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PubMed1995

Effects of passive immunization of ewes against an inhibin-peptide on gonadotropin levels, ovulation rate, and prolificacy.

The experimental objectives were to determine whether injection of semi-purified (sp; ammonium sulfate-precipitated) and highly purified (hp; immunoaffinity-purified) ovine antibody (Ab) against an inhibin-peptide fragment (alpha-IF) before the preovulatory period would 1) stimulate FSH secretion in a dose-response manner, 2) induce an increase in ovulation rate, and 3) affect pregnancy rate and prolificacy (lambs born alive per ewe lambing). During the early breeding season, estrus was synchronized in 30 2-yr-old crossbred ewes through use of progesterone-releasing pessaries (CIDR-G). Two doses (330 and 660 laboratory reference preparation [RP-2] kU) of sp- and hp-alpha-IF-Ab were injected i.m. 48 h before CIDR-G removal (6 ewes per group). Six other ewes received control solution. Plasma alpha-IF-Ab titers peaked at 12 h postinjection. Plasma FSH levels were higher (p < 0.02) in alpha-IF-Ab-treated ewes than in control ewes from 12 to 24 h postimmunization. Magnitudes of FSH increases were similar in ewes administered sp- and hp-alpha-IF-Ab and were greater (p < 0.05) in ewes receiving 660 than in those receiving 330 RP-2 kU. Compared to control values, the higher alpha-IF-Ab dose increased FSH levels by 44 +/- 5% and the lower dose increased the levels by 22 +/- 3%. Plasma LH levels were similar among passively immunized and control sheep. Ovulation rate was increased (p < 0.0005) by alpha-IF-Ab treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Active immunization of heifers against inhibin: effects on plasma concentrations of gonadotrophins, steroids and ovarian follicular dynamics during prostaglandin-synchronized cycles.

We reported previously that active immunization of heifers using a synthetic peptide-based inhibin vaccine (bI alpha(1-29)Tyr30) can enhance ovarian follicular development and ovulation rate during spontaneous oestrous cycles. To extend this study, we investigated the effect of inhibin immunization more closely by monitoring plasma hormone profiles and ovarian activity in bI alpha(1-29)Tyr30-immunized and control (ovalbumin-immunized) heifers (n = 6 per group) over three consecutive oestrous cycles, which were synchronized and shortened by administering a PGF2 alpha analogue at intervals of 14 days. Blood samples were collected at 2-8 h intervals for 40 days and the ovaries were examined daily using ultrasonography. Repeated-measures ANOVA showed that inhibin immunization significantly increased plasma FSH concentration (by 52% overall; P < 0.01) and ovulation rate (by 58%; P < 0.01). Both immunized and control heifers showed the same cyclic pattern of plasma FSH (treatment x time interaction; not significant), indicating that the increase in plasma FSH was sustained throughout the cycle. Immunization did not affect the concentration or pattern of secretion of LH, oestradiol or progesterone and had no influence on the timing of the LH surge or ovulation after PG injection. While inhibin immunization increased the number of 'large' (i.e. growing to > or = 10 mm diameter) follicles that developed during both the preovulatory (by 90%, P < 0.02) and postovulatory (by 190%, P < 0.01) period, there was no difference between groups in the temporal pattern of growth or regression of large follicles or of corpora lutea.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2003

Effects of body condition score in cows peripartum on the onset of postpartum ovarian cyclicity and conception rates after ovulation synchronization/fixed-time artificial insemination.

The aim of this study was to examine whether the nutritional state of cows peripartum was associated with the recovery of ovarian function and conception rates after synchronization of ovulation and fixed-time artificial insemination (OVSYNCH/TAI). The effect of the interval in days from calving to the first ovulation on conception rates after OVSYNCH/TAI was also investigated. Conception rates of cows after OVSYNCH/TAI (n=39) were 43.6%. The conception rates of cows with a body condition score (BCS) of 2.75-3.25 at 30 d postpartum and on the day of OVSYNCH treatment were significantly higher than in cows with a BCS < or =2.5 (P<0.05). The percentage of cows establishing ovarian cyclicity before 55 d postpartum in cows with a BCS of 2.75-3.25 at 30 d postpartum and on the day of OVSYNCH treatment were significantly higher than in cows with a BCS < or =2.5 (P<0.05). The conception rates after OVSYNCH/TAI in cows which recovered ovarian cyclicity within 34 d postpartum were significantly higher than in cows with first ovulation > or =56 d (P<0.05). These results indicated that the nutritional state in cows peripartum influenced the conception rates after OVSYNCH/TAI and the postpartum ovarian cyclicity and also suggested that the conception rates after OVSYNCH/TAI decreased in cows with delayed recovery of ovarian cyclicity.

