Day Of Estrus Research Articles

Effect of royal jelly on puberty of ewe lambs

In this study, we investigated the effect of royal jelly on the puberty of female ¼ Romanov × ¾ Morkaraman crossbred lambs. Royal jelly was applied in two ways: orally and intravaginally. The rate of estrus as well as the day and time (in hours) of estrus were observed and determined by real-time ultrasonography (for pregnancy) and laparoscopic surgery (ovary examination). Three groups of lambs were observed. The first group, consisting of 15 female lambs, was treated intravaginally; in the second group, 15 female lambs were treated orally; and the third group, which served as control, consisted of 10 ewe lambs that were not treated with royal jelly. Estrus rates in the intravaginally and orally treated groups were 13% and 20%, respectively, whereas the control group showed no estrus activity. However, estrus interval in both groups was observed 3-5 days after the withdrawal of the treatment. All the animals had an active ovary when observed during estrus activity by ovary examination. Yearling ¼ Romanov-bred ewes respond positively to royal jelly application. Increasing the doses and extending the duration of royal jelly application might yield better results.

75 Effect of mycobacterium cell wall fraction immunostimulant on conception rates in heifer recipients

In cattle, the average pregnancy for IVF embryos around Days 45 to 90 is 35% (Ealy et al. 2019 J. Anim. Sci. 97, 2555–2568). Among other factors, uterine contamination with pathogens from the vagina during embryo transfer may affect pregnancy success. Prophylactic antibiotic treatment for this purpose in embryo recipients is considered malpractice. An alternative to antibiotics is the use of mycobacterium cell wall fraction (MCWF) immunostimulant (Amplimune, NovaVive Inc.) against these pathogens. Therefore, the objective was to determine the effect of MCWF on conception rates in heifer recipients. For this purpose, Holstein heifers were synchronized with 2 injections of prostaglandin F2α 14 days apart and randomly allocated to 2 groups: (1) MCWF (n=292), single intramuscular injection of 5mL of Amplimune on the day of pretransfer oestrus; (2) Control (n=296): no Amplimune treatment. Embryo transfers using quality 1 frozen IVF embryos were performed in all recipients 7 to 8 days after oestrus and with a corpus luteum ≥22mm, using a double sanitary sheath technique. Data were analysed using the generalized linear mixed model (GLMM). Results are shown in Table 1. In conclusion, treatment with MCWF increased the number of recipients to be used for embryo transfer and improved the conception rate at Day 60. Importantly, MCWF treatment was more efficient for getting a recipient pregnant by Day 60 per total of synchronized recipients. Table 1. Effect of mycobacterium cell wall fraction (MCWF) on pregnancy in heifer recipients transferred frozen embryos (quality 1) Variable MCWF Control Utilisation rate 227/292a 174/296b (No. of transferred recipients/no. of synchronized recipients) (78%) (59%) Pregnancy Day 30 144/227 94/174 (No. of pregnant recipients at Day 30/no. of transferred recipients) (63%) (54%) Pregnancy Day 60 131/227a 83/174b (No. of pregnant recipients at Day 60/no. of transferred recipients) (58%) (48%) Embryo mortality 13/144 11/94 (No. of embryo loss at Day 60/no. of pregnant recipients at Day 30) (9%) (12%) Pregnancy Day 60 per total of synchronized 131/292a 83/296b (No. of pregnant recipients/no. of synchronized recipients) (45%) (28%) a,bValues with different superscripts within a row are different (P ≤ 0.05).

İneklerde Östrus Siklusu Süresince Uterus Ekojenitesindeki Değişikliklerin Araştırılması

The aim of the present study is to examine possible changes that may occur in the uterus by using the echotexture parameters obtained on different days of the oestrus cycle in cows. In the study, 42 cows in the first lactation, with no clinical or subclinical endometritis symptoms, in a private farm in Erzurum were used. Ultrasonographic images were taken on the oestrus day (0thday) and on different days of the cycle (4, 12, 16, 18, 21) in cows with oestrus. The mean gray value (MGL), homogeneity (HOM), and contrast (CON) parameters in the images taken from the uterine endometrium were examined with a computer-assisted image analysis program. Average echotexture parameters on the different days of the estrus cycle in cows were detected as 68.43±0.55 for MGL, 0.080±0.001 for HOM, and 54.23±0.37 for CON. There was a negative relationship between the mean gray value and HOM, and a positive relationship with the CON values, while a negative relationship was observed between the HOM and CON values. As a result, no statistical difference was found between MGL, HOM and CON values in the images taken from the endometrium of cows in different periods of the cycle. When the cycle is evaluated as follicular and luteal period; It was observed that MGL values were high in the follicular phase of the cycle and low in the luteal phase, while homogeneity values were low in the follicular phase and high in the luteal phase.

