Modular genetic control of sexually dimorphic behaviors.

Sex hormones such as estrogen and testosterone are essential for sexually dimorphic behaviors in vertebrates. However, the hormone-activated molecular mechanisms that control the development and function of the underlying neural circuits remain poorly defined. We have identified numerous sexually dimorphic gene expression patterns in the adult mouse hypothalamus and amygdala. We find that adult sex hormones regulate these expression patterns in a sex-specific, regionally restricted manner, suggesting that these genes regulate sex typical behaviors. Indeed, we find that mice with targeted disruptions of each of four of these genes (Brs3, Cckar, Irs4, Sytl4) exhibit extremely specific deficits in sex specific behaviors, with single genes controlling the pattern or extent of male sexual behavior, male aggression, maternal behavior, or female sexual behavior. Taken together, our findings demonstrate that various components of sexually dimorphic behaviors are governed by separable genetic programs.

The uterine secretory cycle: recurring physiology of endometrial outputs that setup the uterine luminal microenvironment.

Conserved in female reproduction across all mammalian species is the estrous cycle and its regulation by the hypothalamic-pituitary-gonadal (HPG) axis, a collective of intersected hormonal events that are crucial for ensuring uterine fertility. Nonetheless, knowledge of the direct mediators that synchronously shape the uterine microenvironment for successive yet distinct events, such as the transit of sperm and support for progressive stages of preimplantation embryo development, remain principally deficient. Toward understanding the timed endometrial outputs that permit luminal events as directed by the estrous cycle, we used Bovidae as a model system to uniquely surface sample and study temporal shifts to in vivo endometrial transcripts that encode for proteins destined to be secreted. The results revealed the full quantitative profile of endometrial components that shape the uterine luminal microenvironment at distinct phases of the estrous cycle (estrus, metestrus, diestrus, and proestrus). In interpreting this comprehensive log of stage-specific endometrial secretions, we define the "uterine secretory cycle" and extract a predictive understanding of recurring physiological actions regulated within the uterine lumen in anticipation of sperm and preimplantation embryonic stages. This repetitive microenvironmental preparedness to sequentially provide operative support was a stable intrinsic framework, with only limited responses to sperm or embryos if encountered in the lumen within the cyclic time period. In uncovering the secretory cycle and unraveling realistic biological processes, we present novel foundational knowledge of terminal effectors controlled by the HPG axis to direct a recurring sequence of vital functions within the uterine lumen.NEW & NOTEWORTHY This study unravels the recurring sequence of changes within the uterus that supports vital functions (sperm transit and development of preimplantation embryonic stages) during the reproductive cycle in female Ruminantia. These data present new systems knowledge in uterine reproductive physiology crucial for setting up in vitro biomimicry and artificial environments for assisted reproduction technologies for a range of mammalian species.

Transcriptomics and metabolomics of blood, urine and ovarian follicular fluid of yak at induced estrus stage.

To gain a deeper understanding of the metabolic differences within and outside the body, as well as changes in transcription levels following estrus in yaks, we conducted transcriptome and metabolome analyses on female yaks in both estrus and non-estrus states. The metabolome analysis identified 114, 13, and 91 distinct metabolites in urine, blood, and follicular fluid, respectively. The Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis highlighted an enrichment of pathways related to amino acid and lipid metabolism across all three body fluids. Our transcriptome analysis revealed 122 differentially expressed genes within microRNA (miRNA) and 640 within long non-coding RNA (lncRNA). Functional enrichment analysis of lncRNA and miRNA indicated their involvement in cell signaling, disease resistance, and immunity pathways. We constructed a regulatory network composed of 10 lncRNAs, 4 miRNAs, and 30 mRNAs, based on the targeted regulation relationships of the differentially expressed genes. In conclusion, the accumulation of metabolites such as amino acids, steroids, and organic acids, along with the expression changes of key genes like miR-129 during yak estrus, provide initial insights into the estrus mechanism in yaks.

Intraperitoneal administration of mouse kisspeptin-10 to mice during estrus stage induces pseudopregnancy.

A simple method for producing pseudopregnant mice supports pup production. In this study, pregnant ICR were obtained mice without mating with vasectomized mice via administration of mouse Kisspeptin-10 (mKp-10) and transferring blastocysts to the uterus. Blastocyst transfer after mKp-10 administration to mice with gapping and reddish pink vagina resulted in 65.2% (15/23) pregnancies, and 39.1% (34/87) of the transferred blastocysts showed full-term growth. Vaginal smears were observed for accurate estrus cycle determination, and subsequent administration of mKp10 to mice during the estrus stage and blastocyst transfer resulted in 95.2% (20/21) pregnancies and 50.7% (104/205) birth rates. Regarding 2-cell transfer after administration of mKp-10, 100% (8/8) of the mice became pregnant, and 45.0% (36/80) of the embryos were born. Administration of mKp-10 to mice during the estrus stage is a convenient way to generate pseudopregnant mice.

