Season Of Birth Research Articles

Evidence of three distinct lactation stages in nursing gazelles: Implications on maternal behaviour assessment

Studying suckling behaviour has been used to understand parent-offspring conflict in mammals when the mother adjusts the amount of resources invested into an offspring during the lactation period. However, most studies report this information as a by-product of studying other types of suckling behaviour, like allosuckling. We aimed to understand this decision-making process by analysing the filial suckling bouts where the interval from the previous filial suckling bout was known. We used a captive population of threatened dorcas gazelles (Gazella dorcas) as a model species. Our findings showed that the lactation period in dorcas gazelle is characterised by three distinctive behavioural stages, where the behaviour of mother and calf changes rather fast, despite the progressive change in suckling duration. Early lactation (EL), when suckling bouts are always terminated by the calf; mid lactation (ML), when both the mother and the calf indistinctly may end up the suckling bouts; and late lactation (LL), when it is the mother who unfailingly ends lactation events. Also, we found evidence of male-biased maternal investment, as mothers tended to offer more investment towards male calves when suckling Additionally, we confirmed a compensational mechanism whereby calves born later in the birth season were suckled for longer (in terms of duration of suckling bouts) than calves born earlier, resulting in similar weaning dates for all studied calves. Therefore, many aspects may be overlooked if the influence of allosuckling on standard suckling is not considered when analysing suckling behaviour. Thus, we suggest this method of standard suckling behaviour analysis, where all behaviours which may alter the calves' demands and mothers' resources are removed (i.e., suckling attempts, allosuckling, and suckling after allosuckling).

Seasonality of Births and Marriages among Bessarabian Bulgarians in the 19th and Early 20th Centuries

The article looks at the seasonality of birth and marriage rates among the Bulgarian population in Bessarabia in the nineteenth – early twentieth centuries. The authors argue that the transition from traditional to modern models of reproduction is accompanied by a transformation in the religious identity of Bulgarians. The work demonstrates that starting a family with children becomes more secular and not as dependent on the practices of the church calendar taboos. The main determinants of marriage and birth seasonality are the mechanisms of migration and further adaptation to new conditions. The calculations reveal the levelling and relative uniformity in the distribution of births through the months of the year. These trends highlight the transition from the traditional to the modern model. The dependence on religious factors is gradually weakening while the agricultural work cycle becomes dominant. It evidences the pronounced secularization of the worldview and social practices.

S124 Antibiotic Exposure Before 2 Years of Age is Associated With Increased Risk of Pediatric IBD in a Norwegian Nation-Wide Study

Background: The incidence of pediatric IBD (PIBD) rises. This development is likely related to environmental factors that cause disturbances in the gut microbiota. The infant’s microbiome is shaped among other factors by exposure to the maternal microbiome and reaches adult diversity around 3 years age. Antibiotics impact the developing microbiome. Earlier studies have shown an association between PIBD and postnatal antibiotic exposure but lack information on prenatal antibiotic exposure and potential confounders. Thus, the primary aim of this study was to determine whether prenatal antibiotic exposure and antibiotics the first 2 years of life are independently associated with subsequent PIBD, before a mature and stabilized gut microbiome is established. Methods: We conducted a nationwide register-based cohort study using data from the Norwegian Patient Registry to identify children with pediatric IBD <18 years born from 2004 to 2012. Dispensed antibiotics were retrieved from the Norwegian Prescription Database, and the Medical Birth Registry of Norway and Statistics Norway contributed with potential confounding factors. The unique personal ID number given to all new-born in Norway was used to connect the registers. All children were followed until December 31, 2020. We analyzed whether use of pre- and postnatal antibiotics until 2 years of age were associated with subsequent IBD by logistic regression adjusted for potential confounders. Results: The study-population included 536,821 children; 758 were classified as PIBD cases distributed as: 403 (53%) Crohn`s Disease, 243 (32%) Ulcerative Colitis and 112 (15%). IBD Unclassified. The IBD cases included 423 boys and 335 girls with a male predominance among the CD cases (2.2: 1). In the main analysis, sex-adjusted odds ratio (aOR) for developing IBD when exposed to antibiotics before 2 years of age compared to no exposure was 1.40 (95% CI: 1.21-1.61). After adjustment for prenatal antibiotic exposure the aOR was 1.39 (95% 1.20-1.59). Further adjustments for potential confounders as mode of delivery, preeclampsia, birthweight and gestational age, season of birth and maternal age, education, smoking, and parity did not change the OR estimates more than +/- 0.01. We found the strongest association for ≥2 courses of antibiotic exposures (aOR 2.14 (95% 1.34-3.43) and for broad-spectrum AB (aOR 2.36 95%CI: 1.45-3.83) compared to no exposure. This association was driven by the CD cases (aOR 1.59 with 95%CI: 1.31-1.94 P<0.01) while no significant association to antibiotic exposure was observed for the UC cases (aOR 1.12 95%CI: 0.87-1.44 P=0.89). Antibiotic exposure during the last trimester was associated with offspring PIBD (aOR 1.23 95%CI: 1.01-1.51), but this association was borderline significant after adjustment for postnatal antibiotic exposure (P = 0.07). Conclusion(s): In a nation-wide, register-based study from Norway, children exposed to antibiotics before 2 years of age were 1.4 -fold more likely to develop IBD before the age 18 years than controls. This association was found for CD only and was robust to adjustments for prenatal antibiotic exposures and other potential confounders.