Skin Mediates the Aphrodisiac Effect of UVB Light Via a Skin-Brain-Gonad Axis

Ultraviolet (UV) light affects endocrinological and behavioral aspects of human sexuality via an unknown mechanism. Using a unique male-female comparative approach, we discovered that the sexual behavioral and hormonal features enhanced by UVB are mediated by the skin. In mice, UV exposure increases hypothalamus-pituitary-gonadal axis hormone levels, resulting in enhanced ovary size, extended estrus days, and anti-Mullerian hormone (AMH) expression. It likewise enhances sexual responsiveness and attractiveness of females and heterosexual interactions of both males and females. Conditional knockout of p53 specifically in skin keratinocytes abolished UV’s effects. In humans, UV exposure enhanced romantic passion in both genders, increased testosterone levels in men and correlated with heightened plasma AMH levels in women. Our data, revealing that UVB triggers a skin-brain-gonadal axis through skin p53 activation, offers therapeutic opportunities for sex-steroid-related dysfunctions. We speculate that during human furless skin evolution, the skin became the front-line regulator of the response to UVB.

Unilateral section of the superior ovarian nerve induces first ovulation in the Zucker fatty (fa/fa) rat

Hyperactivity in the sympathetic nervous system has been shown to be related to the development of ovarian pathologies. In addition, obesity has been found to be associated with multiple reproductive anomalies and is considered a chronic stress condition of low intensity with changes in the peripheral sympathetic activity. Therefore, in the present study, we aimed to evaluate if the information reaching the ovaries through the superior ovarian nerve (SON) modifies the ovarian function of Zucker fatty rats. We performed a unilateral section of the SON at 32 days of age and autopsies were carried out on the day of the first vaginal estrus. The results showed that fatty animals do not ovulate on the day of the first vaginal estrus and exhibit an increase in catecholaminergic fibers and the presence of precystic structures in the ovaries, without changes in the onset of puberty or in the secretion of ovarian and hypophyseal hormones. We also found that the section of the right SON resulted in ovulation on the day of the first vaginal estrus, which was accompanied by a decrease in ovarian noradrenaline content. The section of the left SON caused a delay in puberty without changes in the rest of the parameters. These results provide functional evidence that the peripheral sympathetic innervation participates in the regulation of ovarian functions in an animal model of genetic obesity.

Effects of flaxseed-rich diet on reproductive performance in estrous-synchronized Baluchi ewes.

The purpose of this study was to compare the effects of using different levels of flaxseed in diets on the reproductive performance of estrous-synchronized Baluchi ewes (para 3). Diets contained either basal diet (control) or different levels of extruded flaxseed (2%, 5%, 7%, 10%, and 12%) and were fed from lambing to 60 days after lambing. The ewe estrus cycles were synchronized using controlled internal drug release (CIDR) for 14 days starting from day 16 of fat supplementation. The rams were introduced 24 h after CIDR removal. The ewes fed control diets had the highest mean dry matter intake (1,800±35 g) which was declined with the increase of flaxseed levels. The experimental diets exerted no effects of urea concentration in blood plasma. However, plasma glucose concentration was lower (p <0.05) in the ewes fed the control diet and 2% flaxseed, compared to those in other groups. Nonetheless, there was no difference among the ewes fed 5%, 7%, 10%, and 12% flaxseed in terms of plasma glucose concentrations (p <0.05). The ewes fed 2% flaxseed had the highest level of plasma triglyceride concentration among other groups. In addition, the control group had the lowest level of plasma total cholesterol and low-density lipoproteins concentration in comparison to other groups (p <0.05). However, plasma nonesterified fatty acids and β-hydroxybutyrate concentrations were similar among the groups (P>0.05). The mean interval between CIDR removal and the exhibition of estrus ranged from 30 to 40 h with the shortest interval being recorded in the ewes fed 12% flaxseed (p <0.05). The control group had the lowest number of follicles on estrus day among other groups (p <0.05). Furthermore, the ewes fed 10% and 12% flaxseed had the highest ovulation, pregnancy, and lambing rates, compared to other groups (p <0.05). In conclusion, the findings revealed that feeding the ewes with 10% and 12% flaxseed resulted in the improvement of reproductive performance.

