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PubMed2006

Increase of acetone emitted by urine in relation to ovulation.

BACKGROUND: Selected ion flow tube mass spectrometry allows trace gas quantification in exhaled breath and in the air/vapor above liquids (headspace) down to the 10 parts-per-billion level. During selected ion flow tube mass spectrometry investigation of the volatile compounds emitted by urine, high acetone levels were incidentally identified in the headspace of urine from healthy female volunteers around their mid-cycle. Hence, this study was designed to measure urine headspace acetone levels throughout the menstrual cycle. METHODS: Using selected ion flow tube mass spectrometry we measured daily urine headspace acetone concentrations of seven ovulating (group 1) and three postmenopausal volunteers (group 2). RESULTS: A several-fold increase in urine headspace acetone level was detected 2-3 days after the predicted day of ovulation in 5 of the 7 volunteers in group 1. No such rise was detected in group 2. CONCLUSION: This study provides the basis for future research to understand the reason for and the potential utility of this phenomenon.

Acetone↗
PubMed1991

Spontaneous embryonic death on Days 20 to 40 in heifers.

Transrectal ultrasound examinations were used in nulliparous Holstein heifers to study the association between time of spontaneous embryonic death (cessation of heartbeat) and luteal regression, and to determine the fate of the conceptus after embryonic death. There was no significant difference between nonbred heifers (n = 135) and bred, nonpregnant heifers (embryonic heartbeat never detected, n = 40) for day of onset of luteal regression (means, 17.6 and 17.9, respectively) or for length of interovulatory interval (means, 20.6 and 20.9 days, respectively). Pregnancy was confirmed by detection of an embryonic heartbeat on Day 24 (ovulation = Day 0) or later, or on two consecutive days prior to Day 24; on average, an embryonic heartbeat was detected on Day 22.0 (n = 104). Pregnancy rate on Day 24 was higher (P<0.02) in heifers bred on Day -1 (116/149, 77.8%) than in heifers bred on Day -2 (51/79, 64.6%), and was higher (P<0.05) in heifers with an embryo transferred ipsilateral to the corpus luteum than in heifers with an embryo transferred contralateral to the corpus luteum (3/4 vs 0/5). Embryonic death (lack of embryonic heartbeat following confirmation of pregnancy) and presumptive embryonic death (embryonic heartbeat detected on one day only, prior to Day 24) were detected prior to Day 25 in one and two bred heifers, respectively, and in one and two heifers with an embryo transferred contralateral to the corpus luteum, respectively. In these six heifers, luteal regression preceded, and apparently caused, embryonic death. In seven of eight heifers in which embryonic death was detected between Days 25 and 40, the onset of luteal regression was detected at least 3 d (range, 3 to 42 d) after detection of embryonic death. The incidence of embryonic death on Days 29 to 32 was lower (P<0.02) in heifers bred on Day -1 than in heifers bred on Day -2 (0 of 96 vs 3 of 40, respectively). In heifers in which luteal regression preceded embryonic death, the conceptus was lost rapidly, with minimal evidence of degeneration. In heifers in which embryonic death preceded luteal regression, there was ultrasonic evidence of conceptus degeneration, but conceptus fluid and tissue appeared to be maintained. In all heifers with embryonic death, the conceptus and its breakdown products apparently were eliminated by expulsion through the cervix rather than by resorption.

Journal Article↗
PubMed2004

Induction of ovulation with GnRH and PGF2alpha in lactating Bos taurus x Bos indicus cows.

