Day Of Estrus Research Articles

OR08-3 The Role Of Neuronal Plasticity In The Timing Of Puberty Onset: Insights From A Mkrn3 Deficient Mouse Model.

Makorin ring finger protein 3 (MKRN3) was identified as a regulator of puberty initiation with the report of loss-of-function mutations in association with central precocious puberty (CPP). MKRN3 is a maternally imprinted gene located on chromosome 15q11.2 in humans. In juvenile mice, Mkrn3 is highly expressed in the preoptic area and the arcuate nucleus of the hypothalamus, with a decrease in expression before puberty initiation. Together, these findings suggest an inhibitory role of MKRN3 on GnRH secretion during the prepubertal quiescent period. MKRN3 contains a RING finger motif and several zinc finger motifs, suggesting E3 ubiquitin ligase and RNA binding activities, respectively. To date, the mechanisms of action of MKRN3 in puberty initiation remain unknown. In this study, we used a Mkrn3 deficient mouse model to identify hypothalamic targets of MKRN3’s inhibitory effects. By Western blot and immunohistochemistry, we confirmed that Mkrn3 protein was undetectable in Mkrn3+/- mice (which inherited the mutant allele from their father), but present in wildtype (Mkrn3+/+) mice. Mkrn3 deletion was associated with accelerated puberty onset in female mice and a trend towards early puberty onset in male mice, as shown by an advanced day of female first estrus and a trend towards earlier age of male preputial separation in Mkrn3 deficient (Mkrn3+/-) compared to Mkrn3+/+animals. Hypothalamic mRNA levels of Gnrh1, Kiss1, Tac2 and Tac1, regulators of pubertal initiation, were measured by RT-qPCR in females at different ages across postnatal development (postnatal day (PND)10, PND15, PND20 and PND25). No significant difference was found in Gnrh1 and Kiss1 expression in the preoptic area, nor in Kiss1, Tac2 and Tac1 expression in the arcuate nucleus, between Mkrn3+/+ and Mkrn3+/- mice, at any of the postnatal day ages tested. Thus, to further investigate possible targets of MKRN3 action using an unbiased approach, we compared the transcriptome (via RNA-sequencing) and proteome (via Tandem Mass Tagging (TMT) method) of the arcuate nucleus of Mkrn3+/+ and Mkrn3+/- female mice at PND15. These analyses revealed differences in gene or protein expression between Mkrn3+/+ and Mkrn3+/- animals in factors involved in extracellular matrix organization, cell adhesion, and axon guidance pathways, which together control neuronal development and synaptic plasticity. These findings suggest that Mkrn3 may be important as a postnatal/prepubertal regulator of hypothalamic neuronal plasticity in mice. In humans, puberty has been shown to be a critical time window of neuronal plasticity. Thus, understanding the involvement of MKRN3 in these processes will provide new insights into pubertal disorders such as CPP and delayed puberty, and may lead to the development of new treatment strategies.

Change of daily milk yield during estrous period in Holstein cattle raised under Mediterranean climate.

This study was conducted to determine the effect of estrus on the daily milk yield in Holstein cows and to investigate the chance of using the possible milk yield changes in determining the estrus. During the 3-year period of the study, 103 dairy cows were observed 4days before and 4days after daily milk yield of 240 estruses and a total of 2174 daily milk yields were evaluated. Variance analysis was used to determine the factors affecting the daily milk yield, and the LSD test was used for multiple comparisons. Insemination year, insemination season, number of lactation, milk yield group, and daily milk yield of lactation period were found to be significant (P < 0.01). On the other hand, the effect of estrus days on milk yield was insignificant. In the days of estrus, the least square mean of milk yield is 31.0kg, while the lowest and highest milk yields are 10.2kg and 62.9kg. The daily milk yield in the estruses decreased by an average of 300g, which decreased to 400g by continuing 1day after the estruses. The next day, however, it increased rapidly by 600g, and then dropped again, probably due to the effect of metestrus. It was found that, among all estruses, 31.3% of cows decreased their milk yield, whereas 26.5% of cows increased their milk yield. However, 42.2% of cows both decreased and increased their milk yield in different estruses. The interval between birth and the first insemination after were found to be longer (97.5days and 92.9days) at high milk-yielding cows compared to the low milk-yielding cows. According to the results of this study, daily milk yield changes could not be used as an estrus indicator.

