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Topic:In Vitro Research

In vitro research involving horses refers to the study of equine cells, tissues, or biological molecules outside their normal biological context, typically in controlled laboratory environments. This research approach allows scientists to investigate cellular processes, molecular interactions, and the effects of various treatments without the ethical and logistical complexities of in vivo studies. In vitro studies contribute to understanding equine physiology, pathology, and pharmacology by providing insights into cellular responses to pathogens, drugs, and other stimuli. This page compiles peer-reviewed research studies and scholarly articles that explore various in vitro methodologies and their applications in equine science, including cell culture techniques, molecular assays, and drug efficacy testing.
Susceptibility of equine erythrocytes to oxidant-induced rheologic alterations.
American journal of veterinary research    May 3, 2000   Volume 60, Issue 10 1301-1306 
Baskurt OK, Meiselman HJ.To evaluate the rheologic responses of equine versus human RBC to oxidant stress induced by superoxide anions. Methods: Equine blood samples were obtained from 8 healthy, 3- to 6-year-old various breed horses of either sex; human blood samples were obtained from 8 healthy adults. Methods: Washed RBC were exposed to superoxide anions generated by the xanthine oxidase (XO)-hypoxanthine system (XO activity of 0 to 0.1 U/ml). Deformability of RBC was assessed by ektacytometry, and RBC aggregation was measured in autologous plasma or 3% solution of dextran 70 via a defined-shear photometric techniq...
Primary nucleotide structure of predominant and alternate splice forms of equine insulin-like growth factor I and their gene expression patterns in tissues.
American journal of veterinary research    May 3, 2000   Volume 60, Issue 10 1234-1241 
Nixon AJ, Brower-Toland BD, Sandell LJ.To isolate, clone, and determine primary nucleotide sequence of equine insulin-like growth factor I (IGF-I) and to examine IGF-I gene expression in tissues and cartilage from horses. Methods: Horses of various ages. Methods: Total RNA was isolated from tissues and purified. Complementary DNA (cDNA) was derived by reverse transcription and polymerase chain reaction (PCR) amplification and subcloned to plasmid vectors for sequencing and comparison with other species. Total RNA from various tissues was probed with radiolabeled cDNA or complimentary RNA constructs by use of northern blotting, tube...
Differentiation and genomic and antigenic variation among fetal, respiratory, and neurological isolates from EHV1 and EHV4 infections in The Netherlands.
The veterinary quarterly    May 2, 2000   Volume 22, Issue 2 88-93 doi: 10.1080/01652176.2000.9695031
van Maanen C, Vreeswijk J, Moonen P, Brinkhof J, de Boer-Luijtze E, Terpstra C.Ten monoclonal antibodies (MAbs) were produced against equine herpes virus type 1 (EHV1). Two appeared type-specific, while the other eight were directed against epitopes common to both EHV1 and EHV4. Two MAbs directed against the glycoprotein gp2 recognized linear epitopes, as demonstrated by Western blotting. With pools of type-specific MAbs, 282 field isolates were typed in an immunoperoxidase monolayer assay (IPMA). From a total of 254 fetal or neonatal isolates, 244 (96%) were typed as EHV1, whereas 14 out of 15 (93%) respiratory tract isolates were typed as EHV4. Surprisingly, 3 out of 1...
Osteoclastic resorption of equine cranial and postcranial bone in vitro.
Journal of bone and mineral metabolism    April 28, 2000   Volume 18, Issue 3 148-152 doi: 10.1007/s007740050105
Kingsmill VJ, Gray C, Boyde A.To address possible differences in the resorbability of cranial and postcranial bone, slices of equine frontal bone and leg (first phalanx or third metacarpus) were seeded with embryonic chick bone cells and cultured for 20-24h. After removing the cells and drying the specimens, the areas and volumes of more than 800 resorption pits in each set were measured using a video-rate reflection confocal microscope system. Relative mineralization densities were determined by quantitative electron backscattering analysis. The mean mineralization density was greater in the leg bone, but the mean depths ...
Genetic manipulation of equine arteritis virus using full-length cDNA clones: separation of overlapping genes and expression of a foreign epitope.