Induction of ovulation for timed artificial insemination (TAI) with the Ovsynch protocol was evaluated in 49 anoestrous and lactating Bos taurus x Bos indicus cows. Palpation per rectum and transrectal ultrasonography were used on Days -30, -20, -10 and 0 (start of treatment) to confirm anoestrus but with the presence of follicles > or = 10 mm, and every other day during treatment to determine ovarian activity. Cows were randomly assigned to: (1) Ovsynch (n = 24; Day 0, 200 microg GnRH; Day 7, 150 microg PGF2alpha; Day 9, 200 microg GnRH + TAI 16 to 20 h later) and (2) control (n = 25; no treatment). Rates of ovulation for the first GnRH injection, detection of a corpus luteum (CL) at PGF2alpha injection, pregnancy and induction of cyclicity were greater (P < 0.05) with Ovsynch. There was no effect of body condition score (P > 0.05). In conclusion, the Ovsynch protocol was not effective in obtaining acceptable pregnancy rate for TAI, but it was effective for induction of cyclicity in anoestrous and lactating Bos taurus x Bos indicus cows under tropical conditions.

Animals↗
PubMed1987

Early pregnancy loss in brood mares.

During 1985, linear-array ultrasonography was used to study early pregnancy loss in commercial brood mares: 600/1115 (54%) of the cycles resulted in detected pregnancy at Week 2 after ovulation and 80 (13%) of these pregnancies resulted in early pregnancy loss. The pregnancy loss rate was significantly higher (P less than 0.05) for twin pregnancies (10/41) than for singleton pregnancies (70/559). The pregnancy loss rate was significantly higher (P less than 0.05) at 2-4 weeks (29/60) than at 6-8 weeks (12/60). The pregnancy rate was significantly less (P less than 0.05) for post-partum mares inseminated at the foal heat (157/302) than for those inseminated at a subsequent oestrus (203/334). Mares with a history of endometritis had a significantly higher (P less than 0.05) per cycle pregnancy loss rate (7/26) than did mares with a history of not having endometritis (64/498). When mares that had lost pregnancies were re-mated, 37/75 (49%) detectable pregnancies resulted and 7 (19%) of these pregnancies were again lost. The per cycle pregnancy rate was 56% (153/273), 55% (177/319), 60% (130/216), 51% (72/142), 45% (34/76) and 33% (12/36) for mares aged 2-5, 6-9, 10-13, 14-17, 18-21 and greater than 21 years, respectively. The corresponding per cycle pregnancy loss rates were 12%, 14%, 9%, 14%, 24% and 33%.

Animals↗
PubMed2002

[Cloning and characterization of a LRR resistance like (GhLRR-RL) protein gene from cotton (Gossypium hirsutum L.)].

LRR (Leucine rich repeat) proteins are involved in various biological processes. RACE was used to extend the 5' and 3' unknown sequence of a cDNA-AFLP fragment from cotton ovule, which had sequence similarity to the Arabidopsis thaliana LRR resistance-like (LRR-RL) protein. By joining the sequence of cDNA-AFLP fragment and its 3' and 5' RACE product, it was found that the full-length cDNA (GenBank Accession No. AY040532) of 1259 bp contained an ORF of 987 bp and a putative poly(A) signal. The deduced polypeptide contained 328 amino acids, and consisted of 10 LRRs with extracytoplasmic LRR consensus LXXLXXLXXLXLXXNXGXIPXX. It was demonstrated that the LRR-RL proteins of cotton and A. thaliana were highly homologous, with a distinct structure from other plant LRR proteins, suggesting that LRR-RL proteins belonged to a new LRR protein family. Using 3' RACE, the expression of LRR-RL gene was detected in root, hypocotyls, fiber, and ovules in various developmental stages.

Amino Acid Sequence↗
PubMed1996

Variations in immunoglobulins and IgA subclasses of human uterine cervical secretions around the time of ovulation.

The quantity and subclass distribution of IgA produced by the human uterine cervix may have a significant impact on the defence against sexually transmitted diseases as well as the regulation of fertility. Cervical mucus was obtained from 15 normal ovulating women around the time of ovulation. The total amounts of secreted IgA (including IgA1 and IgA2), IgG, and IgM were determined by ELISA. IgA was detected at high levels in all samples of cervical mucus. When ovulation was ascertained by daily urinary luteinizing hormone testing, IgA production was maximal 2-3 days before ovulation. Equal proportions of IgA1 and IgA2 were detected in cervical mucus, and 80% of the IgA occurred in the polymeric forms. The increased levels of IgA, the ratios of IgA1 to IgA2, and the predominance of polymeric IgA indicate that much of the IgA in human uterine cervical fluid originates from local production.

