Topic:Assisted Reproductive Techniques
Assisted Reproductive Techniques (ART) in horses encompass a range of technologies designed to aid in the breeding process. These techniques include artificial insemination, embryo transfer, intracytoplasmic sperm injection (ICSI), and oocyte transfer. ART is employed to enhance reproductive efficiency, manage genetic diversity, and support breeding programs for both commercial and conservation purposes. Artificial insemination involves the collection and deposition of semen into the mare's reproductive tract, while embryo transfer entails the collection of a fertilized embryo from a donor mare and its implantation into a recipient mare. ICSI involves the direct injection of a single sperm into an oocyte to achieve fertilization. Oocyte transfer involves the transfer of an oocyte from one mare to another for fertilization and gestation. This page compiles peer-reviewed research studies and scholarly articles that examine the methodologies, advancements, and applications of assisted reproductive techniques in equine reproduction.
Viability of stored equine embryos. Equine embryos were recovered nonsurgically 6.5 d after ovulation (Exp. 1) and those greater than 200 microns were stored in one of three media: 1) Ham's F10 + 10% fetal calf serum (FCS) under 5% CO2, 5% O2 and 90% N2 at 24 C (Ham's F10); 2) Minimal Essential Medium with Hank's balanced salts + 10% FCS in air (MEM) at 24 C or 3) MEM at 5 C n = 10/treatment). Embryos less than or equal to 200 micron (n = 10) were bisected microsurgically; one-half of each embryo was stored in Ham's F10 and the other half in either Dulbecco's phosphate-buffered saline + 10% FCS in air at 24 C (DPBS), or MEM in a...
Evaluation of mare oocyte collection methods and stallion sperm penetration of zona-free hamster ova. Comparisons were made between 2 methods of oocyte recovery from the ovarian follicles of slaughtered mares: 500 oocytes (3 per mare) were obtained by aspiration of follicular fluid from ovaries of 162 mares, and 120 oocytes (8 per mare) by isolation and rupture of follicles from ovaries of 14 mares. In the oocytes recovered after rupture of follicles, 89.2% were morphologically unchanged, in comparison to 29.3% obtained by aspiration of follicular fluid. Stallion spermatozoa capacitated in vitro were tested on zona-free hamster oocytes. The stallion spermatozoa were washed in TCM-199 and prein...
Embryo transfers from mares in athletic competition. The objective of this project was to produce multiple pregnant recipient mares during one year from each of four mares which were in athletic training and competition. Twenty-six embryos were recovered from the four mares in 38 collection attempts. Each embryo was surgically transferred to one of 20 recipient mares. Nine of 10 recipient mares which were transferred to on one occasion were detected pregnant at the one week post transfer pregnancy examination and six of eight mares which were transferred to on two occasions were detected pregnant at one of the one-week post transfer pregnancy ex...
Deep freezing of horse embryos. Fourteen horse embryos recovered non-surgically on Days 6-8 after ovulation (Day 0) were cooled slowly to - 35 degrees C (7 embryos) or - 40 degrees C (7 embryos) and stored in liquid nitrogen (- 196 degrees C) for 4-98 days. Surgical transfer of the thawed embryos to unmated recipient mares that had ovulated - 2 to + 1 days with respect to the embryo donors resulted initially in the establishment of 4 conceptuses. However, only one mare maintained her pregnancy to term.
Induction of oestrus and ovulation by means of prostaglandin and gonadoliberin (GnRH) treatment in an old mare barren for two breeding seasons. A 17-year-old Nooitgedacht mare was presented in mid-summer after failing to conceive during the previous 2 breeding seasons. The mare conceived to service during a PG-induced oestrus when synthetic GnRH was used to induce ovulation.
Production of monozygotic (identical) horse twins by embryo micromanipulation. The blastomeres of 192- to 8-cell embryos recovered surgically 1-3 days after ovulation from 23 Pony mares were mechanically separated and inserted, in various combinations, into evacuated pig zonae pellucidae to make 27 'half' and 17 'quarter' micromanipulated embryos. These were embedded in agar and cultured in vivo in the ligated oviducts of ewes for 3.5-5 days to allow development to the late morula/early blastocyst stage. Subsequent surgical or non-surgical transfer of 13 'half' and 17 'quarter' embryos to mares resulted in 10 established pregnancies, including 2 monozygotic pairs. Surgic...