Estrogen to progesterone ratio is associated with conceptus attachment in dairy cows receiving artificial insemination after Double-Ovsynch but not estrus†.

Prediction of pregnancy survival in lactating dairy cows can be determined by the conceptus attachment timeframe via daily pregnancy-specific protein B (PSPB) monitoring. All factors contributing to reduced fertility in dairy cows receiving AI following estrus detection remain unclear. This study aimed to determine differences in time to conceptus attachment in lactating cows treated with the fertility program Double-Ovsynch compared to cows that were detected in estrus. Additionally, we investigated various pre- and post-conception factors potentially influencing fertility outcomes. We hypothesized that AI following a natural estrus detected with automated activity monitors would lead to an extended time to conceptus attachment and lower PSPB concentrations post-attachment compared to Double-Ovsynch. There were no differences in the average time to conceptus attachments between treatments. However, cows inseminated post-estrus that experienced pregnancy loss between conceptus attachment and 60-66 days post-AI exhibited diminished PSPB concentrations on Days 2 and 3 following conceptus attachment. Steroid hormone interactions were assessed with radioimmunoassay to determine the ratios of estrogen to progesterone concentrations on the day of the luteinizing hormone (LH) surge. Notably, estrogen to progesterone ratio proved to predict conceptus attachment in cows subjected to Double-Ovsynch but not in those inseminated post-estrus detection surge. In conclusion, the estrogen to progesterone ratio measured around the time of the pre-ovulatory LH surge emerges as a potentially effective tool for estimating the fertility potential of lactating dairy cows undergoing timed AI, particularly in the context of the Double-Ovsynch program.

Exposure to topiramate and acetazolamide causes endocrine disrupting effects in female rats during estrus.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is a disease characterized by elevated intracranial pressure (ICP) and is a disease of young females. The first line pharmacological treatments include acetazolamide and topiramate and given the nature of IIH patients and the dosing regimen of these drugs, their effect on the endocrine system is important to evaluate. We aimed to assess the effects of acetazolamide and topiramate on steroid profiles in relevant endocrine tissues. METHODS: Female Sprague Dawley rats received chronic clinically equivalent doses of acetazolamide or topiramate by oral gavage and were sacrificed in estrus. Tissue specific steroid profiles of lateral ventricle CP, 4th ventricle CP, CSF, serum, uterine horn and fundus, ovaries, adrenal glands and pituitary glands were assessed by quantitative targeted LC-MS/MS. We determined luteinizing hormone (LH) and follicle stimulating hormones (FSH) levels in paired serum by ELISA. RESULTS: Topiramate increased the concentration of estradiol and decreased the concentration of DHEA in lateral choroid plexus. Moreover, it decreased the concentration of androstenediol in the pituitary gland. Topiramate increased serum LH. Acetazolamide decreased progesterone levels in serum and uterine fundus and increased corticosteroid levels in the adrenal glands. CONCLUSION: These results demonstrate that both acetazolamide and topiramate have endocrine disrupting effects in rats. Topiramate primarily targeted the choroid plexus and the pituitary gland while acetazolamide had broader systemic effects. Furthermore, topiramate predominantly targeted sex hormones, whereas acetazolamide widely affected all classes of hormones. A similar effect in humans has not yet been documented but these concerning findings warrants further investigations.

Effects of prenatal cocaine exposure on estrous cycle, and behavior and expression of estrogen receptor alpha and oxytocin during estrus and diestrus in mice offspring.