Adult↗
PubMed2006

New technologies for the study of carnivore reproduction.

Routine analysis of urinary metabolites of estrogen and progesterone provided substantial information about the estrous cycle of bears. However, these data alone were not adequate to determine the precise timing of ovulation needed to maximize AI success rates, or to distinguish between pregnancy and pseudopregnancy. Therefore, there is a critical need to develop technologies that will enhance understanding of the reproductive mechanisms of ursids. Using the domestic dog as a model, three techniques were investigated for potential application to the propagation of captive endangered bears. In a modification of standard staining of bitch vaginal cells, trichrome staining of giant panda cells revealed two consistent chromic shifts 9 and 2 days prior to the periovulatory decrease in urinary estrone sulfate, enhancing the ability to predict ovarian events preceding ovulation. To further define the relationship between the decrease in estrogen and ovulation, the utility of a rapid immunochromatographic LH assay was investigated for giant pandas using a commercial LH kit canine serum. Serum collected during estrus exhibited positive test results, indicating the cross-reactivity of giant panda LH with canine LH antibodies, and preliminary data supported further development of the LH kit for the detection of LH in bear urine. Due to the limitations of hormone analysis for distinguishing pregnancy from pseudopregnancy in canids and ursids, forward-looking infrared thermography was evaluated as a method to visualize proliferating placental tissue, fetuses, or both. While further investigation is needed to confirm the utility of thermal imaging for pregnancy diagnosis in the domestic bitch, pregnancy and pseudopregnancy were successfully detected in two giant pandas.

Animals↗
PubMed1998

Gamete recovery and follicular transfer (graft) using transvaginal ultrasonography in cattle.

Current in vitro culture systems may not be adequate to support maturation, fertilization and embryo development of calf oocytes. Thus, we initiated a study to investigate an alternative method of assessing oocyte competence in vivo, initially using oocytes from adults. Experiment 1 was done to determine if follicle puncture would alter subsequent follicle development, ovulation and CL formation. In control (no follicle puncture, n = 3) and treated (follicle puncture, n = 3) heifers, ultrasound-guided transvaginal follicle aspiration was used to ablate all follicles > or = 5 mm at random stages of the estrous cycle to induce synchronous follicular wave emergence among heifers; PGF2 alpha was given 4 d later. Three days after PGF2 alpha, the preovulatory follicle in treated heifers was punctured with a 25-g needle between the exposed and nonexposed portions of the follicular wall, and 200 microL of PBS were infused into the antrum. There was no significant difference between control and treated heifers for mean diameter of the dominant follicle prior to ovulation, the interval to ovulation following PGF2 alpha, or first detection and diameter of the CL. Experiment 2 was designed to assess multiple embryo production following interfollicular transfer of oocytes (i.e., transfer of multiple oocytes from donor follicles to a single recipient preovulatory follicle). Follicular wave emergence was synchronized among control (no follicle puncture, n = 5), oocyte recipient (n = 7) and oocyte donor (n = 5) heifers as in Experiment 1. In control and oocyte recipient heifers, a norgestomet ear implant was placed at the time of ablation and removed 4 d later, at the second PGF2 alpha treatment. In oocyte donor heifers, FSH was given the day after ablation, and, 4 d later, oocytes were collected by transvaginal follicle aspiration, pooled and placed in holding medium. Five or 6 oocytes were loaded into the 25-g needle of the follicle infusion apparatus with < or = 200 microL of transfer medium. Puncture of the preovulatory follicle of recipient heifers was done as in Experiment 1. Immediately thereafter, LH was given to control and oocyte recipient heifers, but only the recipients were inseminated. Ovarian function was assessed by transrectal ultrasonography and control and oocyte recipient heifers were sent to the abattoir 2 or 3 d after ovulation, where excised oviducts were flushed. The interval between LH administration and ovulation (33 to 36 h) was highly synchronous within and among control and oocyte recipient heifers. Four of 5 (80%) ova were collected from controls and 16 of a potential 43 (37%) ova/embryos were recovered from oocyte recipients; 8 embryos from 3 heifers. Thus, the gamete recovery and follicular transfer procedure (GRAFT) did not alter ovulation or subsequent CL formation, and resulted in the recovery of multiple ova/embryos in which a total of 19 oocytes yielded as many as 8 early embryos, a 42% embryo production rate.

