Reproductive Events Research Articles

Unmasking seasonal cycles in a high-input dairy herd in a hot environment: How climate shapes dynamics of milk yield, reproduction, and productive status

This study aimed to predict the annual herd milk yield, lactation, and reproductive cycle stages in a high-input dairy herd in a zone with prolonged thermal stress. Also, the impact of climatic conditions on milk yield and productive and reproductive status was assessed. An autoregressive integrated moving average (ARIMA) model was used in data fitting to predict future monthly herd milk yield and reproductive status using data from 2014 to 2020. Based on the annual total milk output, the highest predicted percentage of milk yield based on the yearly milk production was in February (9.1%; 95% CI = 8.3–9.9) and the lowest in August (6.9%; 95% CI = 6.0–7.9). The predicted highest percentage of pregnant cows for 2021 was in May (61.8; 95% CI = 53.0–70.5) and the lowest for November (33.2%; 95% CI = 19.9–46.5). The monthly percentage of dry cows in this study showed a steady trend across years; the predicted highest percentage was in September (20.1%; CI = 16.4–23.7) and the lowest in March (7.5%; 4.0–11.0). The predicted days in milk (DIM) were lower in September (158; CI = 103–213) and highest in May (220; 95% CI = 181–259). Percentage of calvings was seasonal, with the predicted maximum percentage of calvings occurring in September (10.3%; CI = 8.0–12.5) and the minimum in April (3.2%; CI = 1.0–5.5). The highest predicted culling rate for the year ensuing the present data occurred in November (4.3%; 95% CI = 3.2–5.4) and the lowest in April (2.5%; 95% CI = 1.4–3.5). It was concluded that meteorological factors strongly influenced rhythms of monthly milk yield and reproductive status. Also, ARIMA models robustly estimated and forecasted productive and reproductive events in a dairy herd in a hot environment.

A dynamic state variable model suggests a stronger effect of age than individual energetic state on reproductive allocation in burying beetles

Evolutionary fitness is determined by how an organism allocates energy, or other limited resources, to reproduction during its lifetime. For iteroparous organisms, two alternative patterns of lifetime reproductive allocation are terminal investment and reproductive restraint. Terminal investment maximizes an individual’s current reproductive output by allocating all available resources to current reproduction at the cost of future reproduction. In contrast, the reproductive restraint strategy allocates the individual’s resources toward future survival and reproductive events. We used dynamic state variable modeling to investigate the conditions under which the burying beetle, Nicrophorus orbicollis, would balance between reproductive restraint and terminal investment over their lifetime. Our model provides a formal extension, specific to burying beetle biology, of the dynamic terminal investment threshold conceptual model. For young females, we show that delayed reproduction and reproductive restraint are the optimal tactic for all individuals except for those in the highest condition. However, as age increases, terminal investment becomes the optimal tactic over an increasingly broader range of individual conditions. Surprisingly, manipulation of a variety of factors, such as survival rate, resource availability, and metabolic costs, causes only minor changes in the general pattern observed. We suggest that in burying beetles, and other similar organisms, age plays a dominant role in determining the pattern of reproductive allocation over a lifetime. Individual energetic condition is important in changing the boundaries between alternative reproductive strategies, but it does not change the overall pattern of dominance of delayed reproduction or reproductive restraint at early ages and dominance of terminal investment with increasing age.

First record of a neonate bluntnose sixgill shark (Hexanchus griseus) from Baja California Sur, Mexico.

The bluntnose sixgill shark (Hexanchus griseus) is a wide-ranged deep-water shark species found off continental and insular shelves. Despite its global distribution, little is known about the reproductive ecology of the species, particularly with regard to the location and timing of important phenological events such as mating and pupping. In this study, we report the landing of a neonate H. griseus individual from an artisanal fishing camp in Baja California Sur, Mexico. This represents only the ninth confirmed record of the species from the Mexican Pacific and the first to report a neonate specimen in Mexican waters. We discuss this specimen in the context of the environmental conditions in which it was found, ultimately suggesting that these shallow coastal waters may be an important pupping ground for H. griseus in the region. Furthermore, the specimen was found during the winter months (whereas all previous reports have suggested H. griseus pups during the summer), implying regional variation in reproductive periodicity, or the presence of multiple reproductive events per year. This study provides novel insight into the reproductive biology of H. griseus and the ecological characteristics of the species in the Northern Mexican Pacific.

