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Theriogenology.
Publisher:
Geron-X.. [New York, N.Y.?] : Elsevier
Frequency: Sixteen no. a year
Country: United States
Language: English
Start Year:1974 -
ISSN:
0093-691X (Print)
1879-3231 (Electronic)
0093-691X (Linking)
1879-3231 (Electronic)
0093-691X (Linking)
Impact Factor
2.8
2022
| NLM ID: | 0421510 |
| (OCoLC): | 02504829 |
| (DNLM): | T08780000(s) |
| Coden: | THGNBO |
| Classification: | W1 TH677K |
Comparative aspects of somatic cell nuclear transfer with conventional and zona-free method in cattle, horse, pig and sheep. Nuclear transfer (NT) is a complex procedure that requires considerable technical skills. Over the years attempts have been made to simplify the micromanipulations involved and to make the procedure more user-friendly. A significant step forwards has been the development of the zona-free NT methods. We have used zona-free NT with mechanical aspiration of the metaphase plate as a mean of enucleation, in a comparative approach with the conventional nuclear transfer zona-enclosed method in cattle, horse, sheep and pig. The absence of the zona considerably facilitates the enucleation step and sign...
Expression and bioactivity of a single chain recombinant equine luteinizing hormone (reLH). To study structure-activity relationships and the role of equine gonadotropins in the normal and pathophysiology of equine reproduction, the availability of purified hormones is essential. Previous expression studies in transfected CHO cells showed inefficient assembly of the human and bovine alpha and beta subunits, resulting in low levels of recombinant LH. The ability to express a single chain bearing genetically linked alpha and beta subunits bypasses this rate-limiting assembly step. A chimera was constructed by overlap PCR in which the carboxy terminal end of the eLHbeta subunit was gene...
Generation of superoxide anion by equine spermatozoa as detected by dihydroethidium. Low-level production of the superoxide anion (O2*-) is an important signal transduction event in sperm function including capacitation; however, excessive production of O2*- can be detrimental to sperm function. The objective of this study was to assess dihydroethidium (DHE) as a probe for O2*- in equine spermatozoa. Ejaculated spermatozoa were separated by centrifugation over a Percoll gradient (40:80), and loaded with DHE (2.0 microM) as well as with calcein-acetoxymethylester (CAM, 7.8 nM) to determine cell viability. In Experiment 1, cells were incubated with the xanthine-xanthine oxidase ...
Effect of sperm numbers and concentration on sperm transport and uterine inflammatory response in the mare. Our objective was to determine whether the concentration of cooled sperm inseminated influenced sperm transport and intensity of the uterine inflammatory reaction 2, 4 and 24h after insemination. Experimental subjects were 189 estrous mares with a dominant follicle > or =35 mm in diameter and no bacterial growth or neutrophils detected in uterine smears. Each mare was randomly assigned to receive one of the following intrauterine treatments (volume, 20 mL): insemination with 5x10(6) mL(-1) or 25x10(6) mL(-1) or 50x10(6) mL(-1) sperm diluted in 3 mL seminal plasma (SP) and 17 mL skim milk; s...
One year old fillies can be successfully used as embryo donors. One year old fillies are able to conceive but, usually, not to give birth to a living foal. Although embryo transfer allows the production of foals from mature mares with repeated pregnancy losses, no reports are available on the use of one year old fillies as embryo donors. To evaluate this possibility, eleven 12-16 months old Haflinger mares were inseminated with fresh semen and subjected to embryo recovery. Some of the recovered embryos were non-surgically transferred into synchronized mature recipients. Pregnancies were terminated using PGF2alpha at day 25. Fillies' embryo recovery rate an...
Influence of induction of parturition on the neonatal acute phase response in foals. The objectives of the present study were to determine whether induction of parturition in mares at term with low doses of oxytocin (2.5 i.u. i.v. every 20 min) affected the incidence of peri-partum complications or inflammatory responses in the neonatal foal. Parturition was induced in 11 of 26 mares and the remainder foaled spontaneously. Serum concentrations of amyloid A (AA; an acute phase protein) were measured (with a commercial ELISA) from 0 to 72 h postpartum in 18 of the neonatal foals. The incidence of dystocia and premature placental separation was higher in induced mares (2 of 11 an...
Effect of exercise and suspensory on scrotal surface temperature in the stallion. In this study, the effect of exercise (treadmill, riding) on scrotal surface temperature (SST) in the stallion with and without suspensory was evaluated. Experiments were carried out between September and November 2004 using 12 Franches-Montagnes stallions from the National Stud in Avenches (Switzerland). Each stallion performed a standardized incremental treadmill and a ridden test with and without suspensory. The intensity of exercise was monitored by heart rate and blood lactate concentration. For SST measurements, special thermistors were developed and affixed to the most ventral part of t...
