Average Birth Interval Research Articles

Relationship between piglets’ survivability and farrowing kinetics in hyper-prolific sows

BackgroundProlonged farrowing and more piglets born with low birth weight are undesirable consequences of genetic selection for increased litter size. The objective of the present observational study was to evaluate the relationship between piglets’ survivability and farrowing kinetics in hyperprolific sows. A total of 58 sows of different parities and 1190 piglets were included. The entire farrowing process was monitored and the following parameters were recorded: inter-piglet birth interval, birth order, total born, live born, dead born, and mummified piglets, obstetric intervention, weight at birth and 24h, colostrum yield and intake.ResultsThe sows included in this study had on average 20.6 ± 0.6 total piglets born, of which 16.4 ± 0.6 were live born, 3.3 ± 0.4 were stillborn and 0.9 ± 0.2 were mummified piglets. The average farrowing duration and average birth interval were 411.3 ± 31.6 and 20.6 ± 1.7 min, respectively. Farrowing duration was positively associated (p < 0.05) with parity, number of stillborn and mummified piglets. Piglet mortality 24h after birth was negatively affected (p < 0.01) by birth weight and positively affected (p < 0.01) by cumulative birth interval. The last tercile of piglets born (birth order ≥ 17) had the highest (p < 0.01) inter-piglet birth interval (IPBI) (43.4 ± 4.17 min) compared to piglets born in the first (birth order between 2 and 7) (26.5 ± 3.8 min) and second (birth order between 8 and 16) terciles (21.9 ± 3.8 min). Cumulative birth interval, birth weight, occurrence of stillborn piglets and manual intervention were positively associated (p < 0.05) with IPBI. Piglet birth weight was also positively associated (p < 0.01) to individual colostrum intake. Piglets ingesting more colostrum had lower (p < 0.01) mortality from 24h after birth until weaning. Sow’s parity and cumulative birth interval were positively associated with the presence of stillborn piglets (p = 0.02 and p < 0.01, respectively).ConclusionReducing farrowing duration may be crucial to decrease stillbirth rate and neonatal mortality in hyperprolific sows. Moreover, special care must be provided to the lighter piglets within a litter to increase their colostrum intake and minimize piglet’s mortality throughout lactation.

Genome-wide association study reveals the candidate genes for reproduction traits in Yunong black pigs.

Enhancing pig reproductive efficiency has the potential to have a significant positive economic impact on the pig business. We collected four reproduction records of 734 Yunong black pigs in this study, including the total number of piglets born (TNB), the number born alive (NBA), the average birth interval of piglets (ABI) and the average birth weight (ABW). A total of 453 Yunong black pigs were genotyped with Porcine 50K SNP BeadChip. Twenty-five SNPs and 35 genomic areas were found to have a substantial impact on the reproductive performance of Yunong black pigs by single-locus GWAS and single-step GWAS (ssGWAS). For the ssGWAS, we found that the two genomic regions (12.67-13.85 and 14.26-15.01Mb) on Sus scrofa chromosome X were associated with TNB, NBA and ABI. It is worth noting that CNC10110530 and CNC100141254 significantly affected the TNB by both GWAS methods. Finally, we further determined the gene functions by enrichment analysis and a literature search, and identified 28 of them as candidate genes affecting the reproductive performance of Yunong black pigs, including RET, EIF1AX, NELL2, CTPS2, S100G, RBBP7 and PDHA1. This study further promotes understanding of the genetic mechanism of porcine reproductive performance, and also provides more molecular markers for pig breeding.

Defining the Effect of Oxytocin Use in Farrowing Sows on Stillbirth Rate: A Systematic Review with a Meta-Analysis.