Peri-estrus activity and rumination time and its application to estrus prediction: Evidence from dairy herds under organic grazing and low-input conventional production

The objective of this research was to investigate the peri‑estrus changes in activity and rumination time and their use for estrus prediction using data collected by a collar-mounted accelerometer and rumination system (SCR Engineers Ltd., Netanya, Israel). Two experimental dairy herds (low-input conventional: CONV and organic: ORG) of the University of Minnesota West Central Research and Outreach Center, Morris, MN were monitored during the period from June, 2014 to August, 2017. The herds were seasonally bred, and the study comprised three summer breeding seasons (SUM: June to August) and four winter breeding seasons (WIN: December to February). In the winter, both herds were kept in an outwintering lot or a compost-bedded pack barn. In the summer the CONV herd was housed in a dry-lot, and the ORG herd on pasture. The breeding records of 1462 estrus events (849 CONV and 613 ORG) were used as estrus dates. When the day of estrus (day 0) was compared to the reference-period (day -3, -2, -1, +1, +2, +3, relative to the reference period), increased daily activity was observed for 96% of the estrus events (97% for CONV-SUM, 97% for CONV-WIN, 91% for ORG-SUM, and 95% for ORG-WIN), and a decreased daily rumination was observed for 82% of the estrus events (81% for CONV-SUM, 88% for CONV-WIN, 73% for ORG-SUM, and 86% for ORG-WIN). A logistic regression model was developed based on the deviation from a 7-day moving average, 7-day moving standard deviation, and the daily absolute maximum of 6-h-window cumulative change of the data. A successful threshold of alerting estrus (predicted probability > 0.70) was possible when sensitivity and specificity (%) of the model were 75 and 96 for CONV-SUM, 91 and 99 for CONV-WIN, 51 and 92 for ORG-SUM, and 80 and 99 for ORG-WIN. At a lower threshold (predicted probability > 0.30), the sensitivity and specificity (%) were 89 and 81 for CONV-SUM, 97 and 90 for CONV-WIN, 79 and 75 for ORG-SUM, and 90 and 90 for ORG-WIN. A range of trade-offs between sensitivity and specificity was characterized by receiver operating characteristic curves. Additionally, incorporating rumination time data to activity data alone did not improve the prediction performance substantially. In sum, this technology can help detect peri‑estrus changes and there is potential for optimizing prediction performance through improving prediction algorithms or refining alert thresholds.

Inferior fertility and higher concentrations of anti-Müllerian hormone in dairy cows with longer anogenital distance

Anogenital distance (AGD), which is an indicator of prenatal androgen exposure, has been reported to have high variability and negative association with fertility in dairy cows. Prenatal exposure to androgens could influence the development of primordial follicles and size of ovarian reserve, which is related to reproduction. However, the relationship between AGD and size of ovarian reserve has not been studied. Therefore, the present study was conducted to determine the association between AGD and circulating anti-Müllerian hormone (AMH), as an indirect marker of ovarian reserve, and to evaluate serum AMH concentration and reproductive performance in dairy cows with short and long AGD. Anogenital distance was measured 28 to 32 d postpartum, and based on the median of AGD, cows were divided into 2 subsets including short (n = 43) and long (n = 43) AGD groups. Afterward, serum AMH was evaluated on the day of estrus in cows that were estrus-synchronized. Furthermore, reproductive data of dairy cows during the previous lactation period were collected from the herd database. Concentrations of serum AMH tended to be positively associated with length of AGD, and there was a tendency for higher serum AMH concentrations in the long (634.89 ± 74.52 pg/mL) than short (451.39 ± 45.92 pg/mL) AGD group (0.05 <P ≤ 0.10). There was a tendency for more days to first service, lower first service conception rate, and higher proportion of repeat breeders in long (99.95 ± 5.34 d, 30.23% and 32.56%, respectively) than short (89.07 ± 4.97 d, 48.84% and 16.28%, respectively) AGD cows (0.05 <P ≤ 0.10). Services per conception did not differ between short (2.30 ± 0.27) and long (2.93 ± 0.29) AGD cows (P > 0.05). Calving to conception interval was prolonged in long (194.30 ± 17.12 d) than short (147.14 ± 13.11 d) AGD cows (P ≤ 0.05). In conclusion, the present study revealed elevated serum AMH concentrations and poor reproductive performance in cows with longer AGD compared with cows with shorter AGD.

Follicular dynamics and colour Doppler vascularity evaluations of follicles and corpus luteum in relation to plasma progesterone during the oestrous cycle of Surti buffaloes.