Neonatal exposure to genistein affects reproductive physiology and behavior in female and male Long-Evans rats.

The present study was designed to examine the effects of neonatal genistein exposure on measures of reproductive physiology and behavior. Approximately 24 h after birth, female and male Long-Evans rat pups were injected daily with genistein (150 µg, subcutaneous; n = 29) or olive oil (n = 23) between postnatal days 1 and 5. After weaning, we examined all subjects daily until they reached puberty (i.e. vaginal opening in female rats and preputial separation in male rats). For all female subjects, we also examined vaginal cytology. After monitoring estrous cyclicity, the female subjects were given the opportunity to interact with a gonadally intact male or a sexually receptive female rat on the day of behavioral estrus to assess sexual motivation (i.e. partner-preference test with and without physical contact), which has never been evaluated before. For all male subjects, we assessed the development of copulatory behavior and sexual motivation (partner-preference test without physical contact). Consistent with previous findings, we found that neonatal exposure to genistein did not affect puberty onset in female or male rats. However, female rats exposed to genistein displayed significantly more irregular estrous cycles than controls. Neonatal genistein exposure also altered the development of male copulatory behavior, as indicated by an increase in mount frequency and intromission frequency and shorter interintromission intervals. We extended previous findings confirming that neither female nor male sexual motivation was affected by neonatal genistein. The results of the present study have important implications for the development of reproductive physiology and behavior in human neonates exposed to genistein in soy-based baby formula.

Gene expression of FOXP3, indoleamine 2,3-dioxygenase (IDO), IL10 and CSF1 in the uterus of cows that received an intrauterine infusion of maternal and paternal antigens

Sensitization with conceptus antigens has been shown to be useful for improving reproductive performance facilitating maternal acceptance of an allogeneic embryo through the induction of cytokines and immunoregulatory cells in the uterine microenvironment. As FOXP3, IDO, IL10 and CSF1 in the uterus are important on the recognition and development of embryos during early pregnancy, this study aimed to determine whether simultaneous or isolated administration of paternal (semen) and maternal (PBMCs) antigens in the uterus of cow, on the day of estrus, influence the gene expression of these cytokines. Forty crossbred cows were divided into four treatments: T0: Control; T1: Semen; T2: PBMCs (peripheral blood mononuclear cells) from another cow and T3: PBMCs+Semen. Antigens were administered into the uterine body on the estrus day (D0). Uterine biopsies designed for molecular analysis of gene expression were collected in vivo seven (D7) and fourteen (D14) days after immunostimulation. Transcripts from FOXP3, IDO, IL-10 and CSF-1 were detected in all RNA samples extracted from uterine biopsies. The semiquantitative analysis showed that none of the treatments caused significant increase in the expression of these genes. Furthermore, on D14 all treatments led to a decline in the number of CSF-1 transcripts; moreover, treatment with PBMCs+Semen also led to a drop in the abundance of IL-10 transcripts. Such results suggest that isolated or simultaneous administration of both antigens would not increase maternal tolerance to embryo alloantigens, nor would it create favorable conditions to its growth and pre-implantation development, at least regarding the effects mediated by these genes on D7 and D14 of the estrous cycle.

Follicular dynamic and reproductive performance of gilts submitted to estrous cycle synchronization using two different progestogen sources

