Omneity® Pellets
All-In-One Vitamin & Mineral Pellet
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.
Refined genome-wide comparative map of the domestic horse, donkey and human based on cross-species chromosome painting: insight into the occasional fertility of mules. We have made a complete set of painting probes for the domestic horse by degenerate oligonucleotide-primed PCR amplification of flow-sorted horse chromosomes. The horse probes, together with a full set of those available for human, were hybridized onto metaphase chromosomes of human, horse and mule. Based on the hybridization results, we have generated genome-wide comparative chromosome maps involving the domestic horse, donkey and human. These maps define the overall distribution and boundaries of evolutionarily conserved chromosomal segments in the three genomes. Our results shed further lig...
Absence of effects from immunocontraception on seasonal birth patterns and foal survival among barrier island wild horses. Despite a large body of safety data, concern exists that porcine zonae pellucidae (PZP) immunocontraception--used to manage wild horse populations--may cause out-of-season births with resulting foal mortality. Our study at Assateague, Maryland indicated the effects of immunocontraception on season of birth and foal survival between 1990 and 2002 on wild horses from Assateague Island. Among 91 mares never treated, 69 (75.8%) of foals were born in April, May, and June (in season). Among 77 treated mares, 50 (64.9%) were born in season. Of 29 mares foaling within 1 year after treatment (contracep...
Treatment of suckling beef cattle with a progestagen sponge and oestradiol benzoate or equine chorionic gonadotrophin. The ovarian responses of anoestrus beef cows to a combined treatment with medroxy-progesterone acetate (MAP) sponges and oestradiol benzoate or equine chorionic gonadotrophin (eCG) were evaluated. Forty-five suckling Hereford cows were allocated to three equal groups. Group 1 received a MAP sponge for seven days plus an injection of 2 mg oestradiol benzoate when the sponge was inserted (day 0) and 1 mg when the sponge was withdrawn; group 2 received identical treatment until day 7, when a dose of 400 iu of eCG was administered, and group 3 were left untreated as control animals. From day 0 to ...
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...
Blastocyst formation rates in vivo and in vitro of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. This study was conducted to evaluate in vivo and in vitro development of in vitro-matured equine oocytes fertilized by intracytoplasmic sperm injection. Oocytes were collected from slaughterhouse-derived ovaries, matured in vitro, and injected with frozen-thawed stallion sperm. In vivo development was assessed after transfer of injected oocytes to the oviducts of recipient mares. Mares were killed 7.5-8.5 days after transfer and the uterus and oviducts flushed for embryo recovery. Of 132 injected oocytes transferred, 69 (52%) were recovered; of these, 25 (36%) were blastocysts with a blastocoe...
Relationship between seminal plasma lactoferrin and gonadal function in horses. Total 78 semen samples were obtained from 27 Thoroughbred stallions (aged 6 to 27 years), and were subjected to quantification of lactoferrin (Lf) in seminal plasma and examination of the seminal properties. The seminal plasma Lf concentration varied from 21 to 689 microg/ml, with a mean value of 244 +/- 151 microg/ml (S.D.). The seminal plasma Lf concentration and total seminal plasma Lf positively correlated with the sperm concentration (r=0.5938, P<0.001) and with the total sperm number (r=0.6959, P<0.001), respectively. There was no correlation between seminal plasma Lf and sperm mot...
Influence of exogenous GnRH on sexual behavior and frozen/thawed semen viability in stallions during the non-breeding season. Twelve fertile stallions were divided into two groups, either receiving gonadotropin-releasing hormone (GnRH) (n = 6) or Placebo (n = 6). Based on the history of frozen/thawed semen characteristics three stallions within each group were assigned as being "good freezers" [GnRH (+); Placebo (+)] and three stallions were assigned as being "poor freezers" [GnRH (-); Placebo (-)]. The study was performed as a "blinded" investigation and stallions were treated twice daily by an intramuscular injection of 1 ml GnRH (Buserelin), 50 microg) or Placebo. The experiment was divided into three time periods...
Patterns of intracellular calcium oscillations in horse oocytes fertilized by intracytoplasmic sperm injection: possible explanations for the low success of this assisted reproduction technique in the horse. In all species studied, fertilization induces intracellular Ca2+ ([Ca2+]i) oscillations required for oocyte activation and embryonic development. This species-specific pattern has not been studied in the equine, partly due to the difficulties linked to in vitro fertilization in this species. Therefore, the objective of this study was to use intracytoplasmic sperm injection (ICSI) to investigate fertilization-induced [Ca2+]i signaling and, possibly, ascertain problems linked to the success of this technology in the horse. In vivo- and in vitro-matured mare oocytes were injected with a single mo...