Increasing evidence indicates that prenatal cocaine exposure may result in many developmental and long-lasting neurological and behavioral effects. The behaviors of female animals are strongly associated with the estrous cycle. Estrogen receptors and oxytocin are important neuroendocrine factors that regulate social behavior and are of special relevance to females. However, whether prenatal cocaine exposure induces estrous cycle changes in offspring and whether neurobehavioral changes in estrus and diestrus offspring differ remains unclear. On gestational day 12, mice were administered cocaine once daily for seven consecutive days, then the estrous cycle was examined in adult female offspring, as well as locomotion, anxiety level, and social behaviors, and the expression of estrogen receptor alpha-immunoreactive and oxytocin-immunoreactive neurons were compared between estrus and diestrus offspring. Prenatal cocaine exposure resulted in the shortening of proestrus and estrus in the offspring. During estrus and diestrus, prenatally cocaine-exposed offspring showed increased anxiety levels and changed partial social behaviors; their motility showed no significant differences in estrus, but declined in diestrus. Prenatal cocaine exposure reduced estrogen receptor alpha-immunoreactive expression in the medial preoptic area, ventromedial hypothalamic nucleus, and arcuate nucleus and oxytocin-immunoreactive expression in the paraventricular nucleus in estrus and diestrus offspring. These results suggest that prenatal cocaine exposure induces changes in the offspring's estrous cycle and expression of estrogen receptor alpha and oxytocin in a brain region-specific manner and that prenatal cocaine exposure and the estrous cycle interactively change motility and partial social behavior. Estrogen receptor alpha and oxytocin signaling are likely to play important concerted roles in mediating the effects of prenatal cocaine exposure on the offspring.

Augmenting interpretation of vaginoscopy observations in cycling bitches with deep learning model.

Successful identification of estrum or other stages in a cycling bitch often requires a combination of methods, including assessment of its behavior, exfoliative vaginal cytology, vaginoscopy, and hormonal assays. Vaginoscopy is a handy and inexpensive tool for the assessment of the breeding period. The present study introduces an innovative method for identifying the stages in the estrous cycle of female canines. With a dataset of 210 vaginoscopic images covering four reproductive stages, this approach extracts deep features using the inception v3 and Residual Networks (ResNet) 152 models. Binary gray wolf optimization (BGWO) is applied for feature optimization, and classification is performed with the extreme gradient boosting (XGBoost) algorithm. Both models are compared with the support vector machine (SVM) with the Gaussian and linear kernel, k-nearest neighbor (KNN), and convolutional neural network (CNN), based on performance metrics such as accuracy, specificity, F1 score, sensitivity, precision, matthew correlation coefficient (MCC), and runtime. The outcomes demonstrate the superiority of the deep model of ResNet 152 with XGBoost classifier, achieving an average model accuracy of 90.37%. The method gave a specific accuracy of 90.91%, 96.38%, 88.37%, and 88.24% in predicting the proestrus, estrus, diestrus, and anestrus stages, respectively. When performing deep feature analysis using inception v3 with the same classifiers, the model achieved an accuracy of 89.41%, which is comparable to the results obtained with the ResNet model. The proposed model offers a reliable system for identifying the optimal mating period, providing breeders and veterinarians with an efficient tool to enhance the success of their breeding programs.

Correlation between microbial characteristics and reproductive status of the yak uterus based on macrogenomic analysis.

INTRODUCTION: This study aimed to investigate the microbial characteristics of yak uteri collected using intrauterine cotton swabs (CS) during different reproductive stages and the correlation of these microbial characteristics with reproductive status. METHODS: We used a macrogenomic approach to analyze the functional aspects of different microorganisms in samples collected during the pre-estrus, estrus, late estrus, and diestrus stages. RESULTS: The results revealed the presence of 1293 microbial genera and 3401 microbial species in the uteri of yaks at different reproductive stages. The dominant bacterial species varied across the different periods, with Micrococcus and Proteus being dominant during pre-estrus; Pseudomonas, Clostridium, Flavobacterium, Bacillus, and Staphylococcus during estrus; Acinetobacter, Bacillus and Proteus during late estrus; and Pseudomonas, Escherichia coli, and Proteus during diestrus. DISCUSSION: The primary functions of these bacteria are enriched in various metabolic pathways, including carbohydrate and amino acid metabolism, intracellular transport and secretion, post-translational protein modification, and drug resistance. These findings suggest that the microbial diversity in the uterus of yaks plays a crucial role in reproductive regulation and can help prevent reproductive tract-related diseases.

Social effects on behaviorally-scored and pedometer-detected estrus in beef cattle.

