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Topic:Fertility
Fertility in horses encompasses the physiological processes and factors influencing reproductive success in equine species. It involves the study of reproductive anatomy, endocrinology, and behavior, as well as the management practices that affect breeding outcomes. Key aspects include the estrous cycle, conception rates, and factors impacting stallion and mare fertility. Reproductive technologies such as artificial insemination, embryo transfer, and hormonal therapies are also explored to enhance breeding efficiency. This page compiles peer-reviewed research studies and scholarly articles that examine the biological mechanisms, management strategies, and technological advancements related to equine fertility.
Use of two conventional staining methods to assess the acrosomal status of stallion spermatozoa. The acrosome is a highly specialised region of the spermatozoon that is essential for fertilisation. Defects or dysfunction of this structure have been associated with fertility problems in man and various domestic species including stallions. Current methods of evaluating the acrosome of stallion spermatozoa are time consuming and require specialised equipment, which is cost prohibitive to the average practitioner. Objective: To evaluate 2 conventional stains (Dip Quick and Spermac) and determine their usefulness in assessing acrosome integrity in stallions as compared with specific acrosomal...
First field results on the use of stallion sex-sorted semen in a large-scale embryo transfer program. Flow cytometry sex-sorting technology was developed in 1989. However, it is only the bovine species in which offspring of the desired sex are obtained at a commercial level. The aim of the present work was to evaluate efficiency parameters when using fresh sexed semen in a large-scale equine commercial embryo transfer program. During the 2009, 2010 and 2011 breeding seasons, 938 synchronized cycles were artificially inseminated. One hundred (10.6%) mares failed to ovulate, and for the remaining 838 useable cycles, 887 doses of sexed semen were used, representing 1.06 doses per cycle. In genera...
Use of cholesterol-loaded cyclodextrin: an alternative for bad cooler stallions. During the cooling process, sperm may suffer irreversible damage that compromises the fertility rate. Incorporating cholesterol-loaded cyclodextrin (CLC) represents a strategy to increase sperm resistance at low temperatures; however, high levels of cholesterol in the cell membrane can interfere with sperm capacitation. The goals of this study were to determine the CLC concentration and cooling temperature that produce optimal kinetic parameters and viability of sperm from stallions identified as bad coolers (BCs) and good coolers (GCs), as well as the effect of adding CLC on the occurrence of...
Impairment of the interleukin system in equine endometrium during the course of endometrosis. The aim of the study was to characterize endometrial mRNA transcription, immunolocalization, and protein expression of interleukin (IL) 1alpha, IL1beta, IL6, and IL1RI, IL1RII, and IL6Ralpha/beta in the course of endometrosis during the estrous cycle. Additionally, the influence of IL1alpha, IL1beta, and IL6 on prostaglandin (PG) secretion and PG synthase mRNA transcription in endometrial tissue during endometrosis was investigated. The endometrial samples were obtained at the early (n = 12), mid- (n = 12), and late (n = 12) luteal phases and at the follicular (n = 12) phase of the estrous cyc...
Temporal feeding pattern may influence reproduction efficiency, the example of breeding mares. Discomfort in farm animals may be induced by inappropriate types or timing of food supplies. Thus, time restriction of meals and lack of roughage have been shown to be one source of emergence of oral stereotypies and abnormal behaviour in horses which have evolved to eat high-fibre diets in small amounts over long periods of time. This feeding pattern is often altered in domestic environment where horses are often fed low fibre meals that can be rapidly consumed. This study aimed at determining the effect of the temporal pattern of feeding on reproductive efficiency of breeding mares, One hund...
Indenopyride derivative RTI-4587-073(l): a candidate for male contraception in stallions. The objective of this study was to determine whether an indenopyridine derivative RTI-4587-073(l) was a good candidate for male contraception in horses. We hypothesized that a single administration of RTI-4587-073(l) causes significant suppression of testicular function in stallions without affecting sexual behavior. Three Miniature horse stallions received a single dose of 12.5 mg/kg RTI-4587-073(l) orally (group "treated"), whereas three other Miniature horse stallions received placebo only (group "control"). Semen was collected and evaluated from all stallions twice a week for three baselin...
The role of leptospirosis in reproductive disorders in horses. Leptospirosis is a zoonotic disease of global importance and has a worldwide distribution. This infection displays clear seasonal nature in some regions of the tropics, where the rainy season is marked by high temperatures. Household and wild animals carry leptospires and contribute to their dissemination in nature. Transmission mainly occurs by contact with water contaminated with the urine of infected animals, and consequently, it is quite widespread especially in times of rain, since many areas are subject to flooding and have poor sanitation. Serological tests demonstrate that Leptospira s...