Animals↗
PubMed2006

The use of deslorelin implants for the synchronization of estrous in diestrous bitches.

A novel approach to estrous induction in diestrous bitches is described. Twelve spontaneously cycling anestrous bitches served as controls. Thirteen anestrous and 15 diestrous bitches were induced to come into synchronous estrous using prostaglandin (diestrous bitches only) and deslorelin implants (Ovuplant). Implants contained either 2.1 or 1.05 mg deslorelin and were administered beneath the vestibular submucosa. All treated bitches came into estrous, regardless of implant size. Whereas all anestrous bitches ovulated, one of six diestrous bitches treated with the larger implant and three of nine treated with the smaller implant failed to ovulate. Induced bitches generally produced fewer corpora lutea than controls. Sixty-seven percent of control bitches became pregnant, with 0.63 fetuses per corpus luteum, whereas the pregnancy rate and fetuses per corpus luteum were 67 and 70% and 0.42 and 0.55 in the anestrous bitches induced with 1.05 and 2.1 mg deslorelin implants, respectively (not different from controls). Only 2 of 15 induced diestrous bitches conceived a detectable pregnancy, one of which was resorbed. In conclusion, although ovulatory estrous can be induced in bitches that had their most recent ovulation 40-100 days ago, these bitches are very unlikely to become pregnant during the induced estrous. The reason for the poor fertility in these diestrous bitches requires further study.

Animals↗
PubMed1998

Follicular atresia and LH concentrations during the follicular phase of the estrous cycle in the goat (Capra hircus).

The objective of the study was to identify the effects of LH on the final follicle maturation process as well as the incidence of atresia during the follicular phase of the goat's estrous cycle. In Experiment 1, concentrations of the LH were measured during the follicular phase of a synchronized cycle in 8 Canary goats. In Experiment 2, the same animals were synchronized again. On each day of a 4-day experimental period (day 0 = day of sponges withdrawal), 2 of the goats were bilaterally ovariectomized. Follicles with a diameter > 1 mm were dissected out to obtain qualitative histological data in normal, early atretic I, early atretic II, advanced atretic I and advanced atretic II follicles. The total interval from sponge withdrawal to LH peak was 77.5 +/- 9.8 h. LH peak concentration averaged 44 +/- 5.3 ng/ml and the mean length of the preovulatory surge (amounts over 10 ng/ml) was 8.9 +/- 0.9 h. During the total follicular phase, there were more atretic follicles than normal follicles (58 vs. 30, P < 0.05). The number of early and advanced atretic follicles was similar. There were more early atresia I than early atresia II follicles (23 vs. 6, P < 0.05). On day 2, the number of advanced atretic follicles was greater than early atretic follicles (10 vs. 4, P < 0.05). There was an increase in the number of early atretic follicles from day 2 to day 4 (4 vs. 9, P < 0.05), which was consistent with the effects of the preovulatory LH surge.

Administration, Intravaginal↗
PubMed1988

Control of fertility and fecundity of sheep by means of hormonal manipulation.