Virology    April 25, 2000   Volume 270, Issue 1 84-97 doi: 10.1006/viro.2000.0245
de Vries AA, Glaser AL, Raamsman MJ, de Haan CA, Sarnataro S, Godeke GJ, Rottier PJ.Equine arteritis virus (EAV) is an enveloped, positive-stranded RNA virus belonging to the family Arteriviridae of the order Nidovirales. The unsegmented, infectious genome of EAV is 12,704 nt in length [exclusive of the poly(A) tail] and contains eight overlapping genes that are expressed from a 3'-coterminal nested set of seven leader-containing mRNAs. To investigate the importance of the overlapping gene arrangement in the viral life-cycle and to facilitate the genetic manipulation of the viral genome, a series of mutant full-length cDNA clones was constructed in which either EAV open readi...
Meiotic competence in horse oocytes: interactions among chromatin configuration, follicle size, cumulus morphology, and season.
Biology of reproduction    April 25, 2000   Volume 62, Issue 5 1402-1408 doi: 10.1095/biolreprod62.5.1402
Hinrichs K, Schmidt AL.Horse oocytes were collected from an abattoir over a 15-mo period. After classification of follicle size and cumulus morphology, oocytes were either fixed immediately (0 h) or matured in vitro (24 h). There was no effect of season on the number of antral follicles present on the ovaries, or on oocyte maturation rate for any class of oocyte. The proportion of oocytes having condensed chromatin at 0 h increased with increasing follicle size. The oocyte maturation rate also increased with follicle size, and for follicles </= 20-mm diameter, was higher for oocytes initially having expanded cumu...
Intracellular microelectrode recording to characterize inhibitory neuromuscular transmission in jejunum of horses.
American journal of veterinary research    April 20, 2000   Volume 61, Issue 4 362-368 doi: 10.2460/ajvr.2000.61.362
Rakestraw PC, Snyder JR, Sanders KM, Shuttleworth WC.To evaluate electrical activity of jejunal circular muscle in horses and characterize electrical responses to stimulation by intrinsic inhibitory neurons. Methods: Portions of jejunum obtained from horses euthanatized for reasons other than gastrointestinal tract disease. Methods: Isolated circular muscle preparations were perfused with oxygenated modified Krebs solution. Glass microelectrodes were used for intracellular recording of membrane potentials from single smooth muscle cells. Electrical activity and responses to electrical field stimulation (EFS) of intrinsic neurons in the presence ...
Use of specific sugars to inhibit bacterial adherence to equine endometrium in vitro.
American journal of veterinary research    April 20, 2000   Volume 61, Issue 4 446-449 doi: 10.2460/ajvr.2000.61.446
King SS, Young DA, Nequin LG, Carnevale EM.To determine whether specific sugars inhibit adhesion of Streptococcus zooepidemicus, Pseudomonas aeruginosa, and Escherichia coli to equine endometrial epithelial cells in vitro. Methods: Endometrial biopsy specimens collected during estrus from 7 healthy mares. Methods: Endometrial specimens on glass slides were incubated for 30 minutes at 4 C with suspensions of S. zooepidemicus, P. aeruginosa, or E. coli in phosphate-buffered saline solution (PBSS) alone or with various concentrations of D-(+)-mannose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, D-(+)-glucose, galactose, or N-acetyl-...
Metabolic and mitogenic activities of insulin-like growth factor-1 in interleukin-1-conditioned equine cartilage.
American journal of veterinary research    April 20, 2000   Volume 61, Issue 4 436-441 doi: 10.2460/ajvr.2000.61.436
Frisbie DD, Sandler EA, Trotter GW, McIlwraith CW.To determine response of interleukin-1alpha (IL-1alpha)-conditioned equine articular cartilage explants to insulin-like growth factor-1 (IGF-1). Sample Population-Cartilage from the trochlea and condyles of the femur of a clinically normal 4-year-old horse. Methods: Effects of IGF-1 (0 to 500 ng/ml) after addition of IL-1alpha were evaluated by assessing matrix responses, using a sulfated glycosaminoglycan (GAG) assay, matrix 35SO4 GAG incorporation, and release of GAG. Mitogenic response was assessed by 3H-thymidine incorporation into DNA and fluorometric assay of total DNA concentration. Res...