Disease transmission in horses. Bacterial, viral and protozoal infections may cause severe reproductive losses. The present paper reviews the risk factors, clinical signs and preventive measures for the most important venereal or potential sexually transmitted diseases in horses. The stallion and use of semen for artificial insemination represent major risk factors for the transmission of bacterial contaminants of the penis, including Streptococcus equi subspecies zooepidemicus, Pseudomonas aeruginosa and Klebsiella pneumoniae, known to cause endometritis and infertility in the mare. The role of the stallion in disease trans...
Pathogenesis and treatment of endometritis in the mare: a review. Inflammatory conditions of the uterus, collectively known as endometritis, can be classified as acute, chronic, active, or subclinical. This condition causes substantial reductions in mare fertility. To diagnose and treat mares with endometrial inflammation, it is imperative to identify predisposing factors and challenges to the reproductive tract of the mare in a chronological order; these factors change from those of the young maiden filly to the older, multiparous broodmare. This paper addresses predisposing factors, diagnostic procedures and therapy strategies for different mare groups.
Influence of immunization against GnRH on reproductive cyclicity and estrous behavior in the mare. The aim of this study was to evaluate the effect of active immunization against GnRH on ovarian activity, plasma progesterone and estradiol concentrations and on estrous behavior in adult mares. Eighteen cyclic mares were randomly divided into a treatment and control group. Nine mares were immunized twice with 2 mL (400 microg GnRH-protein conjugate) of a GnRH-vaccine (Improvac, CSL Limited, Australia) administered intramuscularly, 4 weeks apart. Control mares received the same amount of saline solution. Ovaries and uterus of all mares were examined weekly by ultrasonography from 3 weeks befor...
Oxytocin does not contribute to the effects of cervical dilation on progesterone secretion and embryonic development in mares. The aim of the present study was, to investigate the effects of oxytocin administration on Day 7 post-ovulation on progesterone secretion, pregnancy rate and embryonic growth in mares. Endogenous stimulation of oxytocin release was compared to the administration of native oxytocin or the long-acting oxytocin analogue carbetocin. At Day 7 after ovulation, mares had to undergo four treatments in a crossover design: (a) control, (b) oxytocin (10 IU i.v.), (c) carbetocin (280 microg i.m.) and (d) cervical dilation. On Day 13, all mares (8 of 8 mares) were pregnant on groups control, oxytocin and c...
Insemination doses: how low can we go? This manuscript presents a brief historical review of investigations related to equine artificial insemination. The origin of recommended insemination doses for use fresh, cooled and frozen semen will be reviewed. Over 30 years ago, an insemination dose of 500 x 10(6) progressively motile sperm (PMS) was recommended to maximize pregnancy rates when mares were bred with fresh semen under less than ideal conditions. Since that time, 500 x 10(6) progressively motile sperm has been almost universally accepted as a standard insemination dose, regardless of a stallion's fertility or the refinements ...
Comparison of three containers used for the transport of cooled stallion semen. Three containers commonly used to transport cooled equine semen (Equitainer, ExpectaFoal and a Swedish-designed semen-transport container, previously called the Salsbro Box and now called Equine Express) were compared, using four ejaculates from each of three stallions. Each ejaculate was diluted to a spermatozoal concentration of 25 x 10(6)/ml with a nonfat dry milk-glucose extender containing amikacin sulfate (1 mg/ml) and potassium penicillin G (1000 units/ml). Extended semen was divided into three 40-ml aliquots for placement in each of the three semen-transport containers. The extended se...
Equine frozen semen: freezability and fertility field results. The freezability of stallion semen defined as the number of selected ejaculates/total number of ejaculates frozen from 161 different stallions was analyzed. Of the stallions, 19, 30, 27 and 24% had a freezability of 0%, 0 to 33%, 33 to 66%, over 66%, respectively In 85 different stallions, the correlation of freezability between first and second year was 0.60 (P < 0.001). The relationship between fertility with fresh and frozen semen and freezability was analyzed in 40 stallions whose freezability and fertility information was recorded during 5 years. There was a strong relationship between...
The effects of parturition and peripartum complications on the peritoneal fluid composition of mares. Abnormalities in peritoneal fluid are diagnostically useful for managing equine colic; however, their significance in post-dystocia mares is not known. This study was to determine what changes, if any, occurred following obstetrical manipulations. Peritoneal fluid samples were collected from 2 groups of foaling mares to establish control values, and from a third group that had developed clinical abnormalities (CAb,n = 14) or had made an uneventful recovery (CN,n = 36) following fetal extraction. In Group 1 mares, samples were collected before and after induced parturitions (n = 7), and althoug...