With an objective to evaluate the follicular dynamics and vascularity changes in follicles and corpus luteum, the ovaries of cyclic Surti buffaloes (n=9) were examined daily sequentially by transrectal B-mode and colour flow mode (CFM) ultrasonography starting from the day of oestrus till the onset of next oestrus. Higher proportion of buffaloes evidenced one-wave cycle (66.66%) compared to two-wave cycle (33.34%) with none showing a three-wave cycle. The dominant follicle of the first follicular wave was the ovulatory follicle and persisted for 19.70±0.50days compared to its persistence for 16.5±1.45days in a two-wave cycle. The maximum diameter of the ovulatory follicle in a one-wave and two-wave cycle did not differ yet their linear growth rates were significantly lower (p<0.01) in a one-wave cycle. Colour flow mode examination of follicles revealed that the percentage of follicles with detectable blood flow in the subsequently determined largest follicle (dominant follicle) was not different from that in the second largest follicle before follicle deviation. The blood flow in the dominant follicle increased significantly on the day of oestrus. The mean diameter and blood flow to the corpus luteum (CL) increased linearly and significantly from Day 5 of oestrus till Day 13 after which both parameters started declining. At or around Day 16, there was precipitous fall in the blood supply to the CL and CL diameter that continued declining thereafter to reach the lowest around Day 20 of the oestrous cycle. Rise in plasma progesterone concentrations was synchronous to CL diameter and vascularity and showed significant and positive correlations. It was concluded that Surti buffaloes evidence a preponderance of one-wave follicular growth pattern with a significant increase in the vascularity of ovulatory follicle on the day of oestrus and corpus luteum on Day 13 of the oestrous cycle.

Automated estrous detection using multiple commercial precision dairy monitoring technologies in synchronized dairy cows

Estrus in dairy cattle varies in duration and intensity, highlighting the need for accurate and continuous monitoring to determine optimal breeding time. The objective of this study was to evaluate precision dairy monitoring technologies (PDMT) for detecting estrus. Estrus was synchronized in lactating Holstein cows (n = 109) using a modified G7G-Ovsynch protocol (last GnRH injection withheld to permit expression of estrus) beginning at 45 to 85 d in milk. Resumption of ovarian cyclicity at enrollment was verified by transrectal ultrasonography for presence of a corpus luteum. Cows were observed visually during 30 min (4 times per day) for behavioral estrus on d -1 to 2 (d 0 = day of estrus). Periods peri-estrus were defined by the temporal blood plasma progesterone patterns on d -5, -4, -3, -2, -1, 0, 2, 4, 6, and 8. Estrous detection by PDMT, an estrous behavior scoring system, and by visual observation of standing estrus were compared with the reference (gold) standard. Only 56% of cows that ovulated were observed standing by visual observation. Sensitivity and specificity for estrous detection were not different among all PDMT. Devices in this study measuring activity in steps, neck movement, high activity of head movement, or a proprietary motion index increased on the day of estrus 69 to 170% from the baseline before estrus. The change in rumination time on the day of estrus decreased for both neck and ear-based technologies (-2 to -16%). Temperature of the reticulorumen, vagina, and ear skin were not different on the day of estrus than day peri-estrus. Daily lying times decreased on average to 24.6% on the day of estrus for IceQube (IceRobotics Ltd., Edinburgh, Scotland). In contrast, lying time increased 15.5 and 33.1% for AfiAct Pedometer Plus (Afimilk, Kibbutz Afikim, Israel) and Track a Cow (ENGS Systems Innovative Dairy Solutions, Rosh Pina, Israel), respectively. All PDMT tested were capable of detecting estrus at least as effectively as visual observation. Four of the 6 PDMT that reported estrous alerts correctly detected 15 to 35% more cows than visual observation 4 times per day. Use of temporal progesterone patterns correctly identified more cows than visual observation alone. Dairy producers considering PDMT should focus on (1) the reference (gold) standard used to test efficacy of a device's alerts and (2) the device that will have the fewest false readings in their operations.

Changes in anti-Müllerian hormone concentrations in bitches throughout the oestrous cycle

Studies in female dogs proved the measurement of anti-Müllerian hormone (AMH) as a diagnostic tool to distinguish ovarioectomized from intact females or to diagnose ovarian remnant syndrome. Furthermore, its usability to diagnose a granulosa cell tumour and predict litter size was also investigated in female dogs. Although serum AMH was previously shown to increase during the transition from anoestrus to pro-oestrus in dogs, changes in AMH concentration over the entire oestrous cycle have not yet been determined. The aim of this study was to investigate the secretion pattern of AMH throughout the oestrous cycle in non-pregnant bitches. As a preliminary step, we tested our assay by measuring AMH concentrations in serum samples of 19 intact bitches (10 in anoestrus, 3 in pro-oestrus, 3 in oestrus, 3 in metoestrus) and 19 spayed females of different age and breed. For the main study, 20 healthy female dogs were examined (10 Beagles, and 10 Labrador crossbreeds, body weight 10–28 kg, age 1–6 years) during a normal oestrous cycle. Serum samples were collected in late anoestrus, at several times during pro-oestrus and oestrus, as well as 28 days and 4.5 months after ovulation. Blood collection was combined with a gynaecological examination including progesterone measurement. Serum concentration of AMH was determined using a chemiluminescence immunoassay validated for dog serum. In the preliminary test, intact bitches in various stages of the oestrous cycle had significantly higher serum AMH levels (0.19–1.45 ng/ml) than spayed females (0.01–0.06 ng/ml, P < 0.001). In cycling Beagle and Labrador crossbreed bitches participating in our main study, AMH concentrations were between 0.09 and 2.65 ng/ml with higher AMH concentrations in Beagles but overall high inter-individual and intra-individual variation. The highest AMH values were reached in the last three weeks before the onset of heat until six days before ovulation, and the lowest AMH concentrations were recorded during preovulatory oestrus in 6, metoestrus in 7 or anoestrus in 7 dogs. Serum AMH concentrations increased significantly from late anoestrus up to six days before ovulation and decreased significantly over the last three days before ovulation. A further significant decrease occurred from the last days of oestrus to metoestrus and mid anoestrus. This study shows that the used AMH assay can clearly distinguish between intact and spayed females and that the serum AMH pattern over the oestrous cycle is similar in all bitches, but with high variation among the breeds and among and within bitches. These changes in the AMH concentration are a challenge in timing serum sample collection and interpreting AMH values in bitches. Further studies are necessary to emphasize the factors influencing the AMH concentration.

