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PubMed1975

Plasma oestrogen and progesterone in relation to superovulation and egg recovery in the cow.

Pregnant mares serum gonadotrophin (PMSG) was used in combination with prostaglandin F2alpha or its analogues to induce superovulation in 25 heifers. Total unconjugated oestrogen and progesterone were determined in peripheral plasma of these superovulated animals, and the levels compared with those found during the normal oestrous cycle. A very high level of oestrogen was found between day 3 and 6 after superovulation, and it seems likely that large unovulated follicles were responsible for the excess steroid. Similarly, progesterone levels were raised in the superovulated animal presumably due to production by the numerous corpora lutea. In two heifers, in which overstimulation of follicular development had occurred, there were no ovulations in one of the animals while in the other animal there were 16 ovulations but early regression of corpora lutea was indicated. It is concluded that the poor recovery of eggs on day 6 after superovulation could have been due to deleterious effects of high levels of oestrogen on either the motility of the genital tract causing the premature transport of eggs, or the properties of the zona pellucida.

Animals↗

PubMed2000

Ciliogenesis in the uterine tube of control and superovulated heifers.

Ciliogenesis was investigated in the uterine tube epithelium of control and superovulated heifers during day 1 to day 7 of the oestrous cycle. Seventy-two heifers were used, consisting of four control groups and four superovulated groups. All heifers received cloprostenol (PG) to induce oestrus (day 0). Superovulated heifers received 24 mg pFSH at doses of 4.5, 3.5, 2.5 and 1.5 mg given twice daily. Control and superovulated heifers were slaughtered on days 1, 3, 5 and 7 of the oestrous cycle. Samples from the ampulla, preisthmus and isthmus of the uterine tube were collected and processed for light and electron microscopy, following standard procedures. Both centriolar and acentriolar pathways were involved in the development of basal bodies. Formation of basal bodies and protrusion of ciliary shafts mostly occurred during days 1 and 3 of the oestrous cycle. The centriolar pathways, in which procentrioles generate with the aid of preexisting centrioles, played a minor role in the heifer uterine tube. In the acentriolar pathways, fibrous granules were the first structures which appeared in the course of ciliogenesis and they initially occurred in association with free ribosomes. Subsequently, deuterosomes arose in the aggregates of fibrous granules, and then procentrioles containing microtubules originated around deuterosomes or apart from deuterosomes. Newly formed centrioles migrated to the apical cytoplasm, and ciliary shafts extended first at the periphery of the luminal surface of ciliogenic cells. Deuterosomes as well as rootlet formation were considered to be related to the fibrous granules. Quantitative examinations by light microscopy showed that the number of ciliated cells in the ampullar, preisthmic and isthmic epithelium of the superovulated heifers was significantly higher than in the control heifers during day 1 and day 3 of the oestrous cycle.

Animals↗

PubMed1983

Ovulation response and fertilization failure in immature rats induced to superovulate.

Immature female rats (75 g body wt, aged 29 days) were injected with 4 or 40 i.u. PMSG on Day -2 and were killed at intervals between 18:00 h on Day -2 and 09:00 h on Day 1. Control animals (4 i.u.) ovulated between 00:30 and 05:30 h on Day 1 whereas the number of ova recovered from superovulated rats (40 i.u. PMSG) increased slowly between 06:00 h on Day -1 and 24:00 h on Day 0 and markedly between 24:00 on Day 0 and 06:00 on Day 1. Similarly treated rats were caged overnight on Day 0 with males of proven fertility and killed between 14:00 and 16:00 h on Day 1. A significantly lower percentage of normal 1-cell ova was recovered from the superovulated rats compared to control animals (71.6 and 98.5%) and of these 1-cell ova a lower percentage was fertilized (69.7 and 99.1%). In the control group all mated animals had a high proportion of ova fertilized whereas 26% of superovulated rats had none or a very low proportion fertilized. In the control animals there was evidence of sperm penetration and pronucleus formation; in superovulated rats significantly fewer ova had pronuclei than were penetrated. These results suggest that reduced fertility of superovulated immature rats is due to complete or partial failure of fertilization in some animals. The extended period during which ovulation occurs may be a contributory factor.