Seasonality of month of birth in patients with autoimmune endocrine diseases: A systematic review

BackgroundExposure to seasonal environmental factors during gestation or early in the postnatal period could influence the development of autoimmunity, determining a seasonality in the month of birth (MOB). There are studies evaluating this potential seasonality in patients with type 1 diabetes (T1D), autoimmune thyroid diseases (AITD), and Addison's disease (ADD), but results have been controversial. MethodsSystematic review according to PRISMA guidelines, using PubMed, Web of Science and WorldCat databases (2005–2020) of studies that explored the association between the seasonality of the MOB and T1D, AITD and ADD. Information on sex and age, location, methodology and internal quality, seasonal patterns, hypotheses and other factors proposed to explain seasonality were extracted. Differences in season and month of birth were further discussed. ResultsThe initial search retrieved 300 articles, and after further screening, 11 articles fulfilled inclusion criteria and were finally selected and reviewed. 73% found a seasonal pattern and 64% showed birth peaks in spring and/or summer. Hashimoto's thyroiditis and women exhibited a higher seasonality. Ultraviolet radiation, Vitamin D levels and viral infections were identified as influencing factors. ConclusionsThe effect of certain seasonal factors during foetal development, reflected by the seasonal differences in the MOB, could contribute to the development of endocrine autoimmune diseases in predisposed patients. Further research is needed to elucidate the mechanisms underlying the observed seasonality.

Influences of maternal factors on the estimate of genetic parameters for goat feed efficiency traits.

The objective of the present study was to estimate the genetic parameters for the feed efficiency traits in Barbari goats. The data records of 9332 progenies born to 413 sires and 2580 dams were collected with respect to the average daily weight gain (ADG), i.e., ADG1 (birth to weaning), ADG2 (weaning to 6months), ADG3 (6 to 12months), as well as derived trait Kleiber ratio (KR), i.e., KR1 (ADG1/3MW0.75), KR2 (ADG2/6MW0.75), and KR3 (ADG3/12MW0.75). The data were corrected for fixed covariates like period of kidding, the season of birth, sex, type of birth, and parity. Univariate and multivariate animal models with an average information function of restricted maximum likelihood (REML) were used to estimate genetic factors for these traits. The best model was evaluated based on the likelihood ratio test. The direct heritability estimates were 0.21 ± 0.03, 0.17 ± 0.03, 0.23 ± 0.04, 0.22 ± 0.04, 0.16 ± 0.04, and 0.26 ± 0.04 for ADG1, ADG2, ADG3, KR1, KR2, and KR3, respectively. However, they were inflated due to high and negative estimates of covariance between direct animal and maternal genetic effects. Moderate estimates of heritability augur the scope for improvement for feed efficiency traits. The maternal genetic effects (m2) significantly contributed to 3-12% of the total phenotypic variance. The realized heritability of mass selection, which takes into account direct and maternal genetic variance together, shows a low to moderate estimate of genetic variance for ADG and KR. The genetic correlation ranged from - 0.48 ± 0.11 (ADG1-KR3) to 0.95 ± 0.00 (ADG1-KR1), phenotypic correlation ranged from - 0.28 ± 0.01 (ADG2-KR3) to 0.94 ± 0.01 (ADG1-KR1), maternal genetic correlation ranged from - 0.22 (KR2-KR3) to 0.96 (ADG1-KR1) and - 0.69 (ADG1-KR3) to 0.95 (ADG1-KR1) for the maternal permanent environment, respectively. Kids can be indirectly chosen for higher feed efficiency since ADG and their associated KR have substantial genetic correlations. It is suggested that the KR should be used as a selection criterion for Barbari goats for improving feed efficiency.

