Reproductive technology in horses encompasses a range of scientific techniques and procedures aimed at assisting and enhancing equine reproduction. These technologies include artificial insemination, embryo transfer, and cryopreservation of gametes and embryos. They are employed to improve breeding efficiency, manage genetic diversity, and preserve valuable genetic material. Artificial insemination involves the collection and introduction of semen into the mare's reproductive tract, while embryo transfer allows for the harvesting and implantation of embryos from donor to recipient mares. Cryopreservation involves freezing and storing sperm, oocytes, or embryos for future use. This page compiles peer-reviewed research studies and scholarly articles that investigate the methodologies, applications, and outcomes of reproductive technologies in equine breeding and management.
Li X, Qin Y, Wilsher S, Allen WR.Various types of cell cycle organization occur in mammals. In this study, centrosome changes during meiosis in horse oocytes, and first cell cycle organization following fertilization, parthenogenesis and nuclear transfer, were monitored. Cumulus oocyte complexes harvested from horse ovaries obtained from slaughtered mares were cultured in vitro. Meiotic oocytes of germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I and II (MI and MII) stages were selected at various set times during in vitro maturation. Embryos at the first cell cycle stage were generated by subjecting MII s...
Tharasanit T, Colenbrander B, Stout TA.Oocyte cryopreservation is a potentially valuable technique for salvaging the germ-line when a valuable mare dies, but facilities for in vitro embryo production or oocyte transfer are not immediately available. This study examined the influence of maturation stage and freezing technique on the cryopreservability of equine oocytes. Cumulus oocyte complexes were frozen at the immature stage (GV) or after maturation in vitro for 30 hr (MII), using either conventional slow freezing (CF) or open pulled straw vitrification (OPS); cryoprotectant-exposed and untreated nonfrozen oocytes served as contr...
Kareskoski AM, Reilas T, Andersson M, Katila T.With the aim of investigating properties of stallion seminal plasma to eventually improve semen-handling techniques, sperm motility and plasma membrane integrity were analysed in different fractions of the ejaculates after storage. Semen was collected using a computer-controlled automated phantom that separates the ejaculates into five successive cups. Samples containing seminal plasma and skim milk extender were compared with samples stored in skim milk extender after the removal of seminal plasma by centrifugation. Fractionated ejaculates were stored cooled for 24 h after dilution with exten...
Sinnemaa L, Järvimaa T, Lehmonen N, Mäkelä O, Reilas T, Sankari S, Katila T.The effect of artificial insemination (AI) volume on uterine contractility and inflammation and on elimination of semen in the reproductive tract of mares was examined for 4 h after AI using two methods, scintigraphy and ultrasonography. The same doses were used in both methods: 2 and 100 ml of skim milk-extended frozen semen. In the scintigraphic study, the number of reproductively normal mares was four per group and in the ultrasonographic study five per group. For scintigraphy, the semen was radiolabelled with technetium-99m. The static scintigrams were acquired immediately before and 30, 6...
Janett F, Burkhardt C, Burger D, Imboden I, Hässig M, Thun R.The objective of this study was to investigate changes of quality and freezability of stallion semen in response to repeated acute treadmill exercise. Ejaculates from 11 stallions were collected, evaluated and frozen weekly during four periods of 4 weeks each defined as before (period 1), during (period 2) and after (periods 3 and 4) intense exercise. In fresh semen the gel-free volume, sperm concentration, motility, normal sperm and sperm with major defects (acrosome defects, nuclear vacuoles, abnormal heads, midpiece defects and proximal droplets) were evaluated. In frozen-thawed semen, moti...
Vidament M.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 before ...
Troedsson MH, Desvousges A, Alghamdi AS, Dahms B, Dow CA, Hayna J, Valesco R, Collahan PT, Macpherson ML, Pozor M, Buhi WC.Seminal plasma has been suggested to be involved in sperm transport, and as a modulator of sperm-induced inflammation, which is thought to be an important part of sperm elimination from the female reproductive tract. This article reports on recent experiments on the importance of seminal plasma components in sperm transport and elimination. In Experiment 1, hysteroscopic insemination in the presence (n = 3) or absence (n = 3) of 2 ng/mL PGE showed an increased portion of spermatozoa crossing the utero-tubal junction in the presence of PGE in two mares, while no difference was observed between ...