Animals↗
PubMed1997

Ovarian follicular dynamics in ewes during the transition from anoestrus to the breeding season.

Daily transrectal ovarian ultrasonography was performed in ten ewes for 5 consecutive days, once in early July, once in late July (anoestrus) and then continuously until from mid-August until ewes had completed one ovulatory cycle. During anoestrus the size range and numbers of ovarian antral follicles were similar to those seen during the breeding season. However, numbers of small antral follicles (2-3 mm in diameter) decreased during late anoestrus, and maximum follicle diameter increased just before the short period of progesterone secretion preceding the first observed ovulation. The ovarian antral follicles that ovulated first and second in the breeding season grew from 2 mm in diameter to 5.7 +/- 0.3 mm and 6.2 +/- 0.3 mm diameter over 4.7 +/- 0.3 days and 4.6 +/- 0.3 days, respectively, and the interovulatory interval was 16.6 +/- 0.2 days. During the first ovulatory cycle, follicles emerged to grow from the 2 mm size class on 11 of the 17 days, but peaks of emergence were seen on days 2 and 11. The first observed ovulation was preceded by a transient increase in serum concentrations of progesterone (6 days duration), with a peak concentration of 1.30 +/- 0.22 nmol l-1. With ultrasonography, no evidence of ovulation was seen before the increase in progesterone secretion and no luteal structures was detected during the small increase in progesterone secretion; however, luteal structures are normally detected by ultrasonography only from 3 to 5 days after ovulation. An LH surge similar to a preovulatory LH surge preceded the first increase in progesterone secretion in five ewes. Oestrus occurred consistently with ovulation only at the second observed ovulation of the breeding season, after a normal luteal phase. LH pulse frequency and mean and basal serum concentrations of LH all increased in late anoestrus, but no major trends in serum concentrations of FSH and oestradiol were seen during this period. It was concluded that at the end of anoestrus there is not major change in ovarian antral follicle dynamics. At this time, increased LH secretion was seen as was a reduction in numbers of small antral follicles and a greater maximum diameter of follicles. A surge release of LH resulted in a short-lived secretion of progesterone, the source of which was unclear; this was followed by the first observed ovulation and the first ovulatory cycle of the breeding season. Oestrus occurred consistently only at the second observed ovulation of the season and the peak concentration of progesterone at each period of progesterone secretion increased to at least the second ovulatory cycle.

Anestrus↗
PubMed1986

Sonographic evaluation of normal and induced ovulation.

The adult premenopausal ovary exists in a dynamic state of flux, with ovarian position, size, activity, and structure constantly undergoing changes. Pelvic sonograms must be interpreted with knowledge of the stage of the menstrual cycle and the expected normal range of sonographic findings, because features that are normal in one phase may be abnormal in another. Only against this background knowledge can the challenging task of interpretation of pelvic sonograms be successfully performed. US also plays an increasingly important role in monitoring ovulation induction and alternative methods of fertilization and has improved pregnancy rates by distinguishing between the presence of one or more mature follicles as opposed to a cohort of immature follicles, suggesting the possibility of multiple ovulation with the risks of hyperstimulation or poor pregnancy outcome from multiple gestation, indicating optimum timing of human chorionic gonadotropin administration, allowing detection and confirmation of normal follicular rupture and ovulation, indicating optimum timing of oocyte retrieval in programs of in vitro fertilization with embryo transfer (IVF-ET) or insemination programs, and assessing pathologic pelvic conditions and ovarian accessibility in IVF-ET programs. Oocyte retrieval and embryo transfer are also being performed under US guidance.

