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PubMed1998

Estrous hormones enhance coupled, rhythmic olivary discharge in correlation with facilitated limb stepping.

Synchronized oscillatory behaviour of neurons within the dorsal accessory olive of the rat were monitored across spontaneous changes in rapid, co-ordinated limb movements associated with the estrous (hormone) and circadian cycles as well as following local administration of estradiol. Facilitation of rapid alterations in limb movement is observed following increases in circulating estradiol and progesterone on the night of behavioural estrus, as assessed by the ability of a rat to maintain a consistent position on a treadmill in response to variable changes in acceleration. Synchronized olivary activity was determined using chronically implanted bundles of microwires (50 microns diameter) to record from as many as 23 individual olivary neurons simultaneously across several four to five day estrous cycles, and in some cases after injection of the estrous hormones, estradiol and/or progesterone, either by systemic or local administration. Rats were tested during non-movement, constant speed locomotion or using a variable acceleration paradigm. Olivary oscillations were most commonly observed during treadmill locomotion with variable changes in acceleration. Local administration of estradiol, in combination with systemic progesterone administration, enhanced rhythmic olivary oscillations during this paradigm. At this time, at least a six-fold increase in the size of the coupled cluster of rhythmically discharging olivary neurons was observed compared with values obtained on diestrus, a low hormone state. Similar facilitating effects on olivary oscillations were observed on estrus, or following systemic injection of both estrous hormones. Administration of either steroid alone was not as effective. During the dark phase of the light:dark cycle, the oscillatory behaviour of these neurons was enhanced more than five-fold than during the light phase, and coupling diameter was maximal on the night of behavioural estrus. The synchronized oscillatory discharge of neurons within the olive is a putative timing mechanism which may underlie hormone-associated facilitation of rapid limb movements. The results from the present study provide evidence that both hormonal and circadian factors can enhance olivary rhythmicity in association with behavioural rhythmicity.

Acceleration↗

PubMed1997

Reproductive management of lactating dairy cows using synchronization of ovulation.

Lactating dairy cows have poor reproductive efficiency because of low fertility and low rates of estrus detection. To eliminate the dependence on detection of estrus, we have recently developed a timed artificial insemination (AI) protocol that synchronized the time of ovulation using GnRH and PGF2 alpha. The effectiveness of this protocol as a management tool was compared with standard reproductive management. Lactating dairy cows (n = 333) from three herds were randomly assigned at parturition to two groups. Control cows were managed according to the typical reproductive strategy of the farm that relied on detection of estrus, the a.m.-p.m. breeding rule, and periodic use of PGF2 alpha. Treated cows had timed AI after synchronization of ovulation with GnRH and PGF2 alpha. For both groups, the voluntary waiting period was 50 d postpartum. Pregnancy diagnosis was performed by ultrasound between 32 and 38 d post-AI. Nonpregnant cows were inseminated again using the original treatment until diagnosed as pregnant or until culled from the herd. Median days to first AI (54 vs. 83) and days open (99 vs. 118) were lower for treated cows than for control cows, respectively. Pregnancy rates for the first AI were similar (37% vs. 39%) for the two groups even though treated cows were bred at an earlier time postpartum. More treated cows than control cows were pregnant at 60 d (37% vs. 5%) and at 100 d (53% vs. 35%) after calving. Thus, this protocol allowed effective management of AI in lactating dairy cows without the need for estrus detection.

Animals↗

PubMed1991

Effect of serum-free co-culture and synchrony of recipients on development of cultured sheep embryos to fetuses.