Morris LH.Since the production of the first live offspring from sex-sorted spermatozoa in 1989, there have been many developments in the fluorescence-activated cell separation (FACS) procedures to preselect X- and Y-chromosome bearing spermatozoa prior to insemination. During this time, FACS technology has been applied to a range of species and has resulted in offspring from rabbits, cattle, sheep, elk and horses. In horses, satisfactory fertility rates have been achieved after hysteroscopic insemination of 20 x 10(6) fresh or stored, sex-sorted spermatozoa. However, many of the sperm processing protoco...
Squires EL.There has and will continue to be reproductive techniques available that have a positive impact upon the equine breeding industry. This review focuses on semen technologies that have been developed or are in the process of being developed. The use of fluorescent dyes and flow cytometry has provided the researcher and clinician with powerful tools to evaluate several sperm attributes. These procedures have been utilized to evaluate sperm viability, acrosome status, mitochondrial status, DNA integrity and stages of capacitation. Flow cytometry allows several sperm attributes to be evaluated on t...
Katila T.In this review, effects of the composition of the inseminate on uterine response and pregnancy rates in mares are discussed. The inseminate can differ for volume, sperm concentration, total sperm numbers, presence, absence, or proportion of seminal plasma, and extender composition. Semen can be used as fresh, cooled, or frozen. The site of semen deposition also plays a role; semen is deposited either into the uterine body (standard artificial insemination (AI)) or into the tip of the uterine horn ipsilateral to the preovulatory follicle (deep AI) using the hysterocopical or transrectally guide...
Lyle SK, Ferrer MS.The typical dose for insemination into the uterine body of the mare is > 300 x 10(6) progressively motile spermatozoa (PMS) and an insemination dose of > 200 x 10(6) PMS is recommended for frozen-thawed semen. Low-dose insemination techniques allow for a drastic reduction in the numbers of spermatozoa required to achieve pregnancy. Acceptable pregnancy rates can be achieved with doses ranging from 1 to 25 x 10(6) PMS in volumes ranging from 20 to 1000 microL. Two techniques have been described: hysteroscopic insemination and transrectally guided deep horn insemination using a pipette. Similar ...
Caillaud M, Duchamp G, Gérard N.A growing body of evidence suggests that the interleukin-1 system is involved in periovulatory events. Previous work from our lab demonstrated that in the mare, interleukin-1beta (IL-1beta) increases the ovulatory rate of metaphase II oocytes. The present study was conducted to analyze in vivo the effect of IL-1 on oocyte cytoplasmic maturation, ovulation and pregnancy rate. In the present work, IL-1beta (experiment 1, n = 13; experiment 2, n = 25) and interleukin-1RA (IL-1RA; experiment 1, n = 25) were injected intrafollicularly by using the transvaginal ultrasound-guided injection method. In...
Gil L, Saura S, Echegaray A, Martinez F, de Blas I, Akourki A, Gonzalez N, Espinosa E, Josa A.The present study evaluated the effect of supplementing the medium used to mature equine oocytes in vitro with oestrous mare serum (EMS) or horse follicular fluid (HFF). To this end, 144 ovaries were obtained from mares aged 16-21 months and transported to the laboratory in Dulbecco's phosphate buffered saline (D-PBS) at 30 degrees C. Oocytes were harvested from the ovaries by slicing, and then selected for in vitro maturation (IVM) according to the number of cumulus cell layers and the characteristics of the cytoplasm. The selected oocytes were washed three times in TCM199 medium plus HEPES (...
Pozor M.Although ultrasound evaluation of the reproductive tract of stallions was introduced to veterinary practice long ago, this examination is not always conducted during routine breeding soundness evaluation. The objective of this study was to investigate the clinical relevance of routine ultrasound evaluation of the stallion's reproductive tract. Breeding soundness evaluation of 113 stallions was performed, including ultrasonography of external and internal genitalia. Various pathological conditions were detected using this technique, with the most frequent being varicocele, thickened vaginal tun...
