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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.
Effect of homologous follicular fluid from medium-sized and large follicles on in vitro maturation of equine cumulus-oocyte complexes. The in vitro maturation (IVM) of equine oocytes is typically performed using various synthetic media; however, an optimal IVM system for equine oocytes has not been developed. The aim of the present study was to evaluate the effects of two types of follicular fluid (FF) obtained from cyclic mares and two incubation intervals for the IVM of equine cumulus-oocyte complexes (COCs). Follicular fluid was collected from medium-sized (20-29 mm diameter) and large (e30 mm; post-human chorionic gonadotrophin administration) follicles using transvaginal ultrasound-guided follicle aspiration. Compact (n ...
Misregulated Wnt/beta-catenin signaling leads to ovarian granulosa cell tumor development. Misregulation of the Wnt/beta-catenin signaling pathway is a hallmark of several forms of cancer. Components of the Wnt/beta-catenin pathway are expressed in ovarian granulosa cells; nevertheless, its potential involvement in granulosa cell tumorigenesis has not been examined. To this end, human (n = 6) and equine (n = 18) granulosa cell tumors (GCT) were analyzed for beta-catenin expression by immunohistochemistry. Unlike granulosa cells of normal ovaries, most (15 of 24) GCT samples showed nuclear localization of beta-catenin, suggesting that activation of the Wnt/beta-catenin pathway plays ...
Capacitation-like changes in equine spermatozoa following cryopreservation. The primary objective of this study was to assess plasma membrane characteristics and activation of signal transduction pathways in equine spermatozoa during both in vitro capacitation and cryopreservation. Significant plasma membrane restructuring, as assessed by measurement of plasma membrane lipid disorder and phospholipid scrambling, was not observed until after cryopreservation and subsequent thawing (P < 0.05). Although in vitro capacitated cells also displayed increased plasma membrane lipid disorder and phospholipid scrambling (P < 0.05), it appeared that regulation of these even...
Possible negative effects of inbreeding on semen quality in Shetland pony stallions. Inbreeding is widely believed to negatively affect reproductive performance. Indeed, in some species, high levels of inbreeding are thought to be the major cause of poor semen quality. It is, however, not clear whether inbreeding affects fertility in horses. In this study, the relationship between inbreeding and semen quality was examined in 285 immature Shetland pony stallions submitted for breeding soundness examination in March-April of the years 1992-1997. The majority of stallions examined were 3 years old (85%) and their coefficients of inbreeding ranged from 0 to 25% (mean+/-S.D.: 3+/-4...
Effects of recombinant human follicle stimulating hormone on follicle development and ovulation in the mare. The only gonadotrophin preparation shown to stimulate commercially useful multiple ovulation in mares is equine pituitary extract (EPE); even then, the low and inconsistent ovulatory response has been ascribed to the variable, but high, LH content. This study investigated the effects of an LH-free FSH preparation, recombinant human follicle stimulating hormone (rhFSH), on follicle development, ovulation and embryo production in mares. Five mares were treated twice-daily with 450 i.u. rhFSH starting on day 6 after ovulation, coincident with PGF(2alpha) analogue administration; five control mare...
Equine spermatozoal motility and fertility associated with the incorporation of d-(+)-mannose into semen extender. Mannose is capable of decreasing bacterial attachment to the uterine mucosa in mares. Bacteria gain entry into the mare's uterus during breeding; therefore, a practical method to deliver mannose to the uterus is to incorporate it into semen extenders. The effect of mannose on spermatozoal motility and subsequent sperm fertilizing capability is unknown. The present study evaluated progressive spermatozoal motility in semen extender formulations incorporating mannose and assessed the fertility of mares inseminated with a mannose-containing semen extender. In Experiment 1, progressive spermatozoa...
Fertility in the mare after repeated transvaginal ultrasound-guided aspirations. Ovum pick-up (OPU) by transvaginal ultrasound guided aspiration (TUGA) is a procedure applied in equine-assisted reproduction programs such as oocyte transfer and in vitro embryo production. Despite a large number of studies reporting that it is a repeatable and safe technique, little information is available about the effect of repeated punctures on fertility of mares. Moreover, even if flushing follicles improves the oocyte recovery rate, to our knowledge the efficiency of flushing estrous and diestrous follicles has not been evaluated. The aims of the present study were (1) evaluate if repe...
Phase and size variable surface-exposed proteins in equine genital mycoplasmas. Mycoplasma equigenitalium and Mycoplasma subdolum have been associated with infertility, endometritis, vulvitis and abortions in mares, and with reduced fertility and balanoposthitis in stallions. Despite their role in equine genital disorder, determinants of virulence and pathogenesis as well as factors provoking specific host immune responses have not been identified, so far. To establish the major immunogenic components of Mycoplasma (M.) equigenitalium and M. subdolum, antigen profiles of their type strains as well as 30 clinical isolates were compared by SDS-PAGE and immunoblot analysis u...