Multistage time-to-event models improve survival inference by partitioning mortality processes of tracked organisms

Advances in tagging technologies are expanding opportunities to estimate survival of fish and wildlife populations. Yet, capture and handling effects could impact survival outcomes and bias inference about natural mortality processes. We developed a multistage time-to-event model that can partition the survival process into sequential phases that reflect the tagged animal experience, including handling and release mortality, post-release recovery mortality, and subsequently, natural mortality. We demonstrate performance of multistage survival models through simulation testing and through fish and bird telemetry case studies. Models are implemented in a Bayesian framework and can accommodate left, right, and interval censorship events. Our results indicate that accurate survival estimates can be achieved with reasonable sample sizes (n≈100+)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$n\\approx 100+)$$\\end{document} and that multimodel inference can inform hypotheses about the configuration and length of survival stages needed to adequately describe mortality processes for tracked specimens. While we focus on survival estimation for tagged fish and wildlife populations, multistage time-to-event models could be used to understand other phenomena of interest such as migration, reproduction, or disease events across a range of taxa including plants and insects.

The regulatory mechanism of rapid lignification for timely anther dehiscence.

Anther dehiscence is a crucial event in plant reproduction, tightly regulated and dependent on the lignification of the anther endothecium. In this study, we investigated the rapid lignification process that ensures timely anther dehiscence in Arabidopsis. Our findings reveal that endothecium lignification can be divided into two distinct phases. During Phase I, lignin precursors are synthesized without polymerization, while Phase II involves simultaneous synthesis of lignin precursors and polymerization. The transcription factors MYB26, NST1/2, and ARF17 specifically regulate the pathway responsible for the synthesis and polymerization of lignin monomers in Phase II. MYB26-NST1/2 is the key regulatory pathway responsible for endothecium lignification, while ARF17 facilitates this process by interacting with MYB26. Interestingly, our results demonstrate that the lignification of the endothecium, which occurs within approximately 26 h, is much faster than that of the vascular tissue. These findings provide valuable insights into the regulation mechanism of rapid lignification in the endothecium, which enables timely anther dehiscence and successful pollen release during plant reproduction.

Reproductive behavior of Phyllomedusa tetraploidea (Anura: Hylidae) Pombal & Haddad, 1992 in the Brazilian Atlantic Forest

The reproductive potential of an individual is crucial for ensuring the production of offspring. However, knowledge about polyandry in anurans is limited. In this report, we present the first documented case of polyandrous reproduction or multiple reproduction in Phyllomedusa tetraploidea (Anura: Hylidae) Pombal & Haddad, 1992. This observation occurred during a rainy night in the Atlantic Forest region of northwest Paraná, Brazil. The multiple reproduction event involved four males (three of which were identified as satellites) and one female. Notable behaviors were recorded, including a vocalizing male assisting the female in folding leaves with his feet before depositing the eggs. The entire multiple reproduction event lasted about 40 minutes. Additionally, we observed a pair of P. tetraploidea engaging in axillary amplexus, where the male and female positioned their bellies toward each other. This amplexus lasted approximately 80 minutes, from their initial meeting until the eggs were deposited and they separated. This study contributes to our understanding of P. tetraploidea's reproductive mode, detailing behaviors from vocalization to egg deposition. It also adds to our knowledge of the evolution of reproductive strategies.

