Duration of continuous fetal gastrointestinal peristalsis before parturition in mares maintained at a breeding farm or in a university hospital.

Citrulline supplementation does not reverse the effects of late gestation heat stress in ewes on feto-placental development.

Effect of season during late gestation on metabolic alterations, inflammatory response, and oxidative stress status in dairy cows and offspring.

Effects of gestational anemia on farrowing duration and reproductive outcomes in highly prolific sows in a tropical climate.

We examined the possible impact of selective serotonin reuptake inhibitor (SSRI)-trajectories describing the timing of different SSRI dosages on adverse perinatal outcomes. Longitudinal register study. Study from Kuopio University Hospital Birth Register. Altogether 553 mothers who reported using SSRIs in pregnancy were matched to a five-fold comparison group (n = 2765), based on depression, psychiatric diagnoses and age. We applied unsupervised k-Means longitudinal clustering to identify four distinct patterns of SSRI use, and propensity score adjusted regression models based on generalised estimating equations to examine the associations between the exposure groups and the perinatal outcomes, using the unexposed group as reference. Secondary analyses assessed linear associations between average SSRI dose and outcomes. Birth weight, placental weight, placental-to-birth-weight ratio (PBWR), umbilical cord length, gestational length, preterm birth (< 37 gestational weeks), low 5-min Apgar score, neonatal intensive care unit (NICU) admission. Compared to the no SSRI group, we found no associations between the use of SSRI up to standard doses and the perinatal outcomes. However, the sustained high dose group (~twice the standard dose) displayed higher placental weight (B = 36.9, 95% CI = 3.2, 70.7) and PBWR (B = 1.54, 95% CI = 0.70, 2.38), and the risk of NICU admission was 2-fold (95% CI = 1.05, 3.76), compared with the no SSRI group. The average SSRI dose was linearly associated with placental weight, PBWR, and umbilical cord length. SSRI use up to standard doses was not associated with adverse perinatal outcomes. However, linear dose-response associations and sustained higher doses suggest potentially reduced placental efficacy and increased risk of adverse perinatal health, warranting caution.

Diurnal cortisol trajectories from mid-pregnancy to one year after birth.

Seasonal breeding is a common adaptation among mammals in seasonal environments, ensuring offspring is born under favourable conditions. As only conception can be controlled but not birth itself, a predictive cue for these favourable conditions is needed (e.g., photoperiodism). Seasonal breeding, however, can also be disadvantageous if there will be time spent waiting until the next breeding season starts. We hypothesized that Old World camelids (OWC; C. bactrianus and C. dromedarius) exhibit a less pronounced seasonal breeding than South American camelids (SAC; L. glama, L. guanicoe, V. vicuna, V. pacos), given the higher costs of strict seasonality in OWC due to their gestation length (OWC ~ 13 months, SAC ~ 11 months). Both groups are expected to be long-day breeders, so that births occur in spring. We assessed data on conceptions of Camelidae, both from literature and zoo populations, and included information on latitude of origin and wet season. All camelid species were able to breed year-round, with the domestic forms of SAC being less seasonally restricted. OWC showed tendencies to long-day breeding, whereas SAC unexpectedly showed tendencies to short-day breeding. Patterns of conception peaks of literature and zoo populations were similar, suggesting the (partial) influence of photoperiodism. Further, inter-individual differences, as described for some rodents, cannot be ruled out. The climatic conditions and vegetational growth pattern of the natural habitat of SAC might explain the surprising short-day breeding seasonality. It deviates from the global pattern insofar as the most beneficial environmental conditions occur in autumn.

Reproductive traits are essential in dairy cattle breeding, and improving body conformation is considered beneficial for reproductive performance. This study systematically analyzed the genetic relationships between six key conformation traits—stature (ST), body depth (BD), loin strength (LS), rump angle (RA), rump width (RW), bone quality (BQ)—and reproductive performance in 1631 Jersey cattle from China. Heritability estimates for conformation traits ranged from 0.05 to 0.62. We identified significant phenotypic and genetic correlations between conformation and reproductive traits, and regression analyses confirmed the predictive value of conformation traits for reproductive outcomes. Genome-wide association studies detected 24 significant SNPs associated with ST, RW, RA, and BQ. Subsequent bioinformatics analysis revealed seven candidate genes (AZIN1, OR2H1, HS6ST3, ERCC4, KCNH5, KRT19, KRT35) involved in embryonic development and estrous cycle regulation. Notably, incorporating six SNPs, which are linked to these candidate genes, into genomic prediction models significantly improved the accuracy for predicting Age at First Calving (AFC) and Gestation Length (GL). These results elucidate the shared genetic basis of conformation and reproduction, providing theoretical support for using conformation traits in marker-assisted selection to enhance reproductive efficiency in Jersey cattle.

