Mean Gestation Length Research Articles

Mean breed performance of the progeny from beef-on-dairy matings

Gains through breeding can be achieved through a combination of both between-breed and within-breed selection. Two suites of traits of particular interest to dairy producers when selecting beef bulls for mating to dairy females are calving-related attributes and the expected value of the subsequent calf, the latter usually being a function of expected carcass value. Estimated breed effects can be informative, particularly in the absence of across-breed genetic evaluations. The objective of the present study was to use a large national database of the progeny from beef-on-dairy matings to estimate the mean breed effects of the used beef sires. Calving performance (i.e., gestation length, calving difficulty score, and perinatal morality) as well as calf value were investigated; a series of slaughter-related traits (i.e., carcass metrics and age at slaughter) of the prime progeny were also investigated. Phenotypic data on up to 977,037 progeny for calving performance, 79,903 for calf price and 103,175 for carcass traits (including dairyxdairy progeny for comparative purposes) were used; sire breeds represented were Holstein-Friesian, Angus, Aubrac, Belgian Blue, Charolais, Hereford, Limousin, Salers and Simmental. Large inter-breed differences existed. The mean gestation length of male calves from beef sires varied from 282.3 d (Angus) to 287.4 d (Limousin) which were all longer than the mean of 280.9 d for Holstein-Friesian sired male calves. Relative to a Holstein-Friesian sire, the odds of dystocia varied from 1.43 (Angus) to 4.77 (Belgian Blue) but, once adjusted for both the estimated maternal genetic merit of the dam and direct genetic merit of the calf for calving difficulty, the range in odds ratios shrunk. A difference of €125.4 existed in calf sale price between the progeny of the different beef breeds investigated which represented over twice the residual standard deviation in calf price within the day of sale - Angus was the cheapest while Charolais calves were, on average, the most expensive calves. Mean carcass weight of steers, not adjusted for age at slaughter or carcass fat, varied from 327.1 kg (Angus) to 363.2 kg (Belgian Blue) for the beef breeds with the mean carcass weight of Holstein-Friesian steer progeny being 322.4 kg. Belgian Blues had, on average, the best carcass conformation with the Herefords and Angus having the worst of all beef breeds. Angus and Hereford steers were slaughtered the youngest of all beef breeds but just 9 d younger than the average of all other beef breeds yet 24 d younger than Holstein-Friesian sired progeny. Clear breed differences in calving and carcass performance exist among beef breeds mated to dairy females. Those breeds excelling in calving performance were not necessarily the best for carcass merit.

Reproductive and developmental toxicity evaluation of cannabidiol.

An important data gap in determining a safe level of cannabidiol (CBD) intake for consumer use is determination of CBD's potential to cause reproductive or developmental toxicity. We conducted an OECD Test Guideline 421 GLP-compliant study in rats, with extended postnatal dosing and hormone analysis, where hemp-derived CBD isolate (0, 30, 100, or 300 mg/kg-bw/d) was administered orally. Treatment-related mortality, moribundity, and decreased body weight and food consumption were observed in high-dose F0 adult animals, consistent with severe maternal toxicity. No effects were observed on testosterone concentrations, F0 reproductive performance, or reproductive organs. Hepatocellular hypertrophy in the 100- and 300 mg/kg-bw/day groups correlated with hypertrophy/hyperplasia in the thyroid gland and changes in mean thyroid hormone concentrations in F0 animals. Mean gestation length was unaffected; however, total litter loss for two females and dystocia for two additional females in the high-dose group occurred. Other developmental effects were limited to lower mean pup weights in the 300 mg/kg-bw/d group than those of controls. The following NOAELs were identified for CBD isolate based on this study: 100 mg/kg-bw/d for F0 systemic toxicity and female reproductive toxicity, 300 mg/kg-bw/d for F0 male reproductive toxicity, and 100 mg/kg-bw/d for F1 neonatal and F1 generation toxicity.