Simple SummaryOxytocin is a hormone that causes smooth muscle contraction and is particularly important during parturition. The administration of exogenous oxytocin to sows at farrowing has been used for decades as a means of assisting sows during parturition. Over the past decade, swine-litter size has dramatically increased, as well as the stillbirth rate. The objective of this systematic review and meta-analysis was to identify the benefits and possible negative side effects of oxytocin use during farrowing. By accumulating data from 25 randomized controlled trials, a meta-analysis examined whether the average number of stillborn piglets, the farrowing duration, and the time interval between the births of piglets were different in the sows that received oxytocin compared to the controls. The results from this study demonstrated that the sows that received oxytocin had an increased average number of stillborn piglets, but experienced reduced farrowing duration and shorter birth intervals between piglets compared to the controls. Future research is required to refine oxytocin usage guidelines, including dosages and the timing of administration. The results of this study demonstrate that it is important to recognize that oxytocin can have adverse side effects, including an increase in stillborn pigs.The objective of this systematic review and meta-analysis was to identify the benefits and possible adverse side effects of oxytocin use during farrowing. Randomized controlled trials that were published in English within the last 50 years were eligible for inclusion. Eligible research needed to contain the PICO elements: population (P)—sows at farrowing; intervention (I):—oxytocin given to sows—comparator (C): sows at farrowing not given oxytocin, as well as sows given different dosages and/or different timing of administration; and outcomes (O):—stillbirths, sow mortality, and piglet viability. Four bibliographic databases were used: PubMed, CAB Direct, Web of Science Core Collection, and ProQuest Dissertations, and Theses Global. In addition, we performed a manual search of the table of contents in the American Association of Swine Veterinarians database for relevant conference proceedings and reports. To assess the risk of bias at the study level, a modified version of the Cochrane 2.0 ROB was used. Meta-analyses were performed to examine the average stillbirth rate, farrowing duration, and birth interval between piglets using random-effect standardized mean difference (SMD) models. To explore heterogeneity, a sub-group analysis was performed on the objectives of the study, dose, time, and route of administration. Of the 46 studies eligible for meta-analyses, only 25 had sufficient information. The pooled analyses of the random effect model demonstrated that the average number of stillborn pigs was lower in the comparator group (SMD = 0.23; CI95% = 0.1, 0.36), and both the farrowing duration (SMD = −8.4; CI95% = −1.1, −0.60) and the birth interval between piglets (SMD = −1.41; CI95% = −1.86, −0.97) were shorter in the oxytocin group. The majority of the studies had an overall risk of bias of ‘some concerns’. It was concluded that the use of oxytocin increases the overall number of stillborn piglets, but decreases the farrowing duration and time interval between piglets. However, future studies should focus on the effect of oxytocin on the experience of dystocia among sows.

Determinants of Under-Five Mortality in Tach- Armachiho District, North Gondar, Ethiopia

Background: Under-five mortality rate, often known by its acronym U5MR, indicates the probability of dying between birth and five years of age, expressed per 1,000 live births. Globally, 16,000 children under-five still die every day. Especially in Sub-Saharan Africa every 1 child in 12, dying before his or her fifth birthday. This study aims to identify the determinants of under-five mortality among women in child bearing age group of Tach-Armachiho district using count regression models. Methods: For achieving the objective, a two-stage random sampling technique (simple random sampling and systematic random sampling techniques in the first and second stages respectively) was used to select women respondents. The sample survey conducted in Tach-Armachiho district considered a total of 3815 households of women aged 15 to 49 years out of which the information was collected from 446 selected women through interviewer administrated questionnaire. Results: The descriptive statistics result showed that in the district 16.6% of mothers have faced the problem of at least one under-five death. In this study, Poisson regression, negative binomial, zero-inflated Poisson and zero-inflated negative binomial regression models were applied for data analysis. Each of these count models were compared by different statistical tests. So that, zero-inflated poisson regression model was found to be the best fit for the collected data. Results of the zero-inflated Poisson regression model showed that education of husband, source of water, mother occupation, kebele of mother, prenatal care, place of delivery, place of residence, wealth of house hold, average birth interval and average breast feeding were found to be statistically significant determinants of under-five mortality. Conclusions: In this study, it was found that the factors like average birth interval and average breast feeding were found to be statistically significant factors in both groups (not always zero category and always zero category) with under-five child deathwhereas education of husband, source of water, place of delivery, mother occupation and wealth index of the household have significant effect on under-five mortality under not always zero group. Place of residence, kebele of mother and prenatal care have a significant effect on under-five mortality in TachArmachiho district on inflated group