Seasonal breeding is a common adaptation among mammals in seasonal environments, ensuring offspring is born under favourable conditions. As only conception can be controlled but not birth itself, a predictive cue for these favourable conditions is needed (e.g., photoperiodism). Seasonal breeding, however, can also be disadvantageous if there will be time spent waiting until the next breeding season starts. We hypothesized that Old World camelids (OWC; C. bactrianus and C. dromedarius) exhibit a less pronounced seasonal breeding than South American camelids (SAC; L. glama, L. guanicoe, V. vicuna, V. pacos), given the higher costs of strict seasonality in OWC due to their gestation length (OWC ~ 13 months, SAC ~ 11 months). Both groups are expected to be long-day breeders, so that births occur in spring. We assessed data on conceptions of Camelidae, both from literature and zoo populations, and included information on latitude of origin and wet season. All camelid species were able to breed year-round, with the domestic forms of SAC being less seasonally restricted. OWC showed tendencies to long-day breeding, whereas SAC unexpectedly showed tendencies to short-day breeding. Patterns of conception peaks of literature and zoo populations were similar, suggesting the (partial) influence of photoperiodism. Further, inter-individual differences, as described for some rodents, cannot be ruled out. The climatic conditions and vegetational growth pattern of the natural habitat of SAC might explain the surprising short-day breeding seasonality. It deviates from the global pattern insofar as the most beneficial environmental conditions occur in autumn.

Background/Objectives: Air pollution is a recognized risk factor for preterm birth (PTB), a major cause of neonatal morbidity and mortality. The biological mechanisms underlying this association remain unclear, partly because PTB is a composite outcome that includes both spontaneous (sPTB, from preterm labor or rupture of membranes) and medically indicated (mPTB, for conditions such as preeclampsia or fetal growth restriction) subtypes. Additionally, PTB spans a range of gestational lengths from 20 to 36 completed weeks, which may reflect distinct etiologic pathways. Methods: This scoping review identified studies evaluating two pollutants strongly linked to PTB—particulate matter &lt; 2.5 µm in diameter (PM2.5) and nitrogen dioxide (NO2)—in relation to PTB phenotypes and gestational length. A comprehensive PubMed search using targeted MeSH terms and keywords included studies published between 1 January 2011 and 28 February 2024. Eligible studies examined associations of PM2.5 or NO2 with PTB and were categorized by whether they specified PTB phenotype (sPTB or mPTB), gestational length, or neither. Results: Of 436 eligible studies, 5 evaluated specific PTB phenotypes, 28 considered gestational length, and 3 addressed both. Reported associations of PM2.5 or NO2 with PTB were frequently significant but varied in magnitude and direction. Conclusions: Few studies have examined pollutant exposure in relation to PTB phenotypes or gestational lengths, revealing an important knowledge gap. Standardized approaches to exposure assessment and PTB classification are needed to clarify causal pathways and inform targeted prevention strategies and policies to reduce pollution-related PTB.

Context Gestation length is an important trait in beef cattle, because it is associated with calf birthweight and dystocia. This paper presents the first genetic parameters for gestation length in Australian tropical breeds, and the genetic relationships with birth and weaning weight. Aims We investigated the genetic and non-genetic effects of gestation length, birthweight and weaning weight for three tropical beef breeds (Brahman, Droughtmaster and Santa Gertrudis) in northern Australia. Genotype by environment interactions were assessed for each trait. Methods Animals were born between 2014 and 2022 from two herds, and after edits, there were 2346, 7044 and 6248 records for gestation length, birthweight and weaning weight, respectively. Animals were by 245 sires, with an average half-sibling family size of 29. Genetic parameters were estimated from pooled breed and breed-specific datasets. To assess genotype by environment interactions, traits at each herd were considered separate traits and bivariate analysis was undertaken. Results Breed, cohort and calf sex were the only non-genetic factors influencing gestation length; males were estimated to have longer gestation lengths of 3.1, 2.4 and 1.9 days for Brahman, Santa Gertrudis and Droughtmaster breeds, respectively. Gestation length was under high genetic influence, with a direct heritability of 0.79 (0.05). Birthweight and weaning weight direct heritability estimates were 0.52 (0.04) and 0.40 (0.04), respectively. Maternal heritability estimates for birth and weaning were 0.10 (0.02) and 0.15 (0.03), respectively. A positive genetic correlation of 0.30 (0.09) was estimated between gestation length and birthweight, whereas no significant genetic relationship was estimated between gestation length and weaning weight. No genotype by environment interactions were detected for gestation length, birthweight and weaning weight. Conclusions Gestation length for three tropically adapted breeds in northern Australia was highly heritable and showed no genotype by environment interaction. Genetic selection of sires for gestation length will reduce gestation length, and indirectly reduce birthweight and calving difficulties without any unexpected correlated effects on weaning weight. Implications Selection for decreased gestation length can indirectly reduce calf birthweight without impacting weaning weight.