The maturation of exploratory behavior in adolescent Mus spicilegus on two photoperiods.

Dispersal from the natal site or familial group is a core milestone of adolescent development in many species. A wild species of mouse, Mus spicilegus, presents an exciting model in which to study adolescent development and dispersal because it shows different life history trajectory depending on season of birth. M. spicilegus born in spring and summer on long days (LD) disperse in the first 3 months of life, while M. spicilegus born on shorter autumnal days (SD) delay dispersal through the wintertime. We were interested in using these mice in a laboratory context to compare age-matched mice with differential motivation to disperse. To first test if we could find a proxy for dispersal related behavior in the laboratory environment, we measured open field and novel object investigation across development in M. spicilegus raised on a LD 12 h:12 h light:dark cycle. We found that between the first and second month of life, distance traveled and time in center of the open field increased significantly with age in M. spicilegus. Robust novel object investigation was observed in all age groups and decreased between the 2nd and 3rd month of life in LD males. Compared to male C57BL/6 mice, male M. spicilegus traveled significantly longer distances in the open field but spent less time in the center of the field. However, when a novel object was placed in the center of the open field, Male M. spicilegus, were significantly more willing to contact and mount it. To test if autumnal photoperiod affects exploratory behavior in M. spicilegus in a laboratory environment, we reared a cohort of M. spicilegus on a SD 10 h:14 h photoperiod and tested their exploratory behavior at P60-70. At this timepoint, we found SD rearing had no effect on open field metrics, but led to reduced novel object investigation. We also observed that in P60-70 males, SD reared M. spicilegus weighed less than LD reared M. spicilegus. These observations establish that SD photoperiod can delay weight gain and blunt some, but not all forms of exploratory behavior in adolescent M. spicilegus.

From January to June: Birth seasonality across two centuries in a rural Polish community

Seasonality of births is a worldwide phenomenon, but the mechanisms behind it remain insufficiently explored. Birth seasonality is likely to be driven by seasonal changes in women’s fecundity (i.e. ability to conceive), which is strongly influenced by their energetic status. We tested whether birth seasonality is driven by high workload and/or low access to food using 200 years of birth data, from 1782 until 2004, in an agricultural rural Polish community. First, we analysed the time series of births and within-annual variance in births, a proxy for the extent of seasonality. Secondly, we tested the hypothesis that a high agricultural workload and/or low access to food decreases number of births. We found seasonality of births throughout more than 200 years of observation in an agricultural Polish population, with a dominant birth seasonality in January and February which gradually shifted towards June in the late twentieth century. The observed pattern does not support the hypothesis that birth seasonality resulted from women’s energetic status. We discuss the possible reasons why our results do not support the tested hypothesis and some implications for our understanding of the birth seasonality.

Influence of maternal socioeconomic deprivation and living environment on newborn bloodspot 25-hydroxyvitamin D levels.