Moussa M, Bersinger I, Doligez P, Guignot F, Duchamp G, Vidament M, Mermillod P, Bruyas JF.Vitrification using open pulled straw (OPS) has provided encouraging results with embryos from other species. The aim of this study was to compare the survival of 6.5- and 6.75-day-old equine embryos after OPS vitrification and slow-cooling. Eighteen embryos were frozen using a slow-cooling method. Embryos were placed in modified PBS with increasing glycerol concentration (2.5%, 5%, 7.5% and 10% (v/v) 5 min each). Embryos were loaded into 0.25 ml straws then placed in a programmable freezer and subsequently plunged into liquid nitrogen. After thawing, cryoprotectant was removed by five steps w...
Kirk ES, Squires EL, Graham JK.Assessing the fertilizing potential of a semen sample is important for effective stallion management and for rapid progress in evaluating new cryopreservation technologies. Unfortunately, sperm motility does not estimate fertility well. These experiments established assays to measure cell viability, acrosomal integrity and mitochondrial function for cryopreserved stallion spermatozoa, using flow cytometry, and determined the variability associated with these assays. Correlations between results for these laboratory assays and stallion fertility were also determined. The inter-assay variability...
Morel MC, Newcombe JR, Swindlehurst JC.Numerous and conflicting reports exist regarding factors that may effect mare reproductive performance, in particular multiple ovulation (MO) and its consequences. Sequential ultrasonic examination was used to monitor 3075 ovulations in 1581 mainly Thoroughbred mares to ascertain: whether increasing age is associated with an increase in MO; whether this is counteracted by an increase in embryo mortality (EM) prior to Day 13; and whether this embryonic loss may be associated with small-for-age embryonic vesicles (Days 13/14). Overall ovulation rate was 1.31, MO occurring in 29.3% of cycles. MO ...
Mari G, Iacono E, Merlo B, Castagnetti C.Diagnosis and management of twin pregnancies in the mare are an ongoing challenge in equine reproduction. Early detection of twin and manual crush of one vesicle are the main steps in the management of twins. Few studies were carried out about the use of transvaginal ultrasound-guided aspiration (TUGA) for reduction of twins in the mare. In this study, the efficiency of TUGA for management of twin pregnancies was investigated. Reduction of unicornuate twins between 16 and 25 days of gestation gave a success rate of 70.0% (14 viable foals/20 twin pregnancies); when reduction was performed after...
Güvenc K, Reilas T, Katila T.It is unclear whether AI of mares deep into the uterine horn causes more or less inflammation of the endometrium than conventional AI. Thus, we compared uterine inflammatory reactions of mares inseminated with two different doses of frozen-thawed semen into the tip of the uterine horn (UH) ipsilateral to the preovulatory follicle with those of mares inseminated into the uterine body (UB). Thirty-two mares were assigned to one of four groups (eight mares/group): UB20=AI into UB, 20 x 10(6)sperm/0.5 mL; UB200=AI into UB, 200 x 10(6)sperm/0.5 mL; UH20=AI into UH, 20 x 10(6)sperm/0.5 mL; UH200=AI ...
Morris LH.The generally recommended minimum number of spermatozoa required for conventional artificial insemination in the mare is in excess of 200 x 10(6) progressively motile spermatozoa. Recent developments in different insemination techniques such as deep uterine, hysteroscopic and oviductal insemination, which have been designed to use significantly fewer spermatozoa, are reviewed in this paper. A number of studies have demonstrated that ultrasound guided deep uterine insemination of 5 x 10(6) fresh spermatozoa can produce satisfactory pregnancy rates. The use of hysteroscopic insemination enables ...
Carnevale EM.Methods for the collection and transfer of equine oocytes have been developed, and uses of these techniques have resulted in new clinical and research possibilities. Because oocyte transfer avoids reproductive problems associated with the oviduct, uterus, and cervix, pregnancies can be produced from many mares that cannot carry a pregnancy or produce embryos. Oocytes for clinical transfers are usually collected from preovulatory follicles and cultured for a short interval or transferred directly into a recipient's oviduct. For oocyte transfer, the recipient is inseminated within the uterus. A ...