Factors affecting spermatogenesis in the stallion. Spermatogenesis is a process of division and differentiation by which spermatozoa are produced in seminiferous tubules. Seminiferous tubules are composed of somatic cells (myoid cells and Sertoli cells) and germ cells (spermatogonia, spermatocytes, and spermatids). Activities of these three germ cells divide spermatogenesis into spermatocytogenesis, meiosis, and spermiogenesis, respectively. Spermatocytogenesis involves mitotic cell division to increase the yield of spermatogenesis and to produce stem cells and primary spermatocytes. Meiosis involves duplication and exchange of genetic materia...
Puberty and growth rate in thoroughbred fillies. We measured progesterone and estradiol levels from birth to the beginning of adult life in 10 Thoroughbred fillies from the Equilia Stud Farm in Avaré SP, Brasil. The animals were measured and weighed monthly for the determination of body development and of a possible correlation between the rate of weight and height gain and the onset of detectable sex hormone levels. Jugular blood was collected twice a week and stored at -20 degrees C until assay of progesterone by a solid phase RIA with a sensitivity of 0.32 nmol L and of estradiol by liquid phase RIA adapted to low levels (3.67 pmol L ). ...
Effect of beta-carotene administration on reproductive function of horse and pony mares. The objective of this study was to determine whether supplemental beta-carotene would influence reproductive function in mares maintained on spring and summer pastures and to characterize plasma carotene concentrations during the estrous cycle. Carotene concentrations in plasma did not vary with day of estrous cycle (P = 0.7455). Mares receiving every other day injections of beta-carotene (400 mg; n = 4) or saline (10 ml; n = 4) during proestrus/estrus did not differ in plasma estradiol (E(2)) concentrations (P = 0.6313), follicle development (P = 0.8068), or plasma progesterone (P(4)) concent...
New staining methods for sperm evaluation estimated by microscopy and flow cytometry. New staining methods and automated instruments are now available to evaluate the sperm cell in vitro. Individual compartments of the sperm cell, such as the nucleus and the plasma and acrosomal membranes, may be investigated, as well as the cell function as shown by mitochondria activity and capacitation. Various probes are used and they can be analyzed by direct light or fluorescent microscopy or by flow cytometry. The automated instruments allow objective and accurate analysis and quantification as well as the ability to evaluate large population of cells in a shorter time, thus providing ac...
Determination of acrosin amidase activity in equine spermatozoa. Acrosin amidase activity of spermatozoa has been been associated with in vitro fertilization success in humans and has been proposed as an additional method for assessing sperm function in vitro. In this study, acrosin amidase activity was determined in equine spermatozoa by the hydrolysis of an arginine amide substrate. This assay includes a detergent to release acrosomal enzymes into a medium of basic pH to activate proacrosin to acrosin, which subsequently hydrolyses N-alpha-benzoyl-DL-arginine para-nitroanilide-HCl (BAPNA) to a chromogenic product. Spermatozoa (n = 3 ejaculates from each o...
Gonadotropin secretion and pituitary responsiveness to GnRH in mares with granulosa-theca cell tumor. Granulosa-theca cell tumors (GTCTs) are able to secrete variable amounts of sex steroids and immunoreactive inhibin (ir-INH). Although the pituitary appears to be affected by the presence of a GTCT, pituitary responsiveness to exogenous GnRH has not been examined. The aims of the present study were to: (i) assess the plasma hormone concentrations of ir-INH, gonadotropins and sex steroids in eight mares with GTCT and (ii) assess the responsiveness of pituitary gonadotroph cells to exogenous GnRH stimulus both before and after tumor removal. In seven mares, the contralateral ovary was firm, smal...
Validation of the sperm mobility assay in boars and stallions. The sperm mobility assay used in the present study measures the rate of sperm penetration in a biologically inert cell-separation solution (Accudenz). When a sample of sperm is overlaid in a cuvette containing Accudenz, sperm penetrate the solution and absorbance of the sample can be measured with a spectrophotometer. This assay has been successfully used to select chicken and turkey semen donors. We validated this assay for semen from boars and stallions. Absorbance was measured after overlaying fresh semen from each species in prefilled cuvettes for 1, 5, 10, 15, 20, and 40 min. There were n...