Ultrasonographic monitoring of 103 recipient mares of different reproductive status during the first 30 days after embryo transfers. Ten pluriparous mares were used as donors to supply embryos which were transferred into 103 recipients, 31 of which were nulliparous, 34 were pluriparous and lactating, and 38 were pluriparous and non-lactating. The embryos were recovered eight days after ovulation and pregnancy was confirmed by ultrasound six days after the transfer; the length of the embryos was measured ultrasonographically on days 12, 14, 16, 18, 20, 25 and 30 after the embryo transfer. One hundred and fifteen of 200 flushes provided embryos, 12 being degenerate and 103 being viable embryos. From the 103 embryo transfers c...
Effect of platelet-activating factor (PAF) on stallion sperm motility, capacitation and the acrosome reaction. Phospholipids are an essential component of all mammalian cells; platelet activating factor (PAF=1-O-alkyl-acetyl-sn-glycero-3-phosphocholine) is a signalling phospholipid that has many biological properties in addition to platelet activation. PAF receptors have been detected on stallion spermatozoa; therefore, the aim of this study was to evaluate the effect of synthetic PAF on the motility, capacitation and the acrosome reaction of stallion spermatozoa. Treatment of ten stallion semen samples with 10(-4)-10(-13) mol PAF l(-1) resulted in significant differences in motility and capacitation (...
Novel purification method for mammalian seminal plasma phospholipid-binding proteins reveals the presence of a novel member of this family of protein in stallion seminal fluid. A family of bull seminal plasma (BSP) phospholipid-binding proteins (BSP proteins), potentiate heparin- and HDL-induced capacitation. The homologous proteins have been purified from stallion and boar seminal plasma, and detected in low concentrations in other mammalian seminal plasma. In this study, we developed a new isolation method for mammalian seminal plasma choline phospholipid-binding proteins wherein they are present in low concentrations. The method is based on the interaction of this family of proteins with egg yolk low-density lipoprotein fraction (LDF). In order to demonstrate the ...
Intracellular calcium oscillations and activation in horse oocytes injected with stallion sperm extracts or spermatozoa. In oocytes from all mammalian species studied to date, fertilization by a spermatozoon induces intracellular calcium ([Ca(2+)](i)) oscillations that are crucial for appropriate oocyte activation and embryonic development. Such patterns are species-specific and have not yet been elucidated in horses; it is also not known whether equine oocytes respond with transient [Ca(2+)](i) oscillations when fertilized or treated with parthenogenetic agents. Therefore, the aims of this study were: (i) to characterize the activity of equine sperm extracts microinjected into mouse oocytes; (ii) to ascertain i...
Characterisation of movement pattern and velocities of stallion spermatozoa depending on donor, season and cryopreservation. The aim of the study was to compare different types of movement pattern and velocities of stallion spermatozoa depending on cryopreservation during breeding and non-breeding season. Ejaculates were collected from four stallions during May (n = 24) and December (n = 24). Parameters of sperm movement were evaluated by computer-aided sperm analysis (CASA) system, and included percentages of motile spermatozoa, different patterns of motility, the velocity, linearity (LIN), amplitude of lateral head displacement (ALH) and beat-cross frequency (BCF). In winter the average percentages of motility wer...
Male, female and management risk factors for non-return to service in Dutch mares. The "effect" of stallion, mare and management-related factors on the odds of pregnancy per cycle in the horse were identified and quantified from the breeding records of Dutch Warmblood (n=4491), Friesian (n=1467) and Shetland-pony mares (n=3267) mated either naturally or by artificial insemination to one of the 88 stallions between 1992 and 1996. A mare was considered to be pregnant when she did not return to oestrous within 28 days of the last insemination. For Dutch Warmblood horses, the percentage of mares that did not return for service within 28 days (NR28) varied between studfarms and r...
Ovarian function and morphology in the mare after multiple follicular punctures. In the mare, ultrasound-guided transvaginal oocyte recovery and transfer might offer a way to circumvent the demanding procedures of in vitro embryo production. Before clinical application, the possible consequences for subsequent fertility have to be considered. Objective: To examine ovarian function and morphology in mares after repeated follicular punctures. Methods: A total of 14-26 follicular puncture sessions were conducted on each of 4 Norwegian pony mares over a period of 8 years. The ovaries of these mares were recovered by bilateral ovariectomy or at post mortem and subjected to macr...