Animals↗

PubMed1983

Induction of superovulation in prepubertal female rats by anterior pituitary transplants.

Transplants of 26-day-old rats of an anterior pituitary gland from adult intact or castrated male, 20-day-old or adult ovariectomized female donors (all of which contained large amounts of FSH) resulted in superovulation in recipients on the morning of Day 29. Transplants of the gland from 20-day-old males and adult cyclic females could not advance the time of first ovulation or induce superovulation. In the rats in which superovulation could be induced, a marked increase in plasma FSH was noted in recipients shortly after transplantation and the high levels of plasma FSH were maintained until at least 12 h after grafting. These rats also showed preovulatory surges of LH and FSH 54 h after grafting. No obvious elevation of plasma FSH was noted over 72 h in recipients in which superovulation could not be induced. These findings suggest that the final maturation of follicles for superovulation is induced by a transient release of a large amount of FSH from the grafted pituitary gland and that the sex of the pituitary donor has no bearing on this phenomenon.

Animals↗

PubMed1990

Effects of superovulation, embryo recovery, culture system and embryo transfer on development of rabbit embryos in vivo and in vitro.

Uninterrupted development of rabbit embryos in vivo was studied in 7 superovulated and 7 normally ovulating (GnRH-treated) does, while another 7 does were superovulated and 1-cell embryos were collected from them at 19 h after LH to compare development in vivo and in vitro. Embryos from the last group were either cultured in the presence or absence of rabbit oviduct epithelial cells for 65 h in Medium 199, or were immediately transferred to recipients. At 84 h after LH or GnRH, blastomere number, embryo volume and stage of development were assessed for all embryos. Intrazonal embryo volumes were significantly reduced in embryos recovered from superovulated donors. Superovulation also had a negative effect on embryo cell numbers. However, this reduction was more severe in embryos remaining in vivo in superovulated donors until 84 h after LH than it was in embryos transferred to nonsuperovulated recipients at the 1-cell stage (19 h after LH). The embryo recovery procedure apparently caused little harm to the embryos, except that the mucin layer on flushed and immediately transferred embryos was significantly thinner than that of embryos residing continuously in vivo. Co-culture with rabbit oviduct epithelial cells resulted in improved development in vitro, but this development was still significantly retarded compared with embryos developing in vivo.

Animals↗

PubMed1998

Successful fertilization after superovulation and laparoscopic intrauterine insemination of the brushtail possum, Trichosurus vulpecula, and tammar wallaby, Macropus eugenii.

Fertilization has been achieved in superovulated brushtail possums and tammar wallabies after laparoscopic intrauterine artificial insemination. Various superovulation protocols and insemination times were examined but a maximum of 2-5 eggs including 1-2 embryos per possum were recovered. The female possums were superovulated by treatment with 15 iu pregnant mares' serum gonadotrophin and then either GnRH (4 x 50 micrograms, at intervals of 90 min) or 4 mg LH, 3 days later. Inseminations were performed within 6 h before or 4-10 h after (pregnant mares' serum gonadotrophin-GnRH group only) the expected onset of ovulation using epididymal spermatozoa. Superovulation in wallabies was achieved by treatment with FSH (8 x 6 mg, at intervals of 12 h for 4 days) followed by 4 mg LH on day 5. Inseminations were performed 4-6 h before the expected onset of ovulation using ejaculated spermatozoa, which resulted in the recovery of 7-8 eggs including 3-4 embryos per female. All embryos recovered were from possums and wallabies examined 1-2 days after insemination and included fertilized eggs, two-cell and four-cell embryos. Motile spermatozoa were recovered from the oviducts and uteri but only immotile spermatozoa were found in the vaginal complex. Five to thirty per cent of spermatozoa recovered from the oviducts of possums examined 2-6 h after insemination had thumbtack morphology, which is thought to be correlated with capacitation. Although embryo yields per female were low, this study has established that intrauterine artificial insemination after superovulation is a feasible assisted breeding strategy for marsupials with implications for species conservation and population control.