Ancestral reproductive bias in continuous-time branching trees under various sampling schemes

Cheek and Johnston (JMB 86:70, 2023) consider a continuous-time Bienaymé-Galton-Watson tree conditioned on being alive at time T. They study the reproduction events along the ancestral lineage of an individual randomly sampled from all those alive at time T. We give a short proof of an extension of their main results (Cheek and Johnston in JMB 86:70, 2023, Theorems 2.3 and 2.4) to the more general case of Bellman-Harris processes. Our proof also sheds light onto the probabilistic structure of the rate of the reproduction events. A similar method will be applied to explain (i) the different ancestral reproduction bias appearing in work by Geiger (JAP 36:301–309, 1999) and (ii) the fact that the sampling rule considered by Chauvin et al. (SPA 39:117–130, 1991), (Theorem 1) leads to a time homogeneous process along the ancestral lineage.

Variables Affecting CA15.3 Tumor Antigen Expression and Antibodies against It in Female National Health and Nutritional Survey Participants.

Cancers of ductal origin often express glycoprotein mucin 1 (MUC1), also known as CA15.3, with higher levels leading to poor prognosis. Conversely, anti-MUC1 antibodies develop in some patients, leading to better prognosis. We sought to identify epidemiologic factors associated with CA15.3 antigen or antibody levels. Levels of CA15.3 antigen and anti-CA15.3 IgG antibodies were measured in archived sera from 2,302 mostly healthy women from the National Health and Nutritional Survey; and epidemiologic predictors of their levels were examined using multivariate and correlational analyses. Among racial groups, Black women had the highest levels of CA15.3 antigen and lowest levels of antibodies. Increasing body mass index and current smoking were associated with low anti-CA15.3 antibody levels. Low CA15.3 antigen levels were seen in oral contraceptive users and high levels in women who were pregnant or lactating at the time of blood collection, with the latter group also having high antibody levels. Past reproductive events associated with high antigen levels included the following: later age at menarche, having given birth, and history of endometriosis. Lower antigen levels were seen with increasing duration of OC use. Anti-CA15.3 antibody levels decreased with an increasing estimated number of ovulatory years. Key determinants of CA.15.3 antigen or antibody levels include the following: race, body mass index, smoking, later menarche, childbirth, number of ovulatory cycles, and endometriosis. This study supports the premise that known epidemiologic factors affecting risk for or survival after MUC1-expressing cancers may, at least partially, operate through their association with CA15.3 antigen or antibody levels.

Long-term monitoring of the columnar cactus Cipocereus minensis reveals unforeseeable reproductive phenology

Phenological studies with species of cactus have grown in recent decades but the number of species studied remains very low, considering the high species richness of this group. In addition, temporal patterns of flowering and fruiting are important to understanding the processes that govern these crucial events of plant demography and ecology. Based on a five-year study of the reproductive phenology of C. minensis we asked if there is seasonality of flowering and fruiting. Secondly, we tested which climatic variables trigger C. minensis reproductive events in the Espinhaço region. We found that not all individuals produced flowers and fruits each year and a few individuals contributed with most flowers. Flower and immature fruit production is higher during the dry months, with fruits maturing during the rainy season or just before. In general, phenological events were seasonal, except for mature fruit production in 2010 and flower production in 2011. Some phenological traits such as flower timing, frequency, duration, and timing of immature fruit production had not been reported for the genus Cipocereus and were detected only because of the long-term phenological observations. Phenological heterogeneity in cactus might be a response to annual climatic fluctuations, mainly rainfall.

Fission as a source of variation for group selection.

Without heritable variation natural selection cannot effect evolutionary change. In the case of group selection, there must be variation in the population of groups. Where does this variation come from? One source of variation is from the stochastic birth-death processes that occur within groups. This is where variation between groups comes from in most mathematical models of group selection. Here, we argue that another important source of variation between groups is fission, the (generally random) group-level reproduction where parent groups split into two or more offspring groups. We construct a simple model of the fissioning process with a parameter that controls how much variation is produced among the offspring groups. We then illustrate the effect of that parameter with some examples. In most models of group selection in the literature, no variation is produced during group reproduction events; that is, groups "clone" themselves when they reproduce. Fission is often a more biologically realistic method of group reproduction, and it can significantly increase the efficacy of group selection.