Dietary Inulin Regulated Gut Microbiota and Improved Neonatal Health in a Pregnant Sow Model

This study aimed to investigate the relationship between maternal dietary fiber intake and piglet health. Multiparous sows were randomly assigned to two groups and fed diets without inulin (control group, n = 20) or 1.6% inulin (1.6IN group, n = 20). The results indicate that 1.6IN prevented the prolonged farrowing duration of sows (P < 0.05) and shortened the average piglet birth interval (P < 0.1). In addition, 1.6IN decreased the percentage of the piglet born weak and the percentage of the piglet with hyperthermia after birth (P < 0.01). Compared with the control group, the 1.6IN group had a lower concentration of urea nitrogen in the colostrum, and also prevented diarrhea, increased litter gain, survival rate, and average daily gain for suckling piglets (P < 0.05). Furthermore, 1.6IN decreased the relative abundance of Firmicutes, Cyanobacteria, and Streptococcus; increased the relative abundance of Bacteroidetes, Desulfovibrio, Paludibacter, CF231, and Prevotella. Overall, this study showed that maternal fiber nutrition during pregnancy regulated the health of offspring, and the response of the maternal intestinal microbes played an important role in intervening in the phenotype of sows and neonatal piglets.

Effects of Hunting on a Puma Population in Colorado

Effects of Hunting on a Puma Population in Colorado

Effects of dietary inulin during late gestation on sow physiology, farrowing duration and piglet performance

In this study there was evaluation of effects of dietary inulin during late gestation on sow physiology, farrowing duration and piglet performance. At day 80 of gestation sows were randomly assigned to four groups：basal diet (CON); or basal diet with 0.8 %; 1.6 %; or 2.4 % inulin. The feeding of the diet with 1.6 % inulin resulted in larger weights of the litter at birth a shorter duration of the farrowing period, lesser average birth interval between piglets, lesser number of piglets dead at birth, and fewer piglets/sow dead at birth (P < 0.05). When sows were fed 0.8 % and 1.6 % IN, there was a larger litter weight at weaning, sow average daily feed intake and piglet average daily gain during lactation compared with values for these variables in the CON group (P < 0.05). Additionally, there was an increase in serum concentration of free fatty acid, total cholesterol, and high-density lipoprotein cholesterol with increasing amounts of inulin in the diet (linear, P < 0.05). Sows fed 1.6 % IN had greater serum concentrations of glucose than those in the CON group (P < 0.05). Furthermore, there was a linear increase in serum activity of total antioxidant capacity, total superoxide dismutase and glutathione peroxidase with increasing amounts of inulin in the diet (P < 0.05). In conclusion, results of the present study indicated feeding inulin during late gestation improved reproductive performance of sows, thus, may be a novel additive for the pig industry in improving efficiency of pork production.

Are there differences in pain intensity between two consecutive vaginal childbirths? A retrospective cohort study