Factors Affecting Gestation Length in Gir Cattle

The present study was planned to understand the factors affecting gestation length in nulliparous and pluriparous Gir cows. A cumulative ten years (2010-2019) full term calving record (n = 1272) of Gir cows were incorporated. The overall mean gestation length of Gir cattle was 283.29 ± 0.16 days. It was shortest in 8th and above parities and longest in 7th parity Gir cows (282.39 and 285.84 days, respectively); with statistically significant (p<0.05) difference. The gestation length remained almost similar from nulliparous to 6th parities cows (ranged from 283.10 to 283.74 days) and the values were more or less close to the overall mean of gestation length. The mean gestation length in cows having female calf was 1.4 days shorter than those with male calf (282.60 vs. 283.99 days). There was period wise significant variation of gestation length in Gir cows (p<0.05). The Gir cattle served during December and March had shortest and longest mean gestation length (282.22 and 284.40 days), respectively; the difference was statistically significant (p<0.05). The mean gestation length across different calving months varied significantly (p<0.05). Season of service and season of birth did not affect gestation length in Gir cattle. The results showed that Gir cows are less affected for gestation length by different factors throughout the year.

Pregnancy course and outcomes of patients with polymyositis and dermatomyositis (PM/DM) managed in a single center

We aimed to determine the association between disease activity during pregnancy and pregnancy outcomes of women with polymyositis and dermatomyositis (PM/DM). Patients with PM/DM who were managed from pregnancy to delivery at Kagawa University Hospital from March 2006 to May 2021 were enrolled. Clinical data were retrospectively analyzed to evaluate the association between disease activity during pregnancy and pregnancy outcomes. Eight pregnancies in 5 women with PM/DM were analyzed. The mean age at conception was 28.3 ± 3.8 years, and mean disease duration was 6.3 ± 3.2 years. Four patients required an increased glucocorticoid dosage because of worsening disease activity (sustained elevation of creatine phosphokinase [CPK] concentration). Two patients who continuously received immunosuppressive drugs from conception to delivery showed no increase in disease activity and did not need increased glucocorticoid dosages. The pregnancy outcomes were 1 spontaneous abortion and 7 live births. The mean gestation length was 35.3 ± 5.2 weeks, and mean birthweight was 2297.7 ± 1041.4 g. Five adverse pregnancy outcomes (APOs) occurred (2 preterm births and 4 low birthweights); most of these cases had sustained elevation of CPK concentration and increased glucocorticoid dosages. No APOs occurred in the 2 patients who received continuous immunosuppressive medication. Continued use of pregnancy-compatible medications and control of disease activity with lower glucocorticoid dosages in pregnancies with PM/DM may be important to achieve good pregnancy outcomes.

Effectiveness and acceptability of home use of misoprostol for medical abortion up to 10 weeks of pregnancy.

The administration of mifepristone, followed by misoprostol, is widely used for medical abortion. Many studies have demonstrated home abortion to be safe in pregnancies up to 63 days of gestation, and recent data support its safety when extended to more advanced pregnancies. We studied the efficacy and acceptability of home use of misoprostol up to 70 days of gestation in a Swedish setting and compared the outcomes between pregnancies with a gestational age of up to 63 days and pregnancies with gestational age 64-70 days. This prospective cohort study was performed between November 2014 and November 2021 at Södersjukhuset and Karolinska University Hospital, Stockholm, and some patients were also recruited from Sahlgrenska University Hospital, Göteborg and Helsingborg Hospital. The primary outcome was the rate of complete abortions and was defined as complete abortion without any need for surgical or medical intervention and assessed by clinical assessment, pregnancy test and/or vaginal ultrasound. Secondary objectives were assessed by daily self-reporting in a diary and included pain, bleeding, side effects and women's satisfaction and perception of home use of misoprostol. A comparison of categorical variables was made with Fisher's exact test. The significance level was set to a p-value ≤0.05. The study was registered at Clinicaltrials.gov on July 14, 2014 (NCT02191774). During the study period we enrolled 273 women opting for medical abortion with home use of misoprostol. In the early group, up to 63 days of gestation, 112 women were included with a mean gestational length of 45 days and in the late group, 64-70 days of gestation, 161 women with a mean gestations length of 66.3 days were included. Complete abortion occurred in 95% (95% CI 89-98) of women in the early group and in 96% (95% CI 92-99) in the late group. No differences were found regarding side effects and acceptability was similarly high in both groups. Our results show high efficacy and acceptability of medical abortion when misoprostol is administered at home up to 70 days of gestation. This supports previous findings about maintained safety when misoprostol is administered at home even past a very early pregnancy.