Luteal function in mares following administration of oxytocin, cloprostenol or saline on day 0, 1 or 2 post-ovulation. Mares (n = 30) were treated in the post-ovulatory period with saline, oxytocin, or cloprostenol (Clo). Dose, administration frequency and treatment day (Day 0, 1 or 2 post-ovulation) were evaluated. Interovulatory interval of control cycles was 22.7 (+/-0.36) days with a range of 20.6 (+/-1.44) to 23.8 (+/-1.39) days among all treatment groups. Mares treated with two micro-doses of cloprostenol on Day 2 post-ovulation had the shortest interovulatory interval. This group also had the lowest mean circulating progesterone concentrations on Days 3-7 and 13, and was the slowest group to reach conce...
The effects of different insemination regimes on fertility in mares. This study investigated the effects of different artificial insemination (AI) regimes on the pregnancy rate in mares inseminated with either cooled or frozen-thawed semen. In essence, the influence of three different factors on fertility was examined; namely the number of inseminations per oestrus, the time interval between inseminations within an oestrus, and the proximity of insemination to ovulation. In the first experiment, 401 warmblood mares were inseminated one to three times in an oestrus with either cooled (500 x 10(6) progressively motile spermatozoa, stored at +5 degrees C for 2-4 h...
Effect of capacitation of stallion sperm with polyvinylalcohol or bovine serum albumin on penetration of bovine zona-free or partially zona-removed equine oocytes. Experiments were conducted to study effects of macromolecules on stallion sperm capacitation and fertilization as determined by penetration of bovine zona-free and equine partially zona-removed oocytes. Stallion sperm were capacitated in TYH medium (modified Krebs-Ringer bicarbonate) supplemented with either 1 mg/mL of polyvinylalcohol (PVA) or 4 mg/mL of BSA. Capacitation was induced with 8 bromoadenosine cyclic monophosphate (8BrcAMP; 0.5 mM) alone or in combination with 0.1 microM of ionomycin. Intraspecies gametes were co-incubated in TYH/PVA or TYH/BSA for 18 to 20 h. For zona-free bovine...
The predictive value of semen analysis in the evaluation of stallion fertility. Pregnancy rates in managed horse populations depend on the innate fertility of the mares and stallions involved and on the quality of breeding management. Of course, because a single stallion usually mates many mares, stallion fertility is a critical factor in the overall success of a breeding program. Unfortunately, accurate evaluation of stallion fertility per se requires a large number of normal mares to be mated and is necessarily retrospective. Rather, the ideal is to predict fertility in advance of the stallion's breeding career, and this is currently attempted by way of a thorough physi...
Pregnancy outcome in mares following insemination deep in the uterine horn with low numbers of sperm selected by glass wool/Sephadex filtration, Percoll separation or absolute number. Mares were inseminated deep in the uterine horn with 25 million sperm selected by glass wool/Sephadex (GWS) filtration, Percoll separation (PS) or absolute number (AN). Deep-horn insemination using a low-volume, smooth tipped, flexible pipette/catheter delivery system allowed more efficient use of stallion sperm and reduced post-breeding uterine reaction in mares. Mares were pregnant in 15/30, 13/30 and 10/30 cycles for GWS, PS and AN selection methods, respectively. Sperm selection method did not effect pregnancy outcome (P=0.422). However, sperm selected for deep-horn insemination by filtrat...
A survey of reproductive success in South African Thoroughbred horse breeding from 1975 to 1999. The data and an analysis of the statistical summaries from the 'Return of Mares' of the General Stud Book of The Jockey Club of Southern Africa from 1975-1999 are presented. The total number of mares covered per season ranged from 7393 (1992) to 5180 (1995). The total living produce in the period surveyed was 95 317 foals. The categories of data examined include: the total number of mares covered per season; the total numbers and percentage of their living produce; the total numbers and percentage dead produce, 'slips' and foals born dead, barren and 'no return' mares; and the total number of ...
Azoospermia associated with bilateral segmental aplasia of the ductus deferens in a stallion. A 3-year-old Quarter Horse halter stallion was referred for routine semen evaluation. Physically, the stallion's reproductive organs appeared normal. Repeated semen evaluations did not reveal any spermatozoa. Because high activities of alkaline phosphatase are detected in the epididymal fluid and indicative of complete ejaculation, alkaline phosphatase activities were analyzed in several samples, which yielded activities far less than reference values and suggested a blockage of the reproductive tract. Endoscopic evaluation of the urethra and the bulbourethral, prostate, and urethral gland duc...