Panasophonkul S, Lohachit C, Sirivaidyapong S.To study the postpartum ovarian activities for investigation of first postpartum oestrus, twenty-five Thai crossbred native mares were monitored after parturition by oestrous detection, transrectal palpation and reproductive ultrasonography. Blood samplings were also taken for estradiol-17beta (E2) analysis. The first ovulation occurred within 20 days postpartum in 92% (23/25) of the mares. The mean intervals of foaling to first oestrus and to first ovulation were 10.3 +/- 2.9 and 13.4 +/- 2.6 days (mean +/- SD) respectively. Serum E2 increased from 7.0 +/- 2.9 to a peak of 10.8 +/- 3.3 pg/ml ...
Liu DY, Lopata A, Pantke P, Baker HW.The present study demonstrates that horse and marmoset monkey sperm can bind to the human zona of salt-stored oocytes that failed to fertilize in vitro. Marmoset monkey sperm are also able to penetrate the salt-stored human zona. In contrast, human sperm do not bind to the zona of either horse or marmoset monkey oocytes. These results suggest that human sperm binding to the zona pellucida is more strictly species-specific than it is for horse and marmoset monkey sperm. In contrast, horse and marmoset monkey sperm contain receptors recognized by the human zona.
Polak KL, Kammlade WG.Vaginal hydrogen ion concentration of Saddlebred mares was measured throughout the behavioral estrous period. The mean pH on the day of ovulation was significantly (P = <.01) lower than on all other tested days of estrus. Follicular development and vaginal pH values in pony mares at time of slaughter were highly correlated. A significant decrease in vaginal pH values, determined through a series of carefully monitored measurements during estrus, was found to be characteristic and indicative of ovulation.
Kask K, Odensvik K, Kindahl H.The pattern of the main metabolite of prostaglandin (PG) F2alpha was recorded following a nonsurgical embryo transfer technique in 9 mares under field conditions in Estonia. Three patterns were observed. Two of them were characterised by PG release, thereas the third was not. A tendency towards a shortened cycle was seen in 3 mares. Observations were made regarding the manipulation of the uterus as being normal or difficult to perform. In general, mares where the procedure was considered difficult were also found to have a PG release.
Kato H, Seidel GE, Squires EL, Wilson JM.In vitro matured horse oocytes with a first polar body (n = 68) were each injected with a single spermatozoon and divided into 2 groups: Group 1 oocytes were treated with 10 microM calcium ionophore A23187 for 5 min while Group 2 oocytes received no activation treatment. After culture in vitro for 2 days, significantly more oocytes treated with A23187 (5/24, 21%) cleaved than oocytes without activation treatment (2/44, 5%, P<0.05). All 7 cleaved zygotes from both treatment groups were transferred to recipient mares but no pregnancies resulted.
Silva ES, Frade SC, Ignácio FS, Pantoja JC, Puoli Filho JN, Meira C.The present study evaluated the effect of altrenogest treatment during 70 or 120 days of gestation on pregnancy maintenance in non-cyclic recipient mares and correlated the hormonal interruption findings with number, supplementary corpora lutea (SCL) formation period, and plasma progesterone (P4). Twenty five mares were used as recipients during anestrus, transitional or ovulatory phase and were assigned into groups according to altrenogest treatment period (70ALT, 120ALT or Control groups) or reproductive status at beginning of treatment (Anestrus, Transition or Cyclic/Control groups). Mares ...
Goretti RG, Araújo RR, Filho AN, Araújo GH, Lopes EP, Guimarães JD.The objective was to evaluate the effects of giving prostaglandin F₂(α) (PGF) to donor mares 48 h prior to embryo collection. Non-lactating donor mares (n = 20 estrous cycles in 10 mares), ranging from 2.5 to 10 y of age and 400 to 500 kg of body weight were used from September 2004 to February 2005 in the southern hemisphere (Brazil). Donor mares were randomly assigned in a cross-over design study. During a Treated cycle, 7.5 mg PGF was given 48 h prior to embryo collection, whereas in the Control cycle, 7.5 mg PGF was given at embryo collection. In Treated Cycles, serum progesterone conce...