The role of metabolic diseases in neonatal convulsions.

The neonatal period is the most vulnerable time for the development of seizures, particularly in the first weeks after birth. These seizures often signify serious malfunction or damage to the immature brain and constitute a neurological emergency, necessitating urgent diagnosis and management. This study was performed to identify the etiology of convulsions during the neonatal period and to determine the rate of congenital metabolic disease. A total of 107 term and preterm infants 0-28 days old who were treated and followed-up in the neonatal intensive care unit of our hospital between January 2014 and December 2019 were analyzed retrospectively based on data obtained by scanning the hospital information system and patient files. The study population included 54.2% male infants, and 35.5% of infants were born by caesarean section. Birth weight was 3,016 ± 560 (1,300-4,250) g, mean length of gestation was 38 (29-41) weeks, and mean maternal age was 27.4 ± 6.1 (16-42) years. Of the infants, 26 (24.3%) were preterm and 81 (75.7%) were term deliveries. Examination of family history revealed 21 (19.6%) cases with consanguineous parents and 14 (13.1%) cases with a family history of epilepsy. Hypoxic ischemic encephalopathy was the most common etiology of the seizures (34.5%). Burst suppression was detected on amplitude integrated electroencephalography in 21 (56.7%) monitored cases. Although subtle convulsions were most common, myoclonic, clonic, tonic and unclassified convulsions were also observed. The convulsions appeared during the first week of life in 66.3% of cases and during the second week or later in 33.7%. Fourteen (13.1%) patients examined by metabolic screening due to suspected congenital metabolic disease had a different congenital metabolic diagnosis. Although hypoxic ischemic encephalopathy was the most common cause of neonatal convulsions in our study, congenital metabolic diseases with autosomal recessive inheritance were detected at a high rate.

Effects of use of conventional and sexed semen on conception rate, calf sex, calf birth weight, and stillbirth in Holstein heifers

Pregnancy rate is low in artificial insemination with sexed semen compared to conventional semen. This situation poses a major problem for dairy farms. The aim of this study was to determine the effects of semen type on conception rate, calf sex and birth weight, stillbirth, pregnancy loss, and postpartum maternal body weight (MBW) in Holstein heifers inseminated with sexed (n = 229), and conventional semen (n = 153). The female and male calf ratios of the heifers inseminated with sexed and conventional semen were found to be 88% to 54.8% and 12% to 45.2%, respectively. There was a significant difference between sperm type and calf sex (p < 0.001). While 36.7% of calves between 34 and 36 kg birth weights were born from heifers inseminated with sexed semen, 15.7% were born from heifers inseminated with conventional semen. Moreover, 46% and 17.3% of calves that had birth weights of 36.1-38.1 kg and > 38.2 kg were born from heifers inseminated with sexed semen while 40% and 44.3% were born from heifers inseminated with conventional semen, respectively. A statistically significant relationship was found between semen type and calf birth weights (p < 0.001). After calving, there was a significant difference between semen type and MBW after calving (p < 0.001). In the sexed and conventional semen groups, the MBW after calving was found to range from 11.3% to 23.5% in the 400-460 kg, 46.7% to 57.4% in the 461-511 kg, and 42% to 19.1% in the 512-587 kg weight categories, respectively. There was no statistically significant difference (p > 0.05) between sperm type and mean gestation length and calf birth weight, pregnancy loss, stillbirth rate, and weaning calf mortality rates. There was a strong positive correlation between semen type, sex, and calf birth weight. Furthermore, there was a significant correlation between the MBW, the gestation period and the survival status of the calves. It was determined that there was a minor positive relationship between the insemination season and the gestation period, MBW, and the survival status of the calves. Our results demonstrated that with careful and consistent application of herd management program in dairy cattle farms, the rates of pregnancy obtained with sexed and conventional semen will increase, whilst parameters such as stillbirth and pregnancy loss will decrease.