BackgroundPain assessment is crucial for in-labour pain management. Even though women's self-rated pain intensity is the standard for pain relief or analgesic administration, multiparas appear to receive worse in-labour pain management than primiparas do. The discrepancy in pain perception between primiparas and multiparas remains unclear. Healthcare providers tend to think that multiparas endure the pain and report less pain because they have experienced childbirth. ObjectiveTo retrospectively analyse the intensity of in-labour pain during first and second vaginal childbirth within the same group of women and explore whether parity may be an influential factor in labour pain intensity. DesignRetrospective cohort study. SettingLabour and delivery in a large academic specialized hospital in Guangzhou, China. ParticipantsWomen were included if they had two consecutive vaginal childbirths with singleton cephalic presentations and cervical dilation ≤ 3 cm for the first childbirth and ≤ 2 cm for the second childbirth. The final study sample consisted of 417 women. MethodsAll childbirth case records between January 2015 and August 2018 were scanned using a structured electronic medical system. Maternal and neonatal demographics as well as obstetric and neonatal outcomes were extracted. The in-labour pain for each childbirth was compared between first and second births. Paired t-tests, McNemar's chi-square tests and mixed-effects modelling were applied to compare the differences in labour pain intensity between the two vaginal childbirths and explore the factors that influenced maximum labour pain scores during the second childbirth. ResultsFour hundred seventeen women were included, with an average birth interval of 1.7 years. The average maximum labour pain score during the latent phase was 6 (5,6) for the first childbirth and 5 (4,6) for the second childbirth (paired t =-6.13, P <0.001). Pain scores decreased in 28.1% (117/417) of women and increased in 13.7% (57/417) of women from the first to the second childbirth. More than half of the women in our study experienced the same maximum labour pain score during the first and second labour. Mixed-effects modelling revealed that parity, education and pregnancy complications were independently associated with maximum labour pain scores. ConclusionsFrom a clinical point of view, in-labour pain is not clinically different for women when comparing their first and second labours. Health care professionals may underestimate in-labour pain in primiparas when comparing them with nulliparas. More studies are warranted to explore options for achieving better pain management for women with more childbirths.

The ‘high infant mortality’ trap’: the relationship between birth intervals and infant mortality – the example of two localities in Bohemia between the 17th and 19th centuries

ABSTRACTThe article further develops the term ‘high infant mortality trap’ as an expression of the concept supposing a mutual relationship between short average birth intervals (corresponding usually to high fertility) and high level of infant mortality. This mutual relationship is among other a consequence of the effect of the same or similar factors standing behind both processes (fertility, infant mortality). In the paper, this relationship is evaluated through the effect of the selected explanatory variables on the probability of infant death (using the Binomial logistic regression) as well as length of birth-birth intervals or time duration from the infant death to the successive birth (using the Cox regression). In the analytical part, the concept is evaluated using data from two localities in Bohemia (today the Czech Republic). The localities differ according the socio-economic as well as ethnic characteristics, what might have affected also the demographic behaviour. The area of the Central Europe has not been fully described in the historical demographic works yet, so this study brings the possibility of comparison of this area with other areas already studied. Particular parts of the analysis prove the assumption of the existence of the high infant mortality trap before the onset of demographic transition.

Effect of different parities on reproductive performance, birth intervals, and tail behavior in sows.

A goal for swine farming is the improvement in the number of live-born and weaned piglets per sow. Hence, the effect of parities should consider the correlation between the component traits of reproductive performance, weaning, and duration. Sows were housed in farrowing pens (W 2.2 × D 1.8 × H 1.2 m) on a partially slatted plastic floor. Twenty sows used in this study were between the first and sixth parity in gilts (P1), parity 2–5 (P3), and parity 6–9 (P6). Data collection by parity was classified into three categories: (1) reproduction performance (gestation length, total number of piglets born, number of piglets live born, number of piglets stillborn, total piglet birth weight; (2) weaning traits (weaning period, number of piglets weaning, total piglets weaning weight); (3) duration traits (farrowing duration, placenta expulsion duration, time from last piglet to first placenta, average birth interval, and tail wagging behavior). Gestation length was higher in P6 than P1 and P3 of different parity sows. The maximum value in P1 and P3 was 117 days, but the median value in P6 was 117 days (p < 0.05). The total number of piglets born (p = 0.113), number of piglets live born (p = 0.118), number of still piglets born (p = 0.151), and total piglet birth weight (p = 0.117) were not affected by parity. The number of live piglets was higher than the other parities by an average of 15.6 ± 2.1 in P1. The duration of farrowing was the lowest at 22.2 min in P6, but the maximum value was 42.2 min more than other parities (p = 0.355). Weaning traits of sows also did not differ significantly (p > 0.05), but the weaning period from P1 was lower than that of the other parities (p = 0.170). The number of piglets weaned was 10 heads on average in P1, P3, and P6 (p < 0.05). However, the mean values of the total piglet weaning weight (p = 0.377) of P6 (62.0 10.4 kg) were higher than those of P1 (54.9 10.2 kg) and P3 (58.4 13.6 kg). The placenta expulsion duration was higher in P6 than that in P1 and P3 (p = 0.447). The time from the last piglet to first placenta was be lower in P3 than that of the other parities (p = 0.206). The average birth interval was higher in P3 than that of the other parities (p = 0.156). Tail wagging (count) behavior was higher in P6 than in the other parities (p = 0.065). The data showed that the reproduction performance, total piglets born, and weight were higher in the gilts group, and higher in the weaning trait than that in the P6 group. This study examined the relationship between reproductive performance, birth interval and tail motion according to sow parity. Regarding duration, farrowing duration was lower in P6 than that in the other parities, but placenta expulsion and tail wagging were higher in P6 than in the other parities. Therefore, it is possible that the results from these sows could be used as basic data for effective farm management.