The number of cows in estrus often influences estrus behavior; however, the effects of social order are not well documented. This study examined the effects of social order on the expression of behaviorally-scored and pedometer-detected estrus, combined with the effects of the number of cows in estrus. In a herd comprising 13 or 15 beef cattle, cows with orders 1st-7th were defined as dominant and the remaining cows as subordinate. Sole or simultaneous estrus was induced by prostaglandin F2α analog injection and/or intravaginal progesterone treatment. Ovulation timing was determined using ultrasonography at 6-hour intervals. Estrous signs and steps of the cows were recorded 49 h before ovulation using video monitoring and a pedometer, respectively. Among the 59 treated cows, 56 behaviorally-scored estruses (27 sole and 29 simultaneous) were detected. In the sole estrus, 61.5% of the dominant-rank cows had no zero-point period; however, 35.7% of the subordinate-rank cows had that period. The dominant-rank cows in estrus alone had a significantly shorter duration of scored estrus than those in simultaneous estrus (P < 0.05). Among the 50 pedometer-detected estruses (24 sole and 26 simultaneous), the subordinate-rank cows in sole estrus had a shorter interval from estrus onset to ovulation than the dominant-rank cows in simultaneous estrus (P < 0.05). The effects of social order varied in response to the number of cows in estrus, which might have influenced determining the optimal time for artificial insemination.

Capturing temperature changes on the ocular surface along with estrus and ovulation using infrared thermography in Japanese Black cows.

Pre-ovulatory follicles are cooler than the neighboring reproductive organs in cows. Thus, measuring the temperature of reproductive organs could be a useful method for predicting estrus and ovulation in cows, and the establishment of a non-invasive technique is required. In this study, we used infrared thermography (IRT) to measure ocular surface temperature as a potential surrogate for reproductive organ temperature. Five Japanese Black cows with synchronized estrus were subjected to temperature measurements in five regions of the ocular surface, including the nasal conjunctiva, nasal limbus, center cornea, temporal limbus, and temporal conjunctiva, twice a day (0800 h and 1600 h) during the experimental period. The temperatures in the five regions significantly declined in cows from estrus to ovulation. To the best of our knowledge, this study is the first to use IRT to show a temperature decrease in the ocular surface along with estrus to ovulation in Japanese Black cows.

Combining reproductive outcomes predictors and automated estrus alerts recorded during the voluntary waiting period identified subgroups of cows with different reproductive performance potential.

The objective was to compare differences in reproductive performance for dairy cows grouped based on the combination of data for predictors available during the prepartum period and before the end of the voluntary waiting period (VWP), automated estrus alerts (AEA) during the VWP, and the combination of both factors. In a cohort study, data for AEA and potential predictors of the percentage of cows that receive AI at detected estrus (AIE), pregnancies per AI (P/AI) for first service, and the percentage of cows pregnant by 150 DIM (P150) were collected from -21 to 49 DIM for lactating Holstein cows (n = 886). The association between each reproductive outcome with calving season (cool, warm), calving-related events (yes, no), genomic daughter pregnancy rate (gDPR; high, medium, low), days in the close-up pen (ideal, not ideal), health disorder events (yes, no), rumination time (high or low CV prepartum and high or low increase rate postpartum), and milk yield (MY) by 49 DIM (high, medium, low) were evaluated in univariable and multivariable logistic regression models. Individual predictors (health disorders, gDPR, and MY) associated with the 3 reproductive outcomes in all models were used to group cows based on risk factors (RF; yes, n = 535 or no, n = 351) for poor reproductive performance. Specifically, cows were included in the RF group if any of the following conditions were met: the cow was in the high MY group, had low gDPR, or had at least 1 health disorder recorded. Cows were grouped into estrus groups during the VWP based on records of AEA (estrus VWP [E-VWP], n = 476 or no estrus VWP [NE-VWP], n = 410). Finally, based on the combination of levels of AEA and RF, cows were grouped into an estrus and no RF (E-NoRF, n = 217), no estrus and RF (NE-RF, n = 276), no estrus and no RF (NE-NoRF, n = 134), and estrus and RF (E-RF, n = 259) groups. Cows received AIE up to 31 d after the end of the VWP, and if they did not receive AIE, they received timed AI after an Ovsynch plus progesterone protocol. Logistic and Cox proportional hazard regression compared differences in reproductive outcomes for different grouping strategies. The NoRF (AIE: 76.9%; P/AI: 53.1%; P150: 84.5%) and E-VWP (AIE: 86.8%; P/AI: 44.8%; P150: 82.3%) groups had more cows AIE and higher P/AI and P150 than the RF (AIE: 64.5%; P/AI: 34.9%; P150: 72.9%) and NE-VWP (AIE: 50.0%; P/AI: 38.9%; P150: 72.1%) groups, respectively. When both factors were combined, the largest and most consistent differences were between the E-NoRF (AIE: 91.3%; P/AI: 58.7%; P150: 88.5%) and NE-RF groups (AIE: 47.3%; P/AI: 35.8%; P150: 69.5%). Compared with the whole population of cows or cows grouped based on a single factor, the E-NoRF and NE-RF groups had the largest and most consistent differences with the whole cow cohort. The E-NoRF and NE-RF groups also had statistically significant differences of a large magnitude when compared with the remaining cow cohort after removal of the respective group. We conclude that combining data for AEA during the VWP with other predictors of reproductive performance could be used to identify groups of cows with larger differences in expected reproductive performance than if AEA and the predictors are used alone.