P-003 Sperm retrieved by microdissection testicular sperm extraction (MD-TESE) is associated with altered sex ratio of offspring after intracytoplasmic sperm injection in men with non-obstructive azoospermia

Abstract Study question Does the sperm retrieved surgically by MD-TESE of men with Non-Obstructive Azoospermia affect the live birth sex ratio? Summary answer Our data indicates that sperm retrieved in men with non-obstructive azoospermia alters the sex ratio in favor of female offspring. What is known already Non-Obstructive Azoospermia is the most severe form of male infertility and is the most common cause of Azoospermia. Among the different surgical techniques, MD-TESE gives the highest rate of sperm retrieval and when combined with intracytoplasmic sperm injection (ICSI), live births had been achieved with variable success, Sex ratio of offspring can vary substantially due to several variables, however no studies have investigated the resultant birth sex ratio in this setting. Study design, size, duration Retrospective Cohort study. Data were collected between May 2009 and December 2019. A total of 100 consecutive men with non-obstructive Azoospermia underwent MD-TESE for sperm retrieval. 46 couples underwent ICSI and live birth rate, cumulative live birth rate and sex ratio of offspring analysed. Participants/materials, setting, methods One-hundred men underwent MD-TESE out of which 46 proceeded with ICSI. Demographic data including male and female age, testicular volumes and serum hormone values are given as mean ± SD with a range (minimum and maximum). Fertility outcomes including sperm retrieval, fertilization rate, number of embryos transferred, and live birth rates and cumulative live birth rates were recorded. Chi-square test was performed to compare the proportions. Main results and the role of chance Sperm retrieval was successful in 58%(58/100). Testicular volume and hormonal parameters did not vary among patients with positive or negative sperm retrieval. Histology gave best correlation with sperm retrieval. Hypospermatogenesis yielded the highest sperm retrieval 93%(26/29), followed by Maturation arrest 78%(7/9), then Hyalinosis 46% (6/13) and lastly Sertoli cell only 38%(19/50). 46 couples underwent ICSI cycles where the mean age of patients and their wives were 36.4 ± 3.7y and 33.0 ± 4.3y. Fertilization rate and mean number of transferred embryos were 51.4 % and 1.7. Live birth rate and Cumulative Live Birth rate per Embryo transfer were 60.5% (26/43) and 74.4% (32/43) and per started ICSI cycle were 56.5% (26/46) and 69.6% (32/46), with a twin rate of 15.3%(4/26). Mean gestational length and mean body weight at birth were 39.0 ± 1.4w and 3228.5 ± 5.5 g. Number of live offspring were 36 (Female: Male = 26:10) giving rise to sex ratio of 2.6 to1 in favor of female offspring (P &amp;lt; 0.05). There were no neonatal death, and one baby had phenylketonuria. Limitations, reasons for caution This is the first study to test the hypothesis of sex ratio variation related to the source of sperm; the strength of our study is that all procedures were performed by the same surgeon, so there are no operator-dependent differences. This finding needs to be confirmed in larger cohort studies. Wider implications of the findings It has been demonstrated that different stressors may alter the sex of the offspring. While in the present study the stressor is the parental hypogonadism associated with non-obstructive azoospermia, We hypothesise that testicular environment may direct spermatogenesis in favor of X carrying sperm around the time of sperm retrieval. Trial registration number N/A

P-403 Progesterone supplementation in frozen embryo transfer with hormonal replacement therapy is associated with a higher incidence of macrosomia