Sociodemographic factors associated with birth interval: a study among rural women in Chandina, Comilla, Bangladesh

The aim of this study was to determine the average birth interval and its possible correlation with sociodemographic factors in Chandina, Comilla, Bangladesh. A cross-sectional study among 128 rural women was conducted in Chandina, Comilla, Bangladesh during a period of two weeks in March 2015. The study was carried out as a house-to-house survey of all households in two selected villages using an interview schedule in the Bangla. This study reported that the mean birth interval among rural women aged between 15 and 49 years old was 46.5 ± 19.47 months, while the median birth interval between two successive live births was 48 months. Respondents’ education was found to be significantly correlated to birth intervals in this study (p = 0.047). The prevalence rate of 21.9% for birth intervals of less than 36 months found in this research provides some insights into the measures that need to be taken to encourage women in rural communities to lengthen their birth intervals to more than 36 months. This could prevent complications that may arise from shorter birth intervals and frequent pregnancies.

The birth order paradox: Sibling differences in educational attainment

This study uses population register data to examine the relationship between birth order and educational attainment in Sweden, and demonstrates that while the net effect of birth order on educational attainment is negative, later-born children often spend longer in education. The explanation for this finding is due to educational expansion in Sweden in the 20th century, which outweighs the negative causal effect of birth order for the affected cohorts. This is particularly true for women due to the fact that the rate of increasing educational enrolment has been greater for women than for men. These results also show that later-borns in large families particularly benefit from educational expansion due to the longer average birth interval between the first and last child in large families, meaning that the supply of educational opportunities increased to a greater extent in the intervening period. However, in periods where education is not expanding, later-born siblings continue to fare worse than first-borns.

Relationship of family formation characteristics with unsafe abortion: is it confounded by women's socio-economic status? - A case-control study from Sri Lanka.

BackgroundLiterature shows that choice for unsafe abortion is often driven by poverty. However, factors related to the family formation behaviour of women are also implied as determinants of this decision. This study assessed which family formation characteristics of women are associated with the risk of unsafe abortion, without being confounded by their low socio-economic status among Sri Lankan women admitted to hospital following post-abortion complications.MethodsAn unmatched case–control study was conducted in nine hospitals in eight districts in Sri Lanka among 171 women with post-abortion complications following unsafe abortion (Cases) and 600 postpartum mothers admitted to same hospitals during the same period for delivery of term unintended pregnancies (Controls). Interviewer-administered-questionnaires obtained demographic, socio-economic and family formation related characteristics. Risk factors of abortion were assessed by odds-ratio (OR), adjusted for their socio-economic status in logistic regression analysis.ResultsLow socio-economic status, characterised by low-education (adjusted OR = 1.5; 95 % CI = 1.1–2.4) and less/unskilled occupations (2.3; 1.4–3.6) was a significant risk factor for unsafe abortion. Independent of this risk, being unmarried (9.3; 4.0–21.6), failure in informed decisions about desired family size (2.2; 1.4–3.5), not having a girl–child (2.2; 1.4–3.4) and longer average birth intervals (0.7 years; 0.6–0.8) signified the vulnerability of women for unsafe abortion. Cases were as fast as the controls in their family completion (4.3 versus 4.5 years; p = 0.4), but were at increased risk for abortion, if their average birth intervals (including the last one) were longer. Previous contraceptive use, age at reproductive events or partners’ characteristics did not impart any risk for abortion.ConclusionsLow socio-economic status is not the most influencing risk factor for unsafe abortions leading to complications, but many other factors in relation to their family formation characteristics that are independent of their low socio-economic status.