Fatty acid profile of milk for determining reproductive status in lactating Holstein Friesian cows

Large percentages of dairy cows do not express behavioural signs of oestrus. Faecal and urine fatty acid concentrations increase during oestrus. The objective of the present study was to determine the milk FA profile of dairy cows during the oestrous and dioestrous periods and the relationship with behavioural signs on the day of oestrus. The activity of 32 Holstein Friesian cows was measured continuously using GEA Rescounter ll pedometers (GEA Farm Technologies, Düsseldorf, Germany) and IceQubes (IceRobotics Ltd., Edinburgh, UK). Milk samples were collected on the day of oestrus and on day 14 of the subsequent oestrous cycle and analysed for FA concentration using gas chromatography (GC) and milk composition was also determined. All cows were artificially inseminated within 12 h of the onset of oestrus. On the day of oestrus, the concentration of acetic acid (P < 0.001), valeric acid (P = 0.016), caproic acid (P < 0.001) and myristoleic (P = 0.035) were greater in milk compared to day 14. On day 14 milk arachidonic acid concentration, however, was greater (P = 0.004) compared to the day of oestrus. Also, on day 14 arachidonic acid concentration was greater (P = 0.002) in non-pregnant compared to pregnant cows. In conclusion, the results of this study indicate there are changes in the concentrations of some milk FA during oestrus and dioestrus in lactating dairy cows.

The mRNA and lncRNA landscape of the non-pregnant endometrium during the oestrus cycle in dairy goat

Cyclic changes in the endometrium are essential for embryo implantation in mammals; many studies report that such changes constitute a complex process involving numerous molecular mediators. In the present study, goat endometria at oestrus Day 5 and oestrus Day 15 were selected to systematically analyse the transcriptome using strand-specific Ribo-Zero RNA sequencing. Over 120 million high-quality paired-end reads were generated and 440400 transcripts were identified in the endometrial tissue of dairy goats. In total, 489 differentially expressed mRNAs and 854 differentially expressed long non-coding RNAs were identified when comparing the endometrium at goat endometria at oestrus Day 5 and oestrus Day 15. Neurotensin was found to play a potentially important role in the non-pregnant goat endometrium during the oestrus cycle. Furthermore, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses of the cis-target genes of the differentially expressed long non-coding RNAs showed that GO:0005198 (structural molecule activity) and ko04510 (focal adhesion) might be involved in cyclic endometrial changes. Taken together, the resulting transcriptomic profiles elucidate global trends in mRNA and lncRNA expression in non-pregnant endometria during the oestrus cycle in dairy goats.

Oestrous cycle of Wistar rats altered by sterol and triterpenes rich fraction of Adansonia digitata (Linn) root bark - A scientific rationale for contraceptive use

Objective: To investigate the effect of different fractions from the aqueous methanolic root bark of Adansonia digitata (Linn) on the estrous cycle of female Wistar rats and to elucidate their phytochemical content.Methods: Crude aqueous methanol extract of Adansonia digitata (Linn) root bark was fractionated by column chromatography using various ratios of hexane, acetyl acetate, methanol and distilled water. Fractions with similar trails on a thin layer chromatography were pooled into four fractions. Each fraction was then screened for its phytochemical content. Forty mature Wistar female rats weighing (135±28) g with regular estrous cycles were given each fraction at two dose levels while a control group received distilled water of equal volume. Treatments were given per os for 15 days starting from the day of estrus. Vaginal smears were observed daily for the duration of each cycle, frequency of occurrence of each stage of the estrous cycle and number of cycles for 15 days before and during treatment. At the end of treatment, rats were humanely sacrificed. Ovaries and uteri were weighed and processed for histopathology.Results: Hexane acetyl acetate and acetyl acetate methanol fractions at 150 mg/kg body weight and 300 mg/kg body weight prolonged the occurrence of proestrus and diestrus and produced atretic cyst-like ovaries at 300 mg/kg body weight. Acetyl acetate methanol treated rats also had low relative ovarian weights when compared to the control.Conclusions: Sterols and triterpenes in hexane acetyl acetate and acetyl acetate methanol fractions of the root bark may be responsible for the disruption of estrous cycle in female Wistar rats and may have a contraceptive effect.