Vitamin D deficiency in neonates can have life-threatening consequences, hence the knowledge of risk factors is essential. This study aimed to explore the effect of maternal socioeconomic status (SES) on newborn 25-hydroxyvitamin D (25OHD) concentrations. Over two 1-week periods (winter and summer of 2019), 3000 newborn heel prick dried blood spots (DBS) and additional data of newborns, from a regional newborn screening laboratory (52° N) in the West Midlands, UK, were gathered. Post code was replaced with lower layer super output area (LSOA). Index of Multiple Deprivation (IMD) quintiles for the corresponding LSOA was used to assess SES [quintile one (Q1): most deprived 20%, quintile five (Q5): least deprived 20%]. Each of the seven domains of deprivation were examined (income, employment, education, health, barriers to housing and services, crime and living environment). 25OHD was measured on 6mm sub-punch from DBS using quantitative liquid chromatography tandem mass spectrometry and equivalent plasma values were derived. In total 2999 (1500 summer-born, 1499 winter-born) newborn DBS (1580 males) were analysed. Summer-born newborns had significantly higher 25OHD (IQR) concentrations [49.2 (34.3; 64.8) nmol/l] than winter-born newborns [29.1 (19.8; 40.6) nmol/l, p<0.001].25OHD levels varied significantly between the different IMD quintiles in the whole (p<0.001) and summer-born cohort (p<0.001), but not in the winter-born cohort (p=0.26), whereby Q1 had the lowest 25OHD concentrations. Among the domains of deprivation, living environment had a significant influence on 25OHD levels (β=0.07, p=0.002). In this subdomain, 25OHD levels varied significantly between quintiles in the whole (p<0.001) and summer-born cohort (mean 25OHD Q1 46.45 nmol/l, Q5 54.54 nmol/l; p<0.001) but not in the winter-born cohort (mean 25OHD Q1 31.57 nmol/l, Q5 31.72 nmol/l; p=0.16). In a regression model, living environment was still significant (p=0.018), albeit less than season of birth and ethnicity. Among the seven domains of deprivation, maternal living environment had the greatest effect on newborn 25OHD levels. Whilst improved living environment positively influenced vitamin D status in the summer-born babies, winter-born had low 25OHD levels irrespective of the environment. Strategies such as enhanced supplementation and food fortification with vitamin D should be considered to overcome the non-modifiable main risk factors for vitamin D deficiency.

Photoperiod influences the development and the expression of personality traits and social behaviour in wild cavies (Cavia aperea)

AbstractSeasonality influences behaviour, physiology and life history of organisms, and photoperiod is a reliable and influential cue gearing individual adaptation to seasonal changes in the environment. Plastic phenotypic adjustments according to the prevailing season are a widespread, well‐studied phenomenon. Less well known are effects on developmental trajectories of animals born into different seasons. By manipulating the photoperiod during pregnancy and lactation independent of food availability and temperature, we studied if maternal behaviour in the precocial wild cavy (Cavia aperea) responds to this seasonal cue and if maternal behaviour and photoperiod shape offspring development and behaviour. We repeatedly observed mothers before and after birth. We investigated if pups differ in risk‐taking behaviours directly after birth (indicating direct prenatal effects) or only after gaining independence of the mother (indicating delayed prenatal or postnatal effects due to own cue sampling). Furthermore, we tested if different simulated seasons of birth affect social and aggressive behaviour of adult animals. While theoretical predictions according to risk‐taking are quite clear, they are contradictory for social behaviours that are much less well studied. We predicted that animals born into spring photoperiods would be aggressive because of a need to gather enough resources for early reproduction and successfully establishing a territory at least in males. Spring‐born males were more aggressive than autumn‐borns, while females did not differ with respect to season. Spring‐born females, however, lost more body mass when they had to integrate into an established group and autumn‐born females initiated more aggressive interactions. Our data demonstrate flexible and long‐term stable seasonal effects on behaviours that likely affect fitness outcomes under natural conditions.

Multivariate Animal Model-based Analysis of Fiber Traits in Kashmir Merino Sheep

ABSTRACT An attempt was made in the present study to elucidate the (co)variance components and genetic parameters of fiber traits in Kashmir Merino sheep population using multivariate animal model. The data pertained to a total of 6836 sheep lambs born over a period of 21 years (1997–2017) and included information on different fiber traits [greasy fleece weight at first (GFW1) and second (GFW2) clips; and fiber diameter (FD) and staple length (SL) at second clip]. Genetic analysis was undertaken using average information restricted maximum likelihood (AI-REML) algorithm in WOMBAT program. The model incorporated six fixed (sex of lamb, season and period of birth, farm of origin, breed and type of birth) and two random effects (direct additive genetic and maternal genetic effects without any covariance between them) in it. The additive genetic heritability estimates for fiber traits were 0.300 ± 0.031; 0.289 ± 0.022; 0.254 ± 0.029 and 0.189 ± 0.028 for GFW1, GFW2, FD, and SL, respectively. The maternal genetic heritability estimates were very low for all traits under study. The genetic correlation between different traits was positive and estimates ranged from moderate to high. The results from present study imply that the variation in these traits has genetic basis which can be exploited in the selection programmes for their improvement. The correlation between different fiber traits was found to be favorable, which can lead to indirect selection response upon formulation of efficient breeding programmes.