The effect of semen extender, seminal plasma and raw semen on uterine and ovarian blood flow in mares. Transrectal color Doppler sonography was used to evaluate the effect of intrauterine infusion of skim milk semen extender, seminal plasma and raw semen on the endometrium and blood flow in the uterine and ovarian arteries in mares. Six Trotter mares (mean age: 12 years) were examined during estrus in three cycles. Each mare received an intrauterine infusion of 20 ml of skim milk semen extender, seminal plasma or raw semen during estrus in one of three cycles. Blood flow measurements in both uterine and ovarian arteries and the determination of intrauterine fluid via sonography were performed b...
Mechanism of follicle deviation in monovular farm species. Diameter deviation is a distinctive change in growth rates among the follicles of a wave, heralding the formation of a dominant follicle and subordinate follicles. When the follicles are about 5mm in cattle and 13 mm in horses, the wave-stimulating FSH surge reaches peak concentrations. Follicle and FSH manipulation studies in both species have shown that the declining portion of the surge before the beginning of deviation is a function of multiple growing follicles that require the decreasing FSH. During this time, all follicles of the wave have the potential for future dominance. Deviation b...
Seasonal changes in semen quality and freezability in the Warmblood stallion. The objective of this study was to investigate seasonal changes in stallion semen quality and to determine the best time for semen cryopreservation. Experiments were performed using 10 Warmblood stallions from the National Stud Farm in Avenches (Switzerland). Ejaculates were collected and frozen every other week during 1 year from January to December 1999. Volume, concentration, and motility, and the number of morphologically normal sperm and sperm with major defects (abnormal heads, acrosome defects, nuclear vacuoles, proximal droplets, abnormal midpieces) were evaluated. For all frozen-thawe...
Testicular measurements and daily sperm output of Tori and Estonian breed stallions. Evaluation of testicular measurements and daily sperm output (DSO) yields valuable information for predicting the reproductive capacity of stallions. The present study evaluated testicular measurements (height, length, width and circumference) and DSO of eight Tori and eight Estonian breed stallions. One ejaculate of semen was collected daily for 10 subsequent days from each stallion. The gel-free volume of semen was measured with a graduated glass cylinder and the sperm concentration was assessed with a Chorjajev chamber. The volume of gel-free fraction was multiplied by the sperm concentrati...
Semen parameters and level of microsatellite heterozygosity in Noriker draught horse stallions. It was the aim of the present study to determine physiological values for different semen parameters in an endangered draught horse breed, the Austrian Noriker. Because small population size is often believed to cause a decrease in fertility and/or semen quality through inbreeding and a reduction in genetic variation, the general genomic heterogeneity of the breed was estimated on the basis of microsatellite variation and correlated to semen parameters. Semen could be collected from 104 of 139 stallions with semen collection being more often successful in younger stallions. Mean volume of ejac...
Use of a GnRH antagonist, antarelix, associated or not with hCG, to control ovulation in cyclic pony mares. The GnRH antagonist antarelix (Teverelix) was administered to mares (0.01 mg/kg, i.v., twice a day) during the periovulatory period. In Experiment 1, 20 mares were divided into a treated (A3d-) and a control (Control-) group. A3d- mares received antarelix for 3 days from the day when the dominant follicle (F1) reached 32 mm (D0). In Experiment 2, 10 mares were divided into a treated (A6d+) and a control (Control+) group. A6d+ mares received antarelix for 6 days from D0 and hCG was injected in all animals (1600 IU, i.v.) on D1. Pregnancies were determined 13 days after ovulation. In both experi...
Interactions of follicular factors and season in the regulation of circulating concentrations of gonadotrophins in mares. Follicle growth and associated changes in circulating hormone concentrations were evaluated after follicle ablation in mares (n = 13) during four 13 day periods beginning at means of -98.5, -61.4, -26.0 and 10 days from the first ovulation and corresponding to mid-anovulatory, early-transitional, late-transitional and ovulatory periods, respectively. During each period, all follicles > 5 mm in diameter were ablated (day 0) followed by no subsequent ablations (all-follicle group) or the ablation of all follicles > 5 mm when a new follicle reached > 10 mm (0-follicle group). A follicula...