Anovulation↗
PubMedDate not supplied

The infertile couple: a cohort study in Duhok, Iraq.

From January 2000 to May 2001 causes of infertility were studied for 250 couples, 193 (77.2%) of whom had primary infertility and 57 (22.8%) had secondary infertility. Male infertility was found in 36.8% of cases. The most common cause of female infertility was ovulation disorders (41%) while tubal obstruction contributed to only 5% of cases. Only 15% of the couples had unexplained infertility. Galactorrhoea and/or increased serum prolactin was seen in 60% of cases. Ultrasonographic detection of mature follicles was consistent with the results of cervical mucus study and endometrial biopsy in 90% of cases.

Adolescent↗
PubMed1997

Serum concentrations of oestradiol-17beta, progesterone, relaxin and chorionic gonadotrophin during blastocyst implantation in natural pregnancy cycle and in embryo transfer cycle in the rhesus monkey.

The present study was undertaken to assess the temporal association between the profiles of serum concentrations of oestradiol-17beta, progesterone, chorionic gonadotrophin (CG) and relaxin in pregnancies established naturally, and after embryo transfer, as well as in failed pregnancies in rhesus monkeys. In naturally mated cycles (group 1) a conception rate of 75% was obtained. In group 1, the mean day of CG detection in serum was 11.5 +/- 1.9 day post-ovulation, and for relaxin, 9.0 +/- 2.5 day post-ovulation. In group 2, embryo transfer to synchronous, non-mated surrogate recipients was performed; seven embryo transfer cycles yielded three pregnancies which were allowed to continue to term and normal infants were delivered. In embryo transfer cycles the mean day of CG detection was 14.8 +/- 1.8 day post-ovulation, and for relaxin, 11.4 +/- 2.6 day post-ovulation. A delay of about 3 days was observed in the appearance in circulation of CG (P < 0.05) and also of relaxin (P < 0.05) between natural mated and embryo transfer conception cycles. Significant differences (P < 0.05 for progesterone and P < 0.03 for oestradiol) were obtained for the areas under the curves for progesterone and oestradiol between days 12 and 16 in conception cycles compared with failed pregnancies. These data provide the first observation of the normal hormonal signals associated with maternal recognition of transferred embryos during the peri-implantation period, and suggest that the use of such an experimental primate embryo transfer model may help to elucidate components of maternal and embryonic signal-response mechanisms during embryo implantation.

Abortion, Veterinary↗
PubMed1989

Hormonal regulation and tissue-specific localization of alpha 2-macroglobulin in rat ovarian follicles and corpora lutea.