The percentage of sheep embryos that continued to develop after collection and immediate transfer on d 2 after estrus was similar when phosphate-buffered saline with 10% fetal calf serum (PBSFCS, 45%), physiological saline (50%), or tissue culture medium 199 supplemented with 10% fetal calf serum (M199FCS, 47%) was used to flush embryos from oviducts. Co-culture of sheep embryos for 3 d with oviductal cells tended (P = .1) to reduce the percentage of embryos that developed to fetuses after transfer compared with those embryos transferred immediately. Tissue culture medium 199 supplemented with .3% BSA (M199BSA) was an adequate substitute for M199FCS for culture of sheep oviductal cells if tissue culture wells were pretreated with fibronectin. Estradiol in concentrations from 10 to 1,000 pg/ml and progesterone at concentrations of 1 or 10 ng/ml in M199BSA failed to stimulate embryo development during 3 d of co-culture beyond that seen in co-culture with M199FCS or M199BSA without added steroid. Transfer of sheep embyros co-cultured for 3 d in M199BSA or M199FCS to recipients synchronized with donors resulted in about 19% of the embryos developing to fetuses, whereas transfer to recipients that were in estrus 24 h after donors resulted in 33% of embryos developing to fetuses. The significant (P less than .05) improvement for delayed recipients may reflect the relatively lesser developmental rate of co-cultured embryos compared with that of embryos in vivo. Embryo development into fetuses was similar after co-culture in M199FCS or M199BSA co-cultures; therefore, serum is not required for the co-culture of sheep embryos.

Animals↗

PubMedDate not supplied

Exposure of thawed frozen bull sperm to a synthetic peptide before artificial insemination increases fertility.

We evaluated the effect on fertility of in vitro exposure of thawed frozen bull sperm to synthetic FertPlus peptide prior to artificial insemination (AI). The peptide represented a 60-amino acid sequence within rat prosaposin. Commercial cryopreserved semen was from three Holstein bulls. Onset of estrus in groups of Holstein nulliparous heifers was synchronized via injection of prostaglandin F2-alpha, and heifers were scheduled for AI 8-24 hours after estrus was detected. Semen was thawed, diluted to 2.4 x 10(6) sperm/ml with buffer, and split to provide control and exposed aliquots (0 or 30 microM peptide) that were incubated at 37 degrees C for 10 minutes and then were held at 32 degrees C. The two aliquots of semen then were used on an alternate basis 2-65 minutes later to inseminate females. Each AI (one per female) involved the deposit of approximately 250,000 sperm into each uterine horn. This procedure for AI was used to reduce the pregnancy rate with control semen to below the maximum value for a given bull and to facilitate detection of any beneficial effect of the peptide. For each bull, approximately 32 heifers were inseminated with control semen, and approximately 32 heifers were inseminated with peptide-exposed semen. Pregnancy was evaluated ultrasonically approximately 60 days after AI. After excluding one group of heifers with unusually low fertility, averaged across all animals, a 29% increase in pregnancy rate resulted from exposure of sperm to peptide (P < 0.04; one-tailed chi-square test; means were 48 vs. 62%). Pregnancy rates for the three bulls for control and peptide-exposed semen, respectively, were 42 and 62%, 44 and 64%, and 56 and 61%; means in the first two pairs of values tended to differ (P approximately equal to 0.10). These observations should be confirmed with sperm from other bulls used in a more conventional manner. However, with insemination of a limiting number of cryopreserved sperm, brief exposure of the thawed bull sperm to FertPlus peptide appeared to improve fertility dramatically.

Animals↗

PubMed1979

[Estrus induction in sheep injected with colostrum at different phases of the sexual cycle].

Investigations on the mechanism of colostrum effect in sheep sex apparatus stimulation were carried out. The experiments included 57 sheep, 10 of them used as a check and the remaining 47 distributed in four treatment groups and injected with colostrum at various phases of the sex cycle. It was established that the effectiveness of injecting cow colostrum on sheep with the aim of inducing synchronous oestrus during the regular reproduction season depends on the sex cycle phase at which the injection takes place. The effectiveness is higher in case injection is performed during the second half of dioestrum. The induced synchronous oestrus of sheep following colostrum injection is equivalent to the normal.

Animals↗

PubMed2002

The use of a progesterone-releasing device (CIDR-B) or melengestrol acetate with GnRH, LH, or estradiol benzoate for fixed-time AI in beef heifers.