This study evaluated reproductive indicators of gilts treated with altrenogest or an intravaginal device (IVD) containing medroxyprogesterone acetate (MPA) for estrous cycle synchronization, starting the protocol on different days of the estrous cycle or replacing the IVD in the middle of treatment. In Experiment 1, 126 gilts were assigned, according to the day of treatment onset (Day 5 or 10 of the estrous cycle), to the following treatments: Control-5 (no hormone); Control-10 (no hormone); IVD-5 (IVD with MPA); IVD-10 (IVD with MPA); ALT-5 (altrenogest); or ALT-10 (altrenogest). The first day of the previous estrus was considered as Day 0 of the estrous cycle, and progestogen groups were treated for 14 d. In Experiment 2, 63 gilts were assigned to Control, ALT, or IVD groups. Progestogen treatment started on Day 10 of the estrous cycle, and the IVD was replaced after 7 d of treatment. In both experiments, no gilts expressed estrus during progestogen administration. In Experiment 1, the interval hormonal withdrawal-to-estrus (IHE) tended to be shorter when treatment started on Day 10 than on Day 5 (3.6 vs. 4.1 d, respectively; P = 0.09). The percentage of gilts expressing estrus after hormone withdrawal was lower for IVD-gilts (76.3%) compared to ALT (100%) and Control-gilts (92.9%; P ≤ 0.07). The percentage of persistent follicles (PFOL) was greater in IVD-10 (60.0%) and ALT-10 (33.3%) than CONT-10 (0.0%; P ≤ 0.06). The adjusted farrowing rate (AFR) was lower in IVD (65.5%) and ALT (80.5%) compared with CONT (97.4%; P ≤ 0.08). In Experiment 2, the IHE was longer for ALT than IVD (4.9 vs. 3.9 d, respectively; P < 0.01). No difference among groups was observed in the percentage of gilts expressing estrus (overall 86.4%), but the occurrence of PFOL was higher in IVD (61.5%) compared to ALT (5.3%), and Control groups (10.5%; P < 0.01). The AFR was lower in IVD (53.8%) than in ALT (88.2%) and Control (94.7%; P ≤ 0.05). The total number of piglets born was not affected by hormonal treatments in either experiment. Estrous expression was delayed in gilts treated with altrenogest or IVD–MPA. However, the reproductive performance of IVD-gilts was compromised, which was not circumvented by IVD replacement in the middle of treatment. Therefore, further studies are necessary to understand MPA pharmacodynamics and investigate alternative devices for a steady release of progestogens in gilts.

Altrenogest affects the development and endocrine milieu of ovarian follicles in prepubertal and mature gilts†.

Altrenogest with gonadotropins is commonly used to synchronize the estrous cycle, but it can also lead to follicular cyst formation, especially in prepubertal gilts. Here, we aimed to investigate how maturity and altrenogest treatment affect the development, endocrine milieu, and molecular control of ovarian follicles. Crossbred prepubertal and mature gilts were challenged or not (control) with altrenogest, and ovaries were collected in the morning on the first day of behavioral estrus. In prepubertal gilts, altrenogest decreased the percentage of primordial and atretic small follicles, but increased large antral follicles when compared with controls. In mature gilts, altrenogest reduced the percentage of primary follicles and elevated the total number of antral follicles. Maturity affected the estradiol level in the follicular fluid of preovulatory follicles, luteinizing hormone (LH)-stimulated cyclic adenosine monophosphate (cAMP) generation, and LH receptor messenger RNA (mRNA) expression in granulosa. Moreover, cytochrome P45017A1 (CYP17A1) mRNA levels in the theca layer were affected and correlated with follicular androstendione and estradiol concentration. Altrenogest negatively affected follicular fluid progesterone concentration and decreased levels of prostaglandin (PG) E2 in prepubertal gilts and PGF2alpha metabolite in mature gilts. LH-stimulated cAMP release in granulosa cells of mature gilts as well as human chorionic gonadotropin- and forskolin-induced cAMP were also affected. In addition, altrenogest downregulated CYP17A1 mRNA in the prepubertal theca layer and PGF2alpha synthase expression in the granulosa and theca layer of mature gilts. To the best of our knowledge, this is the first study to report multiple effects of maturity and altrenogest on the endocrine milieu and molecular regulations governing ovarian follicle development in gilts.

The content of gonadotropin-releasing hormone (GnRH), kisspeptin, and estrogen receptors (ERα/ERβ) in the anteromedial hypothalamus displays daily variations throughout the rat estrous cycle.

The content of gonadotropin-releasing hormone (GnRH), its mRNA, and estrogen receptor alpha (ERα) and beta (ERβ) in the hypothalamus varies throughout the estrous cycle. Furthermore, the abundance of these molecules displays asymmetry between the right and left side. In the present study, we investigated the changes in the content of ERα, ERβ, kisspeptin, and GnRH by western blot in the left and right anteromedial hypothalamus, at four different times during each stage of the rat estrous cycle. The serum levels of the follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were also measured. ERα and ERβ levels changed depending on the stage of the estrous cycle, meanwhile that of kisspeptin was modified according to both the hour of the day and the stage of the cycle. Except in estrus day, ERβ was higher in the right hypothalamus, while ERα was similar in both sides. During both proestrus and estrus, the content of kisspeptin and GnRH was higher in the right hypothalamus. The highest levels of FSH and LH occurred at 17:00h of proestrus. But at estrus, the highest FSH levels were observed at 08:00h and the lowest at 17:00h. Thus, the current results show that the content of ERα, ERβ, kisspeptin, and GnRH in the anteromedial hypothalamus are regulated as a function of the stage of the estrous cycle and the hour of the day. Furthermore, the content of these proteins is regularly higher in the right anteromedial hypothalamus, regardless of the stage of the cycle or time of the day.