The results of four experiments are presented in summary form. The data are considered in relationship to the improvement of the fecundity and fertility of the Australian ewe breeding flock. In the first, three commonly used methods of oestrous synchronization were examined and showed differences that are attributed to the different patterns of hormonal changes associated with the methods demonstrated. The second experiment looked at the use of active immunization against testosterone and concluded that this method can improve fecundity but not fertility. The third experiment, a group of five trials, studied the use of progestagen sponges and PMSG in anoestrous ewes as a means of inducing normal fertility. The extensive data produced in this experiment allowed the relationships between ovulation rate and fertility and between fertility and prolificacy (fecundity) to be examined. Fertility appeared greatest when the mean flock ovulation rate was about 2.5. At this ovulation rate prolificacy was also improved and a high proportion of twins were produced. We concluded that high fertility and low prolificacy (i.e. of 1.00) are an unlikely combination. In the final experiment the effect of post-mating hormonal supplementation on fertility was examined and a number of earlier reports were confirmed by showing that fertility can be improved with supplementary progesterone between days 10 and 25 post-mating. The effect appears to be modified by hormonal and nutritional factors.

Animals↗
PubMed2005

Comparison of artificial insemination versus embryo transfer in lactating dairy cows.

Conception rates (CR) are low in dairy cows and previous research suggests that this could be due to impaired early embryonic development. Therefore, we hypothesized that CR could be improved by embryo transfer (ET) compared with AI. During 365 days, 550 potential breedings were used from 243 lactating Holstein cows (average milk production, 35 kg/day). Cows had their ovulation synchronized (GnRH-7d-PGF(2alpha)-3d-GnRH) and they were randomly assigned for AI immediately after the second GnRH injection (Day 0) or for transfer of one embryo 7 days later. Circulating progesterone concentrations and follicular and luteal size were determined on Days 0 and 7. Pregnancy diagnosis was performed on Days 25 or 32 and pregnant cows were reevaluated on Days 60-66. Single-ovulating cows with synchronized ovarian status had similar CR on Days 25-32 with ET (n = 176; 40.3%) and AI (n = 160; 35.6%). Pregnancy loss between Days 25-32 and 60-66 also did not differ (P = 0.38) between ET (26.2%) and AI (18.6%). When single (n = 334) and multiple (n = 57) ovulators were compared, independent of treatment, multiple ovulators had greater (P < 0.001) circulating progesterone concentrations on Day 7 (2.7 ng/ml versus 1.9 ng/ml) and there was a tendency (P = 0.10) for a greater CR in multiple ovulators (50.9% versus 38.1%). However, there was no difference in CR between AI and ET cows with multiple ovulations (50.0% versus 51.7%). In single-ovulating cows, CR tended to be lower for AI than ET in cows ovulating smaller follicles (diameter < or = 15 mm; 23.7% versus 42.3%; P = 0.06) but not average-diameter follicles (16-19 mm; 41.2% versus 37.3%; P = 0.81) or larger (> or =20 mm; 34.3 versus 51.0%; P = 0.36) follicles. Thus, although ET did not improve overall CR in lactating cows, follicle diameter and number of ovulating follicles may determine success with these procedures.

Animals↗
PubMed2002

Seasonal differences in lamb birthweight do not arise from inherent differences in the oocyte and/or early embryo.

The aim of this study was to determine whether previously observed seasonal differences in conceptus development in ewes are attributable to inherent differences in the oocyte and/or early embryo. Day 6 embryos were recovered from 50 ewes subjected to a standard oestrus synchronization, superovulation and laparoscopic artificial insemination protocol during October (peak breeding season) and April (transition to anoestrus). During the following October, 40 grade 1 and 2 embryos from each month, which had been cryopreserved at the late morula or unexpanded blastocyst stage, were thawed and transferred in singleton to synchronous recipients. Resulting pregnancies were monitored to term. For ewes receiving October- and April-produced embryos, overall mean +/- SEM liveweight at the time of embryo transfer was 72 +/- 0.7 kg, body condition score was 3.1 +/- 0.04 units, and the number of corpora lutea on the ovaries was 2.7 +/- 0.11 per ewe. Thirty-one and 27 ewes, respectively, became pregnant and their gestation lengths were 147 +/- 0.2 and 147 +/- 0.3 days. There was no effect of month of embryo production on peripheral ovine pregnancy-associated glycoprotein concentrations during pregnancy or on fetal and placental characteristics at term, but, for each month, male lambs were heavier than females and were associated with larger placentae. Lamb birthweight was positively correlated with placental weight (r2 = 0.474, P<0.001) and the total weight of cotyledonary tissue (r2 = 0.429, P<0.001), but not to the number of cotyledons. Results demonstrate close relationships between fetal and placental weights at term, and that seasonal effects on conceptus development in ewes do not arise from inherent differences in the oocyte and/or early embryo.