The objective of this experiment was to compare two progestins and three treatments for synchronizing follicular wave emergence and ovulation in protocols for fixed-time AI in beef heifers. On d 0 (beginning of the experiment), Angus and Angus-Simmental cross beef heifers at random stages of the estrous cycle either received a CIDR-B device (n = 257) or were started on 0.5 mg x anima(-1) x d(-1) melengestrol acetate (MGA; n = 246) and were randomly assigned to receive i.m. injections of 100 microg GnRH, 12.5 mg porcine LH (pLH), or 2 mg estradiol benzoate (EB) and 50 mg progesterone (P4). The last feeding of MGA was given on d 6 and on d 7, CIDR-B devices were removed and all heifers received 500 microg cloprostenol (PG). Consistent with their treatment groups on d 0, heifers were given either 100 microg GnRH or 12.5 mg pLH 48 h after PG (and were concurrently inseminated) or 1 mg EB 24 h after PG and were inseminated 28 h later (52 h after PGF). Estrus rate (combined for both progestins) in heifers receiving EB (92.0%) was greater (P < 0.05) than that in heifers receiving GnRH and pLH (combined) and a CIDR-B device (62.9%) or MGA (34.3%). Although the mean interval from PG treatment to estrus did not differ among groups (overall, 47.8 h; P = 0.85), it was less variable (P < 0.01) in MGA-fed heifers (SD = 2.5 h) than in CIDR-B-treated heifers (SD = 8.1 h). Pregnancy rates (determined by ultrasonography approximately 30 d after AI) did not differ (P = 0.30) among the six treatment groups (average, 58.0%; range, 52.5 to 65.0%). Although fixed-time AI was done, pregnancy rates were greater in heifers detected in estrus than in those not detected in estrus (62.6 vs 51.9%; P < 0.05). In conclusion, GnRH, pLH, or EB treatment in combination with a CIDR-B device or MGA effectively synchronized ovulation-for fixed-time AI, resulting in acceptable pregnancy rates in beef heifers.

Animals↗

PubMed2005

The timing of ovulation and insemination schedules in superstimulated cattle.

The development of treatments that control follicular wave dynamics during the bovine estrous cycle has resulted in interesting possibilities for the precise control of follicular wave emergence and the time of ovulation. For superstimulation, follicular wave emergence can be controlled by ultrasound-guided follicle ablation with FSH treatments initiated 1 or 2 d later, or injection of estradiol combined with progesterone at the time of insertion of a progestogen releasing device and FSH treatments beginning 4 d later. These are the most widely used protocols for superstimulation of donor cows because they offer the convenience of being able to initiate treatments quickly and at a self-appointed time, without reducing the number of transferable embryos. However, these protocols still require precise estrus detection of donors following superstimulation in order to conduct AI at the most appropriate time. Recent studies have been designed to develop superstimulation protocols that involve fixed-time AI of donors, without regard to estrus detection. Results presented herein indicate that delaying the removal of a progestogen releasing device, combined with the administration of GnRH or porcine LH (pLH) 12 or 24 h later results in predictable, synchronous ovulations, permitting fixed-time AI without reducing the numbers or quality of embryos. These protocols facilitate the application of on-farm embryo transfer programs because they are practical, easy to administer by farm personnel, and more importantly, they eliminate the need for detecting estrus.

Animals↗

PubMed1996

Progestin and estrogen regulation of pulsatile LH release and development of persistent ovarian follicles in cattle.

When doses of progestin used commercially are administered to synchronize the stage of the estrous cycle among bovine females, fertility is reduced compared with that of untreated controls. The reduced fertility that results from the use of progestin based estrus synchrony regimens is associated with the development of persistent ovarian follicles. Persistent ovarian follicles develop as a result of the greater frequency of LH pulses that occurs during the period of treatment with progestins. The greater release of LH pulses results in enhanced secretion of 17 beta-estradiol from persistent ovarian follicles. The greater frequency of LH release or the greater secretion of 17 beta-estradiol associated with development of persistent ovarian follicles probably contributes to the reduced fertility that occurs when progestins are used to synchronize stage of the estrous cycle.