A comprehensive study was conducted to evaluate the performance five major indigenous cattle breeds-Gir, Sahiwal, Tharparkar, Haryana and Kenkatha under the agro-climatic conditions of Bundelkhand region. The investigation aimed to compare their productive parameters i.e. Average milk yield/day, Lactation yield, Lactation Length, Veterinary expenses/year and reproductive performances i.e. Age at First Calving, Services per Conception, Calving Interval, Gestation Length and Birth weight of calves. A total of 20 lactating cows (4 each breed) were selected from our institutional herds (BUAT Livestock Farm). All cows were between 2nd to 4th lactation and heathy. Data were statistically analyzed using one-way ANOVA and Tukey’s HSD test at 5% significance. Results revealed significant breed effects (p &lt; 0.05) for most parameters except gestation length. Sahiwal recorded the highest milk yield (7.8 ± 1.0 L/day) and lactation production (2434 ± 345 L), followed closely by Gir (7.2 ± 1.1 L/day). Kenkatha, the native Bundelkhand breed, showed lower production (3.9 ± 0.7 L/day) but better adaptation traits such as earlier age at first calving (34 ± 3 months) and reduced veterinary expenditure (₹5800 ± 1300 per year). Statistical correlations indicate positive association between milk yield and fertility traits, while veterinary cost inversely related to breed adaptability. The results emphasize the necessity for local indigenous Kenkatha breed conservation and breed enhancement strategies that balance adaptability and productivity in the semi-arid Bundelkhand region.

In wild mammals, early postnatal growth strongly affects offspring survival and fitness, but little is known about the causes and consequences of variation in prenatal growth. We investigated whether gestational weight gains vary according to maternal traits and social and environmental conditions, and how prenatal growth affects the fates of the resulting offspring, using an exceptionally large sample of repeated pregnant body weight records from individually recognizable wild meerkats (Suricata suricatta). Pregnant meerkats' body weights remained stable during the first half of gestation and then increased linearly until they gave birth. Gestational weight gains were more rapid under favourable environmental conditions and when mothers were experimentally food-supplemented, suggesting that nutrition strongly determines prenatal growth. While social conditions and reproductive competition shape postnatal growth in many social vertebrates (including meerkats), these factors had a limited effect on prenatal growth, and adjustment to gestation lengths were modest and unrelated to social factors. Pups that grew faster in utero were heavier when they emerged from the birth burrow yet this rapid growth was not associated with shortened leukocyte telomeres, and they were consequently more likely to survive to adulthood. Broadly, we identified pronounced variation in gestational weight gains, which is largely driven by food availability and strongly predicts offspring birth weights and survival. Our findings also highlight constraints in the flexibility of prenatal growth and gestation lengths in this species, which may limit adjustments in response to prevailing social conditions, and enhance selection for flexibility in postnatal growth.

Since the Supreme Court's 2022 decision in Dobbs v Jackson Women's Health Organization, state legislatures have enacted laws severely restricting abortion. Facility case studies have reported post-Dobbs increases in patient volume and gestational length at abortion. To understand changes from before to after the Dobbs decision in the overall volume of callers and gestational length of their pregnancies at a large, regional abortion fund. This cross-sectional study used data from monthly caller records (June 2016-June 2024) from the District of Columbia Abortion Fund (DCAF) using interrupted time series analyses with segmented regression. DCAF serves the Washington, DC, area, which is unique in its absence of gestational restrictions, service availability, and proximity to states with post-Dobbs restrictions. Data were analyzed from November 2024 through August 2025. Time in months, with change points and discontinuities after the Dobbs decision. To contextualize trends, change points and discontinuities were examined at the onset of the COVID-19 pandemic, the enactment of a 6-week abortion ban in Texas, and the enactment of a 12-week ban in North Carolina. Overall call volume and gestational length of callers, measured dichotomously (first trimester vs ≥13 weeks) and continuously (weeks' gestation). Among 43 351 DCAF caller records, 31% had pregnancies at 13 weeks' gestation or greater. After the Dobbs decision, there was a sudden and substantial reversal of a prior 6-year trend of increasing call volume, as indicated by both an immediate drop (from 721 to 663 callers per month; coefficient, -10.7% [95% CI, -16.8% to -4.7%]), and a continued decrease over the subsequent year (coefficient, -12.7% [95% CI, -13.6% to -11.6%] per month). Concurrently, there was a sharp increase in the proportion of callers whose pregnancies were at 13 weeks' gestation or later, from approximately 22% just before Dobbs to 32% the month after the Dobbs decision (odds ratio [OR], 1.61 [95% CI, 1.39 to 1.87]); this increase continued (OR per month, 1.07 [95% CI, 1.06 to 1.09]), reaching a peak of 53% per year post-Dobbs. Both trends reversed after the enactment of North Carolina's 12-week ban. In this cross-sectional study of caller records at a large abortion fund, there were immediate and lasting changes in the volume and gestational length of callers following the Dobbs decision, suggesting differential redistribution of access or care-seeking by trimester and/or delays in presentation for care.