The Birth Order Paradox: Sibling Differences in Educational Attainment

This study uses population register data to examine the relationship between birth order and educational attainment in Sweden, and demonstrates that while the causal effect of birth order on educational attainment is negative, later born children actually perform better. The explanation for this finding is due to educational expansion in Sweden in the 20th century, which outweighs the negative causal effect of birth order. This is particularly true for women due to the fact that the rate of increasing educational enrollment has been greater for women than for men. These results also show that later borns in large families particularly benefit from educational expansion due to the longer average birth interval between the first and last child in large families. The difference between the negative causal effect and actual experience of birth order is likely to be contributing to the confusion regarding birth order effects in the literature.

Genomewide association analysis for average birth interval and stillbirth in swine.

Reproductive efficiency has a great impact on the economic success of pork production. Stillborn pigs and average birth interval contribute to the number of pigs born alive in a litter. To better understand the underlying genetics of these traits, a genomewide association study was undertaken. Samples of DNA were collected and tested using the Illumina Porcine SNP60 BeadChip from 798 females farrowing over a 4-yr period (all first parity). Birth intervals and piglet birth status (stillborn or alive) were determined by videotaping each farrowing event. A total of 41,148 SNP were tested using the Bayes C option of GenSel (version 4.61) and 1-Mb windows. These 1-Mb windows explained proportions of 0.017, 0.002, 0.032, 0.029, and 0.030 of the total variation, respectively, for litter average birth interval after deletion of the last piglet born, last birth interval in the litter, number of stillborn piglets ignoring the last piglet born, number of stillborns in the last birth position, and percent stillborn ignoring the last piglet. Significant 1-Mb nonoverlapping SNP windows were identified by using a conservative approach requiring 1-Mb windows to have a genetic variance ≥1.0% of genomic variance and these were considered to be QTL. Quantitative trait loci were located for number of stillborn piglets ignoring the last piglet born (1 QTL), number of stillborns in the last birth position (1 QTL), and percent stillborn ignoring the last piglet (3 QTL). In addition, 2, 13, 3, and 6 suggestive 1-Mb nonoverlapping SNP windows were identified for litter average birth interval after deletion of the last piglet born, number of stillborn piglets ignoring the last piglet born, number of stillborns in the last birth position, and percent stillborn ignoring the last piglet, respectively. Possible candidate genes affecting both birth interval and stillbirth included () and (). Possible genes affecting only birth interval included (), and (), and those affecting only stillbirth included (), LOC100518697 (a nostrin-like gene), and (). The QTL and the suggestive 1-Mb nonoverlapping SNP windows may lead to genetic markers for marker assisted selection, marker assisted management, or genomic selection applications in commercial pig populations.

Determinants and consequences of short birth interval in rural Bangladesh: a cross-sectional study.