Moussa M, Bersinger I, Doligez P, Guignot F, Duchamp G, Vidament M, Mermillod P, Bruyas JF.Vitrification using open pulled straw (OPS) has provided encouraging results with embryos from other species. The aim of this study was to compare the survival of 6.5- and 6.75-day-old equine embryos after OPS vitrification and slow-cooling. Eighteen embryos were frozen using a slow-cooling method. Embryos were placed in modified PBS with increasing glycerol concentration (2.5%, 5%, 7.5% and 10% (v/v) 5 min each). Embryos were loaded into 0.25 ml straws then placed in a programmable freezer and subsequently plunged into liquid nitrogen. After thawing, cryoprotectant was removed by five steps w...
Newcombe JR, Paccamonti D, Cuervo-Arango J.Data were analysed retrospectively from fourteen breeding seasons at an Equine Fertility Clinic for the effect of interval between pre- and postovulatory examinations for immediate postovulatory insemination on pregnancy rate (PR) and embryo loss rate (ELR). Mares of various breeds and ages were examined at intervals which varied from 0.5 to 15h between the pre- and postovulatory period over 867 cycles. When ovulation was detected they were inseminated with a single dose of commercial frozen-thawed semen. All mares were treated in the post-insemination period with intrauterine antibiotics and ...
Morris LH, Allen WR.The need for relatively high numbers of spermatozoa for artificial insemination limits our application of recently available technologies such as sex-sorted semen. The fertility of two different methods of low dose insemination using fresh, frozen and sex-sorted semen are compared in this overview. Satisfactory conception rates are described using very low doses of spermatozoa inseminated by either hysteroscopic or deep uterine insemination methods, proving the stallion is fully fertile. The hysteroscopic method appears to give higher conception rates when inseminating fewer than 5 x 10(6) spe...
McCue PM, Fleury JJ, Denniston DJ, Graham JK, Squires EL.A technique was developed for oviductal insemination of mares, in which a small number of motile spermatozoa are deposited directly into the oviduct. Pregnancy rates in mares inseminated by traditional intrauterine artificial insemination were compared with rates in mares inseminated by oviductal insemination. Fifteen mares were inseminated with 5 x 10(8) progressively motile spermatozoa by intrauterine artificial insemination, and 14 mares were inseminated with 5 x 10(4) progressively motile spermatozoa by oviductal insemination. Pregnancy rates in mares inseminated by intrauterine artificial...
Franz LC, Choi YH, Squires EL, Seidel GE, Hinrichs K.This study was conducted to evaluate the effects of roscovitine on suppression of meiosis, subsequent meiotic maturation, and cleavage rates after intracytoplasmic sperm injection of horse oocytes. Oocytes were classified as having compact or expanded cumuli (Com or Exp oocytes) and were divided into three culture groups: 30 h culture in maturation medium (30 h Mat); 54 h culture in maturation medium (54 h Mat), or 24 h culture in medium containing 66 micro mol roscovitine l(-1) and then 30 h culture in maturation medium (Ros+M). After maturation, oocytes were subjected to intracytoplasmic spe...
Sinnemaa L, Järvimaa T, Lehmonen N, Mäkelä O, Reilas T, Sankari S, Katila T.The effect of artificial insemination (AI) volume on uterine contractility and inflammation and on elimination of semen in the reproductive tract of mares was examined for 4 h after AI using two methods, scintigraphy and ultrasonography. The same doses were used in both methods: 2 and 100 ml of skim milk-extended frozen semen. In the scintigraphic study, the number of reproductively normal mares was four per group and in the ultrasonographic study five per group. For scintigraphy, the semen was radiolabelled with technetium-99m. The static scintigrams were acquired immediately before and 30, 6...
Huhtinen M, Reilas T, Katila T.The pregnancy rate is lower in mares inseminated at the first post-partum (p.p.) oestrus (40-50%) compared with pregnancy rates in subsequent oestrous cycles (55-65%). The causes of the lowered pregnancy rate are not fully understood. The aim of the present study was to examine if embryonic defects could be one of the reasons for lowered pregnancy rate. A total of 23 p.p. and 14 non-lactating control mares were flushed 7 days after detection of ovulation. Embryo recovery rate was 48% and 71% in p.p. and control mares, respectively (p = 0.16). Embryos were photographed, measured, graded and sta...