Abstract Study question Is there an impact of increased progesterone (P4) supplementation in hormone replacement therapy (HRT) frozen embryo transfer (FET) on obstetrical and neonatal outcomes? Summary answer Increased P4 supplementation from the day of FET is associated with a significantly higher risk of macrosomia and a slightly higher risk of preeclampsia. What is known already The most widely used method for endometrial preparation prior to FET is HRT, a sequential regimen with E2 and P4, which aims to mimic the endocrine exposure of the endometrium of the physiological cycle. However, in ∼40% of the patients undergoing HRT-FET cycles P4 levels before FET remain low and this may negatively affect pregnancy rates. Although recent prospective studies have shown that additional P4 supplementation in case of low serum P4 levels results in excellent reproductive outcomes, no data exist concerning the potential effect of this extra amount of P4 on obstetrical and neonatal outcomes Study design, size, duration This is a single-centre, retrospective-observational study. Women undergoing HRT-FET treatment meeting the inclusion criteria were allocated to one of the 2 study groups according to the P4 supplementation. Group A (277) included women with adequate levels (&amp;gt;10.6 ng/ml) of P4, while group B (129) included women who received P4 supplementation due to inadequate levels of P4 (&amp;lt;10.6 ng/ml) on the day before the FET. All FET-HRT cycles were performed between February 2018 and December 2020. Participants/materials, setting, methods All patients received micronized P4 (200 mg trice a day) starting six days prior to the FET and continued until 10 weeks of pregnancy. In case P4&amp;lt;10.6 ng/ml, P4 supplementation was initiated rather with 400mg more micronized P4 (15%) or with subcutaneous P4 (25mg more/once a day) (85%). Only patients with day5-embryos, known P4 levels prior to FET, known obstetrical and neonatal outcomes were included. Multivariable-logistic-model was fitted for macrosomia after adjusting for confounding variables. Main results and the role of chance Patients’ age at oocyte retrieval was 33.5 and 33.6 years (p = 0.833), while the age at delivery was 39.9 and 39.1 years (p = 0.099), respectively for groups A and B. The incidence of diabetes, hypertension, autoimmune diseases, coagulation, and kidney disorders was comparable for both arms. The mean value of P4 was 16 ± 7.7 and 8.2 ± 1.9, respectively for groups A and B. The mean gestational length was 39 weeks in both arms, with comparable rates of premature deliveries (delivery &amp;lt;37 weeks respectively 4.3% and 3.1 % for group A and B; p = 0.553). The rate of cesarean-section was 56% vs 47.3%, respectively for groups A and B (p = 0.103); there were 5 cases of pre-eclampsia in group A and 7 in group B (1.8% vs 5.4%; p = 0.059). The incidence of macrosomia was significantly higher in group B (6.1% vs 12.4%; P = 0.031). Similarly, group B had a higher rate of BGA-big for gestational age- babies (9.7 vs 15.5, p = 0.091). In terms of weight at delivery, pH, Apgar, and sex the two groups were comparable. Multivariable-logistic regression showed an association between macrosomia and P4 supplementation, adjusting for potential confounders such as sex, gestational diabetes, and weeks of gestation (OR 2.3, 95% CI 1.1-4.8). Limitations, reasons for caution The main limitation of this study is its retrospective nature. Other potential limitations are the small sample size to detect obstetrical diseases with low incidence, such as preeclampsia. Furthermore, in our study population the PE rate is lower than in the general population, due to socioeconomic-conditions, race, and previous morbidity. Wider implications of the findings P4-supplemented patients have a higher risk of macrosomia and a tendency for a higher risk of preeclampsia. However, more studies are needed to confirm the present exploratory findings and explain the possible physiological mechanisms underlying the association between progesterone supplementation on macrosomia and preeclampsia. Trial registration number NA

Factors affecting gestation length in small sized breeds of dogs.

A large variation in the gestation length can be expected when the gestation is calculated from the day of mating to birth. The present study was designed to assess the influence of different factors like litter size, breed, parity and age on gestation length in bitches. A total of 89 small sized bitches of different breeds having different age, parity and body weight, were selected for the study. The mean age, body weight and parity of the animals included in the present study were 3.00 ± 0.15 years (1 to 8 years), 9.9 ± 0.25 Kg (6 to 15kg) and 1.14 ± 0.10 (0-4th parity) respectively. The mean gestation lengths observed in different small sized breeds were 60.68 ± 0.55, 59.82 ± 0.54, 60.78 ± 1.74, 58.83 ± 1.35 and 58.17 ± 0.74 in the Pug, Beagle, Dachshund, French Bulldog and the Spitz, respectively. The mean litter size in the study was 4.34 ± 0.13 with a range of 2-8. The mean gestational length in animals having ? 3 litter size was 60.83 ± 0.64 days and 59.90 ± 0.43 days in animals having &gt;3 litter size. Age limit of the animals ranged from 1 to 8 years with a mean of 3 ± 0.15 years. The mean gestation length in bitches aged ?3 years was 60.21 ± 0.23 days (n=63) and this was 60.15 ± 0.3 (n=26) days in bitches in the &gt;3 years group. Mean gestational length observed in nulliparous bitches was 60.86 ± 0.4 days (n=29), while in multiparous bitches it was 59.90 ± 0.5 days (n=60). From the present investigation it could be concluded that no significant difference exists in gestational length between different breeds, litter size, age group and parity.