BackgroundShort birth intervals are known to have negative effects on pregnancy outcomes. We analysed data from a large population surveillance system in rural Bangladesh to identify predictors of short birth interval and determine consequences of short intervals on pregnancy outcomes.MethodsThe study was conducted in three districts of Bangladesh – Bogra, Moulavibazar and Faridpur (population 282,643, 54,668 women of reproductive age). We used data between January 2010 and June 2011 from a key informant surveillance system that recorded all births, deaths and stillbirths. Short birth interval was defined as an interval between consecutive births of less than 33 months. Initially, risk factors of a short birth interval were determined using a multivariate mixed effects logistic regression model. Independent risk factors were selected using a priori knowledge from literature review. An adjusted mixed effects logistic regression model was then used to determine the effect of up to 21-, 21-32-, 33-44- and 45-month and higher birth-to-birth intervals on pregnancy outcomes controlling for confounders selected through a directed acyclic graph.ResultsWe analysed 5,571 second or higher order deliveries. Average birth interval was 55 months and 1368/5571 women (24.6%) had a short birth interval (<33 months). Younger women (AOR 1.11 95% CI 1.08-1.15 per year increase in age), women who started their reproductive life later (AOR 0.95, 0.92-0.98 per year) and those who achieve higher order parities were less likely to experience short birth intervals (AOR 0.28, 0.19-0.41 parity 4 compared to 1). Women who were socioeconomically disadvantaged were more likely to experience a short birth interval (AOR 1.42, 1.22-1.65) and a previous adverse outcome was an important determinant of interval (AOR 2.10, 1.83-2.40). Very short birth intervals of less than 21 months were associated with increased stillbirth rate (AOR 2.13, 95% CI 1.28-3.53) and neonatal mortality (AOR 2.28 95% CI 1.28-4.05).ConclusionsBirth spacing remains a reproductive health problem in Bangladesh. Disadvantaged women are more likely to experience short birth intervals and to have increased perinatal deaths. Research into causal pathways and strategies to improve spacing between pregnancies should be intensified.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-014-0427-6) contains supplementary material, which is available to authorized users.

An evaluation of the recent fertility changes in Afghanistan: a parity-specific analysis

Very limited studies exist on the demography of Afghanistan. Using the only national survey with complete birth history data, the 2010 Afghanistan Mortality Survey, this paper describes the recent fertility changes in the country from a parity-specific perspective. From 1995 to 2009, parity progression ratios, average birth intervals, sex ratio at birth by parity and synthetic lifetime average parity are successively examined. Results show that the progression to higher-order births started to decline in the early 2000s and was accompanied by childbearing postponement. The consistency of the parity analysis is assessed by looking at the sex ratio at birth by parity and comparing the synthetic lifetime average parity to fertility estimates computed from other datasets and/or estimation methods. While the sex ratio at birth indicates strong distortion, casting doubt on the ultimate fertility level, the consistency of the parity-based fertility estimates with other fertility estimates corroborates the fact that misreporting the sex of the child is mainly causing the imbalanced sex ratio at birth and is not significantly affecting the level of fertility. The SPPRs-based analysis provides solid evidence that Afghanistan is in the early stage of its fertility transition.

Effect of empty uterine space on birth intervals and fetal and placental development in pigs

A substantial loss of embryos occurs between Days 30 and 40 of pregnancy in the pig under crowded intrauterine conditions, but it is not clear whether this loss affects the growth of adjacent conceptuses. Birth intervals are known to increase with decreasing litter size, but the factors responsible are unknown. Two possibilities are that increased birth weight associated with reduced litter size and the empty uterine space and resulting constricted uterine regions that occur in pigs with small litters may impair piglet delivery. To address these, pregnant gilts were laparotomized on Day 35 of pregnancy and one or two fetuses were manually crushed through the uterine wall on the ovarian or cervical end of each uterine horn to create an empty uterine space behind or in front of the litter of piglets, respectively, in relation to the route of delivery from the uterus. A subset of gilts was slaughtered at 105 days of gestation to confirm that the empty uterine spaces were successfully created and to determine their effects on placental and fetal weights of adjacent conceptuses. At slaughter, the lengths of all externally visible empty constricted regions of the uterus were measured. The uterine horns were opened and the lengths of each placenta were measured from the umbilicus toward the ovary and toward the cervix to assess whether placentas developed symmetrically, and then each fetus and placenta was weighed. Fetal crushing successfully created constricted empty uterine regions on the ovarian and cervical ends of the uterine horns. Ovarian-side placental lengths were greater than cervical-side for conceptuses adjacent to fetuses crushed on the ovarian end of the horn. Cervical-side placental lengths were greater than ovarian-side for conceptuses adjacent to fetuses crushed on the cervical end. Both placental and fetal weights were greater (10% and 6%, respectively, P < 0.05) for conceptuses adjacent to crushed fetuses compared to nonadjacent conceptuses. Remaining gilts were farrowed to determine the effect of litter size, average birth weights, and treatment on birth intervals of piglets, which were monitored using 24-h video surveillance. The negative association between number of piglets born alive and average birth interval was confirmed and was not explained by litter size-induced reduction in litter average birth weights. Birth intervals and stillbirth rate did not differ between cervically- and ovarian-treated gilts. These results indicate that conceptus loss on Day 35 of gestation can benefit the growth of adjacent placentas and fetuses, but the benefit is small. Increased average birth weight and the presence of empty uterine space that occurs when litter size is reduced does not fully explain the effect of litter size on birth intervals.