The influence of factors associated with past reproductive histories on migraines in middle-aged premenopausal women: a nationwide population-based study in Republic of Korea.

Women can experience various reproductive events, such as pregnancy, childbirth, lactation, and contraception, which cause long-term changes in female hormones. In middle-aged women, the prevalence of migraine is high, and a clear gender difference is evident. This study investigated the effects of factors associated with past reproductive events on the risk of new migraine in middle-aged premenopausal women. The influence of reproductive factors on migraine in middle-aged women was investigated using the Korean National Health Insurance Service (KNHIS) and Korean Health Examination (KHE) databases. The reproductive factors of interest were parity, breastfeeding, and oral contraceptive (OC) use. The study included 949,704 middle-aged premenopausal women 40-60 years of age. The study population was divided into two groups based on new diagnosis of migraine during the follow-up period (2009-2018). The risk of new migraine tended to increase in the primiparous (hazard ratio, HR: 1.179; 95% confidence interval, CI: 1.137-1.221) and multiparous groups (HR: 1.181; 95% CI: 1.142-1.221) compared with the nulliparous group. The breastfeeding ≥12 months group (HR: 1.071; 95% CI: 1.052-1.091) showed a significantly increased risk of new migraine compared with the non-breastfeeding group. All women in the OC groups (< 1 year, HR: 1.048; 95% CI: 1.028-1.069 and ≥ 1 year, HR: 1.100; 95% CI: 1.067-1.134) showed a higher risk of new migraine than those in the non-OC group. The results of the current study indicate that childbirth, longer breastfeeding, and OC use may be associated with a higher risk of new migraine in middle-aged premenopausal women.

Reproductive adverse events in patients with non‐Hodgkin lymphoma treated with chemotherapeutic regimens including cyclophosphamide, doxorubicin, vincristine, prednisone or CHOP with rituximab: A systematic review and meta‐analysis

AbstractThe regimen of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) or CHOP with rituximab (R‐CHOP) is the first‐line treatment for non‐Hodgkin lymphoma (NHL). NHL patients treated with CHOP/R‐CHOP have a high risk of reproductive adverse events. The aim of this article was to evaluate the reproductive toxicity of regimens and make further suggestions on reproductive protection. We systematically searched with appropriate terms from January 1980 to June 2021 for observational studies in patients treated with CHOP/R‐CHOP, without any language restriction. We conducted meta‐analyses of one‐sample proportions of patients suffering reproductive adverse events after using CHOP/R‐CHOP. In addition, subgroup analyses were performed to determine the effect of sex. Nine articles involving 331 patients were included in the meta‐analysis, and the pooled proportion of reproductive adverse events was computed to be 22.3% (95% confidence interval [CI] 11.4%–33.2%; heterogeneity test Q = 65.3; τ2 = 0.0231; I2 = 87.70%; p &lt; 0.001) using the random‐effects model. And, the pooled proportion of male gonadal toxicity was 29.2% (95% CI 11.0%–47.4%; heterogeneity test Q = 46.65; τ2 = 3.055; I2 = 89.3%; p &lt; 0.0001). The pooled proportion of female gonadal toxicity was 16.5% (95% CI 8.5%–24.5%; heterogeneity test Q = 18.6; τ2 = 0.0112; I2 = 67.8%; p = 0.005). The findings suggest that NHL patients have a relatively high risk of reproductive adverse events after treatment with CHOP/R‐CHOP. Men are more likely to have gonadal damage than women. Evaluation of reproductive function is particularly necessary both before and after treatment. Some reproductive protection strategies implemented for patients who want to preserve their fertility.