Association between genomic daughter pregnancy rate and expected milk production on the resumption of estrus behavior in Holstein cattle.

The objective of this observational study was to evaluate estrous expression at the first estrus occurring between 7 to 30 d in milk (DIM), as detected by an automated activity monitor (AAM), and its association with genomic daughter pregnancy rate (GDPR) and genomic expected milk production (GEM) in lactating dairy cows. A total of 4,119 lactations from 2,602 Holstein cows were included. Cows were enrolled as first lactation (n = 1,168), second lactation (n = 1,525) and third and greater lactation (n = 1,426). Hair samples were collected from the tail switch, and cows were genotyped using an SNP platform (Clarifide, Zoetis, São Paulo, SP, Brazil). Postpartum cows were examined daily by the farm personnel from calving until 10 DIM. Calving was classified as assisted (forced calf extraction) and unassisted (normal calving). Retained fetal membranes (RFM), hyperketonemia (KET), and left displaced abomasum (LDA) were also recorded. Mean GDPR (± SD) was -0.29 ± 1.4, and the intensity and duration of the first estrus event was 15.9 ± 13.1 x-factor (intensity unit measurement) and 11.1 ± 3.8 h, respectively. Cows that had greater GDPR had greater intensity and longer duration of estrus at the alert, independent of parity. Overall resumption of estrous expression, between 7 to 30 DIM, was 41.2% (1,695/4,119), where 58.8% (2,424/4,119) did not have an estrus event, 31.0% (1,274/4,119) of cows had one event of estrus, and 10.2% (421/4,119) of cows had 2 or more events of estrus early postpartum. Mean DIM (± SD) at first estrus event, detected by the AAM, was 19.4 ± 4.4 d. Days in milk at first event for cows with one event was 20.7 ± 1.6 d and 15.9 ± 3.1 d for cows with 2 or more events of estrus. First lactation cows were more likely to have an estrus event early postpartum when compared with second and third and greater lactation cows (45.2 ± 1.4% [530/1168] vs. 41.6 ± 1.3% [636/1525] vs. 37.2 ± 1.3% [529/1426], respectively). There was an interaction of parity and GDPR on the proportion of cows demonstrating an early postpartum estrus. There was no difference in the proportion of cows with an early postpartum estrus between those with assisted or unassisted calving, RFM, or LDA. However, cows that had KET were less likely to have an alert early postpartum when compared with cows that did not have KET. Mean genomic expected milk production (± SD) was 256.8 ± 600.1 kg. There was no interaction between GEM and parity on estrous expression (i.e., intensity and duration). There was no interaction between GEM and GDPR on the proportion of estrus early postpartum.

Effect of postpartum body condition score change on the pregnancy outcomes of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after a synchronized estrus versus a synchronized ovulation.