Animals↗

PubMed2004

Impaired fertility in T-stock female mice after superovulation.

Superovulation of female mice with exogenous gonadotrophins is routinely used for increasing the number of eggs ovulated by each female in reproductive and developmental studies. We report an unusual effect of superovulation on fertilization in mice. In vivo matings of superovulated T-stock females with B6C3F1 males resulted in a two-fold reduction (P <0.001) in the frequencies of fertilized eggs compared with control B6C3F1 matings. In addition, approximately 22 h after mating, only 15% of fertilized eggs recovered in T-stock females had reached the metaphase stage of the first cleavage division versus 87% in B6C3F1 females (P <0.0001). Matings with T-stock males did not improve the reproductive performance of T-stock females. To investigate the possible cause(s) for the impaired fertilization and zygotic development, the experiments were repeated using in vitro fertilization. Under these conditions, the frequencies of fertilized eggs were not different in superovulated T-stock and B6C3F1 females (51.7 +/- 6.0 and 64.5 +/- 3.8%, P=0.10). There was a seven-fold increase in the frequencies of fertilized eggs that completed the first cell cycle of development after in vitro versus in vivo fertilization in T-stock females. These results rule out an intrinsic deficiency of the T-stock oocyte as the main reason for the impaired fertility after in vivo matings, and suggest that superovulation of T-stock females may induce a hostile oviductal and uterine environment with dramatic effects on fertilization and zygotic development.

Animals↗

PubMed2005

Estrous stage- and animal age-independent superovulation in the BrlHan:WIST@Jcl(GALAS) rat.

In most strains of rats, the effects of treatment for the induction of superovulation show major strain differences and are strongly influenced by the stage of the estrous cycle. This study demonstrated, however, that superovulation was easily induced in Wistar strain Brl Han:WIST@Jcl(GALAS) rats by PMSG and hCG administration. To confirm the effects of such treatment, we studied age differences in egg collection efficiency. After superovulation was induced by intraperitoneal administration of 150 IU/kg PMSG and 75 IU/kg hCG given 48 h apart, the mean numbers of oocytes obtained from rats at 4, 8, 12, 20 and 28 weeks of age were 38.9, 33.5, 46.1, 26.9 and 21.3, respectively. No differences caused by the estrous stage at the PMSG administration were observed. In an embryo transfer experiment, fertilized eggs obtained from superovulated rats at each week of age showed equivalent viability until full-term to those from untreated rats. These results suggest that estrous stage-independent superovulation is effective not only in the pre-pubertal stage but also in adult rats.

Aging↗

PubMed1982

Superovulation induced by a single pituitary gland transplanted beneath the kidney capsule in adult rats.

Different numbers of rat pituitary glands, taken from male and female rats before and after puberty, were transplanted into various sites in female rats at different stages of the oestrous cycle. Ovulation was checked by counting ova in oviducts on the next expected day of ovulation. Ovulation was induced by transplantation beneath the kidney capsule in early dioestrus of half, one or three glands from 35- to 41-day-old male rats (18.6+/-3.1 (S.E.M.), 32.6+/-2.8 and 49.8+/-4.8 ova shed respectively). The transplantation of glands from mature female rats did not induce supraovulation but inhibited the expected ovulation. The most effective stage for inducing superovulation was early dioestrus and, to a lesser extent, most effective stage for inducing superovulation was early dioestrus and, to a lesser extent, oestrus; transplantation during late dioestrus was ineffective. The effective sites of transplantation were beneath the kidney capsule and intramuscularly but not subcutaneously. Representative pituitary glands from 35- to 41-day-old male rats and adult female rats were assayed for LH and FSH content to interpret the mechanisms of superovulation . The pituitary glands from the male rats contained larger amounts of LH and especially of FSH than those found in the female rats. The experiments indicated that superovulation can be induced successfully by the transplantation of a single pituitary gland from male and immature female rats without any additional treatment with human chorionic gonadotrophin; the failure of the female pituitary transplants to induce superovulation may be due to the insufficient content of LH and FSH.

Animals↗

PubMed1982

Milk progesterone concentration and production in superovulated Holstein cows.