Effectiveness of cervical pessary in women with arrested preterm labor compared to those with asymptomatic cervical shortening

Objective To determine whether the effectiveness of cervical pessary is different in women who experienced cervical shortening after a threatened preterm labor episode compared to those with asymptomatic short cervix. Methods Retrospective study on singleton pregnancies at risk for preterm delivery (PTD) due to cervical length <25 mm before 28 weeks, who were treated with Arabin cervical pessary. Two groups of patients were compared: those who had contractions causing shortening of the cervix, prior to pessary placement, and those who had asymptomatic cervical shortening. Patients carrying a multiple pregnancy and those who underwent iatrogenic PTD were excluded. The primary outcome was the incidence of PTD at different gestational ages. Secondary outcome was the rate of preterm premature rupture of membrane (pPROM). The groups were compared using univariate and multivariate analyses. Results 115 patients that met the inclusion criteria were identified. Of these, 91 (79%) had asymptomatic cervical shortening, while 24 (21%) had an episode of threatened preterm labor that resolved, and the pessary was placed after the contractions had stopped. The two groups were similar for maternal characteristics, obstetric history, mean gestational age and length of the cervix at the time of pessary insertion. The median gestational age at delivery was significantly lower (36.4 vs 38.0 weeks, p = .02), and the incidence of PTD significantly higher (58.3% vs 30.8%, OR 4.69, 95% CI 1.68–13.1, p < .01) among women who had arrested preterm labor before the pessary was placed compared to the asymptomatic group, after controlling for confounders. The incidence of PTD before 34 and before 32 weeks was also significantly higher in the symptomatic group (p = .02 and p = .005, respectively). Women with asymptomatic cervical shortening had a longer interval between the placement of the pessary and delivery (median 15 weeks). pPROM occurred with a similar incidence in both groups. Conclusions Arabin cervical pessary to prevent preterm delivery seems be less effective in women with a short cervix following an episode of threatened preterm labor than in those with asymptomatic cervical shortening in the second trimester. This finding may help physicians to select patients in which cervical pessary is more likely to be effective, and to improve patient’s counseling about this intervention.

Associations of COVID-19 lockdown with gestational length and preterm birth in China

BackgroundThe effects of COVID-19 lockdown measures on maternal and fetal health remain unclear. We examined the associations of COVID-19 lockdown with gestational length and preterm birth (PTB) in a Chinese population.MethodsWe obtained medical records of 595,396 singleton live infants born between 2015 and 2020 in 5 cities in Guangdong Province, South China. The exposed group (N = 101,900) included women who experienced the COVID-19 Level I lockdown (1/23–2/24/2020) during pregnancy, while the unexposed group (N = 493,496) included women who were pregnant during the same calendar months in 2015–2019. Cumulative exposure was calculated based on days exposed to different levels of emergency responses with different weighting. Generalized linear regression models were applied to estimate the associations of lockdown exposure with gestational length and risk of PTB (< 37 weeks).ResultsThe exposed group had a shorter mean gestational length than the unexposed group (38.66 vs 38.74 weeks: adjusted β = − 0.06 week [95%CI, − 0.07, − 0.05 week]). The exposed group also had a higher risk of PTB (5.7% vs 5.3%; adjusted OR = 1.08 [95%CI, 1.05, 1.11]). These associations seemed to be stronger when exposure occurred before or during the 23rd gestational week (GW) than during or after the 24th GW. Similarly, higher cumulative lockdown exposure was associated with a shorter gestational length and a higher risk of PTB.ConclusionsThe COVID-19 lockdown measures were associated with a slightly shorter gestational length and a moderately higher risk of PTB. Early and middle pregnancy periods may be a more susceptible exposure window.