Ovarian follicular changes and hemodynamics in Egyptian buffaloes under CIDR-PGF2α and Ovsynch-CIDR estrus synchronization treatments

This study aimed at investigating the efficacy of two protocols of estrous synchronization on follicular changes and hemodynamics. Pluriparous Egyptian buffaloes (n = 36) were synchronized either with controlled internal drug release (CIDR)-PGF2α (7-days CIDR insert with PGF2α injected on the 6th day; n = 18) or Ovsynch-CIDR (Ovsynch protocol concurrent with 7-days CIDR insert; n = 18). Blood sampling and ovarian ultrasound examinations (Grayscale, color and power Doppler modes) were conducted on the Day of CIDR removal, estrus, and luteal phase. Mean follicle diameter (MFD), first (1st-LF) and second (2nd-LF) largest follicle diameters, and E2 levels significantly increased in the CIDR-PGF2α group at CIDR withdrawal. Ovsynch-CIDR markedly fortified higher follicle population, MFD, and 1st-LF diameter at estrus and corpus luteum (CL) volume at the luteal phase in concomitant with increases (P < 0.05) in E2 (at estrus) and P4 (at luteal phase). At CIDR removal, the blue pixels in the dominant follicle (DF) were higher (1.5 times; P = 0.054) in the Ovsynch-CIDR than in the CIDR-PGF2α. At estrus, total blood flow (TBF) and power Doppler pixels (PDP) to DF(s) were noticeably higher (seven and 1.6 times; respectively) in the Ovsynch-CIDR than in CIDR-PGF2α (5906 ± 237 vs. 830 ± 60 pixels, P < 0.01 and 5479 ± 322 vs. 3377 ± 19 pixels, P < 0.05; respectively). At the luteal phase, TBF and PDP to the CL increased in the Ovsynch-CIDR group than in the CIDR-PGF2α group (11060 ± 965 vs. 7963 ± 480 pixels, 1.4 times, P = 0.05 and 18900 ± 1350 vs. 13220 ± 568 pixels, 1.1 times, P = 0.005; respectively). In conclusion, based on the improvement in synchronized follicular activity and hemodynamics, the Ovsynch-CIDR regimen is persuaded in Egyptian buffaloes.

Reproductive performance of fixed-time artificial insemination in swine and factors for the technology success

ABSTRACT: Fixed-time artificial insemination (FTAI) is a reproductive technology that aids in obtaining an appropriate time to perform single artificial insemination (AI), thus reducing the number of inseminations per sow bred. FTAI protocols can either be based on estrus detection or day of weaning, aiming to synchronize ovulation using ovulation inducers. The protocols involving estrus detection usually employ porcine luteinizing hormone (pLH) as an inducer and, in general, satisfactory reproductive performance is observed. For protocols based on weaning day, the main hormone used is analog of gonadotropin-releasing hormone such as triptorelin and buserelin. Regardless of the protocol, the number of piglets born is usually not affected by FTAI. However, a possible compromise in the farrowing rate should be considered. The FTAI in gilts requires progestogen treatment for estrus synchronization, increasing the labor requirement and cost of protocol. Some of the benefits of FTAI are a reduced number of semen doses required, advantage of planning the breeding time and; consequently, optimizing labor involved. However, the limitations include a slight reduction in the fertility index due to the compromised farrowing rate in some cases, costs incurred by following the protocol, and difficulty in measuring all the conceptual benefits under commercial conditions. The aim of this review is to approach the reproductive performance of the current protocols of FTAI, considering the benefits and limitations of this technology in swine production.