Environmental factors influencing milk yield and lactation length in Italian Mediterranean buffaloes in Türkiye

This study was conducted to investigate the effects of the environmental factors including, birth season, lactation number, age, and service period, on the annual average lactation milk yield and lactation period of the Italian Mediterranean Buffaloes that were milked by rotary milking systems. The research was carried out on the data of 347 buffaloes in a modern dairy farming between 2016 and 2018 years. Their annual average lactation milk yield and lactation period were found to be 1587.55 ± 33.82 L and 247.66 ± 4.39 days. It was observed that the prolonged service period had a positive effect on the total lactation milk yield and lactation period. The season did not affect the lactation milk yield, but the lactation period was longer in the buffaloes calving in winter months. The service period has a direct effect on the economic profitability, and it was observed that the service periods of buffaloes calving in winter was shorter. It was also determined that milk productivity was positively affected due to the increase in age and lactation number, but there were wide variations in the herd. In conclusion, age, lactation number, and service period were efficient on the annual average milk yield and lactation period, but, on the other hand, the season did not affect the annual average milk yield. More breeding studies are required to minimize variations in buffalo herds milked by different milking techniques.

19 Heterosis Effects on Pre-Weaning Traits in a Multibreed Beef Cattle Herd in Panama

Abstract The aim of this study was to estimate the influence of heterosis and breed percentage on birth weight (BW) and weaning weight (WW) in beef cows in a tropical environment. Data from 900 calves and 2,843 individuals in the pedigree, from the multibreed herd of the Panama Agricultural Innovation Institute (IDIAP) in Gualaca, Panama were used. The herd was comprised of the following genetic groups and according to their breed percentage: tropical adapted Brahman (BR), Nellore (Ne), Un define Bos indicus (BI), Guaymi Creole (CR), Senepol (SP) Romosinuano (RS); Bos taurus (BT), Simmental (SM), Angus (A), Red Angus (AR), Limousin (LM), Charolais (CH), Wagyu (Wa), and Others (Oth); crossbreeds (cx), Beefmaster (BF), Three cx(F1 x different BT), R1(Backcross BR), R2 (Backcross BT), Composite (combination of at least 4 different breeds with less than 25% of Zebu), Upgrade (87.5% BR 12.5% BT), B1 (62.5% Zebu + 37.5% BT), B2 (62.5% BT + 37.5% Zebu). A bivariate animal model for BW and WW, was utilized to estimate variance components. Contemporary group was defined as year of birth. The effects of sex, birth season, weaning season, and age of dam were included as categorical fixed effects. Weaning age, degree of outcross and breed percentage were included as linear covariates. The estimated regression coefficient for BW on heterosis was not significant (P &amp;gt; 0.05), and for WW was 0.072 ± 0.027 kg (P &amp;lt; 0.05). Lower BW and WW were observed for the Japanese, and B1, while R2 and Upgrade had the highest average (P &amp;lt; 0.05). Heritability for BW was found to be low (0.14 ± 0.06) and moderate for WW (0.26 ± 0.09). The proportion of variation of WW accounted by maternal permanent environment for WW was (0.2 ± 0.09). The estimated genetic correlation between additive genetic BW and WW was 0.63 ± 0.30, while a negative, additive genetic correlation was observed for WW and WW maternal (-0.43 ± 0.37). These results suggested that heterosis had a beneficial influence on WW but limited effect on BW. Additionally, increasing the percentage of Wa, and BR negatively influenced WW measurements in a multibreed beef cattle herd in Panama.

Estimation of genetic parameters of growth traits for direct and maternal effects in Murrah buffalo.