Animals↗
PubMed1984

Luteinizing hormone secretion after withdrawal of exogenous progestogen in heifers fed three levels of dietary energy.

As experiment was conducted with 15 Angus X Hereford heifers that were 16 mo of age at the time the experiment was initiated. The heifers were assigned randomly in equal numbers to be fed low (L), maintenance (M) or high (H) energy diets for 191 d. Overall average weight for heifers at the time the experiment was initiated was 294 +/- 6 kg. All heifers were exhibiting estrous cycles at regular intervals and estrus was synchronized using a progestogen implant (norgestomet) in combination with an injection of estradiol valerate and norgestomet before initiation of dietary treatments. Dietary treatments started at time of implant removal and this day was designated as d 0. Blood samples were collected every other day from d 150 to 160 and progesterone concentrations were quantified to evaluate estrous cycle activity. In order to resynchronize the reproductive state, all heifers were retreated with norgestomet implants and injected with the estradiol valerate and norgestomet combination on d 160. Implants were removed on d 170. Serial blood samples were collected for 4-h periods at 20-min intervals starting at 0, 10, 20 and 30 h after implant removal and luteinizing hormone (LH) concentrations were quantified. Progesterone was quantified in samples collected at daily intervals (170 to 191 d) to evaluate whether a normal estrous cycle occurred subsequent to removal of the implant. Four of five heifers in each of the L and M treatment groups were not cycling, whereas all heifers in the H treatment were cycling at the time of progestogen implantation on d 160.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2002

Detection of oestrus in Bunaji cows under field conditions.

The objective of this study was to determine the efficacy of some aids for detecting oestrus in 72 Bunaji cows synchronized using two injections of prostaglandin F2 alpha (PGF2 alpha) 13 days apart. Blood samples to determine the accuracy of the aids and ovarian activity by radioimmunoassay technique were collected daily from the day of the second PGF2 alpha injection until oestrus or for 168 hours for 'non-responders'. The aids for detecting oestrus, tail painting, KaMar detectors and a chin-ball mating device (CMD) were applied at the time of the second injection. The oestrus response rate was 73.6% and 61.1%, from the serum progesterone concentration and visual observation, respectively. Based on the total number of oestrus events observed, unaided visual observation, tail painting, KaMar and CMD detected 52.2%, 82.6%, 82.6% and 76.8%, respectively. Visual observation of standing oestrus alone failed to detect 47.8% of the occurrence of oestrus as shown by the concentration of progesterone in the serum and 30.4%, 30.4% and 24.6%, respectively, of the oestrus periods recorded by tail painting, KaMar and CMD. Twenty-eight cows showed abnormalities in progesterone concentration. These investigations showed that oestrus may be detected by using the aids in cows that have been regarded as 'anoestrous' by visual observation of standing heat.

Animals↗
PubMed1990

[Use of synchronized heifer-recipients in view of the effectiveness of embryo transfer in cattle].

A possibility was investigated of using heifers prepared for embryo reception by i. m. double application of Oestrophan (Spofa) luteolytic preparation. After a clinical examination of ovaries and corpus luteum, out of the total number of 2894 animals synchronized for nonsurgical ipsilateral transfer in the D7 stage only 2038 (70.4%) recipients were used. Almost 30% (856) heifers were discarded from the role of recipients, mostly due to the functional disorders of the cyclic activity of ovaries manifesting themselves as luteal cysts (22.5%), cysts of corpus luteum (16.5%), small or young corpora lutea (12.7%), postovulation states (4.5%), and also as a high frequency of the follicular activity without the presence of corpus luteum (37.9%). The occurrence of follicular cysts (1.4%) and nonfunctional ovaries (2.8%) was considerably lower. The high number of discarded recipients which results, in the complex of causes, from qualitative nutritional disorders, husbandry and zoo-hygienic shortcomings and stress-inducing factors in the course of recipient selection and preparation, diminishes the transfer efficiency and considerably increases the claims for the numbers of recipient prepared for ovulation. In the conditions of our workplace where 10.6 to 12.8 transferable embryos are recorded from one successful superovulation and their survival is 65 to 68.6%, it will be necessary, at the present level of recipient discarding, to prepare 13.8 to 16.6 heifers per donor to make full use of the superovulation effect.