Serum Progesterone, Oestradiol-17β, FSH and LH levels in Anestrus Surti buffaloes treated with Ovsynch alone and in combination with PRID

This study was carried out on 18 postpartum anestrus Surti buffaloes, divided into three equal groups (6 in each) to evaluate the serum progesterone, oestradiol-17β, FSH and LH concentrations (by ELISA) before, during and after Ovsynch and Ovsynch + PRID protocols. Six anestrus buffaloes each were treated with standard Ovsynch protocol (T1) and Ovsynch along with PRID (Progesterone releasing intravaginal device) protocol (T2) with fixed-time AI (FTAI). Six anestrus buffaloes were kept as untreated control (T3). Blood samples were obtained from the animals on day 0 (before treatment), day 4 (during treatment), day 8 (after PGF2α injection), day of induced estrus/FTAI and day 18 post-AI (after treatment). The mean serum progesterone level on day 4 was significantly (p less than 0.01) higher in the T2 group as compared to T1 and T3 groups, while the level on day 8 was significantly (p less than 0.01) higher in both the treatment groups (T1 and T2) as compared to control group, however there was no significant difference (p&gt;0.05) on the day of estrus between three groups. The mean serum oestradiol-17β and follicle stimulating hormone (FSH) levels on 8th day were significantly higher (p less than 0.01) in both the treatment groups (T1 and T2) as compared to control group (T3). However, there was no significant difference on day 0, 4, day of estrus and day 18 post-AI between groups. The mean serum luteinizing hormone (LH) levels of acyclic buffaloes were not found significantly different (p&gt;0.05) among days in any of the treatment and control groups. But the mean LH concentration on the day of estrus in the T1, T2 and T3 was significantly higher (p less than 0.01) and thereafter decreased markedly on 18th day post-AI in all the groups. The conception rates at FTAI/first estrus in three groups were 66.66%, 50.00% and 75.00%, respectively.

88 Evaluation of embryo transfer results using embryos cryopreserved in ethylene glycol for 8 years or in glycerol for 30 years

Various permeating cryoprotectants, such as glycerol and ethylene glycol, have been used in the cryopreservation of embryos to help maintain cellular viability during indefinite and prolonged periods of storage in liquid nitrogen. The objective of this study was to compare the efficiency of glycerol (G) and ethylene glycol (EG) after storage in liquid nitrogen for a considerable period of time before transfer. The work was carried out in Palenque, Chiapas, Mexico. A total of 50 embryos were transferred, 24 Brahman (G) cryopreserved in the 1990s and 26 Brangus (EG) cryopreserved in 2010. Synchronous recipients were selected based on 3 characteristics: body condition (5-7, scale of 1-9), reproductive health, and multiparity. Recipient cows (n=62) were synchronized using a FTET protocol as follows. On Day 0, cows received a progesterone intravaginal device (CIDR) and 2mg of oestradiol benzoate IM. On day 8, the CIDR was removed and all cows received 25mg of dinoprost tromethamine (Lutalyse, Pfizer Animal Health, Montreal, Quebec, Canada), 200IU of eCG, and 0.5mg oestradiol cipionate IM. Day 10 was considered the day of oestrus and embryos were transferred (n=50) to the ipsilateral uterine horn of those recipients with a corpus luteum greater than 1.5cm in diameter on Day 17. The G embryos were produced with 4 bulls whereas the EG embryos were produced with 6 different bulls. The G straws were thawed for 12s in the air plus 12s in 20°C water. Embryos were immersed for 8min in a thawing solution containing 1.0M sucrose (ViGRO One-Step) and then transferred to holding medium (ViGRO Holding) for rehydration before loading into straws for embryo transfer. The EG embryos were thawed by allowing the straws to stand in air for 10s and then immersing them in a 30°C water bath for 10s and were transferred immediately. Pregnancy diagnosis 35 days after the transfer revealed 19 pregnancies of 50 embryos transferred (38%), distributed as 46% embryos in EG (12 pregnant of 26 transferred) and 29% embryos in G (7 pregnant of 24). A Fisher’s exact test was performed showing that no significant difference existed between groups (P&amp;gt;0.05). There was no effect of bull on pregnancy rates, and Brahman breed results by individual bull were 5 pregnancies of 13 (38%), 2 of 6 (33%), 0 of 4 (0%), and 0 of 1 (0%) for bulls I to IV, respectively. Pregnancy rate by Brangus bulls were 6 pregnancies of 7 (86%), 2 of 3 (67%), 2 of 4 (50%), 2 of 4 (50%), 0 of 4 (0%), and 0 of 3 (0%) for bulls 1 to 6, respectively. It is important to remember that the embryos cryopreserved in G remained in the nitrogen tank for more than 30 years, whereas the embryos cryopreserved in EG remained stored in liquid nitrogen for less than 10 years. Although pregnancy rate was numerically lower with Brahman embryos stored in G, pregnancy rates were considered acceptable considering the length of storage. Future research is needed with greater numbers and different breeds to determine whether G or EG will consistently produce higher embryo viability and pregnancies after storage for considerable periods before transfer.

Effect of insulin or insulin-like growth factor-I administration at mid-luteal phase of the estrous cycle during superovulation on hormonal profile of Sahiwal cows.