An understanding of genetic principles and environmental factors affecting the growth traits is essential to implement optimal breeding and selection programs. Early growth is an indicator of future success in production and reproduction status of dairy animals. In this study, a total of 18,989 records of body weight were used to estimate genetic parameters of body weight at birth (BW), 3months (3BW), 6months (6BW), 9months (9BW),12months (12BW), 18months (18BW), 24months (24 BW), 30months (3BW), and 36months (36BW) in Murrah buffalo at ICAR-NDRI Karnal, Haryana, for the period 1974-2019. The genetic parameters were estimated using the average information restricted maximum likelihood (AIREML) procedure by excluding or including maternal effects. Six analytical models were fitted in order to optimize the model for each trait. The most appropriate univariate model was selected based on the log likelihood ratio test (LRT). Influencing factors like calf sex, period of birth, season of birth, and dam's parity were investigated. The results showed that the maternal genetic effects, in addition to direct additive effects, were important for unbiased and accurate genetic parameter estimates of growth traits in Murrah buffaloes. Total heritability estimates h2T1 for BW, 3BW, 6BW, 9BW, 12BW, 18BW, 24BW, 30BW, and 36BW were 0.25, 0.04, 0.14, 0.16, 0.10, 0.15, 0.21, 0.24, and 0.23, respectively. Maternal effect was significant for birth weight and accounted for 13% variation through maternal genetic and 5% variability through maternal permanent environmental effect. Maternal genetic effect was also important for other traits. However, it interfered with the estimates of variance ratios in live weight traits owing to large and negative covariance between direct and maternal genetic effects. Direct genetic correlations between body weight traits were positive and high ranging from 0.10 to 0.94. Results revealed that the Murrah herd has a sizable genetic variability for growth traits and hence, there is sufficient scope for selection for achieving better growth rate if selection in this direction is applied. Owing to higher positive genetic correlation of 6BW with later ages, the scope of indirect selection for optimum growth in later ages can be aimed at by selecting animals for their higher 6-month live weight.

No seasonality in the risk of multiple sclerosis in an equatorial country: A case–control ecological study

Background: Multiple sclerosis risk has been shown to have seasonal variations that are more pronounced in higher latitudes. However, this phenomenon has not been adequately studied near the Equator. Objective: To explore the risk of multiple sclerosis associated with month, season of birth, and sunlight exposure variables in Colombia. Methods: In this case–control study, 668 multiple sclerosis cases were matched to 2672 controls by sex and age. Association of multiple sclerosis with each month/season of birth and sunlight exposure variables was estimated with multilevel mixed-effects logistic regression and ecological regression models, respectively. Seasonality in the births of multiple sclerosis was assessed with a non-parametric seasonality test. Results: We found a higher probability of multiple sclerosis in September (0.25; 95% confidence interval (CI) = 0.21–0.31) and lower in March (0.15; 95% CI = 0.10–0.18), which turned non-significant after a multiple comparisons test. Sunlight exposure variables had no significant effect on the risk of MS, and the tests of seasonality in the births of MS did not show significant results. Conclusion: Our results show no seasonality in the risk of multiple sclerosis near the Equator, supporting the hypothesis that this phenomenon is latitude dependent.

Impact of the first wave of the COVID-19 pandemic on birth rates in Europe: a time series analysis in 24 countries.

Did the first wave of the COVID-19 pandemic have an impact on monthly birth rates in Europe? Using datasets on live births per month in Europe, collected from the Human Fertility Database, we found a -14.1% decline in live births in January 2021 (i.e. 9-10 months after the epidemic peaks and first lockdowns), compared to the average number of live births in January 2018 and 2019. Previous pandemics in the 20th and 21st centuries have been associated with a decline in birth rates 9 months after their peak, and a rebound in births over time. Lockdowns were necessary to control the first wave of the COVID-19 pandemic and may have had an impact on subsequent birth rates. Monthly time series data on live births from January 2018 to March 2021 were extracted to provide a time-series analysis of birthrates during and after the first wave of the COVID-19 pandemic in 24 European countries. We conducted a random-effect generalized least squares regression to assess the seasonality of births from January 2018 to March 2021, and to identify potential differences in monthly live births after the first wave of the COVID-19 pandemic, considering the seasonality of births. To quantify these potential differences, we estimated the variation rate between the monthly live births observed during 2020 and 2021 and the mean of the 2018-2019 monthly live births in Europe. Factors potentially associated with a variation in monthly birth rates were assessed using univariable and multivariable generalized linear regressions. When considering the seasonality of births, January 2021 was the only month with a significant difference in live births. A drop of -14.1% was observed compared to the average number of live births in January 2018 and 2019. At the national level, this drop was observed 9-10 months after the epidemic peaks in 13 countries. The duration of lockdowns was the variable that had the stronger association with this decrease, whereas higher incomes per capita could be a factor limiting this decline. A rebound in births compared to the previous years occurred in March 2021 in 13 countries. Our data are based on national data, limiting the power in the multivariable models used and the identification of other potential factors contributing to a decrease or an increase in birth rates. In addition, we collected only live births up to April 2021, which precludes the identification of a difference in births seasonality in 2021. As with previous pandemics, the COVID-19 outbreak was associated with a decline in births 9 months after its first wave. This trend may be associated with the duration of the lockdowns. Although there was a rebound in births in the following months, it does not seem to compensate for this decline. The authors receive no external funding and have no conflict of interest to declare. N/A.