In vitro effects of erythromycin, lidocaine, and metoclopramide on smooth muscle from the pyloric antrum, proximal portion of the duodenum, and middle portion of the jejunum of horses.
American journal of veterinary research    April 20, 2000   Volume 61, Issue 4 413-419 doi: 10.2460/ajvr.2000.61.413
Nieto JE, Rakestraw PC, Snyder JR, Vatistas NJ.To evaluate effects of erythromycin, lidocaine, and metoclopramide on smooth muscle of the pyloric antrum (PA), proximal portion of the duodenum (PD), and middle portion of the jejunum (MJ) of horses. Sample Population-Strips of smooth muscle from 7 horses. Methods: Isolated muscle strips were suspended in a bath and attached to isometric force transducers. Once stable spontaneous contractions were observed, agents were added. Isometric stress responses were compared with the amplitude of spontaneous contractions. Results: A single dose of erythromycin to the PA increased contractile amplitude...
Consideration of the role of antigenic keratan sulphate reacting to a 1/14/16H9 antibody as a molecular marker to monitor cartilage metabolism in horses.
The Journal of veterinary medical science    April 19, 2000   Volume 62, Issue 3 281-285 doi: 10.1292/jvms.62.281
Okumura M, Tagami M, Fujinaga T.The role of keratan sulphate (KS) as a marker of cartilage metabolism was evaluated by using an in vitro model of equine articular cartilage. Articular cartilage was harvested from clinically healthy 6-month-old foals (n=3). Chondrocytes were centrifuged and cultured as pellets. Chondrocyte pellets were stimulated by insulin-like growth factor (IGF)-Ialpha or interleukin (IL)-1alpha for 2 weeks. The sulfated glycosaminoglycans (GAG) and antigenic KS concentrations in the culture media were measured by a 1,9-dimethyl-methylene blue (DMMB) colorimetric assay and an inhibition ELISA using a 1/14/...
Actions and interactions of ADP, 5- HT, histamine and PAF on equine platelets.
Research in veterinary science    April 11, 2000   Volume 68, Issue 2 175-180 doi: 10.1053/rvsc.1999.0356
Bailey SR, Andrews MJ, Elliott J, Cunningham F.Platelets are thought to play a role in equine diseases such as acute laminitis and verminous arteritis and may be involved in allergic disease. Mediators implicated in the pathophysiology of these conditions activate platelets and responses may be enhanced by interactions between mediators. The present study compared platelet aggregation, thromboxane production and release of radiolabelled [(3)H]5- HT in response to 5- HT, histamine, ADP and PAF alone and in combination in vitro.PAF caused concentration-related aggregation, [(3)H]5- HT release and thromboxane production. In contrast, ADP caus...
Equine osteoclast-like cells generated in vitro demonstrate similar characteristics to directly isolated mature osteoclasts.
Research in veterinary science    April 11, 2000   Volume 68, Issue 2 161-167 doi: 10.1053/rvsc.1999.0367
Gray AW, Davies ME, Jeffcott LB.We report on novel methods to isolate osteoclasts (OC s) and generate osteoclast-like cells (OCL s) from the bone and bone marrow of the equine femur. OC s were successfully isolated from bone scrapings taken from the endosteal surface of the femurs of three horses. OCL s were generated from bone marrow cells taken from the same animals. The validity of using the formation of OCL s as a method for studying OC differentiation and activity was confirmed by the similar characteristics of these two cells. In particular, they both were multinuclear, expressed the enzyme tartrate resistant acid phos...
Equine immunity to bacteria.
The Veterinary clinics of North America. Equine practice    April 7, 2000   Volume 16, Issue 1 29-iv doi: 10.1016/s0749-0739(17)30117-7
Giguère S, Prescott JF.The remarkable ability of the horse and other animals to prevent infection by most bacterial pathogens encountered is the result of a complex set of distinct but overlapping defense mechanisms. This article summarizes the current state of knowledge on innate and adaptive immunity to bacterial pathogens and reviews various ways in which some bacteria have evolved in order to evade components of the host response.