Six Holstein cows in a commercial herd (three superovulated and three controls) and eight Holstein cows superovulated a total of 12 times in an experimental herd were studied. Superovulation was induced primarily by treatment with follicle stimulating hormone and prostaglandin F2 alpha. Milk was weighed twice daily for 30 days following treatment in the commercial herd with no effect on production. Milk samples were saved on Monday, Wednesday, and Friday to determine progesterone content. Last milk at mid-cycle averaged 8.2 ng/ml of progesterone for the cows in the experimental herd, and 7 days after superovulation they averaged 52.6 +/- 10.2 ng/ml (mean +/- standard error) of progesterone. The correlation with number of embryos recovered was .86. Therefore, milk progesterone may be useful in monitoring superovulatory response. Also, injection of prostaglandin F2 alpha into superovulated cows 9 days after a previous injection did not initiate a new estrous cycle, a fact accurately monitored by milk progesterone determinations.

Animals↗

PubMed2003

Influence of nutrition on the effectiveness of superovulation programmes in ewes: effect on oocyte quality and post-fertilization development.

Two experiments were carried out to study the effect of nutrition on embryo development in two periods in superovulated ewes (Expt 1) and on oocyte developmental capacity during the late follicular phase (Expt 2). In Expt 1, a lower superovulation response in terms of animals ovulating (P < 0.05), ovulation rate per ewe ovulating (P = 0.1) and number of good quality embryos per animal treated (P < 0.07) was noted in ewes fed an ad libitum diet compared with ewes offered control (1.5 times the daily maintenance energy requirements, 1.5 x M) or low energy (0.5 x M) diets. Nutrition also modified the morphological and functional quality of the oocytes and embryos recovered. Thus, 92% of day 4 embryos recovered from ewes offered the control diet were classified as good embryos, compared with 70 and 82% of those recovered from ewes offered the ad libitum and low diets, respectively (P < 0.05). Ewes offered the ad libitum diet had a greater percentage of poorly developed embryos compared with ewes offered the control or low diets (P < 0.05). Ewes fed the low diet tended to have more non-fertilized oocytes than ewes offered the control diet (P = 0.09). Diet of recipient ewes to which good quality embryos were transferred on day 4 did not affect embryo quality, when assessed 12 days later (day 16 of pregnancy). However, recipient diet affected prostaglandin F(2alpha) (PGF(2alpha)) production in vitro, and uterine tissue that originated from recipient ewes on the low diet secreted more PGF(2alpha) relative to uterine tissue that originated from recipients on the control diet (P < 0.05). In Expt 2, fewer total (P < 0.05) and good quality (P < 0.01) oocytes and a lower percentage of good quality oocytes (P < 0.01) were obtained from superovulated ewes offered the ad libitum diet compared with ewes offered the low diet. In addition, cleavage rate tended to be higher (51 versus 35%, P = 0.09) in ewes offered the low diet compared with ewes offered the ad libitum diet. In conclusion, changes in diet can affect the quality of the oocyte and embryo in superovulated sheep. A lower superovulation response and a decrease in the quality of oocytes and embryos indicate that ad libitum diets are highly detrimental for superovulatory programmes when compared with low and control diets. In addition, the results from the present study indicate that a low energy diet during early embryo development increased the uterine production in vitro of PGF(2alpha) which could lead to a poor uterine environment thereby compromising the development of the embryo.

Animal Nutritional Physiological Phenomena↗

PubMed1979

Successful superovulation, nonsurgical collection and transfer of embryos from Brahman cows.