Comparative analysis of the ovarian transcriptome reveals novel insights into fertility differences in Large White sows.

Fertility is the most important economic trait in sows, as it is critical for profitability. Considerable phenotypic variation in litter size exists in Large White sows. However, relatively little is known about the underlying molecular and genetic bases. An experiment was conducted to screen key genes that affect the fecundity of pigs during the luteal (L) and follicular phases (F) of the estrous cycle. Eight sows (n = 4 for high fertility sows and n = 4 for low fertility sows) were sacrificed on day 14 (day 1 = first day of estrus) after estrus in the L phase. Another eight sows were slaughtered on day 20 of the estrous cycle in the F phase. Sixteen ovarian tissue samples were collected at the different sacrifice time points. Total RNA extracted was used to construct the library and then sequence on an Illumina HiSeq X10 system. Differentially expressed genes (DEGs) between high and low fertility in Large White sows were identified, and their potential biological functions were analyzed using bioinformatics analysis. In total, 457 DEGs (161 up-regulated and 296 down-regulated genes) were detected in the ovarian tissues of the high and low fertility groups in the L phase of the estrous cycle. Furthermore, 475 DEGs (253 up-regulated and 222 down-regulated genes) were identified in the F phase. Twenty-nine DEGs were common to both comparisons. Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that the DEGs were mainly associated with steroid biosynthesis, the Hippo signaling pathway, and lysosomes. Others, such as MSMO1, CYP27B1, and CTSB, were related to reproduction. These results will contribute to a better understanding of the individual differences in fertility at the transcriptome level, which may provide useful information to explore new ways to improve fertility in pigs.

OR27-03 Duration of Testosterone-Induced Acyclicity Influences Corpora Lutea Formation and Stromal Changes in a Transgender Mouse Model

The impact and reversibility of long-term gender-affirming testosterone (T) therapy on the reproductive axis of transgender men has not been well-established. Little is known about outcomes for transgender men interested in pausing T therapy to harvest oocytes or get pregnant. We previously established a translational mouse model to investigate T-induced acyclicity and ovarian perturbations. We hypothesized that the duration of T-induced acyclicity would impact the reversibility of cyclic and ovarian changes. To test this hypothesis, T-treated mice were assigned to two groups: (SHORT) 6 weeks of T therapy with immediate reversibility (1.5 mg T propionate pellet implant/removal, n = 5) and (LONG) 6 weeks of T therapy with a prolonged T washout phase (subcutaneous oil injections of T enanthate at 0.9 mg once weekly, n = 5). Control groups (placebo pellets n = 5, sesame oil vehicle injections n = 5) were run in parallel. Estrous cycles were monitored using daily vaginal cytology. Following cessation of T therapy, mice were sacrificed in diestrus after resumption of cyclicity for 4 cycles and ovarian histology examined. Data were analyzed in GraphPad Prism using Welch’s t-test or Mann-Whitney where appropriate. T therapy led to persistent diestrus within a week after T administration for all T-treated mice and none of the controls. The total duration of acyclicity was 6±1 weeks for the SHORT group, which was significantly shorter than the 11±2 weeks for the LONG group (mean ± s.d., p = 0.0079). With resumption of cyclicity, both the SHORT and LONG groups had a significantly lower percentage of days in estrus and higher percentage of days in metestrus as compared to their parallel age-matched controls. Ovarian histology for the SHORT group all showed regular corpora lutea and minimal stromal changes, however, 3/5 mice in the LONG group lacked corpora lutea and 4/5 revealed marked stromal cell hypertrophy. Similar stromal cell changes were not seen in control mice. In conclusion, the length of time of T-induced acyclicity appears to impact the development of stromal cell hypertrophy and formation of corpora lutea even after resumption of cyclicity with similar alterations to the estrous cycles. These findings may have clinical relevance for transgender men interested in fertility, based on duration of gender-affirming T therapy. Future work will aim to separate out the respective contributions of T exposure and acyclicity to the stromal phenotype.