alpha 2-Macroglobulin (alpha 2M) is a broad spectrum protease inhibitor associated with inflammatory responses and proposed to be important in tissue remodeling. alpha 2 M also functions as a carrier of specific growth factors and cytokines, including platelet-derived growth factor, transforming growth factor-beta, basic fibroblast growth factor, interleukin-1, interleukin-6. To determine whether alpha 2M is associated with remodeling phenomena in the rat ovary, the expression of alpha 2M mRNA and protein has been analyzed in specific ovarian cell types during ovulation, luteinization, and luteolysis. Before ovulation, alpha 2M mRNA is not detectable in granulosa cells. Twelve hours after injection of an ovulatory dose of hCG a 5.2-kilobase alpha 2M mRNA is detectable in luteinizing follicles, which is increased further by 48 h and maintained in corpora lutea (CL) for up to 96 h. Administration of PRL from 24-96 h results in both inhibition of luteolysis and marked increases in alpha 2M mRNA in CL, but not in residual tissues, of these same ovaries, isolated 48, 72, and 96 h after an ovulatory dose of hCG, alpha 2M mRNA is also induced by PRL in cultures of luteinized granulosa cells. These changes in alpha 2M mRNA in follicles or developing CL do not appear to reflect the amount of alpha 2M protein present: alpha 2M protein (188K monomer) is present (immunoblot and immunofluorescence data) in small antral and preovulatory follicles even though mRNA is not detectable; after an ovulatory dose of hCG the protein level transiently increases by 12 h (approximately 5-fold) and declines thereafter through 96 h; the decrease in alpha 2M protein observed at 48-96 h is delayed but not abolished by treatment with PRL, even though the mRNA levels continue to rise during this same time period. In contrast, changes in alpha 2M mRNA and protein are regulated coordinately in CL of pregnant rats. alpha 2M mRNA is present, but in low concentration, from days 4-11 of gestation, increases markedly between days 11-21, and decreases at parturition, when functional luteolysis occurs. Hysterectomy of day 10 pregnant rats combined with hormone replacement determined that alpha 2M mRNA levels are regulated primarily by PRL through day 12 and by placental lactogens during midgestation (days 12-15). The increase in alpha 2M mRNA during pregnancy precedes the 40-fold increase (peak) in a alpha 2M protein observed on day 15, which remains elevated through day 21.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

Time schedules of intrauterine insemination after urinary luteinizing hormone surge detection and pregnancy results.

A urinary luteinizing hormone (LH) test (LH Color, Organon, Oss, The Netherlands), was used to time intrauterine insemination in 177 cycles. Morning and evening urine samples were tested. In 58 women (33%) the test was positive in the morning urine sample. Fifteen of these patients were inseminated 8-10 h thereafter and one patient (6.7%) conceived. The remaining 43 women were inseminated the following day, 25-31 h after LH detection, and seven pregnancies (16.3%) ensued. In 119 cycles showing a positive urinary test in the evening sample, insemination was performed the next day, between 17 and 23 h after the LH surge, and 18 patients (15.1%) became pregnant. Statistical analysis showed no significant differences in pregnancy rates between the three different schedules, or in the time of insemination between conceptional and non-conceptional cycles within each group. Most ovulations occurred between 16 and 28 h after the positive test was observed. These findings suggest that while the lifespan of the gametes allows a relatively long period for fertilization, from 8 to 31 h after urinary LH surge detection, better results may be expected when inseminating about 24 (+/- 6) h after the positive test.

Adult↗
PubMed2005

Changes in mitochondrial membrane potential and accumulation of reactive oxygen species precede ultrastructural changes during ovule abortion.

In many species, environmental stress reduces plant fertility. In Arabidopsis thaliana, a significant fraction of this reduction in plant fertility results from ovule abortion and embryo senescence. In this species, environmental conditions were identified that induced 94% of the developing ovules to either undergo stress-induced ovule abortion or embryo senescence (Sun et al. Plant Physiol 135:2358-2367, 2004). Following salt stress, physiological and anatomical changes were first detected in the female gametophyte of an aborting ovule. Two to four hours after a period of salt stress that induces most ovules to abort, the mitochondrial membrane potential dissipated. Subsequently, cells in the gametophyte accumulated reactive oxygen species, which are known to be molecules that promote programmed cell death (PCD). Because mitochondria often play an important role in PCD, these organelles were closely examined for changes in structure. Although the anatomy of mitochondria varied, reproducible changes in mitochondria structure were not observed. Nonetheless, other changes in ultrastructure were found. In some aborting gametophytes, concentric rings of endoplasmic reticulum were formed. In a fraction of the aborting ovules, cytoplasmic contents and organelles were invaginated into the vacuole. Even in cryofixed sections, many of these bodies appeared indistinct, which is consistent with the degradation of their contents.

Arabidopsis↗
PubMed1998

Changes of ovarian structures, plasma LH, FSH, progesterone and estradiol-17 beta in a cow with ovarian cysts showing spontaneous recovery and relapse.