Animals↗
PubMed1988

Influence of nutrition on serum concentrations of progesterone, luteinizing hormone and estrous behavior in dairy heifers.

Thirty postpubertal Holstein heifers were used to investigate the influence of dietary intake on 1) serum concentrations of progesterone (P4) and luteinizing hormone (LH) during diestrus and 2) estrous behavior. Heifers were randomly allotted to receive either 80, 100 or 120% of the National Research Council (NRC) requirements for energy, protein and dry matter intake for 139 d. Heifers were fed their respective diets in groups in outdoor lots for 114 d at which time individual feeding of diets was initiated in a stanchion barn. Estrus was synchronized with two injections of prostaglandin (PG) so that on d 138 of dietary treatment the heifers were in diestrus (means = d 8 of estrous cycle). Also, on d 138, blood samples were collected via jugular cannula at 20-min intervals for 12 h beginning at 0630. After collection of the 37th blood sample, all heifers were treated with PG and additional blood samples were collected at 1-h intervals for 24 h. Immediately thereafter, all heifers were moved to a common outdoor lot for 72 h of continuous observation for estrous behavior. Weight gains during the experimental period differed among groups and were 46 +/- 5, 83 +/- 5 and 113 +/- 4 kg for the heifers fed 80, 100 and 120% of the NRC requirements, respectively. Mean serum concentrations of P4 for the 80% NRC group (4.6 +/- .6 ng/ml) tended to be lower than both the 100% (5.9 +/- .6 ng/ml) and 120% (6.0 +/- .5 ng/ml) NRC groups, respectively. Mean serum concentrations of LH, number of LH secretory peaks/12 h and LH peak amplitude were similar among all NRC groups. Rate of decline in serum P4 after PG was also similar among all NRC groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena↗
PubMed1997

Effect of service on duration of oestrus and ovulation in dairy goats.

In the autumn, Nubian goats (n = 24) were randomly divided into two equal groups after oestrus had been synchronized using fluorogestone acetate intravaginal pessaries (FGA, 30 mg) over a 20 day period. The onset of oestrus was detected at 8 h intervals using either of two vasectomized bucks fitted with an apron during the 5 days following pessary removal. A buck was permitted to mount and serve each doe only twice in 30 min within the first 8 h of oestrus initiation in the SER group. In the CON group, a buck was only permitted to mount. Ovulation was determined by laparoscopy at 8 h intervals starting 24 h after onset of oestrus. Duration of oestrus for SER and CON groups was (mean +/- SD) 26.7 +/- 7.1 and 36.0 +/- 8.0 h, respectively (P < 0.01). The first and last ovulations for SER and CON groups were 34.7 +/- 3.9 and 37.3 +/- 6.2 h, and 35.3 +/- 5.4 and 38.0 +/- 6.0 h from oestrus initiation, respectively (P > 0.05). No differences were found between right and left ovarian activity (P > 0.05). Ovulation rates did not differ (2.17 +/- 0.58 and 2.17 +/- 0.94). Ovulations occurred principally towards the end of oestrus in the CON group and after oestrus had ended in the SER group. Service reduced the duration of oestrus without affecting ovulation times or ovulation rates in Nubian dairy goats.

Animals↗
PubMed1988

[Qualitative and quantitative changes in the hypothalamus and the ependyma of the 3d cerebral ventricle in sheep after irradiation and hormonal stimulation].