Animals↗

PubMed2002

Use of steroid hormone treatments prior to superovulation in Nelore donors.

The objective of this study was to evaluate the effectiveness of synchronization of follicular wave emergence using steroid hormone treatments in Nelore cows. Donors were placed into three groups. Those that were between days 9 and 12 of their cycle (estrus=day 0) formed the TI group (n=60), whilst those that were in any other stages of their estrus cycle constituted groups TII (n=60) and TIII (n=60). TI donors were submitted to a standard protocol of superovulation, however, TII and TIII donors were treated with the Syncro-Mate-B (SMB) or Controlled Internal Drug Releasing Device (CIDR-B) programs, respectively. Superovulation was induced with p-FSH, divided into eight decreasing doses at intervals of 12h. The donors received cloprostenol 48h after the beginning of the treatment and progestagens were removed 12h later. Artificial inseminations (AI) were done at 12 and 22h after the initiation of estrus and the embryo collections were done 7 days after AI. In the donors which displayed behavioral estrus, mean (+/-S.E.M.) total ova and viable (transferable) embryos were 15.8+/-1.4 and 8.3+/-1.0 (TI, n=56); 15.6+/-1.3 and 8.9+/-1.0 (TII, n=56); 17.3+/-1.0 and 9.9+/-0.9 (TIII, n=57), respectively, with no significant difference (P > or =0.05) among groups. In those animals that did not displayed behavioral estrus, the mean values of total ova and viable embryos were 3.5+/-1.6 and 0.7+/-0.5 (TI, n=4); 11.5+/-3.9 and 9.0+/-4.4 (TII, n=4); 8.7+/-5.0 and 5.0+/-2.9 (TIII, n=3), respectively, with no significant differences (P > or =0.05) among groups. Pregnancy rates of 62.2% (TI, n=235); 66.4% (TII, n=284) and 65.1% (TIII, n=244) were obtained with embryos transferred from these collections and did not differ significantly (P > or =0.05) among groups. It was concluded that the synchronization of the emergence of follicular waves in Nelore donors is usable and does not harm the efficiency of embryo transfer programs. In addition, in contrast to the standard superovulation protocol, this method permits the use of a large number of donors in a short time period, at any stage of the estrus cycle, minimizing the costs of embryo transfer.

Animals↗

PubMed2005

Walking activity at estrus and subsequent fertility in dairy cows.

Poor detection of estrus, still a major problem in the dairy industry, has prompted the development of electronic estrous detection technologies. One of the features of estrous behavior is a marked increase in walking activity. The objectives of the present study were to evaluate the effects of various management factors on walking activity increase at estrus, and the relationship between this trait and fertility. Data from 5883 artificial inseminations (AI) conducted in two high-producing dairy herds were analyzed. Detection of estrus was performed using a pedometer system. Of the total AI investigated, 2072 (35.2%) resulted in pregnancy. The following data were recorded for each animal at AI: herd, lactation number, milk production (average for the 3 days prior to AI), lactation stage (early, mid, and late lactation), previous estrous synchronization (cloprostenol or progesterone releasing intravaginal device [PRID] for animals showing estrus within 7 days of treatment), season (warm versus cool period), insemination number following parturition, inseminating bull, inseminator, and pedometer measurements. Variables were screened for associations with walking activity by analysis of variance (ANOVA) through generalized linear model procedures (PROC GLM). Increased parity and milk production, and insemination during the warm period were associated with lower pedometer measurements. No significant effects of the herd, estrous synchronization, and lactation stage were observed. The link between walking activity and fertility was determined by applying logistic regression models. We detected no significant effects of herd, milk production, estrous synchronization, lactation stage, and inseminator on pregnancy rate. A higher lactation and insemination number, and insemination during the warm period were negatively correlated with the pregnancy rate. The likelihood of pregnancy was greater when semen from one of the bulls was used and when physical activity at estrus was increased. Our findings indicate that cow and management factors contribute intensely to walking activity at estrus, and also reveal a close link between increased walking activity and fertility.