Environmental and sow-related factors affecting the duration of farrowing

A short duration of farrowing is important for piglet survival as a delay can increase the number of stillborn. Many factors may affect the duration of farrowing, including breed, age of the sow, length of gestation, number of piglets born, housing (CRATE vs. PEN), body condition of the sow and state of constipation. The aim of the present study was to investigate these factors and how they interact with each other and thus increasing the risk of prolonged farrowing. The total duration of farrowing and average piglet birth interval were recorded in 172 sows from two herds (HERD-1, n = 76; HERD-2, n = 96). Back-fat measurements and intestinal activity (based on the mean of a constipation index) were measured in all 172 sows. The total duration of farrowing was 272 ± 152 min (mean ± SD, n = 172): 301 ± 165 min ( n = 115) in the CRATE group and 212 ± 95 min ( n = 57; P < 0.05) in the PEN group. The average piglet birth interval was 26 ± 25 min (mean ± SD, n = 172): 29 ± 29 min ( n = 115) in the CRATE group and 19 ± 10 min ( n = 57; P < 0.05) in the PEN group. Housing ( P < 0.05), stillborn ( P < 0.001), back-fat average ( P < 0.001) and constipation index ( P < 0.05) significantly correlated with the duration of farrowing. In conclusion, allowing the sow to move freely before farrowing, reducing the constipation state and avoid excessive fattening during late pregnancy all appear to be key factors in shortening farrowing time and reducing perinatal mortality.

Impact of contraception use among women seeking tubal ligation in the rural Democratic Republic of the Congo

Introduction. Investing in health is recommended for economic growth and the reduction of inequity in developing countries. Family planning is one such investment that benefits women and children. But resource-constrained environments, such as countries in conflict, present logistical and other challenges to the implementation of health programmes. For this reason even a proven cost-effective health intervention still needs to be contextualised to assess the actual benefit or impact in resource-constrained settings. Objectives. To describe user characteristics and analyse the impact of reversible contraception use among women who underwent tubal ligation in a rural health district of the Democratic Republic of Congo over a 4-year period. Methods. A retrospective analysis of family planning programme registers for 4 years (1990 - 1994). During the study period, 400 women underwent tubal ligation. All records except for 76 that were incomplete were included in the study. Results. A sample of 324 women was analysed. Most of the subjects (96%) were older than 30 years and of the Christian protestant faith (85%). Most had an education level less than secondary. Of the participants 99% were married; 98% of participants did not work outside the home. There was no significant difference in the average birth interval between contraceptive users and non-users (p = 0.246), but small families of less than 5 children were significantly more common (p = 0.006) in the small group of contraception users compared with non-users (10.1% and 2.8% respectively). Conclusions. The demand for surgical contraception comes mainly from married women with low education and economic status. Previous use of contraception did not make a difference in terms of birth spacing, suggesting a high prevalence of inconsistent or incorrect use of contraception SAJOG Vol. 13 (1) 2007: pp. 15-18