFT) at the tail head, withers, shoulders, and retroperitoneal space. A fasted oral sugar test (OST) was conducted on all stallio...
Penzhorn BL, van der Merwe NJ.Testis mass of adult Cape mountain zebra stallions (mean 70.0 g) was appreciably less than that of other zebra species and domestic horses. The histological appearance of the testes of 11-, 24- and 29-month-old colts was typically prepubertal. Spermatogenic activity of a 4-year-old stallion obtained at the end of summer was at a very low level, while a 4.5-year-old stallion obtained 6 weeks after the winter solstice showed a marked increase in spermatogenesis compared with the 4-year-old. Stallions 6.5-19 years of age collected in different seasons all showed active spermatogenesis.
Davolli GM, Ball BA, Esteller-Vico A, Claes AN, Canisso IF, Fedorka CE, Woodward EM, Troedsson MH, Squires EL.The GnRH antagonist, acyline, has not yet been investigated in the stallion. Our study aimed to: (1) evaluate the downregulation of the stallion hypothalamic-pituitary-gonadal axis by acyline through assessment of seminal parameters, testicular volume, and sexual behavior; (2) assess hormonal response of acyline-treated stallions to GnRH stimulation; and (3) verify reversibility after treatment. Stallions were assessed pretreatment and subsequently treated (every five days) for 50 days: acyline (n = 4; 330 μg/kg acyline) or control (n = 4, vehicle). The stallions were then monitored for 62...
Robles M, Dubois C, Gautier C, Dahirel M, Guenon I, Bouraima-Lelong H, Viguié C, Wimel L, Couturier-Tarrade A, Chavatte-Palmer P.Primiparous mares are known to produce smaller foals than multiparous mares. This difference seems to be partly explained by the reduced exchange surface and volume of the placental villi in primiparous compared to multiparous placentas. The effect of maternal parity on foals' post-natal growth, metabolism and sexual maturation, however, has been given little consideration. The objectives of this work were to analyse placental biometry and structure at term, growth of foals and yearlings, their metabolism and testicular maturation at one year of age. Twenty multiparous mares (M), aged over 6 y...
López ML, de Souza W.The presence and distribution of cholesterol in mature and immature epididymal spermatozoa was analyzed using filipin as a cytochemical tool in freeze-fracture replicas and thin section preparations. The polyenic-antibiotic filipin formed complexes with 3, beta -OH sterols, producing characteristic protrusions, or pits, that were heterogeneously distributed in the plasma membrane of stallion spermatozoa, revealing a specific organization in a functionally specialized area of the gamete. The acrosomal region of the sperm head presented a significantly higher density of filipin sterol complexes ...
Gracia-Calvo LA, Ezquerra LJ, Ortega-Ferrusola C, Martín-Cuervo M, Tapio H, Argüelles D, Durán ME.In order to know reproduction-related complications due to standing laparoscopic peritoneal flap hernioplasty, histological characteristics of the testicles from five stallions one year after surgery were compared with seven testicles from four healthy stallions. Moreover, the daily sperm output (DSO) was determined before (T0) and one year after surgery (T12). DSO did not show significant differences between T0 and T12. The diameter of the seminiferous tubules was significantly decreased in the samples from the hernioplasty group. The percentage of tubules with full spermatogenesis was smalle...
Klug E, Deegen E, Lazarz B, Rojem I, Merkt M.Successful empirical treatment of 17 out of 24 stallions, which had failed to ejaculate after normal penile erection, intromission and friction, by chemical blockage of beta-receptors and additional stimulation of alpha-receptors led us to investigate stallions with normal ejaculatory patterns. In an initial experiment one adult half-bred stallion was injected with 4.88 mg noradrenaline hydrochloride (treatment A), 10 mg bunitrolol (treatment B = beta-receptor blockage) and a combination of treatment A and B. Investigations of the same stallion on dated occasions without treatment served as co...
Salazar P, Graham JK, Parrish JJ, Susko-Parrish J, Squires EL.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...