Comparison of an extender containing defined milk protein fractions with a skim milk-based extender for storage of equine semen at 5 degrees C. A problem of semen extenders based on milk or egg yolk is the fact that these biological products consist of a variety of substances. Extenders containing only components with clearly protective effects on spermatozoa would thus be an advantage. In this study, we have compared the effects of an extender containing defined caseinates and whey proteins only (EquiPro, defined milk protein extender) with skim milk extender on equine spermatozoa during cooled storage. The defined milk protein extender was used with and without the antioxidant N-acetyl cysteine (NAC). In a second experiment, semen w...
Surfactant protein A and D in the reproductive tract of stallion. The presence of surface-active material in the lung alveolus has been known for several decades as being essential for normal lung function. The host defense and controlling inflammatory processes of the lung are the major functions of SP-A and SP-D. SP-A and SP-D were originally demonstrated in alveolar type II cells, but recent studies have shown extrapulmonary expression of SP-A and SP-D indicating systemic roles of these proteins. Present study describes the presence of SP-A and SP-D in the stallion genital tract, prepuce, prostate, testis, and seminal vesicle using Western blotting and im...
Holding immature equine oocytes in the absence of meiotic inhibitors: effect on germinal vesicle chromatin and blastocyst development after intracytoplasmic sperm injection. Holding immature oocytes before the onset of maturation simplifies oocyte transport and aids in scheduling later manipulations. We report here a method for holding equine oocytes in the absence of meiotic inhibitors. In Experiment 1, immature oocytes with expanded cumuli were cultured at 38.2 degrees C in medium containing cycloheximide, or were held at room-temperature in M199 with Hanks' salts, for 16-18 h before maturation. Control oocytes were matured immediately after recovery. Oocytes were fertilized by intracytoplasmic sperm injection and cultured for 4d. Embryo development was not diff...
Reproduction in high body condition mares with high versus low leptin concentrations. Previous results from our laboratory indicated that a majority of mares with high body condition scores (BCS) displayed estrous cycles or had considerable follicular activity during the winter. Among these high BCS mares, about 35% of them exhibited a persistent hyperleptinemia and hyperinsulinemia. The current experiment was designed to compare the reproductive characteristics of high BCS mares with hyperleptinemia to those with normal (low) plasma concentrations of leptin during the winter and the first estrous cycle (or the first full cycle encountered for those already cycling). Light hors...
Immunolocalization of estrogen and androgen receptors and steroid concentrations in the stallion epididymis. The presence of steroids and their receptors throughout development, specifically androgen receptor (AR), estrogen receptor alpha (ERalpha) and estrogen receptor beta (ERbeta), in the epididymis of a high estrogen producing species like the stallion has not been determined. Epididymal and testicular samples were collected for analysis of testosterone and estradiol-17beta (E(2)) concentrations and for immunolocalization of AR, ERalpha and ERbeta. The concentration of testosterone in the testis and epididymis were not different among age groups (P>0.05). AR was localized in the principal cell...
Importance of using guarded techniques for the preparation of endometrial cytology smears in mares. Material for endometrial cytology can be collected by veterinarians using guarded or unguarded swabs, or digitally with a gloved hand, and is an important diagnostic tool in establishing the endometrial health of mares prior to breeding. The aim of this study was to determine whether the use of unguarded endometrial samples is a reliable indicator of the presence of neutrophils in the uterus. Duplicate endometrial smears were collected from 41 genitally normal, non-pregnant fertile mares by both double-guarded swabs (DGS) and in an unguarded manner by digital scraping (DS) of the endometrium. ...
Nuclear status of immature and mature stallion spermatozoa. 'The highly packed chromatin of mature spermatozoa results from replacement of somatic-like histones by highly basic arginine- and cysteine-rich protamines during spermatogenesis, with additional conformational changes in chromatin structure during epididymal transit. The objective of the present study was to compare the nuclear characteristics of immature and mature epididymal stallion spermatozoa, using a variety of experimental approaches. Resistance to in vitro decondensation of chromatin, following exposure to SDS-DTT and alkaline thioglycolate, increased significantly in mature spermatoz...
Real-time ultrasound measure of the fetal eye (vitreous body) for prediction of parturition date in small ponies. Ultrasonographic fetal eye measures have been used to estimate gestational age of the fetus in light horse mares. However, fetal eye measures have not been published for smaller pony breeds. This study was conducted to develop reference ranges for ultrasonographic measures of fetal eyes in small ponies for the purpose of predicting days before parturition (DBP) when breeding or ovulation dates are unknown. Twenty-three Shetland-type pony mares were studied across one (n = 10) or two (n = 13) gestations in 2004 (18 pregnancies) and 2005 (18 pregnancies). Measurements of fetal eyes were obtained...