Animals↗

PubMed1987

[The effect of hormonal stimulation on the follicle population in the ovaries of ewes during estrus and anestrus].

In the oestral and anoestral periods, 129 ewes of the Slovak Merino breed were treated with different doses of the stimulants PMSG, PGF2 alpha, HCG, SG and FSH after synchronization by means of Ageline tampons. In the anoestral period, PMSG doses of 750 and 1000 i. u. were found to increase the number of tertiary follicles from 12.3 to 17.2 and 18.6, whereas the dose of 1500 i. u. was found to reduce this number from 18.6 to 13.5. PGF2 alpha increases the average number of tertiary follicles from 12.3 to 22.2 and when it is combined with 750 i. u. PMSG, the increase is to 29.3 tertiary follicles. At higher PMSG doses the ratio of atretic (A) to non-atretic (N) tertiary follicles rose and the number of ovulations increased from 2.5 to 4.0. After synchronization with Ageline and administration of PMSG at the doses of 750 and 1000 i. u., the number of tertiary follicles increased from 16.0 to 18.4 and the number of ovulations from 3.1 to 5.7; the number of atretic tertiary follicles showed no change. In the oestral period, the dose of 1000 i. u. PMSG administered after PGF2 alpha reduced the number of tertiary follicles from 18.9 to 14.5 and increased the number of ovulation from 1.6 to 2.6; an increase was also recorded in the number of atretic tertiary follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Anestrus↗

PubMed2005

Ovulation failure and double ovulation in dairy cattle: risk factors and effects.

Ovulation failure and double ovulation rates were examined in 1917 inseminations performed in high-yielding dairy cows under standard commercial conditions. The ovulation rate was determined 11 days post-insemination by ultrasound detection of at least one corpus luteum in the ovaries. Analyzing the double ovulation and pregnancy rates, the study population consisted only of ovulated cows (n = 1792). Data were analyzed using logistic regression methods. A failure to ovulate was recorded in 125/1917 (6.5%) services: 82/663 (12.4%) during the warm and 43/1254 (3.4%) during the cool period. Based on the odds ratios, the risk of ovulation failure was 3.9 times higher for inseminations performed during the warm period. No significant effects of estrous synchronization, milk production and days in milk at AI, and service and lactation number on ovulation failure were found. Double ovulation was recorded in 277/1792 (15.5%) services: 146 (52.7%) unilateral double ovulations (42.5% left versus 57.5% right); 115 (41.5%) bilateral double ovulations; and 16 (5.8%) triple ovulations. Double ovulation was recorded in 72 (12.4%) and 205 (16.9%) AI during the warm and the cool period, respectively. The percentages of double ovulation for first, second and third or more lactations were 6.7, 16.6 and 25%, respectively. Double ovulation rates for early (less than 90 days), mid- (90-150 days) and late (more than 150 days) lactation periods were 13, 20.7 and 14.2%, respectively. Reaching estrus during the warm period decreased the likelihood of double ovulation by a factor of 0.86; the risk of double ovulation was lower in cows with higher milk production (a 1 kg increase in milk yield led to a 0.97-fold reduced risk of double ovulation); cows in their second and in their third or more lactations showed a likelihood of double ovulation (using the first lactation as reference) increased by factors of 3.4 and 5.6, respectively; and reaching estrus during the early and late lactation period was related to a decreased probability of double ovulation (using the mid-lactation period as reference) by factors of 0.56 and 0.84, respectively. No significant effects of synchronization and service number on the double ovulation rate were found. Pregnancy was recorded in 914/1792 (51%) services: rates of 53.5% (811/1515) were recorded for single ovulations; 37.2% (103/277) for double ovulations: 28.8% (42/146) for unilateral double ovulations; 45.2% (52/115) for bilateral double ovulations; and 56.3% (9/16) for triple ovulations. The likelihood of pregnancy diminished in cows: inseminated during the warm period (by a factor of 0.5); inseminated by one particular bull (by a factor of 0.33); with higher milk production (a 1 kg increase in milk yield decreased the probability of pregnancy by a factor of 0.98); or undergoing unilateral (by a factor of 0.31) and bilateral (by a factor of 0.64) double ovulation. Logistic regression analysis indicated no significant effects of synchronization, days in milk, lactation number and service number on pregnancy rate. Collectively, our results indicate that cows showing estrus in conditions of heat stress had a high risk of ovulation failure. The effect of milk production on double ovulation was negative, whereas lactation number was positively correlated with this factor; the highest incidence of double ovulation occurring during the mid-lactation period.