Equine endometrial cytology and bacteriology: effectiveness for predicting live foaling rates. Endometritis is an important cause of sub-fertility in mares. The critical indicator of reproductive success and financial return for commercial studs is live foaling rate. Endometrial bacteriology and/or cytology are used to diagnose endometritis and thus identify mares at risk of early embryonic death. However, mares with endometritis may conceive but then abort in late gestation. The aims of this study were to establish, as part of a standard breeding examination (1) whether a threshold percentage of uterine polymorphonuclear neutrophils (PMNs) exists above which a significant reduction in ...
Biochemical characterization of stallion prostasomes and comparison to their human counterparts. Release of nanometer-sized prostasomes into human and equine semen suggests essential functions in their relationships with sperm cells and the fertilization process. The two types of prostasomes displayed ultrastructural similarities, albeit the human prostasomes were somewhat larger than the stallion prostasomes. A high ratio of saturated fatty acids was characteristic for the two prostasome types. Electrophoretic separation systems revealed an equine prostasomal pattern different from that of human. The 21 distinctive low molecular weight protein spots in the 2D-gel (with no counterparts in...
Involvement of miRNAs in equine follicle development. Previous evidence from in vitro studies suggests specific roles for a subset of miRNAs, including miR-21, miR-23a, miR-145, miR-503, miR-224, miR-383, miR-378, miR-132, and miR-212, in regulating ovarian follicle development. The objective of this study was to determine changes in the levels of these miRNAs in relation to follicle selection, maturation, and ovulation in the monovular equine ovary. In Experiment 1, follicular fluid was aspirated during ovulatory cycles from the dominant (DO) and largest subordinate (S) follicles of an ovulatory wave and the dominant (DA) follicle of a mid-cycle...
Effect of sex sorting on stallion spermatozoa: Heterologous oocyte binding, tyrosine phosphorylation and acrosome reaction assay. The interest on sex sorting by flow cytometry on the equine industry has been increasing over the years. In this work, three different tests were performed in order to evaluate the membrane status of sorted stallion spermatozoa: assessment of binding ability to porcine oocytes, evaluation of acrosome integrity after stimulation with A23187, and detection of tyrosine phosphorylation. These evaluations were made after incubation for 0h, 1.5h and 3h in a capacitating medium. Sorted stallion spermatozoa attached similarly to the porcine oocytes, when compared with control samples. Sorted spermatoz...
Trypan blue/giemsa staining to assess sperm membrane integrity in salernitano stallions and its relationship to pregnancy rates. Aim of this study was to test the reliability of Trypan blue/Giemsa staining to evaluate sperm membrane integrity, acrosomal intactness and morphology in stallion to verify whether it could be applied in vitro as useful tool for sperm fertilizing ability. Fertility data on inseminated mares were collected to evaluate the relationship of sperm quality to pregnancy rates. Forty-one ejaculates were collected from 3 stallions of Salernitano Horse Breed and evaluated for gross appearance, volume, visual motility and membrane integrity with Trypan blue/Giemsa staining and thirty-five mares were inse...
Foaling rates after surgical repair of ventral cervical lacerations using a Trendelenburg position in 18 anesthetized mares. To (1) describe a surgical technique for repair of lacerations of the ventral aspect of the cervix in anesthetized mares in Trendelenburg position; and (2) report conception rates and foaling after repair. Methods: Case series. Methods: Mares (n = 18). Methods: Cervical lacerations were repaired in 2 layers with anesthetized mares in Trendelenburg position. The cervix was retracted caudally with stay-sutures, and after excision of the healed margin of the laceration, the internal cervical mucosa and fibromuscular tissue were sutured in 1 layer with a continuous Lembert pattern. The externa...
Time of foaling in Arabian mares raised in Tiaret, Algeria. To enhance effectiveness of reproduction management in Arabian mares, factors influencing the time of foaling were investigated in this study. Methods: Data were collected at the National Haras of Tiaret in Algeria from 2003 to 2010. The foaling time of 255 Arabian pure bred mares, aged from 3 to 20 years were used for this study. Results: A total of 78.07% of foaling happens between 7 pm and 6 am. Conclusions: The influence of the month of foaling and the sex of the foal, on the time of foaling was statically significant.