10 Impact of the month of birth on the development of juvenile idiopathic arthritis among Tunisian children

BackgroundJuvenile idiopathic arthritis (JIA) is the most common inflammatory disease influenced by genetic as well as environmental factors. Prior studies from Israel and USA suggested that JIA had a seasonality of birth, with birth peaking in winter and especially in January.ObjectivesThe aim of the study was to evaluate the impact of month of birth and season, and the onset of JIA in Tunisian children.MethodsWe conducted a case-control study including 27 children with JIA compared with a homogeneous control group of 27 children hospitalized in a pediatric orthopedic unit for traumatic reasons and healthy for any chronic inflammatory rheumatism. Statistical differences between groups were also analyzed by non-parametrical tests.ResultsFifty-four patients (25 females and 29 males) were enrolled. The mean age was 11.04 ± 5.58 years and the mean duration of the diseases was 5.29 ± 3,18 years. The frequency of each JIA subset was at follows: polyarticular rheumatoid factor positive (n = 2), polyarticular rheumatoid factor negative (n = 5), psoriatic arthritis (n = 1), enthesitis-related arthritis (n = 11) and oligoarthritis (n = 8). Although the majority of children with JIA were born in November (22.2%) and December (18.5%), there was no significant difference in month of birth distribution between the cases and the controls. Likewise, there was no significant correlation between season of birth and the onset of the disease (p = 0,6).ConclusionThis study didn’t show any correlation between season and month birth, and the onset of JIA. Our result may be explained by the weather in Tunisia which is relatively warm with little variation in temperature between seasons compared with the country where they found a significant correlation. It also may be due to the limited number of our cases.

​Risk Factors Associated with Preweaning Mortality of Barbari, Jamunapari and Jakhrana Goat Kids

Background: High mortality of goat kids due to infectious and non-infectious diseases negatively impacts goat husbandry. Methods: To study the influence of genetic and nongenetic factors on preweaning mortality of goat kids, three years’ data (July, 2015 to June, 2018) of breeds maintained at Indian Council of Agricultural Research-Central Institute for Research on Goats (ICAR-CIRG) viz. Barbari, Jamunapari and Jakhrana was analyzed to find effect of breed, parity, birth weight, litter size, season of birth, sex and kid’s age on mortality. Postmortem findings as entered in the record have been considered to arrive at the cause of mortality. Result: A preweaning mortality rate of 2.59% was recorded in kids of all the three breeds studied. Mortality rate of Barbari, Jamunapari and Jakhrana kids was found to be 2.15%, 3.39% and 2.13% respectively. Kids birth weight, sex or age had no effect on mortality. Highest mortality was observed in kids born as triplet/quadruplet (4.49%) followed by that in twins (2.88%) and singlets (2.01%). Highest mortality was observed in kids born to primiparous dams (3.95%) followed by kids born to dams having =/ greater than 5th parity (3.01%) and least in 2nd to 4th parity (1.82%). Most of the kids died due to enteritis (38.3%) followed by pneumonia (28.3%), debility and anemia (11.7%) septicemia (10%) and others in remaining 11.7% cases.