Aim:The present study was designed to study the effect of insulin and insulin-like growth factor-1 (IGF-I) administration during luteal phase of the estrous cycle on the hormonal profile of Sahiwal embryo donor cows during superovulation.Materials and Methods:Cows (n=18) were selected and divided into three groups; control (n=6, untreated), T-I (n=6, insulin-treated), and T-II (n=6, IGF-I treated). Insulin and IGF-I were given S/C on 5th, 6th, 7th, and 8th days of estrous cycle. Superovulatory treatment was started on day 9th of the estrous cycle. With the sixth dose of follicle-stimulating hormone, prostaglandin was injected to induce superovulatory heat. The superovulated cows were bred, and superovulatory response of each animal was recorded. The embryos were collected non-surgically on the 7th day of superovulatory estrus. About 15 ml blood without anticoagulant was collected on days 5, 7, 9, 11, 13, 15, 17, 19, and 21 or day of embryo recovery where day 0 of estrous cycle was taken as day of estrus. Serum was separated, centrifuged, and transferred into sterilized serum vials. All samples were stored at −20°C till analysis. Progesterone, insulin, and IGF-I were estimated in blood serum by radioimmunoassay using radioimmunoassay kits.Results and Discussion:The mean concentration of progesterone on days 7 and 11, insulin on days 7 and 9, and IGF-I on days 5, 7, 9, 11, and 15 was significantly higher in insulin-treated T-I groups as compared to untreated control.Conclusion:It may be concluded that exogenous insulin administration during mid-luteal phase may be helpful in follicular and embryonic development through modulation of progesterone, insulin, and IGF-I in indigenous (Bos indicus) Sahiwal embryo donor cows.

Neonatal and juvenile exposure to perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS): Advance puberty onset and kisspeptin system disturbance in female rats

Perfluorooctanoate (PFOA) and perfluorooctane sulfonate (PFOS) are widespread and persistent chemicals in the environment, and limited data about their effects on puberty development are available. In order to explore the effects of neonatal and juvenile PFOA/PFOS exposure on puberty maturation, female rats were injected with PFOA or PFOS at 0.1, 1 and 10 mg/kg/day during postnatal day (PND) 1–5 or 26–30. The day of vaginal opening (VO) and first estrus were significantly advanced in 10 mg/kg PFOA, 1 and 10 mg/kg PFOS groups after neonatal and juvenile exposure. Besides, neonatal PFOA/PFOS exposure increased body weight and anogenital distance (AGD) in a non-dose-dependent manner. Estradiol and luteinizing hormone levels were also increased with more frequent occurrences of irregular estrous cycles in 0.1 and 1 mg/kg PFOA/PFOS exposure groups. Although no altered ovarian morphology was observed, follicles numbers were reduced in neonatal groups. Kiss1, Kiss1r and ERα mRNA expressions were downregulated after two periods’ exposure in the hypothalamic anteroventral periventricular (AVPV) and arcuate (ARC) nuclei. PFOA/PFOS exposure also suppressed kisspeptin fiber intensities, especially at the high dose. In conclusion, neonatal and juvenile are critical exposure periods, during which puberty maturation may be vulnerable to environmental exposure of PFOA/PFOS, and kisspeptin system plays a key role during these processes.

Peri-follicular blood flow in the follicle from which ovulation occurs in cows

The hypothesis of the study was that the vascularity of ovulatory follicles (OF) determines the ovulatory status. The peri-follicular blood flow characteristics of OF were sequentially recorded using Color Doppler Imaging ultrasonography from the onset of induced estrus (Day 0) to ovulation at 12 h intervals. The OFs were categorized into two groups based on the timing of ovulation (i) Normal ovulation (OFN) - When ovulation occurred within 36 h after the onset of estrus (n = 18) and (ii) Delayed ovulation (OFD) - When ovulation occurred after 36 h (n = 15). The blood flow velocity, Doppler pulse duration (DPD) and Pulsatility index (PI) of the OF were recorded during each examination. The OF was well vascularized with a detectable blood flow signals, while the subordinate or atretic follicles were devoid of detectable blood flow. On Day 0, the DPD (874.33 ± 56.99 ms) and PI (0.62 ± 0.01) values were less in the OFN when compared to OFD (1140.56 ± 27.54 ms and 1.28 ± 0.15 respectively) group. In the OFD group, ovulation occurred between 36 and 60 h after onset of estrus when the DPD value reduced to 878.17 ms. Based on ROC analysis, it was evident that the DPD value of < 929 ms is a necessary factor for induction of ovulation. The decreased DPD and PI values of the OF on the day of estrus are positive indicators of a normal ovulation process.