SUN-243 Deletion of KNDy Neuron-Specific KISS1 Disrupts Estrous Cyclicity and LH Pulsatility in Female Mice

Kisspeptin (encoded by Kiss1), a neuropeptide critically involved in neuroendocrine regulation of reproduction, is primarily synthesized in two discrete hypothalamic nuclei: the anteroventral periventricular area (AVPV) and arcuate nucleus (ARC). AVPV Kiss1 is important for the pre-ovulatory luteinizing hormone (LH) surge unique to females as well as estrogen-induced positive feedback control of GnRH and LH. In contrast, ARC Kiss1 neurons, which largely co-express the neuropeptides NKB and dynorphin (collectively known as KNDy neurons), are major regulators of pulsatile release of GnRH and LH, and mediate estrogen-induced negative feedback control of both GnRH and LH. Previous studies have not fully separated the specific roles for Kiss1 in the AVPV versus KNDy-ARC neurons in the downstream control of GnRH and LH release. Therefore, we generated a Pdyn-Cre/Kiss1fl/fl (KO) mouse model to target Kiss1 in the KNDy neurons to differentiate KNDy neuron-specific function from AVPV Kiss1 function in the maturation and maintenance of the reproductive axis. qRT-PCR data documented a significant reduction of Kiss1 expression in the mediobasal hypothalamus (containing ARC) compared to controls, whereas Kiss1 in the preoptic area (containing AVPV) was similar in both KO and controls. Immunofluorescent IHC confirmed a loss of kisspeptin immunoreactivity in the ARC of KO animals while expression in the AVPV remained intact. Markers of pubertal onset (day of vaginal opening and first estrus in females; day of preputial separation in males) were normal in KO mice, suggesting that AVPV Kiss1 and/or other neural signals may be sufficient for pubertal onset. In addition, body weight throughout pubertal growth was comparable between KO and control animals of both sexes. Interestingly, KO female mice had disrupted estrous cycles presenting with persistent diestrus and a small vaginal opening. In order to test our hypothesis that conditional deletion of Kiss1 in KNDy neurons disrupts or ablates episodic GnRH/LH pulsatile release, we collected serial tail blood samples from mice at diestrus and measured LH. KO female mice exhibited significantly fewer LH pulses in a 3-hour timespan compared to controls, suggesting that KNDy neurons were functionally compromised. These observations indicate the central role of KNDy neurons in the regulation of GnRH/LH pulsatility and estrous cyclicity. The functional effects of disrupted estrous cyclicity and slower LH pulses observed in KO females are currently under study to assess potential abnormalities in ovarian folliculogenesis and fertility. Future experiments will determine whether ARC Kiss1 deletion disrupts the KNDy-driven negative feedback response of LH to gonadectomy, as well as address potential sex differences in ARC Kiss1-mediated negative feedback control of LH release.

In Utero and Lactational Exposure to Flame Retardants Disrupts Rat Ovarian Follicular Development and Advances Puberty.

Brominated flame retardants (BFRs), including polybrominated diphenyl ethers and hexabromocyclododecane, leach out from consumer products into the environment. Exposure to BFRs has been associated with effects on endocrine homeostasis. To test the hypothesis that in utero and lactational exposure to BFRs may affect the reproductive system of female offspring, adult female Sprague Dawley rats were fed diets formulated to deliver nominal doses (0, 0.06, 20, or 60 mg/kg/day) of a BFR dietary mixture mimicking the relative congener levels in house dust from prior to mating until weaning. Vaginal opening and the day of first estrus occurred at a significantly earlier age among offspring from the 20 mg/kg/day BFR group, indicating that the onset of puberty was advanced. Histological analysis of ovaries from postnatal day 46 offspring revealed an increase in the incidence of abnormal follicles. A toxicogenomic analysis of ovarian gene expression identified upstream regulators, including HIF1A, CREB1, EGF, the β-estradiol, and PPARA pathways, predicted to be downregulated in the 20 or 60 mg/kg/day group and to contribute to the gene expression patterns observed. Thus, perinatal exposure to BFRs dysregulated ovarian folliculogenesis and signaling pathways that are fundamental for ovarian function in the adult.