In the submitted work we concentrated our attention on the study of the changes in neurosecretion. PAS positive mucopolysaccharides in the hypothalamus and ependyma of the IIIrd cerebral ventricle and on studying the changes in the volume of the cell nuclei of the neurons of nucl. supraopticus (NSO), nucl. hypothalamicus centromedialis (NVM) and nucl. tuberomamillaris (NTM) of sheep after irradiation and after hormonal stimulation. We made our observations on 28 sheep of the Slovak Merino breed, of average live weight 35 to 40 kg, two- and three-years old in the period of physiological anoestrum. The first group of four ewes and the second group of four yearling lambs were controls. The third group of six ewes and the fourth group of six yearlings were exposed to irradiation all over with a dosage of 2.46 Gy (250 R) for a period of five days. To synchronize the oestrum of all the sheep we used agelline sponges which we fitted five days before irradiation. After the irradiation and removal of the sponges we gave the test sheep hormonal stimulation with 3 X 500 i. u. of serum gonadotropin. The fifth group of four ewes and the sixth group of four yearlings were only stimulated without irradiation. The fifth day after stimulation we slaughtered the sheep. We processed the brain samples by the usual histological methods. We carried out karyometric analysis with 3000X magnification and the measurement of 200 cells from one sample. We processed the values obtained mathematically according to Fischer and Inke (1956). We evaluated the quantity of neurosecretion material with a light microscope according to Nakahara (1962). We found that the multiplication of neurosecretion and the increased activity of the PAS reaction in the hypothalamic nuclei studied show that the irradiation and hormonal treatment stimulate the function of the hypothalamic structures. The results of the karyometric analysis in the yearlings also confirm this opinion. In the ewes the inhibitive influence of irradiation was probably manifest. The giving of hormones in combination with irradiation causes the multiplication of ependyma cells and the desquamation of surface layers.

Animals↗
PubMed1998

The effect of gonadotrophin releasing hormone and follicle stimulating hormone in conjunction with pregnant mare serum gonadotrophin on the superovulatory response in crossbred sheep in India.

Thirty-two mature crossbred (Fine Wool Synthetic, FWS) sheep developed for fine wool production in India were treated for superovulation and oestrus synchronization in spring season. The ewes were randomly allocated to four treatment groups in a factorially designed experiment. For induction of superovulation, pregnant mare serum gonadotrophin (PMSG) was administered alone (group 1), in combination with gonadotrophin releasing hormone (GnRH) (group 2) or with follicle stimulating hormone (FSH) (group 3) and with both (group 4). Oestrus was synchronized in all the ewes by two injections of prostaglandin F2 alpha (PGF, 10 mg each) administered at an interval of 10 days. Superovulation treatment started 48 h prior to the second PGF injection. The proportion of ewes in oestrus did not differ significantly (p > 0.05) in the four groups. The use of GnRH set the ewes into oestrus earlier than the ewes in the other groups. Treatment with PMSG (800 IU) in conjunction with 4 micrograms of Buserilin (GnRH) increased the ovulation rate (9.1 +/- 2.6 corpora lutea (CL)) above that observed when PMSG was used alone (3.0 +/- 0.7 CL). The use of FSH (0.5 U ovagen) in conjunction with PMSG was characterized by a decrease in the proportion of ewes with < or = 2 CL (4/8 vs 7/8; p < 0.05) and in the number of ovulations, i.e. CL observed (2.4 +/- 0.6 vs 9.1 +/- 2.6), and a nonsignificant increase in the incidence of large follicles (LF) (4.6 +/- 1.28 vs 3.25 +/- 0.6; p > 0.05). The interaction between treatments of FSH and GnRH was not significant (p > 0.05). It is concluded that use of GnRH, in conjunction with either PMSG alone or PMSG plus FSH treatment, advanced the onset of oestrus and increased the ovulation rate in FWS sheep.

Animals↗
PubMed1994

Effect of exogenous gonadotrophins on oestrus, the LH surge and the timing and rate of ovulation in red deer (Cervus elaphus).