Assessing the impact of group antenatal care on gestational length in Rwanda: A cluster-randomized trial

Research on group antenatal care in low- and middle-income contexts suggests high acceptability and preliminary implementation success. We studied the effect of group antenatal care on gestational age at birth among women in Rwanda, hypothesizing that participation would increase mean gestational length. For this unblinded cluster randomized trial, 36 health centers were pair-matched and randomized; half continued individual antenatal care (control), half implemented group antenatal care (intervention). Women who initiated antenatal care between May 2017 and December 2018 were invited to participate, and included in analyses if they presented before 24 weeks gestation, attended at least two visits, and their birth outcome was obtained. We used a generalized estimating equations model for analysis. In total, 4091 women in 18 control clusters and 4752 women in 18 intervention clusters were included in the analysis. On average, women attended three total antenatal care visits. Gestational length was equivalent in the intervention and control groups (39.3 weeks (SD 1.6) and 39.3 weeks (SD 1.5)). There were no significant differences between groups in secondary outcomes except that more women in control sites attended postnatal care visits (40.1% versus 29.7%, p = 0.003) and more women in intervention sites attended at least three total antenatal care visits (80.7% versus 71.7%, p = 0.003). No harms were observed. Group antenatal care did not result in a difference in gestational length between groups. This may be due to the low intervention dose. We suggest studies of both the effectiveness and costs of higher doses of group antenatal care among women at higher risk of preterm birth. We observed threats to group care due to facility staff shortages; we recommend studies in which antenatal care providers are exclusively allocated to group antenatal care during visits. ClinicalTrials.gov NCT03154177.

EFFECTS OF SEASON AND LITTER SIZE ON GESTATION LENGTH IN SWINE

488 gestations (309 Large White and 179 Landrace) and the size of all litters resulting from services which occurred between January 1967 and March 1970 were analysed. The mean gestation length was 113.96 days for the Large White and 113.74 days for the Landrace while the mean values for the litter size were 9.14 and 9.58 respectively. There was a significant negative correlation between these two traits in both breeds (P 0.01). A slight and non-significant seasonal effect (P 0.10) was shown with the highest and lowest gestation lengths being recorded in July (114.38 days) and in January and February (113.40 days). Breed effect and interaction between breed and season were also not significant.

Genetic and environmental analysis of female calf survival in the Israel Holstein cattle population

The objectives were to estimate the effects of various environmental factors on female calf survival of Israeli Holsteins, to estimate the economic value of calf survival under Israeli conditions, to estimate the genetic and environmental variance components for calf and cow survival using the individual animal model, to perform GWAS analyses of survival to first calving and herd life after first calving, to estimate the genetic and environmental trends for calf survival since 1985, to estimate genetic correlations of calf survival with the traits included in the current Israeli breeding index, and to estimate the consequences of inclusion of calf survival in the national selection index. Mean calf survival rate of Israeli Holsteins from 2001 through 2008 was 0.85, and the mean economic value of survival to first calving was $526. Birth month, gestation length, dystocia, and twin birth significantly affected calf survival rate. Dystocia and twin birth each reduced survival rate by 0.034. Survival rate was highest for calves born in October and lowest for calves born in February. The difference between these months was 3.4%. Maximum survival was at a gestation length of 276 d, the mean gestation length for this population. Survival rate was reduced to 0.76 for calves born after a gestation length of 260 d. The individual animal model was applied for all the genetic analyses. Heritability for calf survival to first calving, as estimated by REML, was 0.009, whereas heritability of herd life from first calving was 0.15. The complete data set for genetic analysis of survival to first calving included 1,235,815 calves born between 1985 and 2017. Annual genetic and phenotypic trends for calf survival were 0.019 and 0.015%, respectively. Correlations of transmitting abilities of 226 sires born since 2010 for calf survival with the traits included in the Israeli breeding index were significant only for the maternal effects of dystocia and stillbirth. The GWAS analysis was based on the transmitting abilities of 1,493 bulls with genotypes and reliabilities >0.5 for calf survival and cow herd life. There were 7 single nucleotide polymorphisms with coefficients of determination >0.03 for calf survival and 12 single nucleotide polymorphisms with coefficients of determination >0.05 for cow survival. There was no overlap between the genome-wide significant markers for the GWAS analyses of calf survival and cow herd life. This corresponds to the conclusion from the REML results and the low correlations between the sire evaluations that the genetic control of the 2 traits are not similar. Inclusion of calf survival in the Israeli breeding would result in a 0.5% increase in calf survival over 10 yr but reduce progress for the other traits by 8%.

REPRODUCTIVE AND BODY WEIGHT PERFORMANCE OF THE NEW ZEALAND WHITE RABBITS IN THE HUMID TROPICS OF NIGERIA.