Blood Biochemical Components and Progesterone Hormone on Day of Estrus in Crossbred Cattle in Egypt

Deficiencies or excess minerals such as P, Cu, and Zn are associated with subnormal fertility and anoestrus conditions in cows. This study was conducted in a veterinary unit in Menufiya, Egypt. Eighteen head of crossbred cows were randomly selected at random at estrus time (estrus group) and as a control 14 head of crossbred cows were selected from newly-calving dams at about 6-12 hours after calving (control group). The aim of this study was to use the components of biochemistry and progesterone hormone on estrus day of crossbreeding cattle in Egypt. The information from this study will be used to confirm estrus time to improve mating percentage. In blood plasma, the concentrations of all biochemical components and progesterone concentrations in estrus animals are higher than control cows except globulin. The results showed that blood plasma from control animal obtained Mg, Ca / P ratio, Co, Cu, Zn, Se, and Mo concentration is higher than estrus cattle. On the other hand, blood plasma concentrations of Na, K, Ca, P, Mn, and Fe are higher in estrus cattle. The progesterone concentration of estrus cattle is lower during summer than in winter. In estrus cows, higher plasma macro-elements were found in winter than in summer except for K, Ca and Ca/P ratio. On the other side of estrus cattle, all trace elements of blood plasma are higher in winter than in summer except Zn, Mn, Se, and Fe.

Sphingolipid synthesis and role in uterine epithelia proliferation.

Sphingolipids are involved in the regulation of cell proliferation. It has been reported that diacylglycerol and sphingosine-1-phosphate generation, during the synthesis of phospho-sphingolipids, is necessary for both, G1-S transition of cell cycle during the sustained activation of protein kinase C in various cell models (MDCK, Saccharomyces and Entamoeba) and AKT pathway activation. During the estrous cycle of the rat, AKT signaling is the main pathway involved in the regulation of uterine cell proliferation. The aim of the present study was to investigate the role of sphingolipid synthesis during proliferation of uterine cells in the estrous cycle of the rat. On metestrus day, when both luminal and glandular uterine epithelia present the maximal BrdU-labeled cells (S phase cells), there was an increase in the relative abundance of total sphingomyelins, as compared to estrus day. Myriocin, a sphingolipid synthesis inhibitor administered on estrus day, before the new cell cycle of epithelial cells is initiated, decreased the abundance of sphingomyelin, accompanied by proliferation arrest in uterine epithelial cells on metestrus day. In order to study the sphingolipid signaling pathway affected by myriocin, we evaluated the activation of the PKC-AKT-GSK3b-Cyclin D3 pathway. We observed that total and phosphorylated protein kinase C diminished in uterine epithelial cells of myriocin treated animals. Interestingly, cyclin D3 nuclear localization was blocked by myriocin, concomitantly with a decrease in nuclear pRb expression. In conclusion, we demonstrate that sphingolipid synthesis and signaling are involved in uterine epithelial cell proliferation during the estrous cycle of the rat.

Changes in milk characteristics and fatty acid profile during the estrous cycle in dairy cows

The relationship of the estrous cycle to milk composition and milk physical properties was assessed on Holstein (n = 10,696), Brown Swiss (n = 20,501), Simmental (n = 17,837), and Alpine Grey (n = 8,595) cows reared in northeastern Italy. The first insemination after calving for each cow was chosen to be the day of estrus and insemination. Test days surrounding the insemination date (from 10 d before to 10 d after the day of the estrus) were selected and categorized in phases relative to estrus as diestrus high-progesterone, proestrus, estrus, metestrus, and diestrus increasing-progesterone phases. Milk components and physical properties were predicted on the basis of Fourier-transform infrared spectra of milk samples and were analyzed using a linear mixed model, which included the random effects of herd, the fixed classification effects of year-month, parity number, breed, estrous cycle phase, day nested within the estrous cycle phase, conception, partial regressions on linear and quadratic effects of days in milk nested within parity number, as well as the interactions between conception outcome with estrous cycle phase and breed with estrous cycle phase. Milk composition, particularly fat, protein, and lactose, showed clear differences among the estrous cycle phases. Fat increased by 0.14% from diestrus high-progesterone to estrous phase, whereas protein concomitantly decreased by 0.03%. Lactose appeared to remain relatively constant over diestrus high-progesterone, rising 1 d before the day of estrus followed by a gradual reduction over the subsequent phases. Specific fatty acids were also affected across the estrous cycle phases: C14:0 and C16:0 decreased (-0.34 and -0.48%) from proestrus to estrus with a concomitant increase in C18:0 and C18:1 cis-9 (0.40 and 0.73%). More general categories of fatty acids showed a similar behavior; that is, unsaturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, trans fatty acids, and long-chain fatty acids increased, whereas the saturated fatty acids, medium-chain fatty acids, and short-chain fatty acids decreased during the estrous phase. Finally, urea, somatic cell score, freezing point, pH, and homogenization index were also affected indicating variation associated with the hormonal and behavioral changes of cows in standing estrus. Hence, the variation in milk profiles of cows showing estrus should potentially be taken into account for precision dairy farming management.