Intra- and interspecific embryo transfer. The procedures that are collectively referred to as embryo transfer (ET) have many uses. They were first used as research tools to study fetal-maternal physiology. Since the first successful mammalian embryo transfer in 1890, ET has been utilized for enhancement of genetic selection; diagnosis and treatment of infertility; control of infectious disease transmission; screening for genetic defects; propagation of rare and endangered species; and the study of developmental biology. Most of the embryo transfers have been intraspecific. A listing of the species includes rabbit, rat, sheep, mouse, g...
Induction of multiple ovulations during the ovulatory season in mares. The efficacy of an equine pituitary extract for induction of multiple ovulations during the ovulatory season was studied in 112 horse mares in four experiments. Combined for all experiments, 70% of the mares (78/112) had multiple ovulations for an average of 3.0 ovulations per mare. The interval between first and last ovulation was decreased (P<0.01) when human chorionic gonadotropin (hCG) was included in the treatment regimen (0.0+/-0.0 versus 1.6+/-0.4 days). Ovulation rate was lower (P<0.01) when extract treatment was initiated at day 19 (1.3+/-0.2) than when initiated at day 15 post-...
Collection of semen from stallions at stud. Semen was collected from 222 stallions of 13 breed or colour types in southern Queensland and northern New South Wales. A total of 648 collection attempts were made, using an artificial vagina, during 4 consecutive breeding seasons (1974/5 to 1977/8). Modifications were made to the techniques used by previous workers because collections were made at commercial studs using minimal animal restraint. Of all collection attempts, 621 (96%) were successful, while at least one semen sample was collected from each of 216 stallions (97%). There were no significant relationships between stallion collect...
Fertility of donor mares following nonsurgical collection of embryos. Embryos were collected nonsurgically on Day 7 or 8 after ovulation from 7 Quarter horse mares using a modified 30-ml Foley catheter to flush the uterine horn ipsilateral to the recent ovulation with 500 ml TCM-199 containing Hepes buffer. After collection, the uteri were infused with nitrofurazone to reduce the chances of infection due to the procedure. Eleven collections from 7 mares resulted in recovery of 9 embryos and nonsurgical transfer of 4 of these resulted in the birth of one foal. After collections, 8 oestrous cycles averages 22.75 days and 2 extended oestrous cycles were 43 and 59 d...
Induction of ovulation and multiple ovulations in seasonally anovulatory and ovulatory mares with an equine pituitary extract. A crude equine pituitary ethanol extract (EE) was used to induce single and miltiple ovulations in seasonally anovulatory pony mares 3-15 years of age. 12 mares were injected daily for 14 days with EE; 6 of the EE-treated mares were also treated with human chorionic gonadotropin (HCG), and 6 control mares received saline vehicle only. In a 2nd experiment designed to determine if EE treatment could induce multiple ovulations in seasonally ovulatory mares, 7 mares were treated during diestrus, 7 mares were treated beginning on Day 1 of estrus, and 7 remained untreated. The results of experiment ...
Equine artificial insemination. The use and techniques of artificial insemination for horses in Germany over the last 30 years is described. Artificial insemination appears to produce pregnancy percentages equal to those from normal breeding methods and its continued availability under veterinary supervision is recommended in conditions where disease, disability or distance debar normal service.
A surgical technique applied to the study of tubal eggs in the mare. An efficient surgical technique of collecting eggs from the oviducts of mares is described. Within 6 days after ovulation recovery was successful in 22/29 mares. The technique has been used to investigate the retention and ageing of eggs in the oviducts and to determine the origin and the nature of the accessory CL during pregnancy.
Surgical and non-surgical egg transfer in horses. Surgical and non-surgical methods used for the recovery and transfer of fertilized horse eggs are described. Sixteen of the twenty-three zygotes recovered surgically between Days 1 to 6 after ovulation from thirty donor mares were transferred surgically to synchronized recipients; seven pregnancies resulted. Seven of the eleven zygotes recovered non-surgically between Days 6 to 8 after ovulation from twenty-eight donor mares were transferred non-surgically to synchronized recipients; five pregnancies resulted.
The evaluation of stallion semen in aspects of fertility control and its use for artificial insemination. Choice of the best methods for semen examination is dictated by the purpose of the examination, whether it be to assess the fertility of an individual stallion or to evaluate individual semen samples for routine purposes. In the author's experience of examining stallion semen, emphasis should be placed upon morphological examination, sperm cinematography and survival tests in vitro. Special problems concerning examination of frozen semen are discussed and the ultrastructure of spermatozoa frozen in the presence and absence of glycerol is described.