In a cow diagnosed as having ovarian cysts, we observed changes in the ovarian structures by ultrasonography for 71 days and examined plasma concentrations of sex hormones. The cow had 2 regressing cysts at the start of this study and 3 new follicles subsequently developed into cysts. With regression of these cysts, 2 new follicles developed and ovulated spontaneously, followed by the formation of 2 corpora lutea. On the day prior to ovulation, a preovulatory luteinizing hormone (LH) surge was detected. With regression of the corpora lutea, a new follicle developed and underwent atresia. Meantime, another follicle developed and became a cyst without ovulation. No preovulatory LH surge was observed during the period from regression of the corpora lutea to cyst formation. The results indicate that absence of the preovulatory LH surge is associated with occurrence of ovarian cysts and this endocrine aberration is reversible.

Animals↗
PubMed1987

Exogenous hormone regimens to utilize successfully mares in dioestrus (days 2-14 after ovulation) as embryo transfer recipients.

Two hormone regimens were utilized for recipient mares which were 2-14 days after ovulation at the time of non-surgical embryo transfer. In Exp. I, 20 embryos were transferred non-surgically into recipient mares which had been given 22 mg altrenogest daily starting the day of recipient ovulation. Higher (P less than 0.05) pregnancy rates (50% vs 0%) were obtained in mares which were 2-6 days after ovulation at the time of transfer compared with mares which were 7-12 days after ovulation. In Exp. II, on the day the donor mare ovulated (Day 0), 10 mg PGF-2 alpha were given to the recipient mare at 0 h, 20 mg oestradiol cypionate at 12, 24 and 36 h, 500 mg progesterone in oil at 48 h and then 22 mg altrenogest at 60, 72 and 96 h. Altrenogest (22 mg/day) was continued until Day 28 (fetal heart beat). The pregnancy rate (58% vs 10%) was higher (P less than 0.05) for the 12 recipient mares which were 10-14 days after ovulation than for the 10 mares that were 5-8 days after ovulation when treatment began. Early embryonic loss was detected in 4/8 pregnant recipient mares between Days 21 and 28 of gestation. We suggest that mares which are 2-14 days after ovulation and not in ovulation synchrony with the donor may be used as embryo transfer recipients; mares which are in early dioestrus can be given altrenogest while those in mid- to late dioestrus can be placed on the more complex hormone regimen.

Animals↗
PubMed1991

Distribution, morphology and epithelial interactions of bovine spermatozoa in the oviduct before and after ovulation: a scanning electron microscope study.

In cows undergoing spontaneous oestrous cycles and mated during the first 6 hours of oestrus, the distribution of spermatozoa in the oviduct isthmus and changes in their surface membranes and neighbouring epithelium have been examined shortly before and after ovulation. In agreement with previous histological studies, relatively few spermatozoa were detected in the oviduct lumen: most were located in the caudal isthmus before ovulation, frequently among folds and in the presence of a viscous secretion. A majority of spermatozoa in this region showed strands and droplets of secretory material distributed over the anterior portion of an intact head before ovulation, whereas distribution of material over the post-nuclear cap of spermatozoa close to vesiculation or already acrosome-reacted was characteristic of the post-ovulatory situation. These changes in sperm head membranes were viewed as an expression of the completion of capacitation, and seemingly permit microvillous engagement with the rostral tip of the head. In conjunction with a narrow lumen and viscous secretions in the caudal isthmus, microvilli may thus serve to regulate periovulatory sperm progression towards the site of fertilisation, and be the basis of intermittent phases of adhesion to the oviduct epithelium as seen by phase-contrast microscopy. Although cilia do not similarly engage the heads of bull spermatozoa (cf. boar spermatozoa), they may act to regulate progression of capacitated spermatozoa by contacting the principal piece of the flagellum. In the light of these observations, changes in the molecular composition of sperm surface domains during the process of capacitation in vivo now require specific definition.

Animals↗