The effect of oxytocin on contractility of the equine oesophagus: a potential treatment for oesophageal obstruction.
Equine veterinary journal    April 1, 2000   Volume 32, Issue 2 151-155 doi: 10.2746/042516400777591660
Meyer GA, Rashmir-Raven A, Helms RJ, Brashier M.This study was performed to determine the effect of administration of i.v. oxytocin on the contractility of the musculature associated with the equine oesophagus. Nine clinically normal horses were fitted with a nasogastric tube modified with inflatable latex cuffs. These cuffs were connected to piezoelectric pressure recording devices. Oxytocin in 3 different doses or saline controls were administered i.v. in a randomised block pattern. Systolic blood pressure, ECG, heart rate and nasogastric tube cuff pressures were then measured for 60 min. Administration of oxytocin i.v. at 0.11 and 0.22 i...
Spontaneous production of nitric oxide (NO), prostaglandin (PGE2) and neutral metalloproteinases (NMPs) in media of explant cultures of equine synovial membrane and articular cartilage from normal and osteoarthritic joints.
Equine veterinary journal    April 1, 2000   Volume 32, Issue 2 140-150 doi: 10.2746/042516400777591598
von Rechenberg B, McIlwraith CW, Akens MK, Frisbie DD, Leutenegger C, Auer JA.Nitric oxide (NO), prostaglandin E2 (PGE2), and the activity of neutral metalloproteinases (NMPs) were measured in conditioned media of equine synovial membrane and articular cartilage explant cultures from horses with normal joints (n = 7) and from horses affected with moderate (n = 7) or severe osteoarthritis (n = 14) as judged by macroscopic appearance. Normal articular cartilage appeared glossy and bluish-white, was of normal thickness and showed no evidence of discolouration, fibrillation or other cartilage discontinuity. Slight discolouration and fibrillation or minor clefts of the carti...
Melanin affinity: a possible explanation of isoxsuprine retention in the horse.
Equine veterinary journal    April 1, 2000   Volume 32, Issue 2 114-118 doi: 10.2746/042516400777591606
Törneke K, Larsson CI, Appelgren LE.Isoxsuprine is used in veterinary medicine as a vasodilating agent. The drug has been detected in the urine of horses up to 6 weeks after the cessation of administration. In the present study, the distribution pattern of 3H-isoxsuprine was investigated using whole body autoradiography in mice to find a possible site of retention. Melanin was the only place of retention identified. Additional in vitro studies showed an affinity of isoxsuprine to both melanin and keratin. The K(d) values were 0.02 mmol/l and 1 mmol/l, and the B(max) values were 0.2 micromol/mg and 2 micromol/mg, respectively. A ...
Affinity of isoxsuprine for adrenoreceptors in equine digital artery and implications for vasodilatory action.
Equine veterinary journal    April 1, 2000   Volume 32, Issue 2 119-124 doi: 10.2746/042516400777591543
Belloli C, Carcano R, Arioli F, Beretta C.We used isolated equine digital arteries to study the vasodilatory mechanism of isoxsuprine, and fowl caecum preparations to investigate the affinity of the drug for beta-adrenoceptors. Isoxsuprine is a potent vasodilator of arterial smooth muscle that has been precontracted by an alpha-adrenoceptor agonist such as noradrenaline (log EC50 = -6.33 [-5.98; -6.68]). The present study indicates that its effect is due to alpha-adrenoceptor blockade since: (1) after a long lasting exposure to cumulative doses of isoxsuprine the vasoconstricting action of noradrenaline cannot be restored; (2) isoxsup...
Proton electron nuclear double resonance from nitrosyl horse heart myoglobin: the role of His-E7 and Val-E11.
Biophysical journal    March 29, 2000   Volume 78, Issue 4 2107-2115 doi: 10.1016/S0006-3495(00)76757-9
Flores M, Wajnberg E, Bemski G.Electron nuclear double resonance (ENDOR) spectroscopy has been used to study protons in nitrosyl horse heart myoglobin (MbNO). (1)H ENDOR spectra were recorded for different settings of the magnetic field. Detailed analysis of the ENDOR powder spectra, using computer simulation, based on the "orientation-selection" principle, leads to the identification of the available protons in the heme pocket. We observe hyperfine interactions of the N(HisF8)-Fe(2+)-N(NO) complex with five protons in axial and with eight protons in the rhombic symmetry along different orientations, including those of the ...