Biomarkers from automatic milking system for cows reproduction success

This Research Communication addresses the hypothesis that some biomarkers from automatic milking system can be indicators of cows reproduction success. The pregnancies were tested with ultrasound after 30–35 d post-insemination. Those cows which were pregnant were assigned to the PG+ group (n = 36) and those which were not pregnant, were assigned to the PG- group (n = 32). On oestrus day the pH, temperature of the contents of cow reticulorumens and cow activity were measured using specific smaX-tec boluses manufactured for animal care. Rumination time, body weight, milk yield, milk fat – protein ratio, milk lactose, milk somatic cell count, milk electric conductivity of all quarters of udder (front right, front left, rear left, rear right), and consumption of concentrates were registered with the help of Lely Astronaut® A3 milking robots.We estimated that the reticulorumen pH (P < 0.001) and reticulorumen temperature (P < 0.01) were higher in PG+ cows compared to PG− cows, which were found to have higher (P < 0.001) productivity (MY). Between the reticulorumen pH and the MY in PG− cows a positive relationship was calculated (P<0.001). In PG+ group was estimated a higher milk fat ant protein ratio (F/P = 1.19 ± 0.013) compared to PG− group (P < 0.001) and a higher content of milk lactose (4.59 ± 0.003%; P < 0.001). Cows of PG + group were more active compared to the PG− group (1.94%; P < 0.001) and consumed less concentrates (17.50%, P < 0.001). We can conclude that higher reticulorumen pH and temperature, milk lactose and lower consumption of concentrates and higher activity of cows were associated with the reproduction success. Correlation coefficients between values of automatic measurements of reticulorumen pH and temperature in PG+ and PG− cows were fluctuating and differed at different times of day. Analysis multivariable logistic regression have shown that the key reliable indicators of cow reproduction success are changes in productivity and activity.

Concentration of serum estradiol, progesterone and cortisol during biological stress period of normal cyclic and silent Oestrous crossbred cows of Assam

The present study was planned to compare the concentration of serum estradiol, progesterone and cortisol level during biological stress period of normal cyclic and silent oestrous cycles of crossbred cows of Assam. Jugular blood samples were collected from ten normal cyclic and ten silent oestrous cows on day 0, 10, 17 and 20 of cycles for the present study. These 3 hormones were estimated by using ELISA kit manufactured by LDN GmbH& Co.KG, Germany, by solid phase enzyme-linked immunosorbent assay. Both estradiol and progesterone concentrations in serum were varied significantly (P< 0.01) between days of oestrous cycles of normal and silent oestrous cows. Lowest level of progesterone with concomitant highest level of estradiol was recorded on the day of oestrus. On the other hand, highest concentration of progesterone was found on the day 10 of cycles with lowest concentration of estradiol on day 17 of cycle. The mean levels of cortisol varied significantly between days of cycles with highest level on the day of oestrus.

Reproductive performance of sows associated with single, fixed-time insemination programs in commercial farms based on either average herd weaning-to-estrus intervals or postweaning estrous activity

ABSTRACT Objective Three separate studies were conducted to determine the effectiveness of adjusting the timing of triptorelin (Ovugel, United Animal Health, Sheridan, IN) administration based on historical weaning-to-estrus intervals (Exp. 1), the occurrence of proestrus (Exp. 2), or the occurrence of estrus (Exp. 3) on reproductive performance of weaned sows. Materials and Methods All studies were conducted on commercial farms in eastern North Carolina during the summer months when both the length and variation associated with weaning-to-estrus intervals for sows were increased. In Exp. 1, sows were assigned at weaning to receive triptorelin at either 96 ± 6 h (n = 196) or 120 ± 6 h (n = 196) followed by a single insemination 22 ± 2 h later. Sows bred once each day of estrus (n = 398) served as the control treatment. In Exp. 2, sows were given boar exposure beginning on d 3 after weaning and at proestrus were assigned to 1 of 2 treatments: (1) control (n = 301), which were bred once each day of detected estrus, or (2) triptorelin (n = 296) followed by a single insemination 22 ± 2 h later. In Exp. 3, sows were given boar exposure beginning on d 3 after weaning, and those detected in estrus on d 4 or 5 were assigned to be bred once each day of estrus (control d 4, n = 98 and control d 5, n = 118) or treated with triptorelin (d 4, n = 97 and d 5, n = 117) followed by a single insemination 22 ± 2 h later. Results and Discussion Reproductive performance was significantly reduced (P ≤ 0.05) when triptorelin was given at a fixed time after weaning irrespective of estrous status compared with the control sows that were bred once each day of estrus (Exp. 1). This was due to the subset of treated sows that were not in estrus when they were bred. In contrast, weaned sows treated with triptorelin at either proestrus or estrus and bred once 22 ± 2 h later had similar reproductive performance (P ≥ 0.63) compared with their counterparts bred once each day of estrus. Implications and Applications Use of either proestrus or estrus as the criterion for intravaginal administration of triptorelin and the subsequent fixed-time AI in herds with extended or variable weaning-to-estrus intervals was effective in terms of maintaining reproductive performance equivalent to conventional AI strategies.