Deichsel K, Schrammel N, Aurich J, Aurich C.Increasing day length in spring stimulates reproductive functions in horses. In this study, we have analysed the effect of artificial long days on the quality of cooled-stored and cryopreserved semen in Shetland stallions. Stallions of the treatment group (AL, n = 8) were exposed to 16 h light and 8h darkness from 15th December to 20th March while control stallions (CON, n = 7) were kept under natural photoperiod. Semen was collected once weekly and processed for cooled-storage and cryopreservation once per month. Total and progressive motility and percentage of membrane intact spermatozoa wer...
Bucci D, Giaretta E, Merlo B, Iacono E, Spinaci M, Gadani B, Mari G, Tamanini C, Galeati G.Alkaline phosphatase (AP) is present in equine seminal plasma and spermatozoa, but its functional role is not fully understood yet. Being that, sperm-oocyte interaction in equine species has been reported to be enhanced at a slightly basic pH, this work aimed at verifying whether exogenous alkaline phosphatase exerts any role on stallion spermatozoa and sperm-oocyte interaction at different pHs (7.4; 8.0; 9.0). Stallion spermatozoa were capacitated in Tyrode's medium at pH 7.4, 8.0, and 9.0 for 4 hours at 38 °C, 5% CO with 2.5-IU AP (AP group) or without AP (capacitated spermatozoa group); ...
Laseca N, Cánovas Á, Valera M, Id-Lahoucine S, Perdomo-González DI, Fonseca PAS, Demyda-Peyrás S, Molina A.The phenomenon in which the expected Mendelian inheritance is altered is known as transmission ratio distortion (TRD). The TRD analysis relies on the study of the transmission of one of the two alleles from a heterozygous parent to the offspring. These distortions are due to biological mechanisms affecting gametogenesis, embryo development and/or postnatal viability, among others. In this study, TRD phenomenon was characterized in horses using SNP-by-SNP model by TRDscan v.2.0 software. A total of 1,041 Pura Raza Español breed horses were genotyped with 554,634 SNPs. Among them, 277 horses ge...
Blanc G, Magistrini M, Palmer E.Semen from three ejaculates from each of 4 stallions was frozen in liquid nitrogen. Morphology was evaluated by coating the spermatozoa with fluorescein-labelled Concanavalin A (FITC-ConA2) and motility was measured by computer-assisted image analysis. Coating was performed at each step of the freezing procedure (dilution, cooling, addition of glycerol and freeze-thawing) and observations were made after each step, to evaluate changes, or after subsequent steps, to determine protection provided by the coating method. All the parameters showed progressive changes during the freezing procedure. ...
Zeng W, Alpaugh W, Stefanovski D, Schlingmann K, Dobrinski I, Turner RM.The study of spermatogenesis in the horse is challenging because of the absence of an in vitro system that is capable of reproducing efficient spermatogenesis and because of the difficulties and costs associated with performing well-controlled studies in vivo. In an attempt to develop novel methods for the study of equine spermatogenesis, we tested whether cells from enzymatically digested pre-pubertal equine testicular tissue were capable of de novo tissue formation and spermatogenesis following xenografting under the back skin of immunocompromised mice. Testes were obtained from normal pre...
Snoeck PPDN, Pessoa THO, Pereira MGS, Bastos ICL, de Melo MIV.The objective of this study was to compare the BotuCrio extender with the Merk - egg yolk and the INRA 82 modified by the inclusion of acetamide, methyl cellulose and trehalose in substitution of glycerol for freezing equine semen. The semen was diluted after centrifugation to obtain 100 x 10 of sperm/ml in: BotuCrio (control); Merk - egg yolk or INRA 82 modified (Experiment 1). The extended semen was packaged in 0.5 ml straws, cooled and frozen in a freezing machine. The control extender was superior in preserving the motility, VCL, VSL, VAP, LIN, STR and the BCF when compared to the Merk - e...