Breaking down causes, consequences, and mediating effects of telomere length variation on human health

BackgroundTelomeres form repeated DNA sequences at the ends of chromosomes, which shorten with each cell division. Yet, factors modulating telomere attrition and the health consequences thereof are not fully understood. To address this, we leveraged data from 326,363 unrelated UK Biobank participants of European ancestry.ResultsUsing linear regression and bidirectional univariable and multivariable Mendelian randomization (MR), we elucidate the relationships between leukocyte telomere length (LTL) and 142 complex traits, including diseases, biomarkers, and lifestyle factors. We confirm that telomeres shorten with age and show a stronger decline in males than in females, with these factors contributing to the majority of the 5.4% of LTL variance explained by the phenome. MR reveals 23 traits modulating LTL. Smoking cessation and high educational attainment associate with longer LTL, while weekly alcohol intake, body mass index, urate levels, and female reproductive events, such as childbirth, associate with shorter LTL. We also identify 24 traits affected by LTL, with risk for cardiovascular, pulmonary, and some autoimmune diseases being increased by short LTL, while longer LTL increased risk for other autoimmune conditions and cancers. Through multivariable MR, we show that LTL may partially mediate the impact of educational attainment, body mass index, and female age at childbirth on proxied lifespan.ConclusionsOur study sheds light on the modulators, consequences, and the mediatory role of telomeres, portraying an intricate relationship between LTL, diseases, lifestyle, and socio-economic factors.

Abstract PO5-08-03: Breastfeeding and Breast Cancer Screening Among Carriers of Pathogenic Variants in BRCA 1 and BRCA 2 and Other High Penetrance Genes: Knowledge and Perspectives

Abstract Objectives: Carriers of pathogenic variants in high penetrance mutations, including BRCA 1 or BRCA 2 face higher lifetime risks of developing breast and tubo-ovarian cancers, and possibly endometrial cancers, than non-carriers. In particular, relative risks are higher among carriers than non-carriers at younger ages, suggesting the value of early initiation of breast cancer screening and the use of sensitive imaging methods, such as magnetic resonance imaging (MRI). Further, breastfeeding appears protective for these three cancers in the general population, and potentially among mutation carriers, albeit based on limited evidence. Given that data related to knowledge and perspectives of carriers about these issues are limited, we surveyed mutation carriers regarding breastfeeding, cancer risk, and the deferral of breast cancer screening coinciding with reproductive events. These data may guide future cancer prevention research and developing of targeted communication campaigns. Methods: Researchers at Mayo Clinic, in collaboration with Facing Our Risk of Cancer Empowered (FORCE) – a large, national non-profit organization that addresses the needs of people and families affected by inherited mutations linked to cancer – designed and conducted a survey using the Mayo Clinic’s external RedCap system. The survey covered genetic testing and results, history of live births and breastfeeding history for mothers, history of risk-reducing surgery, personal cancer history, sources of information about cancer screening, breastfeeding knowledge, and breast cancer screening at various times, including during pregnancy, while breastfeeding, and after weaning. The survey was disseminated through FORCE’s electronic newsletter, website, social media pages, and advocacy partners. Survey responses were collected anonymously and analyzed descriptively using standard descriptive statistics, including frequency and percentages for categorical responses and means (SD) or medians (IQR) for continuously scaled responses. The open-ended responses were analyzed qualitatively using standard qualitative methodology. Results: Respondents included 253 women, of whom 88.7% were U.S. residents and 92.9% were white. The mean age + SD was 47(13) years, 61.7% were parous, with a mean age at first birth of 22.58 (13.16) years. Approximately 60% of women were carriers of mutations in BRCA1 or BRCA2 or both genes and all but two of the remaining women reported mutations in other genes linked to increased cancer risk. At the time of the survey, 92% of women had undergone a mammogram, with first screen at a mean age of 35 (6.49) years, and 85.3% had undergone breast MRI, with first screen at a mean age of 43 (12.39) years. Among 34.3% of participants, their 1st postpartum mammogram occurred &amp;gt;3 years after the birth of their last child and 57% had 1st MRI 3 years postpartum. Preliminarily, our analysis shows that nearly 90% of women were unaware of their mutation status prior to pregnancy and approximately 1/3 did not undergo radiologic screening until 3 years postpartum. While 62.6% of respondents believed that breastfeeding lowers breast cancer risk, 74.2% of participants responded that nursing had no effect on tubo-ovarian cancer risk, and 78.2% considered that nursing did not impact endometrial cancer risk. Discussion and Conclusions: Preliminarily, we conclude that most women in the surveyed population were unaware of their mutation status when pregnant years earlier and many had not undergone screening until years after delivery. Many participants did not consider breastfeeding a potentially protective factor for women’s cancers. These data raise issues about the potential value of discussing genetic testing with women when considering family planning and mutation carriers, addressing complex issues about breast cancer screening while pregnant and breastfeeding. Citation Format: Laura Pacheco-Spann, Mark Sherman, Susan Friedman, Diane Rose, Miriam Levi, Alex Hochwald, Jennifer Ridgeway, Sophia Blumenfeld. Breastfeeding and Breast Cancer Screening Among Carriers of Pathogenic Variants in BRCA 1 and BRCA 2 and Other High Penetrance Genes: Knowledge and Perspectives [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-08-03.