Nonsurgical recoveries and transfers of embryos were performed at the McKellar Embryo Transplant Center from 122 superovulated Brahman cows. FSH-P (Armour) was used to superovulate all cows at dose levels ranging from 36 to 48 mg total FSH-P. Luteal regression was induced by use of 40 mg PGF(2(alpha)) in all 122 cows. Embryos were transferred into recipients 6, 7 or 8 days after observed estrus. Embryos were successfully collected from 82% of the FSH-P treated cows. The dose level of FSH-P affected numbers of embryos collected (P<.05). Numbers of embryos collected from cows superovulated with 36-38, 40, 42, 43, 44, 45, 46 and 47-48 mg FSH-P were 2.8 +/- 1.0, 6.8 +/- 1.1, 9.4 +/- 1.4, 10.0 +/- 2.7, 7.1 +/- 1.6, 6.8 +/- 2.0, 5.0 +/- 1.7 and 4.6 +/- 2.0 embryos, respectively. The dose level of FSH-P also affected numbers of embryos transferred (P<.10). Number of embryos transferred from cows superovulated with 36-38, 40, 42, 43, 44, 45, 46 and 47-48 mg FSH-P were 2.8 +/- 1.9, 5.2 +/- 0.9, 6.9 +/- 1.2, 6.7 +/- 2.1, 4.8 +/- 1.3, 5.1 +/- 1.4, 3.4 +/- 1.2 and 3.2 +/- 2.1 embryos, respectively. The developmental stage (D) of the embryo was also a factor in pregnancy rate of recipients (morula = 13.8%, blastocyst = 22.1% and expanded blastocyst = 29.9%; P<.005). The skill of the technician (T) transferring the embryo had a dramatic effect upon subsequent pregnancy rate of the recipients (T 1 = 46.0% vs T 2 = 22.6% pregnancy rate; P<.005). Pregnancy rate of recipients was also affected by the stage postestrus (S) at which the embryo was transferred (day 6 = 23.5%, day 7 = 25.5% and day 8 = 42.3% pregnancy rate; P<.05). Interactions were found between T x S, T x D, S x D and T x S x D (P<.05). These data indicate that use of 40, 42, or 43 mg total doses of FSH-P were quite effective in superovulating the Brahman cow. Recipients transferred on day 8 postestrus achieved higher pregnancy rates than recipients transferred on days 6 or 7 postestrus. Embryos transferred in the expanded blastocyst stage of development proved to yield the highest pregnancy rates in recipients.

Journal Article↗

PubMed1987

Inhibition of sperm transport and fertilization in superovulating ewes.

In Experiment 1, all ewes were treated with follicle stimulating hormone (FSH-P) to induce superovulation. Ewes came into natural estrus or were treated with prostaglandin F(2)alpha (PGF(2)alpha) or 6-methyl-17-acetoxyprogesterone (MAP) to regulate the time of estrus. The ewes were mated during estrus and necropsied 3 h after mating. Regulation of estrus with either compound reduced the number of sperm recovered from the cervix, uterus, and oviducts and increased the proportions of sperm recovered from the cervix and uterine body that were immotile, dead, or had disrupted membranes. In Experiment 2, all ewes were in natural estrus. They either ovulated naturally or were superovulated, and ewes in each group were necropsied at 3 or 23 h after mating. Superovulation reduced the number of sperm in oviducts, uterus, and anterior segments of the cervix at both time intervals and increased the proportions of sperm that were immotile, dead, or had disrupted membranes. In Experiment 3, of 3x2 design, ewes were in either natural estrus or estrus regulated with PGF(2)alpha or with MAP; they ovulated naturally or were superovulated. Ewes were necropsied 3 d after mating and ova were examined. Both regulation of estrus and superovulation reduced the proportion of ova that were fertilized and reduced the number of accessory sperm attached to fertilized ova.

Journal Article↗

PubMed1988

Superovulation, collection and transfer of embryos and demi-embryos from Boran(Bos indicus ) cows and heifers.