Aurich C, Seeber P, Müller-Schlösser F.To maintain the fertility of stallion spermatozoa during cooled storage, extender media are added to semen. In this study, three semen extenders were compared: EquiPro which contains defined caseinates and whey proteins instead of dried skim milk. The extender is provided in dry form and dissolved in distilled water prior to use. EquiPro TM has the same composition as EquiPro but is provided in a sterilized ready-to-use liquid form. AndroMed-E contains soybean lecithin as protein source. Semen was collected from seven stallions. Ejaculates were divided into three aliquots, diluted with the dif...
DelVento VR, Amann RP, Trotter GW, Veeramachaneni DN, Squires EL.A sample of testicular parenchymal tissue, approximately 2 x 7 x 7 mm, was aseptically removed from 1 testis in each of 9 stallions on day 0. Slight to moderate hemorrhage from the tunica albuginea was observed in 8 stallions, but bleeding from the parenchyma was detected in only 2 stallions. Stallions were castrated 27 days later. Normal development of granulation tissue was evident at the biopsy site, but hematomas were not observed. In situ measurement of the widths of the right and left testes, total scrotal width, and evaluation of testicular echogenicity during ultrasonography were varia...
Gonçalves AR, Telo da Gama L, Antunes L, Guimarães H, Bliebernicht M, Duarte JC, Cosinha C, Duarte Rego B, Ferro da Costa P, Guimarães T, Rocha A....The objectives of this study were to establish baseline information for seminal traits in Lusitano stallions, to assess the impact of inbreeding, interval between collections and age on semen quality during the breeding and non-breeding seasons, and to estimate the corresponding genetic parameters. A total of 2129 ejaculates by 146 Lusitano stallions used for artificial insemination, obtained from four equine reproduction centers distributed throughout Portugal, over a period of 14 years (2008-2021), were included in the study. The seminal traits analyzed, and the corresponding means and stand...
Jones LS, Berndtson WE.Testes from 47 stallions, 1-20 yr of age, were used to examine the influence of age on Sertoli and germ cell populations as well as on functional activity of Sertoli cells. For these stallions, the number of Sertoli cells per paired testes declined linearly with age, and was only 41.7% as great at age 20 as at age 2. However, development of reproductive organs proceeded until age 12-13, as evident from increases in paired testes weight and quantitative rates of spermatozoal production. Although the absolute number of Sertoli cells declined during this period of development, individual Sertoli ...
Pessoa GA, Martini AP, Trentin JM, Minela T, Fiorenza MF, Rubin MIB.The aim of this study was to compare the sperm separation technique using filtration through glass wool compared with just diluted cooled semen. Eighteen ejaculates were collected from 6 pony stallions of the Brazilian pony breed. Evaluations were done on pH, osmolarity, total motility, membrane functionality (HOST), membrane integrity (CFDA/PI), morphology and mitochondrial viability (MTT) in fresh, 24 and 48 h of cooled semen at 5°C. After dilution, the half of the extended semen was cooled (control group). The other half was cooled after filtration trough glass wool (filtered group). Reta...
Unilateral orchiectomy (UO) may interfere with thermoregulation of the remaining testis caused by inflammation surrounding the incision site, thus altering normal spermatogenesis and consequently sperm quality. Two measures of sperm DNA quality (neutral comet assay and the sperm chromatin structure assay [SCSA]) were compared before UO (0 days) and at 14, 30, and 60 days after UO to determine whether sperm DNA changed after a mild testis stress (i.e., UO). The percent DNA in the comet tail was higher at 14 and 60 days compared to 0 days (P < 0.05) after UO. All other comet tail measures (i....
Álvarez C, González N, Luño V, Martínez F, Gil L.The aim of this study was to test and compare two new components in extenders for freezing donkey semen: mare colostrum and jenny colostrum. Colostrum was obtained from four mares and four jennies right after the foal's birth. Ejaculates were collected from five fertile donkeys. Sperm samples were pooled, diluted and cryopreserved in three different experimental extender groups: lactose supplemented with egg yolk extender (20%) as the control group, lactose supplemented with jenny colostrum extender (20%), and lactose supplemented with mare colostrum extender (20%). After thawing, we evaluated...