Cushioned versus noncushioned centrifugation: sperm recovery rate and integrity. It was hypothesized that optimal sperm recovery rate (RR) without damage to the sperm would be obtained after centrifugation without a cushion solution. Semen collected three times from six light breed stallions was extended to 25 × 10(6) sperm/mL and centrifuged at CON (noncentrifuged), 900NC (no-cushion), 900C (cushion), 1800NC, and 1800C × g for 10 minutes. Sperm concentration, motility (TM and PM), and intact plasma membranes (PLM) and acrosomes (ACR) pre- and postcentrifugation (D0) and after 24 hours (D1) of cooling were evaluated. The RR in the CON (100 ± 0.0), 900NC (93.7 ± 2.9), a...
Relationship between the Placental Retention Time and the Reproductive Performance at the Foal Heat in Thoroughbred and a Comparison with Heavy Draft. The aim of this study was to clarify the relationship between the placental retention time (PRT) and the reproductive performance following mating at the foal heat in Thoroughbreds. For this purpose, we interviewed 292 farmers over a period of 3 years with questionnaires evaluating foaling, expulsion of placenta and reproductive performance at the foal heat in 1,432 mares. The obtained data were later compared with a previous study of heavy draft mares. The average of the PRT of the 1,432 Thoroughbred mares was 58 ± 88 min (mean ± SD). The mean PRT of Thoroughbreds was significantly shorter ...
Influence of equine growth hormone, insulin-like growth factor-I and its interaction with gonadotropins on in vitro maturation and cytoskeleton morphology in equine oocytes. In horses, successful in vitro fertilization procedures are limited by our inability to consistently mature equine oocytes by in vitro methods. Growth hormone (GH) is an important regulator of female reproduction in mammals, playing an important role in ovarian function, follicular growth and steroidogenesis. The objectives of this research were to investigate: the effects of equine growth hormone (eGH) and insulin-like growth factor-I (IGF-I) on the in vitro maturation (IVM) of equine oocytes, and the effects of eGH in addition to estradiol (E2), gonadotropins (FSH and LH) and fetal calf seru...
[Factors affecting pregnancy rates in the German Thoroughbred Breed]. The aim of this study was to evaluate factors affecting pregnancy rates in the German Thoroughbred Breed with particular emphasis on optimisation of fertility rates for breeding stallions of older ages. Methods: Data from the studbooks of the German Thoroughbred Breeding Association from 1996 to 2009 analysed. This analysis included the records of 319 stallions and 6622 brood mares, resulting in 21,372 pregnancies at the end of the season. Results: Pregnancy rates were significantly affected by the age of the stallion and mare as well as the season (month in the breeding season in which coveri...
Induction of ovulation in seasonally anestrous mares under ambient lights using recombinant equine FSH (reFSH). Traditionally, mares are put under artificial lights to advance the first ovulation of the year. The aim of the present study was to determine the efficacy of recombinant equine FSH (reFSH) in stimulating follicular development and advancing the first ovulation of the year in seasonally anestrous mares compared with anestrous mares given a placebo. Both groups of mares were housed under ambient light conditions. Sixty deep anestrous mares of light horse breeds (follicular diameters ≤ 20 mm in diameter and progesterone <1 ng/mL) were maintained under a natural photoperiod at three differen...
Focal adhesion kinases and calcium/calmodulin-dependent protein kinases regulate protein tyrosine phosphorylation in stallion sperm. Protein tyrosine phosphorylation (PY) is a hallmark of sperm capacitation. In stallion sperm, calcium inhibits PY at pH 7.8). These results show for the first time a role for calcium/calmodulin-dependent kinases in PRKA-dependent sperm PY; a non-PRKA-dependent pathway regulating sperm PY; and the apparent involvement of the FAK family of protein tyrosine kinases downstream in both pathways.
Region-specific expression of aquaporin subtypes in equine testis, epididymis, and ductus deferens. The process of water movement in the excurrent duct system of the male reproductive tract is pivotal for establishment of male fertility. The objective was to elucidate expression of aquaporin (AQP) water channels in the stallion reproductive tract. Real-time RT-PCR detected expression of AQP0-5 and AQP7-11 in testis, epididymis, and ductus deferens of mature stallions. There were two main expression patterns: (1) higher expression in testis than in epididymis and ductus deferens (AQP0, -4, -5, -8, -10, and -11); and (2) lower expression in testis than in epididymis and ductus deferens (AQP1, ...
Reactive oxygen species in stallion semen can be affected by season and colloid centrifugation. There are anecdotal reports that equine fertility may decline towards the end of the breeding season. Previous studies have examined differences in sperm quality between the breeding season and non-breeding season but few studies have investigated the proportions of superoxide or peroxide containing spermatozoa at different times during the breeding season. The purpose of this study was to measure the content of these reactive oxygen species (ROS) at the beginning and end of the Swedish breeding season, using flow cytometric analysis of the fluorescence produced after staining with hydroethidi...