Twenty-three Boran(Bos indicus ) cows and heifers were superovulated with pregnant mare serum gonadotropin (PMSG); a total of four embryos and 4.1 +/- 0.3 (mean +/- SEM) ova per ova-producing donor resulted. Follicle stimulating hormone (FSH-P) was then used to superovulate 49 Boran cows for a total of 106 superovulations, of which 63 (59.4%) produced an average of 3.7 +/- 0.4 (mean +/- SEM) embryos. The embryo production was not influenced by either the season or the number of times(one to five) the cows were superovulated. A higher pregnancy rate was obtained when the selection of Boran recipients was based on their plasma-progesterone values (overall 52.5%, single embryos 63.3%, twin demi-embryos 45.8%) than when they were selected by palpation per rectum only (overall 43.8%, single embryos 50%, twin demi-embryos 36.4%). The twinning rate of twin demiembryos was 62.5%, whereas only single calves were born after transfer of two embryos per recipient. No pregnancies were produced following transfer of twin demi-embryos without zonae pellucidae. Transferring single demi-embryos gave a low pregnancy rate (13.3%). Twelve donor Boran cows (21 superovulations) bred with their fathers resulted in a high rate of early embryonic death; additionally, only 20.9% (overall) of the recipients became pregnant. Estrus synchronization of Boran cows with a progesterone releasing intravaginal device (PRID) for a short period (7 d) combined with one injection of prostaglandin (Day 6) produced a larger number of good quality recipients (70.5%) than using double prostaglandin injections (60%).

Journal Article↗

PubMed1989

Improved embryo yield and condition of donor ovaries in cows after PMSG superovulation with monoclonal anti-PMSG administered shortly after the preovulatory LH peak.

Nonlactating Dutch-Friesian cows were selected from a local slaughterhouse and synchronized with Syncro-Mate B. Cows with a normal progesterone pattern were treated with PMSG (3,000 I.U. i.m.) on Day 10 followed by PG (Prosolvin 22.5 mg) 48 h later. Blood samples were collected daily and at hourly intervals from 30 h after PG. Monoclonal anti-PMSG (Neutra-PMSG) was administered i.v. at 5.8 h after the LH peak in 16 cows; controls (n = 16) did not receive Neutra-PMSG. For comparison, 16 additional cows were superovulated with FSH-P in decreasing doses, twice a day (total 32 mg), starting at Day 10. All cows were inseminated at 10 h after the LH peak. Embryos were evaluated on Days 6 and 7 after flushing upon slaughter (recovery 87%). The number of corpora lutea and follicles on the donor ovaries were counted. No significant differences in the concentrations of progesterone and LH were observed between the three superovulation groups. Upon Neutra-PMSG, PMSG in blood was completely neutralized, it was decreased to < 0.5 ug/l at AI from 7.0 ug/l at the LH peak. The number of transferable embryos was significantly higher after Neutra-PMSG (9.1 per cow) than without Neutra-PMSG (5.3). or upon FSH-superovulation (4.6). The number of cysts on the ovaries of Neutra-PMSG-treated cows was reduced similarly to that after FSH-superovulation. Treatment with Neutra-PMSG shortly after the LH peak positively affects final follicular maturation in PMSG-superovulated cows and results in a nearly two-fold increase of transferable embryos.

Journal Article↗

PubMed1992

Use of PMSG antiserum in superovulated cattle?

Two Pregnant Mare Serum Gonadotrophin (PMSG) antisera were tested in 174 dairy cows that were superovulated with PMSG and were then given prostaglandin at 60 hours after PMSG. At 48 hours after injection of prostaglandin, the cows were given either PMSG antiserum (monoclonal (n=56) or polyclonal (n=57)), or saline as control (n=61). Ova (n=1,206) were recovered either nonsurgically or after slaughter. Of these, 757 were evaluated morphologically to be transferable embryos. A proportion of these embryos (n=295 from 52 flushed donors) were transferred to synchronized recipients and the pregnancy results were recorded. The reproductive function of 37 flushed donors was followed for 6 months after superovulation. No significant effect of the PMSG antisera could be demonstrated in any of the parameters studied (i.e., ovulation rate, number of follicles at collection, total yield of ova, fertilization rate, number of transferable embryos, pregnancy results after transfer of embryos, or period required by the donor cows for restitution of reproductive function after superovulation and recovery). It is concluded that use of PMSG antiserum did not improve the embryo yield in terms of the number and quality of transferable embryos or enhance normalization of reproductive function of the donor in the 6-month period after superovulation. Therefore, in an embryo transfer operation, the routine use of PMSG antiserum in a PMSG superovulation regimen in cattle is not recommended.

Journal Article↗

PubMed1994

Ovulation rate, zygote recovery and follicular populations in FSH-superovulated goats treated with PGF(2alpha) and/or GnRH.