Yang F, Wu S, Yang W, Yu J, Liu B, Zeng S.To study the effects of exercise on donkey semen parameters, Dezhou donkey (Equus asinus) jackasses (n = 18) were assigned to three groups: control (CN, n = 6), 1-hour exercise (1 h EX, n = 6) and 2-hour exercise (2 h EX, n = 6) groups. They were exercised with a walking machine for 3 days/week for 8 weeks. Semen parameters and reproductive hormones were evaluated weekly. The heart rate, rectal temperature, blood haematology indexes, and the body condition score (BCS) were also measured. Results showed that the ejaculation volume increased while the sperm concentration decreased after ...
Mouguelar H, Díaz T, Borghi D, Quinteros R, Bonino F, Apichela SA, Aguilar JJ.The objectives of this work were to describe some morphometric characteristics and to establish quantitative parameters of different regions of the equine oviductal mucosa from the isthmus, ampullary-isthmic junction (AIJ), and ampulla. Twenty-one mixed-bred mares were used for this study. Mares were selected in the following reproductive phases: anestrus, estrus, and diestrus. The left oviducts were examined with light microscopy, and rights ones were studied through the intraoviductal molds. The isthmus showed the smallest luminal area, mucosal area, epithelial perimeter, and luminal diamete...
Fitzgerald BP, Affleck KJ, Barrows SP, Murdoch WL, Barker KB, Loy RG.Two groups of mares were exposed to an abrupt, artificial increase or a natural increase in daylength. In both groups, mean LH pulse frequency increased with time of year and was accompanied by a reciprocal decrease in LH pulse amplitude. A non-pulsatile pattern of LH secretion was observed in some mares sampled close to the day of ovulation. Maximum mean LH pulse frequency and the onset of the breeding season occurred earlier in those mares exposed to an abrupt artificial increase in daylength. In blood samples collected frequently, mean serum LH concentrations increased in relation to time o...
Pace MM, Sullivan JJ.Fertilization rate was highest in mares inseminated with frozen semen within 12 hr of ovulation. Foaling rate was improved (P less than 0-05) by increasing the number of motile spermatozoa inseminated from 40 X 10(6) to 80 X 10(6) but was not further improved by increasing the number to 160 X 10(6) or by increasing the frequency of insemination from once to twice daily. The fertilizing capacity of spermatozoa frozen in one of the hydrogen ion extenders studied was dependent upon relative osmotic pressure and method of freezing (ampoules or pellets). Adjusting glycerol concentration from 7% to ...
Mari G, Bucci D, Love CC, Mislei B, Rizzato G, Giaretta E, Merlo B, Spinaci M.The aim of this study was to compare the effect of presorting centrifugation (cushioned [CC] or single-layer colloid [SLC]), with simple dilution (SD), on the quality of sex-sorted stallion semen before and after sorting and after freezing and thawing. Four ejaculates from each of two fertile stallions were collected 1 week apart and evaluated for percent total sperm motility (TM), percent viable acrosome-intact sperm (VAI), and DNA quality (percentage of DNA fragmentation index). Freezing caused, independently from CC and SLC treatments, a significant decrease of TM (P < 0.05) and VAI (...
Álvarez C, Luño V, González N, Gil L.Sperm quality in donkeys (Equus asinus) after freezing thawing is still considered lower than that from other animals, including horses. The aim of this study was to test a new freezing extender supplemented with jenny colostrum on donkey sperm. After thawing, we evaluated sperm motility by means of computer-assisted analysis, viability by SYBR-14 and propidium iodide (PI), membrane functional integrity by HOS-test and acrosome integrity by isothiocyanate conjugated with peanut agglutinin (FITC-PNA) and PI. Ejaculates were collected from five fertile Donkeys. Sperm samples were pooled, diluted...
Raz T, Gray A, Hunter B, Card C.Superovulatory treatment may potentially increase the embryo recovery rate and the per-cycle pregnancy rate in normal or subfertile mares that are managed properly. However, some studies suggest a possible negative effect of superovulatory treatment on ovarian follicular maturation and embryo viability. Objectives of the present study were to investigate the early effects of eFSH treatment in reproductively normal mares in terms of: folliculogenesis, pregnancy rate, early embryonic development, reproductive tract parameters (tone and edema), and serum estradiol-17beta and progesterone concentr...