Land use change and coastal water darkening drive synchronous dynamics in phytoplankton and fish phenology on centennial timescales

AbstractAt high latitudes, the suitable window for timing reproductive events is particularly narrow, promoting tight synchrony between trophic levels. Climate change may disrupt this synchrony due to diverging responses to temperature between, for example, the early life stages of higher trophic levels and their food resources. Evidence for this is equivocal, and the role of compensatory mechanisms is poorly understood. Here, we show how a combination of ocean warming and coastal water darkening drive long‐term changes in phytoplankton spring bloom timing in Lofoten Norway, and how spawning time of Northeast Arctic cod responds in synchrony. Spring bloom timing was derived from hydrographical observations dating back to 1936, while cod spawning time was estimated from weekly fisheries catch and roe landing data since 1877. Our results suggest that land use change and freshwater run‐off causing coastal water darkening has gradually delayed the spring bloom up to the late 1980s after which ocean warming has caused it to advance. The cod appear to track phytoplankton dynamics by timing gonadal development and spawning to maximize overlap between offspring hatch date and predicted resource availability. This finding emphasises the importance of land–ocean coupling for coastal ecosystem functioning, and the potential for fish to adapt through phenotypic plasticity.

Incidence of Cardiometabolic Associated Reproductive Events from 2010–2020 in Alberta, Canada

Incidence of Cardiometabolic Associated Reproductive Events from 2010–2020 in Alberta, Canada

Deep learning insights into the architecture of the mammalian egg-sperm fusion synapse

A crucial event in sexual reproduction is when haploid sperm and egg fuse to form a new diploid organism at fertilization. In mammals, direct interaction between egg JUNO and sperm IZUMO1 mediates gamete membrane adhesion, yet their role in fusion remains enigmatic. We used AlphaFold to predict the structure of other extracellular proteins essential for fertilization to determine if they could form a complex that may mediate fusion. We first identified TMEM81, whose gene is expressed by mouse and human spermatids, as a protein having structural homologies with both IZUMO1 and another sperm molecule essential for gamete fusion, SPACA6. Using a set of proteins known to be important for fertilization and TMEM81, we then systematically searched for predicted binary interactions using an unguided approach and identified a pentameric complex involving sperm IZUMO1, SPACA6, TMEM81 and egg JUNO, CD9. This complex is structurally consistent with both the expected topology on opposing gamete membranes and the location of predicted N-glycans not modeled by AlphaFold-Multimer, suggesting that its components could organize into a synapse-like assembly at the point of fusion. Finally, the structural modeling approach described here could be more generally useful to gain insights into transient protein complexes difficult to detect experimentally.

Deep learning insights into the architecture of the mammalian egg-sperm fusion synapse.