Our objective was to compare insemination rate and pregnancies per artificial insemination (P/AI) of lactating Jersey cows inseminated at first service with sexed Jersey or conventional beef semen after submission to a Double-Ovsynch protocol for timed artificial insemination (TAI) versus a protocol to synchronize estrus at similar days in milk (DIM). Secondary objectives were to determine the effect of protocol synchrony and postpartum body condition score (BCS) change on P/AI. Lactating Jersey cows (n = 1,272) were allocated by odd versus even ear tag number, which was randomly allocated within the herd, within parity and semen type for submission to a Double-Ovsynch protocol (DO; n = 707) or a protocol to synchronize estrus (ED; n = 565). All ED cows detected in estrus were inseminated (EDAI; n = 424), with undetected cows receiving TAI after an Ovsynch protocol (EDTAI; n = 141). There was a treatment by parity interaction on insemination rate with 100% of DO cows receiving TAI, but a tendency for fewer primiparous ED cows to be detected in estrus and AI than multiparous cows (69.5% ± 0.04% vs. 77.1% ± 0.02%, respectively). For cows inseminated with sexed Jersey or conventional beef semen, DO cows tended to have and had more P/AI than EDAI cows (sexed, 49.2% ± 0.03% vs. 43.6% ± 0.03%; beef, 64.2% ± 0.04% vs. 56.3% ± 0.05%, respectively) and had more P/AI than EDAI+EDTAI cows (sexed, 49.1% ± 0.03% vs. 40.6% ± 0.03%; beef, 65.5% ± 0.04% vs. 56.2% ± 0.04%, respectively). Overall, 29.1% of DO cows expressed estrus with 5.0% and 24.2% of cows detected in estrus ≥24 h before and at TAI, respectively, and there was no difference in P/AI 61 ± 4 d after AI based on expression of estrus at TAI. The synchronization rate was greater for DO than EDAI cows (92.1% ± 0.01% vs. 79.2% ± 0.02%, respectively); however, synchronized DO cows had more P/AI than synchronized EDAI cows (55.0% ± 0.02% vs. 49.2% ± 0.03%, respectively). There was an interaction between BCS change from 7 to 39 ± 2 DIM and treatment on P/AI 61 ± 4 d after AI with no difference between DO and EDAI cows that lost = 0.25 (49.8% ± 0.04% vs. 51.0% ± 0.05%, respectively) or maintained or gained (55.6% ± 0.04% vs. 50.8% ± 0.05%, respectively) BCS, but within cows that lost ≥0.5 BCS, DO cows had more P/AI than EDAI cows (54.1% ± 0.04% vs. 36.1% ± 0.04%, respectively). In conclusion, submission of lactating Jersey cows to a Double-Ovsynch protocol for first insemination increased insemination rate and fertility to first insemination compared with AI after a detected estrus regardless of semen type and expression of estrus, particularly for cows with excessive postpartum BCS loss.

Reproductive physiological outcomes of dairy cows with different genomic merit for fertility: Biomarkers, uterine health, endocrine status, estrus features, and response to ovarian synchronization.

Our overarching objective was to characterize associations between genomic merit for fertility and the reproductive function of lactating dairy cows in a prospective cohort study. In this manuscript, we present results of the association between genomic merit for fertility and indicators of metabolic status and inflammation, uterine health, endocrine status, response to synchronization, and estrous behavior in dairy cows. Lactating Holstein cows entering their first (n = 82) or second (n = 37) lactation were enrolled at parturition and fitted with an ear-attached sensor for automated detection of estrus. Ear-notch tissue samples were collected from all cows and submitted for genotyping using a commercial genomic test. Based on genomic PTA values for daughter pregnancy rate (gDPR), cows were classified into a high (Hi-Fert; gDPR >0.6; n = 36), medium (Med-Fert; gDPR -1.3 to 0.6; n = 45), or low (Lo-Fert; gDPR <-1.3; n = 38) group. At 33 to 39 DIM, cohorts of cows were enrolled in the Presynch-Ovsynch protocol for synchronization of estrus and ovulation. Body weights, BCS, and uterine health measurements (i.e., vaginal discharge, uterine cytology) were collected from parturition to 60 DIM, and milk yield was collected through 90 DIM. Blood samples were collected weekly through 3 wk of lactation for analysis of BHB, nonesterified fatty acids (NEFA), and haptoglobin plasma concentrations. Body weight, BCS, NEFA, BHB, and haptoglobin were not associated with fertility groups from 1 to 9 wk after parturition. The proportion of cows classified as having endometritis at 33 to 36 DIM tended to be greater for the Lo-Fert than the Hi-Fert group. The proportion of cows that resumed cyclicity did not differ at any time point evaluated, and there were no significant associations between probability or duration and intensity of estrus with fertility group. Cows of superior genetic merit for fertility were more likely to ovulate, have a functional corpus luteum, have greater circulating progesterone, and have larger ovulatory size than cows of inferior fertility potential at key time points during synchronization of estrus and ovulation. Despite observing numerical differences with potential performance consequences for the proportion of cows that responded to synchronization of ovulation and were both cyclic and responded to the Ovsynch portion of the synchronization protocol, we did not observe significant differences between fertility groups. Although not consistent and modest in magnitude, the collective physiological and endocrine differences observed suggested that cows of superior genetic fertility potential might have improved reproductive performance, at least in part, because of modestly improved endocrine status, uterine health, and ability to ovulate.

Taurine dynamics in serum during the oestrous cycle in buffaloes.