Hinrichs K.In vitro embryo production is not yet successful in the horse, largely due to low rates of fertilization in vitro. However, methods to produce embryos from isolated oocytes have been developed. Oocytes may be recovered from living mares by aspiration of the dominant preovulatory follicle by trans-abdominal puncture, and from both preovulatory and immature follicles by trans-vaginal ultrasound-guided puncture. Transfer of in vivo-matured oocytes to the oviducts of bred recipient mares has resulted in good pregnancy rates (75-85%). Little work has been done on transfer of horse oocytes matured i...
Sieme H, Bonk A, Hamann H, Klug E, Katila T.The effects of different artificial insemination (AI) techniques and sperm doses on pregnancy rates of normal Hanoverian breed mares and mares with a history of barrenness or pregnancy failure using fresh or frozen-thawed sperm were investigated. The material included 187 normal mares (148 foaling and 39 young maiden mares) and 85 problem mares with abnormal reproductive history. Mares were randomly allotted into groups with respect to AI technique (routine AI into the uterine body, transrectally controlled deep intracornual AI ipsilateral to the preovulatory follicle, or hysteroscopic AI onto...
Malmgren L.The storage and transport of cooled, liquid semen is an effective way of facilitating the use of desirable stallions for breeding mares located on distant farms. The Equitainer System is the most widely used transport container and it has been shown that it is possible to ship semen in this container and obtain good conception rates. However, the cost of Equitainers is high, and stud-farms that ship large quantities of semen have tended to rely on cheaper alternatives, even though little documentation exists concerning their reliability, especially under extreme temperature conditions. Two dif...
Squires EL.There has and will continue to be reproductive techniques available that have a positive impact upon the equine breeding industry. This review focuses on semen technologies that have been developed or are in the process of being developed. The use of fluorescent dyes and flow cytometry has provided the researcher and clinician with powerful tools to evaluate several sperm attributes. These procedures have been utilized to evaluate sperm viability, acrosome status, mitochondrial status, DNA integrity and stages of capacitation. Flow cytometry allows several sperm attributes to be evaluated on t...
Zhou H, Liu C, Wang W.This study was conducted to reconstruct heterogeneous embryos using equine skin fibroblast cells as donor karyoplasts and the bovine oocytes as recipient cytoplast for investigating the reprogramming of equine somatic cell nuclear in bovine oocyte cytoplasm and the developmental potential of the reconstructed embryos. Adult horse skin fibroblast cells serum-starved were used as donor somatic cells. Bovine oocytes matured in vitro were employed as recipient cytoplasts. The fusion of fibroblast cells into recipient cytoplasm was induced by electofusion. The fused eggs were activated by inomycin ...
Aurich C, Budik S.Although the horse is a seasonal breeding species, a considerable number of mares continue to cycle throughout autumn and winter. Slower equine embryo growth during the non-breeding season has been hypothesized, and because smaller embryo size is beneficial for cryopreservation, embryo collection outside the breeding season could be an interesting approach for the production of frozen horse embryos. In the present retrospective study, we have therefore analysed embryo recovery rates and conceptus size in mares (n = 30) throughout the year. Conceptus diameter was either size determined after co...
Lopes Ede P, Siqueira JB, Pinho RO, Guimarães JD, Rocha AN, de Carvalho GR, Torres CA.The objective of this study is to evaluate the reproductive efficiency in donors and recipient Mangalarga Marchador mares in commercial programmes of embryo transfer (ET) and the effects of some reproductive characteristics and ET methodology on conception rates in the recipient mares. A total of 1140 flushing procedures were performed and 830 embryos (72.8%) were recovered. There were no differences between the rates of embryonic recovery in the different breeding seasons (p > 0.05) and 92.8% of the recovered embryos were 8-9 days old. There was no difference in the embryonic recovery regardi...
Campbell MLH.This paper assesses whether cloning horses is ethical by reviewing ethical arguments against cloning of nonequine species and determining whether they apply to horses, analysing ethical arguments about horse cloning which do not apply to noncompetitive species and considering the ethical dilemmas faced by veterinarians involved in horse cloning. The author concludes that concerns about the health and welfare of cloned horses render the technique ethically problematic and that the onus is on those providing commercial equine cloning services to collate data and provide a stronger evidence base ...