Is the pre-partum serum progesterone decline associated with litter size in dogs? A retrospective study.

Genetic background of calving ease in beef-on-dairy.

Abstract This study assessed the effects of incorporating varying levels (0, 10, 20, and 30 g/kg) of tiger nut (Cyperus esculentus L) into rabbit diets on the growth, reproductive performance, and blood characteristics of three rabbit breeds: New Zealand White, Hyla Max, and Dutch Belted. A total of 420 rabbits (270 does and 150 bucks), originating from 48 mature individuals aged 20–22 weeks and weighing between 2.24 and 2.50 kg, were randomly allocated to the four diets in a 3×4 factorial design. Growth traits such as body weight and linear measurements were taken at 35 days post-kindling. Reproductive performance data included gestation length, litter size at birth and weaning, individual and litter weights, and pre-weaning mortality. Blood samples were collected for haematological and biochemical analyses. Results indicated that dietary inclusion of tiger nut at 20–30 g/kg improved growth and reproductive performance, enhanced milk production and composition, and did not adversely affect health indicators. These findings support the use of tiger nut as a beneficial dietary supplement in rabbit production.

In the present study, a novel stacked Sparse Autoencoder-Deep Neural Network (SAE-DNN) learning prediction model was applied to predict calf sex, weight, and daily milk yield for dairy buffalo. First, SAE stage extracts the unique statistical features of calf records (protocol type, sire, gestation length, lactation season, calving interval, parturition season, open days, and dry period). Next, the DNN stage utilizes the extracted statistical sparse features to predict calf sex, weight, and daily milk yield production. The results showed that the proposed SAE-DNN model introduces a robust model with 80% accuracy, an R-squared value of 0.9149, a Mean Absolute Error (MAE) of 0.2097, and a Root Mean Squared Error (RMSE) of 0.4579 for calf sex. An accuracy of 87%, an R² value of 0.7122, a MAE of 3.9394, and an RMSE of 2.7635 for calf weight. As well as 86% accuracy, R2 value of 0.7964, a MAE of 2.0475, and an RMSE of 2.7798 for daily milk yield.

This study investigated the effects of environmental factors on gestation length and neonatal survival indicators in Thoroughbred horses. Data used in the study were obtained from 201 mares and their foals raised at the Adana Seyhan Covering Station, İzmit Covering Station, and Karacabey Boarding Stud Farm of the Turkish Jockey Club. The traits including gestation length, parturition duration, birth weight, time to first standing, and time to first suckling were analyzed. The least square means were determined as follows: 336.71±1.56 days for gestation length, 11.57±0.82 min for parturition duration, 49.42±0.67 kg for birth weight, 62.80±3.06 min for time to first standing, and 77.64±3.90 min for time to first suckling. Gestation length was significantly affected by foal sex (P

In recent years, Beef-on-Dairy (BoD) crossbreeding programs have gained momentum to enhance dairy cattle's economic and genetic merits while meeting the demand for high-quality beef. However, bulls with superior growth potential can lead to calving problems; thus, Holstein dairy farmers must decide which semen to use to avoid calving problems while producing heavier BoD calves. In this study, our objective was to genetically evaluate beef sires using a BoD crossbred reference population for three major economic traits, i.e., gestation length (GL), birth weight (BW), and calving ease (CE). A population comprising 4420 BoD calves sired by bulls from Angus (ANG), Limousin (LIM), Wagyu (WAG), and White-Belgian Blue (WBB) was used to perform a joint genetic evaluation of the sire for traits. Univariate and bivariate (linear-linear or threshold-linear) models were applied to estimate variance components and genomic breeding values using single-step methods. Estimates from CE models were transformed from the liability to the observable scale for more straightforward interpretation. Direct heritabilities for GL, BW, and CE (after transformations) ranged from 0.33 to 0.35, 0.33 to 0.37, and 0.02 to 0.14, respectively, while maternal heritabilities ranged from 0.11 to 0.17 for all traits. Generally, male BoD calves had higher probabilities for calving difficulty, with calvings being more difficult if sired by LIM (13%) as compared to ANG (7%) and WBB (9%) when considering male calves. The bivariate models outperformed the univariate models. For CE, the accuracy of predictions was up by 95% with a reduction in bias and dispersion. WBB sires were preferred when crossing with higher parity cows compared to ANG sires. These findings demonstrate that a well-structured BoD reference population enables accurate genomic evaluation of beef sires, facilitating the selection of sires that produce economically viable calves with reduced calving difficulties.