Animals↗

PubMed1988

Splenocyte natural killer cell activity and metastatic potential are inversely dependent on estrous stage.

We have previously shown that the timing of surgical removal of an estrogen-receptor-bearing mammary adenocarcinoma within the estrous cycle of the female C3HeB/FeJ mouse profoundly influences the frequency of subsequent tumor cell metastasis. In order to investigate the role of the immune response in this phenomenon, we measured splenic natural killer (NK) cell activity and interleukin-2 (IL-2) production in 80 female cycling mice, 16 to 18 weeks old, assigned to one of four estrous stages as determined by relative quantity of vaginal cellularity; proestrus, estrus, metestrus, and diestrus. After prolonged synchronization on 12-hours-on, 12-hours-off light-dark circadian schedules, daily vaginal smears were obtained for 2 weeks to characterize estrous cycling. On the day the animals were killed, vaginal smears were performed and single-cell suspensions were prepared from the harvested spleens. Direct cytotoxicity of spleen cells against the YAC tumor target was assessed immediately in a 3 1/2 hour 51Cr release assay and expressed as NK activity in lytic units (LU 20%). IL-2 production was determined in a bioassay with the IL-2-dependent CTLL-2 cell line. Significant differences in NK activity among estrous stages mimicking the variation found in frequency of surgical cure from mammary adenocarcinoma were observed (p = 0.035; one-way analysis of variance), with the time of lowest metastatic potential corresponding precisely with the time of highest splenocyte NK activity. These both occurred during the proestrus and estrus stages, characterized by high fertility, ovulation, and peak FSH, LH, and estrogen concentrations. In addition, NK activity was found to correlate significantly with IL-2 production (r = 0.4, p less than 0.0005). These results indicate that important components of the cellular immune response to cancer vary rhythmically with hormonal changes in the host and may represent one of the factors affecting the delicate balance between host and tumor that alters the frequency of postsurgical metastatic dissemination.

Animals↗

PubMed1985

Insemination management for a one-injection prostaglandin F(2)alpha synchronization regimen. I. One daily insemination period versus use of the a.m./p.m. rule.

Following detection of estrus in a one-injection prostaglandin F(2)alpha (PGF(2)alpha) synchronization regimen, 261 dairy heifers were randomly inseminated (A.I.) either once between 0800 and 0900 h daily (a.m.) or about 12 h after detection of estrus (a.m./p.m.). During the regimen, 31.8 and 33.3% for the a.m./p.m. and a.m. groups, respectively showed estrus and received A.I. during the pre-PGF(2)alpha period. The remaining heifers were injected with PGF(2)alpha with 95.6% from a.m./p.m. and 96.5% from a.m. showing estrus and receiving A.I. within five days after PGF(2)alpha. Pregnancy rates of 62.9% for a.m./p.m. and 62.0% for a.m. did not differ. Progesterone at the time of injection was similar between groups and was not correlated with either response to PGF(2)alpha or fertility. Percentages of heifers in estrus <24, 25-48, 49-72, 73-96 and >96 after PGF(2)alpha were 4.7, 30.2, 45.6, 14.3 and 5.3, respectively, with a mean time of 61.0+/-1.9 h. Satisfactory conception rate was attained with a.m. insemination.