Acute and chronic maternal exposure to fine particulate matter and prelabor rupture of the fetal membranes: A nation-wide survey in China

BackgroundPrelabor rupture of the fetal membranes (PROM) is a major contributor to adverse perinatal outcomes. Some epidemiologic studies explored the association between maternal PM2.5 exposure and PROM but failed to treat the labor induction and prelabor cesarean section as censored observations. ObjectiveWe aimed to evaluated whether acute and chronic maternal ambient PM2.5 exposure may increase the risk of PROM in China. MethodsThis study was based on the China Labor and Delivery Survey, a nationwide multicenter investigation. Included in the current analysis were 45,879 singleton spontaneous births in 96 hospitals in mainland China from 2015 to 2017. Outcomes were PROM, preterm PROM (<37 weeks’ gestation) and term PROM (≥37 weeks’ gestation). Daily concentration of PM2.5 at 1 km spatial resolution was estimated by gap-filling model. Generalized linear mixed model and mixed effects Cox model were applied to assess the associations of acute (from 0 to 4 days before delivery) and chronic (average gestational and trimester-specific) ambient PM2.5 exposure with outcomes, respectively. ResultsSignificant associations were found between acute PM2.5 exposures (per interquartile range increase) and the risk of preterm PROM (OR = 1.11; 95 % CI: 1.03, 1.19 for PM2.5 on delivery day; OR = 1.10; 95 % CI: 1.02, 1.18 for PM2.5 1 day before delivery) but not for term PROM. An interquartile range increase in PM2.5 during the second trimester was associated with elevated risks of PROM (HR = 1.14; 95 % CI: 1.07, 1.22), preterm PROM (HR = 1.22; 95 % CI: 1.02, 1.45) and term PROM (HR = 1.13; 95 % CI: 1.06, 1.22), respectively. Women who were less educated, obese, or gave birth in a cold season appeared to be more sensitive to ambient PM2.5 exposure. ConclusionOur findings suggest that both acute and chronic maternal exposures to ambient PM2.5 during pregnancy are risk factors for PROM.

Prenatal exposure to nitrate from drinking water and the risk of preterm birth: A Danish nationwide cohort study.

Background:Evidence is emerging that preterm birth (PTB, birth before 37 completed weeks of gestation), a risk factor for neonatal mortality and future morbidity, may be induced by maternal nitrate () exposure from drinking water. The objective of this study is to assess the association between maternal exposure to nitrate and the risk of PTB in a nationwide study of liveborn singletons.Methods:We estimated maternal nitrate exposure from household tap water for 1,055,584 births in Denmark to Danish-born parents during 1991–2015 by linkage of individual home address(es) with nitrate concentrations from a national monitoring database. Nitrate exposure during pregnancy was modeled using four categories and continuously. Logistic models adjusted for sex, birth year, birth order, urbanicity, and maternal age, smoking, education, income, and employment, with generalized estimating equations were used to account for sibling clusters.Results:A total of 1,009,189 births were included, comprising 51,747 PTB. An increase in the risk of PTB was seen across categories of exposure (P < 0.001) with an odds ratio (OR) in the uppermost category (>25 mg/L nitrate) of 1.05 (95% confidence interval [CI] = 1.00, 1.10). Evidence of an exposure–response relationship was observed in models using continuous nitrate (OR = 1.01 [95% CI = 1.00, 1.03] per 10 mg/L nitrate). In sensitivity analyses, results were robust to the addition of variables for short inter-pregnancy interval (<1 year between births), maternal pre-pregnancy body mass index, paternal socioeconomic status and age, season of birth, and inclusion of post-term births. Results were virtually unchanged when the analysis was restricted to women exposed to less than the current European Union standard of 50 mg/L.Conclusion:We observed an increasing risk of PTB with increases in nitrate in household tap water. These findings add to a growing body of evidence of adverse effects from nitrate in drinking water at levels below current regulatory levels.

Análise multidimensional de escala para investigar as relações entre o rendimento do leite e os parâmetros de fertilidade

ABSTRACT Milk yield and fertility traits in dairy cattle and their relationship with the influencing factors were investigated using multidimensional scaling analysis (MDS) in this study. The study focused on the relationship between lactation length, 305-day milk yield, actual milk yield and peak remaining days from milk yield characteristics, and service period, dry period, insemination per conception and calving interval from fertility traits, as well as the influencing factors such as calving age, lactation number, birth season, and birth year. When the MDS results were examined, it was discovered that all the traits had close Euclidean distances from each other, save for the birth season and birth year. As a result of MDS analysis, R2 and Stress Coefficient were calculated as 88.4% and 0.099, respectively. Consequently, the selection direction was tried to be identified by determining the milk yield and fertility traits and the relationship between these traits and the influencing factors through the MDS analysis and it was concluded that the MDS method could be employed in this field.