The sperm chromatin structure assay: a review of clinical applications. The sperm chromatin structure assay (SCSA) was introduced by as a method to determine the susceptibility of sperm DNA to denaturation and how those results related to fertility. This initial study used human sperm and was followed by studies in bulls and boars . This assay was one of the first to introduce the technique of flow cytometry, which has the ability to evaluate specific sperm compartments of large numbers of sperm in a short time, as a methodology to evaluate sperm quality and further define the relationship of sperm quality to fertility. For any assay to be of use clinically, it mu...
Seasonal effects on attempts to synchronize estrus and ovulation by intravaginal application of progesterone-releasing device (PRID) in mares. To investigate seasonal effects on the efficacy of estrus synchronization in mares, we administered a progesterone-releasing device (PRID) intravaginally to eight Haflinger mares for 11 days. In January 3 of 8 mares responded to the treatment with estrus and ovulation, in March 7 with estrus and 6 of 7 mares with ovulation, in June 6 of 7 and in October 7 of 8 mares with estrus and ovulation. Follicle distribution patterns at PRID insertion were different between January/October, March/June and June/October (P<0.05). Number of follicles decreased during PRID treatment in January, March and ...
The role of stallion seminal proteins in fertilisation. Seminal plasma proteins are secretory proteins originating mainly from the epididymis and the accessory sex glands. They are involved in the remodelling of the sperm surface which occurs during sperm transit through the male genital tract and continues later at ejaculation. During this process, collectively called post-testicular sperm maturation, the spermatozoa acquire the ability to fertilise an egg. Seminal plasma proteins have been shown to contribute to early and central steps of the fertilisation sequence, e.g. the establishment of the oviductal sperm reservoir, modulation of capacitati...
Systemic concentrations of hormones during the development of follicular waves in mares and women: a comparative study. Changes in systemic concentrations of FSH, LH, oestradiol and progesterone during the ovulatory follicular wave were compared between 30 mares and 30 women. Based on a previous study, the emergence of the future ovulatory follicle was defined as occurring at 13.0 mm in mares and 6.0 mm in women, and deviation in diameter between the two largest follicles was expected to begin at 22.7 mm in mares and 10.3 mm in women. Mean FSH concentrations were high in mares during the luteal phase, resulting from statistically identified FSH surges occurring in individuals on different days and in different ...
Adding cholesterol to the stallion sperm plasma membrane improves cryosurvival. Cryopreservation induces partially irreversible damage to equine sperm membranes. Part of this damage occurs due to membrane alterations induced by the membrane changing from the fluid to the gel-state as the temperature is reduced lower than the membrane transition temperature. One way to prevent this damage is to increase the membrane fluidity at low temperatures by adding cholesterol to the membrane. Different concentrations of cholesterol-loaded-cyclodextrins (CLC) were added to stallion sperm to determine the CLC concentration that optimizes cryosurvival. Higher percentages of motile sper...
Aversive conditioning of periodic spontaneous erection adversely affects sexual behavior and semen in stallions. Periodic spontaneous erection and penile movements known as masturbation (SEAM) occur normally at approximately 90 min intervals in awake equids. SEAM in horses has traditionally been misunderstood by many horsemen as aberrant behavior that should be eliminated. Accordingly, it is not uncommon for trainers of performance stallions or managers of breeding stallions to punish SEAM in an attempt to eliminate the behavior. Previous clinical observations and preliminary unsystematic trials had suggested that attempts to stop stallion SEAM may lead to an increase rather than a decrease in SEAM, and ...
French field results (1985-2005) on factors affecting fertility of frozen stallion semen. Results on procedures for freezing stallion semen and the subsequent fertility during 20 years are presented. The present system applied in French National Stud includes: (1) a freezing protocol (dilution in milk, centrifugation and addition of freezing extender (INRA82+egg yolk (2%, v/v)+glycerol (2.5%, v/v) at 22 degrees C, a moderate cooling rate to 4 degrees C and freezing at -60 degrees C/min in 0.5-ml straws); (2) selection of ejaculates showing post-thaw rapid motility >35%; and (3) an insemination protocol (mares examined once daily, two AI of 400 x 10(6) spermatozoa 24 h apart befo...
Temporal folate status during lactation in mares and growth in foals. To identify changes in folate status of mares and foals during lactation and growth, respectively. Methods: 20 Thoroughbred mares and foals. Methods: Pregnant mares, and following foaling the same mares with their foals, were maintained on mixed grass-legume pasture and fed either a traditional dietary supplement rich in sugar and starch (SS) or a dietary supplement high in fat and fiber (FF). Blood samples were collected monthly from mares and foals up to 6 months after foaling. Total folate concentration in feed and forage was determined. Analyses of plasma folate, RBC folate, plasma homocys...