Estrus identification is one of the common issues in buffaloes because of their short estrus duration and silent estrus problem. Hence, specific biomarkers facilitating in identifying the estrus stage would be helpful to buffalo farmers and researchers. In our previous studies, taurine, a non-protein amino acid that helps in the secretion of reproductive hormones such as GnRH, was found to be associated with postpartum anestrus in buffaloes. Therefore, the present study was conducted to explore the level of taurine in serum during different stages of the oestrous cycle in healthy cyclic buffaloes. Blood samples were collected from healthy cyclic buffaloes (n = 4), and taurine was estimated at the estrus (0th day), proestrus (-2nd day), metestrus (3rd day) and diestrus (+10th day) stages using TLC method. The days of the oestrous cycle were determined by ultrasonography and observation of behavioural signs by trained professionals. The results revealed that taurine was consistently present in the serum. However, the highest concentration of taurine was observed at the proestrus (0.20 ± 0.03 mg/mL) stage, which was greater (p < .05) than metestrus (0.10 ± 0.05 mg/mL) and diestrus (0.13 ± 0.03 mg/mL) stages, but comparable with the estrus stage. These results were also validated in the simulated population datasets of population size 6 to 10,000. Further, ROC curve analysis for the large simulated population indicated the efficiency of taurine to distinguish proestrus from metestrus and diestrus stages at a lower cutoff value of <0.1643 mg/mL with 60% sensitivity and specificity. Therefore, the present study concludes that serum taurine concentration could help in detecting proestrus stage of buffalo estrous cycle.

Temporal disposition of pelvic girdle, vagina and vulva in relation to urovagina in cycling and pregnant-postpartum cows.

Urovagina (UV) is less studied in cows. The vaginal contents, constrictor vestibule muscle activity, circulating progesterone, pelvic girdle, vagina and vulva angles were compared on Days 0 and 14 within and between UV (UV group; n = 36) and normal (N group; n = 36) cows. The oestrous duration was compared among the groups. Parameters for various UV severities were also compared. Another set of pregnant-postpartum cows (P-PP group; n = 31) underwent monthly evaluations for UV and the angles from the third month of pregnancy until the second month postpartum. The effect of age, parity and body condition score on UV severities on Day 0, and parity on angles in the P-PP group was evaluated. Different variables were correlated in different groups. The UV group was repeat breeder, exhibited prolonged oestrus and reduced progesterone on Day 14. The latter increased with UV severity on Day 0. On Day 14, severe form of UV was more prevalent. The UV severity increased with parity. In the UV group, a cranioventral pelvic girdle on Day 0 became more cranioventral on Day 14 and was correlated with the vagina moving from a caudodorsal position on Day 0 to a cranioventral position on Day 14. In the P-PP group, the pelvic girdle and vagina remained caudodorsal and UV was undetectable throughout the study. Vagina and vulva displayed a parity-by-month interaction in the P-PP group. To summarize, the UV characteristics were influenced by the oestrous cycle stage, pelvic girdle angles, and parity.

Early prediction of oestrus for herd fertility management in cattle and buffaloes - a review.

Oestrus is defined as a period when a female animal exhibits characteristic sexual behaviour in the presence of a mature male. Oestrous manifestation in dairy animals is due to the oestrogen (E2) effect on the central nervous system (CNS). It is a critical issue to be considered on a priority basis. Inefficient oestrous detection reduces the fertility status of the herd. The primary and most reliable indicator of oestrus is standing to be mounted by a bull or another female herd mate, signalling receptivity and the pre-ovulatory state in dairy cattle. Oestrous detection is primarily a management challenge requiring skill and vigilance. To improve the efficiency of oestrous detection in dairy cattle, visual observation is one of the best methods if done three times a day; however, heat detection aids, if combined, give better results. However, techniques like using teaser bulls, tail painting, chin ball markers, ultrasound (USG) examination, hormonal analysis and examination of cervicovaginal mucus (CVM) improve oestrous detection efficiency. Moreover, the changes in production systems have reduced the expression of oestrous behaviour among cows, due to higher oestrogen (E2) metabolism. Therefore, automated systems, such as pedometers, accelerometers and acoustic sensors like infrared thermography (IRT) and image processing, have significantly enhanced reproductive performance by facilitating oestrous detection and optimizing insemination schedules. From this review, we would conclude that oestrous detection alone contributes considerably to the reproductive status of the herd; therefore, applying different methods of oestrous detection reduces the incidence of missed oestrus and improves the fertility status of the herd.

Effect of prostaglandin alone and in combination with trace minerals on the follicular and luteal dynamics, estrus response and pregnancy in sub-estrus buffaloes (Bubalus bubalis).