Inflammatory response in repeat breeder buffaloes

The aim of this study was to investigate the repeat breeding condition in Italian Mediterranean buffaloes that failed to conceive after at least 300 days in milk. The trial was carried out on 40 pluriparous Italian Mediterranean buffaloes with more than 300 days in milk. All the animals underwent ultrasound examination to assess endometrial thickness and oestrus synchronization by the Ovsynch-TAI Program. On the day of oestrus, blood samples were collected for the haemocytometric cell count and biochemical assay, and the animals were slaughtered in a local abattoir. A post-mortem uterine flushing was performed using sterile saline for microbiological analyses. Furthermore, uterine biopsies were carried out for histopathological assessment. Finally, endometrial samples were used for real-time PCR (RT-PCR) analysis to evaluate the expression of genes involved in innate immune recognition of pathogens and the inflammatory response, such as Toll-like receptor (TLR)1, TLR8, interleukin (IL)-1β, IL-6, IL-8, COL4A2, connective tissue growth factor (CTGF), and cysteine-rich angiogenic inducer 61 (CYR61). Statistical analysis was performed by one-way ANOVA. Based on the infiltration of lymphocytes and plasma cells or endometrial gland, lymphatic, and blood vessel ectasia recorded in the histopathological examination, the animals were classified into three groups: healthy (H Group; n = 5), moderate endometritis (M Group; n = 25), and severe endometritis (S Group; n = 10). A significantly greater (P < 0.01) endometrial thickness was recorded in the S Group compared to that in the H and M Group (1.07 ± 0.03 vs. 0.70 ± 0.07 and 0.81 ± 0.04 cm in the S, H, and M Group, respectively). The white blood cell count was lower in the H Group compared to that in the M and S Group (6.3 ± 0.6 vs. 9.3 ± 0.4 and 10.5 ± 0.5 in the H, M, and S Group, respectively). To perform RT-PCR analysis, five animals from groups M and S were randomly selected in order to have balanced results. A higher (P < 0.01) expression of TLR1, together with a lower expression of COL4A2, IL-1β, IL-6, IL-8, and CYR61, was recorded in the H Group, compared to both the M and S Groups. In conclusion, about 90% of repeat breeder buffaloes show moderate or severe endometritis, associated with an altered histopathological endometrial profile and altered mRNA expression of pro-inflammatory and fibrotic factors.

A neural circadian signal essential for ovulation is generated in the suprachiasmatic nucleus during each stage of the oestrous cycle.

What is the central question of this study? Is the suprachiasmatic nucleus the structure that generates the neural circadian signals that occur during every stage of the oestrous cycle, not only pro-oestrus, and are these signals essential for proper regulation of ovulation? What is the main finding and its importance? Transient inhibition of Na+ -dependent action potentials in the suprachiasmatic nucleus by tetrodotoxin microinjection at 14.00h inhibits ovulation irrespective of the stage of the oestrous cycle at which the procedure is performed. Microinjection of saline solution into the suprachiasmatic nucleus has a disruptive effect on ovulation that depends on the stage of the cycle at which it is administered. Reproduction is a highly timed process that depends on both the reproductive and circadian systems. The core oscillator of the latter resides at the suprachiasmatic nuclei (SCN) and it is pivotal for the regulation of the pro-oestrus pre-ovulatory surge of gonadotropins in females. There is evidence to suggest that this system may be involved in the regulation of neuroendocrine events that are essential for ovulation and that occur prior to pro-oestrus. We explored this possibility by transiently inactivating the SCN. Female rats were implanted with guide cannulas aimed at the SCN. After recovery of the oestrous cycle, animals were injected with tetrodotoxin (TTX), artificial cerebrospinal fluid (ACSF) or saline solution while freely moving. Injections were performed at 14.00h of each stage of the oestrous cycle. Animals were killed on the next predicted oestrus day, the number of ova shed was counted and intact rats at oestrus stage were used as absolute control. ACSF did not modify ovulation. Saline solution blocked ovulation in oestrus- and dioestrus-injected rats. Irrespectively of the stage of the oestrous cycle, TTX blocked ovulation. These results lead us to suggest that a neural circadian signal, pivotal for triggering the gonadotropin pre-ovulatory surge, arises from the SCN during the critical window of pro-oestrus. We also suggest that a similar signal, needed for the regulation of other events that are indispensable for proper regulation of ovulation, is also generated in this nucleus during the other stages of the cycle at a similar time.