Red deer hinds (n = 38) were treated in the breeding season with five different gonadotrophin regimens to investigate the temporal relationship between oestrus, ovulation and the LH surge. All hinds were treated with progesterone-impregnated controlled internal drug release (CIDR) devices to synchronize oestrus. The five treatments were as follows: treatment 1, controls; treatments 2, 3 and 4, 1200 iu pregnant mares' serum gonadotrophin (PMSG) was administered i.m. 72 h before CIDR device withdrawal (treatments 3 an 4 were also injected i.v. with 0.4 mg synthetic GnRH 12 or 18 h after CIDR device withdrawal, respectively); treatment 5, 200 iu PMSG was administered i.m. 72 h before CIDR device withdrawal and 0.5 iu FSH was administered in eight equal doses at intervals of 12 h starting from the time of PMSG injection. The hinds were run with crayon-harnessed stages to determine the time of oestrus onset. Blood samples were collected every 2 days for 26 days after CIDR device removal to determine concentrations of plasma progesterone and every 2 h for 72 h after CIDR device removal to determine plasma LH profiles. Laparoscopy for ovary examination was performed 6 or 12 h after oestrus onset and was repeated twice at intervals of 12 h. Final ovulation rate was determined on day 7 after CIDR device removal. All hinds received 500 micrograms cloprostenol i.m. on day 13. A total of 30 and 34 hinds exhibited oestrus and ovulation, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Endocrine responses and conception rates in fallow deer (Dama dama) following oestrous synchronization and cervical insemination with fresh or frozen-thawed spermatozoa.

In Expt 1, 59 mature fallow deer does were allocated to six treatments (n = 9-10 per treatment). Does assigned to treatments 1, 2 and 3 each received an i.m. injection of 500 micrograms cloprostenol on day 13 of a luteal cycle. Does in treatments 2 and 3 received 50 or 100 iu pregnant mares' serum gonadotrophin (PMSG), respectively, at the time of prostaglandin administration. Does assigned to treatments 4, 5 and 6 each received single intravaginal controlled internal drug release (CIDR) devices for 14 days. Does in treatments 5 and 6 received 50 or 100 iu PMSG, respectively, at the time of CIDR device withdrawal. Incidence of oestrus was higher following treatment with CIDR devices than with prostaglandin (29 of 30 versus 12 of 29, P < 0.001). PMSG induced earlier onset of oestrus (34.6 +/- 0.9 h versus 44.7 +/- 2.4 h, P < 0.01) and reduced the range in the time to onset of oestrus (from 22 to 8 h for prostaglandin-treated does and from 36 to 14 h for progesterone-treated does). The number of LH surges was higher following treatment with CIDR devices than with prostaglandin (10 of 12 versus 3 of 12, P < 0.01). The overall mean peak LH concentration and time to LH peak were 30.2 +/- 3.4 ng ml-1 and 45.2 +/- 2.2 h after prostaglandin administration or CIDR device withdrawal. The overall median time of ovulation was 26 h after the onset of oestrus.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

The interhaemal barrier in the chorioallantoic placenta of the greater mustache bat, Pteronotus parnellii, with observations on amplification of its intrasyncytial lamina.

Chorioallantoic placentae were obtained from a reproductively synchronized wild population of greater mustache bats for ultrastructural and immunocytochemical examination. The single discoidal placenta was always located in a lateral to mesometrial position on the right side of the uterus, which in the non-pregnant state is partially bicornuate. The placenta was labyrinthine and haemodichorial in advanced pregnancy. The interhaemal barrier included syncytiotrophoblast that lined the maternal vascular spaces and an underlying, continuous layer of cytotrophoblast. The barrier also contained a discontinuous extracellular layer, the intrasyncytial lamina, that was usually completely surrounded by syncytiotrophoblast. Two lines of evidence suggest that the intrasyncytial lamina may serve, in part, to strengthen the interhaemal barrier: (1) the lamina became significantly thicker as the maternal vascular channels became larger; and (2) the syncytiotrophoblast in the walls of the smallest vascular tubules expressed only very limited amounts of cytokeratins, normally a major component of the cytoskeleton of cells of epithelial origin, while the cytokeratin-rich cytotrophoblast was often highly attenuated. It was not uncommon to see gaps between the ectoplasmic processes of syncytiotrophoblast which exposed portions of the intrasyncytial lamina to the maternal vascular space. As platelet adhesion was never observed in such areas, the intrasyncytial lamina may be augmented in part by material that is non-thrombogenic.

Allantois↗