Sub-estrus is a condition when buffaloes do not display behavioural estrus signs, despite being in estrus and causes a delay in conception and increases the service period. The present study describes the effect of synthetic prostaglandin (PGF2α) alone and in combination with trace minerals on the follicular and corpus luteum (CL) dynamics, serum estradiol (E2) and progesterone (P4) concentration correlating estrus response and pregnancy outcome in sub-estrus buffaloes during the breeding season. A total of 50 sub-estrus buffaloes, identified through ultrasonography (USG) examination, were randomly allocated into three groups, viz. T1 (Synthetic PGF2α, Inj. Cloprostenol 500 µg, i.m, n = 17), T2 (Synthetic PGF2α + Trace mineral supplementation, Inj. Stimvet 1 mL/100 kg body weight, i.m., n = 17) and control (untreated; n = 16). Following treatment, 100% of sub-estrus buffaloes were induced estrus in the T1 and T2 groups, while only 18.75% were induced in the control. The CL diameter and serum P4 concentration were significantly lower at post-treatment, whereas the pre-ovulatory follicle (POF) size and serum E2 concentration were significantly higher in the T1 and T2 groups as compared to the control (p < .05). The buffaloes of the T2 group had a greater proportion of moderate intensities estrus than those of T1. Moreover, the proportion of buffaloes conceived in the T1 and T2 were 41.2% and 52.95%, respectively. The larger POF diameter and higher serum E2 concentration were associated with intense intensity estrus and higher conception rate (66.7%) in sub-estrus buffaloes. Similarly, CL regression rate, POF size and serum E2 concentration were relatively higher in the buffaloes conceived as compared to those not conceived. It is concluded that synthetic PGF2α in combination with trace minerals induces moderate to intense intensities estrus in a greater proportion of sub-estrus buffaloes and increases the conception rate during the breeding season. Moreover, behavioural estrus attributes correlating follicle and luteal morphometry, serum E2 and P4 concentration could be used to optimise the breeding time for augmenting the conception rate in sub-estrus buffaloes.

Effects of supplementation of grazing Nellore cows with ß-carotene and vitamins A + D3 + E + biotin on follicle diameter, oestrus, establishment of pregnancy, and foetal morphometry.

The objectives of this experiment were to evaluate the effects of supplementation of Nellore (Bos indicus) cows with ß-carotene + vitamins A + D3 + E + biotin on body condition score (BCS), oestrus, pregnancy, and foetal morphometry. Lactating cows (n = 497) from two herds were balanced for BCS and calving period [early calving (EC); late calving (LC)] and were assigned randomly to: Control (n = 251)-supplementation with a mineral supplement; and SUP (n = 246)-supplementation with the mineral supplement fed to control + ß-carotene (150 mg/day) + vitamin A (40,000 IU/day) + vitamin D3 (5000 IU/day) + vitamin E (300 mg/day) + biotin (20 mg/day). Cows were supplemented from Days -30 to 30 (Day 0 = timed artificial insemination; TAI). Pregnancy was diagnosed 30 days after TAI and foetal crown-rump distance and thoracic diameter were measured at 30 and 77 days of gestation. Cows in the SUP treatment were more likely to have BCS ≥3.0 on Day 0 (63.0 ± 3.1 vs. 60.2 ± 3.1; p < .01) and were more likely to gain BCS from Days -30 to 30 (57.7 ± 3.3 vs. 44.1 ± 3.3%; p < .01). Fewer LC cows in the SUP treatment were detected in oestrus at the time of the first TAI (Control: LC: 75.4 ± 4.4 vs. SUP: LC: 64.0 ± 5.2 vs. Control: EC: 65.3 ± 4.0 vs. SUP: EC: 71.8 ± 3.7; p = .04). There was a tendency for the SUP treatment to increase pregnancy to the first TAI (64.2 ± 3.0 vs. 56.6 ± 3.1%; p = .08). A greater percentage of SUP cows was detected in oestrus at the time of the second TAI (70.1 ± 5.0 vs. 52.3 ± 4.8%; p = .01). The SUP treatment increased pregnancy to the second TAI among LC cows (SUP: LC: 75.9 ± 8.0% vs. Control: LC: 50.0 ± 8.3% vs. Control: EC: 52.0 ± 5.9% vs. SUP: EC: 41.4 ± 6.5%; p = .02). The SUP treatment increased foetal size (crown-rump; p = .04 and thoracic diameter; p < .01) at 30 days of gestation and, despite decreasing crow-rump length at 77 days after the first TAI among EC cows (p < .01), it increased the thoracic diameter at 77 days after the first TAI independent of calving season. Our results support that pregnancy establishment and foetal growth can be improved when grazing Nellore cows are supplemented with ß-carotene and vitamins A + D3 + E + biotin.