Follicular development and ovulation were examined in superovulated Nubian and Nubian-cross dairy goats following prostaglandin F(2alpha) (PGF(2alpha)) and/or gonadotropin releasing hormone (GnRH) treatment. Estrus was synchronized with Synchromate-B((R)) implants. Superovulation was induced with follicle stimulating hormone (FSH) and augmented with GnRH and/or PGF(2alpha). The PGF(2alpha) treatment was administered on Day 2 of superovulation. Implants were removed from all goats on Day 3 of superovulation. The GnRH treatment was administered 24 h after implant removal. All does were exposed to fertile males for 48 h at the time of GnRH injection. Surgical embryo recovery and ovarian response evaluation were conducted 64 to 78.5 h after implant removal. The number of ovulations was higher with GnRH treatment (18.5 +/- 7; x +/- SEM) than that in the controls (5.3 +/- 4.1; P < 0.05). There were fewer follicles in the GnRH-treated does than in the untreated does (10.9 +/- 2.9 vs 22.1 +/- 3.2; P < 0.05). The number of follicles smaller than 4 mm in diameter (5.8 +/- 0.8) did not differ between treatments. The GnRH-treated does had fewer 4- to 8-mm follicles (4.2 +/- 2.0 vs 9.1 +/- 1.6; P < 0.05) and fewer follicles larger than 8 mm (0.7 +/- 1.4 vs 7.3 +/- 1.6; P < 0.01) than the controls. Predicted times for 1- and 2-cell embryo recoveries were 68.5 and 73.7 h following implant removal, respectively. This study demonstrates that GnRH is an effective supplement used with FSH superovulation regimens in dairy goats. Moreover, GnRH provides for enhanced early embryo collection for DNA microinjection studies.

Journal Article↗

PubMed1994

Fertilization rates in superovulated and spontaneously ovulating mares.

Embryo recovery per ovulation has been shown to be lower in superovulated mares than in untreated controls. The objectives of this study were to 1) determine whether follicles stimulated with superovulatory treatment ovulate or luteinize without ovulation, 2) determine fertilization rates of oocytes in oviducts of superovulated and control mares, and 3) evaluate viability of early stage embryos from superovulated and control mares when cultured in equine oviductal cell-conditioned medium. Cyclic mares were randomly assigned to 1 of 2 groups (n=14 per group) on the day of ovulation (Day 0): Group 1 received 40 mg of equine pituitary extract (EPE; i.m.) daily beginning on Day 5 after ovulation; mares assigned to Group 2 served as untreated controls. All mares were given 10 mg PGF(2alpha) on Day 5 and Day 6, and 3,300 IU of human chorionic gonadotropin (hCG) were administered intravenously once mares developed 2 follicles >/=35 mm in diameter (Group 1) or 1 follicle >/=35 mm in diameter (Group 2). Mares in estrus were inseminated daily with 1 x 10(9) progressively motile spermatozoa once a >/=35 mm follicle was obtained. Two days after the last ovulation the ovaries and oviducts were removed. Ovaries were examined for ovulatory tracts to confirm ovulation, while the oviducts were trimmed and flushed with Dulbeccos PBS + 10% FCS to recover fertilized oocytes. All fertilized oocytes (embryos) recovered were cultured in vitro for 5 d using TCM-199 conditioned with equine oviductal cells. Ninety-two percent of the CL's from EPE mares resulted from ovulations compared with 94% for mares in the control group (P>0.05). The percentages of ovulations resulting in embryos were 57.1 and 62.5% for EPE-treated and control mares, respectively (P>0.05). Eighty-eight (Group 1) and 91% (Group 2) of the freshly ovulated oocytes recovered were fertilized (P>0.05). After 5 d of culture, 46.4 and 40.0% of the embryos from EPE-treated and control mares developed to the morula or early blastocyst stage (P>0.05). In summary, the CL's formed in superovulated mares were from ovulations not luteinizations. Although embryo recovery was less than expected, fertilization rates and embryo development were similar (P>0.05) between superovulated and control mares.

Journal Article↗