Relationships between intrauterine infusion of N-acetylcysteine, equine endometrial pathology, neutrophil function, post-breeding therapy, and reproductive performance. Persistent endometritis in the mare is associated with hypersecretion of mucus by endometrial epithelium and migration of neutrophils into the uterine lumen. This study examines the relationships between N-acetylcysteine (NAC), a mucolytic agent with anti-inflammatory properties, and endometrial architecture, serum neutrophil function, post-breeding therapy, and reproductive performance of NAC-treated mares in a clinical setting. In study 1, endometrial biopsies from mares receiving intrauterine saline (fertile-control, n = 6) or 3.3% NAC (fertile-treatment, n = 6; barren-treatment, n = 10) we...
Factors affecting live foal rates of Thoroughbred mares that undergo manual twin elimination. Mares diagnosed with twin vesicles at 13-17 days after ovulation commonly have one of 2 vesicles manually reduced. It is not known whether vesicle location (adjacent vs. nonadjacent), mare age, mare reproductive status, parity, month of breeding or mare plasma progesterone concentration affects live foal rates. Objective: To determine factors associated with a positive outcome (live foal) in mares undergoing manual twin reduction between 13 and 17 days post ovulation when performed by a single operator. Methods: Retrospective case-control study. Methods: Breeding records and the Jockey Club re...
Pre-selection by double layer density gradient centrifugation improves the fertilising capacity of frozen-thawed, capacitated stallion sperm. The effect of combining double layer density gradient centrifugation (DL-DGC) with different capacitation treatments on the fertilising capacity of frozen-thawed stallion sperm was examined via a heterologous assay involving in vitro-matured, zona pellucida-free bovine oocytes. In a first experiment, aliquots of frozen-thawed stallion sperm were subjected to one of five capacitation treatments without DL-DGC - ionomycin at 1.0μM, 0.1μM, 0.05μM or 0.01μM, or caffeine at 200μg/mL. The fertilising capacity of the semen was then assessed at 18h by staining the above oocytes with 4,6-diamidino...
Sperm trajectories form chiral ribbons. We report the discovery of an entirely new three-dimensional (3D) swimming pattern observed in human and horse sperms. This motion is in the form of 'chiral ribbons', where the planar swing of the sperm head occurs on an osculating plane creating in some cases a helical ribbon and in some others a twisted ribbon. The latter, i.e., the twisted ribbon trajectory, also defines a minimal surface, exhibiting zero mean curvature for all the points on its surface. These chiral ribbon swimming patterns cannot be represented or understood by already known patterns of sperms or other micro-swimmers. The...
The absence of ER-β results in altered gene expression in ovarian granulosa cells isolated from in vivo preovulatory follicles. Determining the spatial and temporal expression of genes involved in the ovulatory pathway is critical for the understanding of the role of each estrogen receptor in the modulation of folliculogenesis and ovulation. Estrogen receptor (ER)-β is highly expressed in ovarian granulosa cells, and mice lacking ER-β are subfertile due to inefficient ovulation. Previous work has focused on isolated granulosa cells or cultured follicles and, although informative, provides confounding results due to the heterogeneous cell types present including granulosa and theca cells and oocytes and exposure to in...
New seminal plasma removal method for freezing stallion semen. Seminal plasma removal, an indispensable step in equine semen cryopreservation, is usually done by centrifugation, but this might cause mechanical damage to sperm. A new method for seminal plasma removal from stallion semen, namely a filter composed of a synthetic hydrophilic membrane (Sperm Filter, BotuPharma, Botucatu, Sao Paulo, Brazil), was recently proposed. The objective of this study was to test the use of the Sperm Filter in the removal of seminal plasma before freezing stallion semen. Ejaculates from 31 stallions were divided into two groups and cryopreserved. In group 1 (G1), seminal...
The effects of kisspeptin on gonadotropin release in non-human mammals. The Kiss1 gene encodes a 145-amino acid pre-peptide, kisspeptin, which is cleaved into smaller peptides of 54, 14, 13, and 10 amino acids. This chapter reviews in detail the effects of kisspeptin on gonadotropin secretion in non-human mammals. Studies of kisspeptin's effects have included both acute and chronic administration regimens via a number of administration routes. Acute kisspeptin stimulates gonadotropin secretion in a wide range of species of non-human mammals, including rats, mice, hamsters, sheep, pigs, goats, cows, horses, and monkeys. In general, the stimulatory effect of kisspep...