Journal Article↗

PubMed1990

Necrotic oophoritis in heifers vaccinated intravenously with infectious bovine rhinotracheitis virus vaccine during estrus.

Twenty-two Hereford heifers were injected IM with prostaglandin F2 alpha a, 11 days apart to synchronize estrous cycles. Twelve of 14 heifers that had signs of estrus were inoculated IV with 1 of 3 modified-live infectious bovine rhinotracheitis virus vaccines, and 2 were assigned to a nonvaccinated control group. Also, 6 of the 8 anestrous heifers were inoculated IV with 1 of the 3 vaccines on the fourth day after the last prostaglandin injection and the other 2 were assigned to the nonvaccinated group. Vaccine virus was isolated from the blood and nasal and vaginal secretions from the vaccinated heifers on postvaccination days 4, 7, and 9. On postvaccination day 9, all heifers were ovariectomized and ovarian tissues were processed for virus isolation and histologic examination. Vaccine virus was isolation and histologic examination. Vaccine virus was isolated from ovarian tissues of some heifers in each of the vaccine groups. Necrotic oophoritis characterized by multifocal areas of ovarian tissue necrosis, hemorrhage, and mononuclear lymphocytic infiltration was observed. The corpora lutea and surrounding ovarian tissues taken from vaccinated heifers in each group had varying amounts of necrotic and inflammatory change, but the changes appeared to be more severe in 1 group than in the other 2. Virus also was isolated from 2 of the controls; these heifers apparently became infected with vaccine virus that had been excreted from the vaccinated animals.

Animals↗

PubMed2003

Birth of piglets after deep intrauterine insemination with flow cytometrically sorted boar spermatozoa.

The present study was carried out to determine the pregnancy rates, farrowing rates and litter size in sows with either induced or spontaneous ovulation inseminated with flow cytometric sorted spermatozoa using deep intrauterine insemination technology. Spermatozoa were stained with Hoechst 33342 and sorted by flow cytometry/cell sorting but not separated into separate X and Y populations. In Experiment 1, sows (n=200) were weaned and treated for estrus/ovulation induction with eCG/hCG. Inseminations with either sorted (70 or 140 million) or non-sorted (70 or 140 million) spermatozoa were done using a specially designed flexible catheter. Farrowing rates were 39.1 and 78.7% for 70 million of sorted and non-sorted, respectively, and 46.6 and 85.7% for 140 million of sorted and non-sorted, respectively (P<0.05). The litter size in sows inseminated with sorted spermatozoa showed a tendency to be lower than when non-sorted spermatozoa were inseminated. In Experiment 2, sows (n=140) were inseminated as in Experiment 1 except that natural estrus was used. The ovaries of these sows were evaluated by transrectal ultrasonography. Farrowing rates were 25 and 77.2% for 70 million of sorted and non-sorted, respectively, and 32 and 80.9% for 140 million of sorted and non-sorted, respectively (P<0.05). These results show that the Deep Intrauterine Insemination technology can be successfully used to produce piglets from sorted spermatozoa when sows are hormonally treated to induce synchronous post weaning oestrus and ovulation.

Animals↗

PubMed2004

Expression of the bovine aromatase cytochrome P450 gene (Cyp19) is primarily regulated by promoter 2 in bovine follicles and by promoter 1.1 in corpora lutea.