A crucial event in sexual reproduction is when haploid sperm and egg fuse to form a new diploid organism at fertilization. In mammals, direct interaction between egg JUNO and sperm IZUMO1 mediates gamete membrane adhesion, yet their role in fusion remains enigmatic. We used AlphaFold to predict the structure of other extracellular proteins essential for fertilization to determine if they could form a complex that may mediate fusion. We first identified TMEM81, whose gene is expressed by mouse and human spermatids, as a protein having structural homologies with both IZUMO1 and another sperm molecule essential for gamete fusion, SPACA6. Using a set of proteins known to be important for fertilization and TMEM81, we then systematically searched for predicted binary interactions using an unguided approach and identified a pentameric complex involving sperm IZUMO1, SPACA6, TMEM81 and egg JUNO, CD9. This complex is structurally consistent with both the expected topology on opposing gamete membranes and the location of predicted N-glycans not modeled by AlphaFold-Multimer, suggesting that its components could organize into a synapse-like assembly at the point of fusion. Finally, the structural modeling approach described here could be more generally useful to gain insights into transient protein complexes difficult to detect experimentally.

Microwave Dielectric Response of Bovine Milk as Pregnancy Detection Tool in Dairy Cows.

The most reliable methods for pregnancy diagnosis in dairy herds include rectal palpation, ultrasound examination, and evaluation of plasma progesterone concentrations. However, these methods are expensive, labor-intensive, and invasive. Thus, there is a need to develop a practical, non-invasive, cost-effective method that can be implemented on the farm to detect pregnancy. This study suggests employing microwave dielectric spectroscopy (MDS, 0.5-40 GHz) as a method to evaluate reproduction events in dairy cows. The approach involves the integration of MDS data with information on milk solids to detect pregnancy and identify early embryonic loss in dairy cows. To test the ability to predict pregnancy according to these measurements, milk samples were collected from (i) pregnant and non-pregnant randomly selected cows, (ii) weekly from selected cows (n = 12) before insemination until a positive pregnancy test, and (iii) daily from selected cows (n = 10) prior to insemination until a positive pregnancy test. The results indicated that the dielectric strength of Δε and the relaxation time, τ, exhibited reduced variability in the case of a positive pregnancy diagnosis. Using principal component analysis (PCA), a clear distinction between pregnancy and nonpregnancy status was observed, with improved differentiation upon a higher sampling frequency. Additionally, a neural network machine learning technique was employed to develop a prediction algorithm with an accuracy of 73%. These findings demonstrate that MDS can be used to detect changes in milk upon pregnancy. The developed machine learning provides a broad classification that could be further enhanced with additional data.

Neuroactive steroids in the neuroendocrine control of food intake, metabolism, and reproduction.

Neuroactive steroids are a type of steroid hormones produced within the nervous system or in peripheral glands and then transported to the brain to exert their neuromodulatory effects. Neuroactive steroids have pleiotropic effects, that include promoting myelination, neuroplasticity, and brain development. They also regulate important physiological functions, such as metabolism, feeding, reproduction, and stress response. The homoeostatic processes of metabolism and reproduction are closely linked and mutually dependent. Reproductive events, such as pregnancy, bring about significant changes in metabolism, and metabolic status may affect reproductive function in mammals. In females, the regulation of reproduction and energy balance is controlled by the fluctuations of oestradiol and progesterone throughout the menstrual cycle. Neurosteroids play a key role in the neuroendocrine control of reproduction. The synthesis of neuroestradiol and neuroprogesterone within the brain is a crucial process that facilitates the release of GnRH and LH, which in turn, regulate the transition from oestrogen-negative to oestrogen-positive feedback. In addition to their function in the reproductive system, oestrogen has a key role in the regulation of energy homoeostasis by acting at central and peripheral levels. The oestrogenic effects on body weight homoeostasis are primarily mediated by oestrogen receptors-α (ERα), which are abundantly expressed in multiple brain regions that are implicated in the regulation of food intake, basal metabolism, thermogenesis, and brown tissue distribution. The tight interplay between energy balance and reproductive physiology is facilitated by shared regulatory pathways, namely POMC, NPY and kisspeptin neurons, which are targets of oestrogen regulation and likely participate in different aspects of the joint control of energy balance and reproductive function. The aim of this review is to present a summary of the progress made in uncovering shared regulatory pathways that facilitate the tight coupling between energy balance and reproductive physiology, as well as their reciprocal interactions and the modulation induced by neurosteroids.