The relationship of increased susceptibility of sperm DNA to denaturation and fertility in the stallion.
Theriogenology    March 29, 2000   Volume 50, Issue 6 955-972 doi: 10.1016/s0093-691x(98)00199-x
Love CC, Kenney RM.The relationship between fertility and susceptibility of sperm DNA to denaturation was determined in a group of 84 actively breeding, clinically fertile stallions. Susceptibility of DNA to denaturation was determined using the sperm chromatin structure assay (SCSA). The SCSA measures, mean of alpha-t (mean alpha t), standard deviation of alpha-t (SD alpha t), and the COMP of alpha-t (cells outside the main population)] were significantly correlated with the percentage seasonal pregnancy rate (SPR; mean alpha t, r = -0.24, P < or = 0.05; % COMP alpha t, r = -0.27, P < or = 0.05); percentage pre...
Effectiveness of two systems for transporting equine semen.
Theriogenology    March 29, 2000   Volume 50, Issue 6 833-839 doi: 10.1016/s0093-691x(98)00188-5
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...
Effects of glutamine, proline, histidine and betaine on post-thaw motility of stallion spermatozoa.
Theriogenology    March 29, 2000   Volume 52, Issue 1 181-191 doi: 10.1016/s0093-691x(99)00120-x
Trimeche A, Yvon JM, Vidament M, Palmer E, Magistrini M.The supplementation of the freezing diluent with 3 amino acids (glutamine, proline and histidine) and 1 amino acid-related compound (betaine) in preserving stallion spermatozoa diluted in INRA82 extender containing 2.5% (v/v) glycerol and 2% (v/v) egg yolk (control extender) during freezing and thawing was studied at 0, 40, 80, 120 and 160 mM in 20 split ejaculates (10 stallions x 2 ejaculates; Experiment 1). Glutamine and proline were studied at 0, 10, 20, 30, 40, 50, 60, 70 and 80 mM in 20 split ejaculates (10 stallions x 2 ejaculates; Experiment 2). In each experiment, spermatozoa were eval...
Two-dimensional polyacrylamide gel electrophoresis of equine seminal plasma proteins and their correlation with fertility.
Theriogenology    March 29, 2000   Volume 52, Issue 5 863-873 doi: 10.1016/S0093-691X(99)00178-8
Brandon CI, Heusner GL, Caudle AB, Fayrer-Hosken RA.The objectives of this study were to 1) identify proteins found in stallion seminal plasma utilizing two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) in conjunction with Western blot analysis; and 2) to determine if any of these individual proteins were correlated with stallion fertility utilizing regression analysis. Fertility was quantified by assigning a breeding score for each stallion. Each score was calculated by dividing the number of conceptions by the number of breedings for each stallion for four successive breeding seasons (1992-1995). Ejaculates from stallions of known ...
Generation of an equine oviductal epithelial cell line for the study of sperm-oviduct interactions.
Theriogenology    March 29, 2000   Volume 52, Issue 5 875-885 doi: 10.1016/S0093-691X(99)00179-X
Dobrinski I, Jacob JR, Tennant BC, Ball BA.Equine oviductal epithelial cells (OEC) were transformed with simian virus 40 large T antigen (SV 40 T-ag) to create a cell line for the study of the interaction of equine spermatozoa with oviductal epithelium. One cell line was established based on the expression of the SV 40 T-ag and extended lifespan in culture. Immortalized equine OEC retained the characteristics of differentiated OEC such as the formation of monolayers with characteristic epithelial morphology and cell polarization as well as expression of cytokeratin and equine major histocompatibility complex I. Monolayers of immortaliz...
Effect of time during transport of excised mare ovaries on oocyte recovery rate and quality after in vitro maturation.