Follicular development and differentiation are closely associated with increasing steroidogenesis. During the present study transcript concentration of Cyp19, Cyp11A1, and 3beta-hydroxysteroid dehydrogenase delta (3beta-HSD) encoding the steroidogenic enzymes P450(arom), P450(SCC), and 3beta-HSD were determined by real-time PCR in bovine granulosa cells (GC) as potential markers for follicular differentiation. Ovaries were collected from a local abattoir (experiment 1) and from synchronized animals at day 4 of estrus cycle (experiment 2). To study effects of luteinization, steroidogenic transcripts were also quantified in corpora lutea (CL) 4 and 20 days after fertilization. In most follicles, all three steroidogenic transcripts were detected, however, at very different concentration. Expression of 3beta-HSD and Cyp11A1 was highly significantly co-regulated and showed a significant correlation with follicular size. Contrary, Cyp19 expression was extremely variable even in follicles of similar size. Cyp19 transcripts were derived predominantly from promoter P2 and less abundant from promoters P1.1 and P1.5. After luteinization, the concentration of 3beta-HSD and Cyp11A1 transcripts increased (75-fold and fivefold, respectively) whereas the Cyp19 transcript level dropped (160-fold). Residual Cyp19 transcripts in CL were almost exclusively derived from P1.1. The data indicate that Cyp19 expression in GC is predominantly regulated by P2 and to a minor extend by P1.1, whereas P1.1 is almost exclusively responsible for residual Cyp19 expression in CL. Correlation analyses suggest that the expression of 3beta-HSD and Cyp11A1 primarily depend on the size of follicles whereas the concentration of P2 derived Cyp19 transcripts in GC is a marker for follicular differentiation towards selection and dominance.

Animals↗

PubMed2025

Manipulating seasonality by using PMSG and Kisspeptin hormones and the impact of the MTNR1A gene on reproduction efficiency in ewes.

BACKGROUND: One of the most important problems in sheep is seasonal anestrus, which limits the reproductive efficiency of the sheep. Estrous synchronization is considered the first plan for reproductive performance in sheep due to the pregnancy time is limited, and parturition as well as an increase in twining and reached good genetic characteristics. AIM: This study aimed to manipulate seasonality that limits fertility in ewes by induction estrus during seasonal anestrous in sheep by using Pregnant Mare Serum Gonadotropin (PMSG), Kisspeptin hormone, and study the impact of MTNR1A gene on reproduction efficiency in ewes. METHODS: This study examined 36 Awassi ewes divided into two groups, each containing 18 ewes, 2-3 years old, and two fertile rams aged 3-4 years and weighing 60-65 kg. All non-pregnant ewes were synchronized using vaginal sponges (60 mg Medroxy Progesterone acetate) for 10 days. The injection of treatment when sponges are draws. The first group (G1) received 500 IU of PMSG injection, and the second group (G2) injection a Kisspeptin hormone 5 μg/kg B.W. RESULTS: The results showed the G1 treated by PMSG 500IU were higher significantly (p ≤ 0.05) of estrus response, induction estrus and pregnancy (89%, 89%, and 89%), respectively, comparative with G2 treated by (Kisspeptin 5 mg/kg) were (72%, 72%, and 66%), respectively, and non-significant changes in estrus were observed in all groups. The average peripheral progesterone concentration significantly increased from day 0 to 5th month in G1 comparative with G2 in pregnant ewes. Serum progesterone levels were significantly p < 0.05 during of 4th month in G1 treatment by (PMSG 500IU) compared with day 0 and all other months during pregnancy of ewes. The average days to lambing in genotypes CT and TT (150 ± 2.5 and 152 ± 3.5 days), respectively, were significant comparative with CC genotype; however, the litter size and lambing rate observed in the enrolled ewes were non-significant in all genotypes. CC, CT, and TT represent three possible genotypes at a specific location (locus) in the genome, often referring to a single nucleotide polymorphism (SNP). These genotypes indicate the combination of alleles an individual inherits from their parents for a particular gene. They refer to the presence of two alleles for a particular nitrogenous base: C and T are nitrogenous bases: C = Cytosine and T = Thymine. CONCLUSION: In conclusion, the application of PMSG and Kisspeptin was effective in achievement good higher significantly of reproduction efficiency in this study. The genotypes CT and TT of the MTNR1A gene polymorphism were connected with a short significant of days to lambing in genotypes.

Animals↗