Theriogenology    March 29, 2000   Volume 52, Issue 5 757-766 doi: 10.1016/S0093-691X(99)00169-7
Guignot F, Bezard J, Palmer E.In the mare only a limited number of oocytes can be successfully collected in vivo, so that when large numbers of oocytes are needed for experimentation, ovaries harvested from slaughtered mares must be used. The resulting temperature changes and time intervals mandated by handling and transport of ovaries from the slaughterhouse to the laboratory adversely affect the rate of oocyte recovery and their quality after IVF and maturation. We chose to study the effect of temperature and time in transit of excised ovaries by evaluating rate of oocyte recovery, nuclear maturation stage reached before...
Heme orientation affects holo-myoglobin folding and unfolding kinetics.
FEBS letters    March 29, 2000   Volume 470, Issue 2 203-206 doi: 10.1016/s0014-5793(00)01319-3
Moczygemba C, Guidry J, Wittung-Stafshede P.Native myoglobin (Mb) consists of two populations which differ in the orientation of the heme by 180 degrees rotation (as verified by nuclear magnetic resonance) but have identical absorption spectra and equilibrium-thermodynamic stability. Here, we report that these two fractions of native oxidized Mb (from horse) both unfold and refold (chemical denaturant, pH 7, 20 degrees C) in two parallel kinetic reactions with rate constants differing 10-fold. In accord, the oxidized heme remains coordinated to unfolded horse Mb in up to 4 M guanidine hydrochloride (pH 7, 20 degrees C).
Interaction of bull, stallion and boar seminal plasma proteins and sperms with acidic polysaccharides.
Folia biologica    March 25, 2000   Volume 44, Issue 5 177-183 
Liberda J, Tichá M, Zralý Z, Svecová D, Vezník Z.The interaction of seminal plasma proteins, sperms and detergent-released sperm proteins of three species with different types of acidic polysaccharides was studied. Heparin-binding activity of boar, bull and stallion seminal plasma proteins, sperms and sperm proteins was compared with their ability to interact with polysaccharides differing in the presence of the sulfate groups or in their saccharide moiety (chondroitin sulfate, dextran sulfate, fucoidan, hyaluronic acid). Bull seminal plasma proteins were characterized by higher affinity to heparin, fucoidan and dextran sulfate, while signif...
Effect of mare’s age and recovery methods on the recovery rate of equine follicular oocytes for IVM procedures.
Theriogenology    March 25, 2000   Volume 49, Issue 4 735-741 doi: 10.1016/S0093-691X(98)00022-3
Erice I, Gil L, Josa A, Echegaray A, Martinez F, Espinosa E.Mares (n = 39) were classified according to age as young (less than 1.5 yr, n = 17) or old (more than 1.5 yr, n = 22) and sacrificed. Ovaries were measured and weighed, and the number of follicles and CL were counted. Follicle size and distribution were recorded (external: > 20 mm, 5 mm, < 5 mm). External follicles were aspirated while internal follicles were sliced. The number and Type of oocytes recovered using each method were recorded. Oocyte recovery rates (oocytes/ovary) resulted in a mean of 0.92 oocytes by aspiration and 1.36 oocytes by additional slicing. The mean numbers of av...
Effect of passive immunization against inhibin on FSH secretion, folliculogenesis and ovulation rate during the follicular phase of the estrous cycle in mares.
Theriogenology    March 25, 2000   Volume 50, Issue 4 545-557 doi: 10.1016/s0093-691x(98)00160-5
Nambo Y, Kaneko H, Nagata S, Oikawa M, Yoshihara T, Nagamine N, Watanabe G, Taya K.Physiological roles of inhibin in mares were investigated by means of passive immunization using an antiserum to inhibin that had been raised in a castrated goat. Eight mares were given an intravenous injection of either 100 mL (n = 4) or 200 mL (n = 4) of inhibin antiserum 4 d after a single intramuscular injection of PGF2 alpha on Day 8 after ovulation, 4 control mares were treated with 100 mL castrated goat serum in the same manner. Jugular vein blood samples were collected after treatment with the serum until 192 h post treatment. Follicular growth and ovulations were monitored by ultrasou...
Production of embryos by assisted reproduction in the horse.
Theriogenology    March 25, 2000   Volume 49, Issue 1 13-21 doi: 10.1016/s0093-691x(97)00398-1
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...