Fifty two litters obtained over a period of 8 months (December 1986-July 1987) from the mating of eight bucks with twenty nine does (first mating) and twenty three does (second mating) all belonging to the New Zealand White breed of rabbits were used in this analysis. Mean gestation length, number of mating to conception, litter size at birth and parturition interval were 31.6 ± 0.2 days, 1.4 ± 0.1, 5.6 ± 0.3 pups and 79.0 ± 14.5 days respectively. Litter weight at birth, 3,6 and 8 weeks of age were 230.4 ± 9.5g, 602.1 ± 35.6g, 1247.5 ± 81.5g and 1673.0 ± 112.3g respectively. Parity significantly (P &lt;0.05) affected the number of mating to conception and litter birth weight. Litter weight at all ages were influenced (P&lt;.01) by corresponding litter sizes at such ages. Sire neither had any effect on litter weight at all ages nor on any of the reproductive parameters studied. Litter size at birth was negatively correlation with gestation length (-0.08), number of matings to conception (-0.27) and average birth weight (-0.42).

Reproductive indices and performance of captive reared grasscutters (Thryonomys swinderianus Temminck)

Two male and 8 female grasscutters were severally observed and paired to characterize certain indices of reproduction as important requirements for successful propagation of the animal in captivity. Observations on some of the reproductive indices are reported. Grasscutter possesses some specialized stages of courtship and coitus that were not readily available for observation Females openly showed no receptivity to all courtship moves by male. 71% of the mating exercises were however successful, resulting in 36 youngs from 9 litters, comprising 20 females and 16 males. Mean gestation length was 163.11 ± 1.58 days (Range 152-170 days). Litter size ranged from 2 to 7 (X = 4.00 ± 0.52, n= 9). Baby grasscutters were born with eyes opened, body fully haired and teeth well developed and capable of inflicting painful bites. Mean birth weight of litters was 117.70 ± 34.08g. Male birth weights were generally heavier (X = 118.10 ± 27.70g) than females (X = 100.90 ± 27.50g). Litter size and weight at birth were negatively correlated (r = - 0.42) and not significant (P>0.05). Breeding occurred in January, March, April, June, July, November and December. About 67% of the parturition occurred at night. Breeding success among other things affirmed the feasibility of commercial rearing of the grasscutter to supplement the prevailing inadequate animal protein supply in the country. Keywords: Grasscutter, rearing, captivity, reproduction performance

Reproductive indices and performance of captive reared grasscutters (Thryonomys swinderianus Temminck)

Two male and 8 female grasscutters were severally observed and paired to characterize certain indices of reproduction as important requirements for successful propagation of the animal in captivity. Observations on some of the reproductive indices are reported. Grasscutter possesses some specialized stages of courtship and coitus that were not readily available for observation. Females openly showed no receptivity to all courtship moves by male. 71% of the mating exercises were however successful, resulting in 36 youngs from 9 litters, comprising 20 females and 16 males. Mean gestation length was 163.11 + 1.58 days (Range 152-170 days). Litter size ranged from 2 to 7 (X -4.00 + 0.52, n=9). Baby grasscutters were born with eyes opened, body fully haired and teeth well developed and capable of inflicting painful bites. Mean birth weight of litters was 117.70 + 34.08g. Male birth weighis were generally heavier (X = 118.10 +27.70g) than females (x= 100.90 + 27.50g). Litter size and weight at birth were negatively correlated (r = . 0.42) and not significant (P&gt; 0.05). Breeding occurred in January, March, April, June, July, November and December. About 67% of the parturition occurred at night. Breeding success among other things affirmed the feasibility of commercial rearing of the grasscutter to supplement the prevailing inadequate animal protein supply in the country.

Evaluation of gestation length in Czech Holstein cattle

An objective of our study was to evaluate gestation length and its genetic variability in the Czech Holstein population. Data set consisted of 770 865 records of gestation length in 375 574 Holstein cows and covered the period from 2012 to 2018. Mean gestation length was 277 ± 4.9 days, and it was 1.4 days longer in male calves compared to females, and 1.1 days longer in cows compared to heifers. Animal repeatability model with maternal effect was employed for variance component estimation. The direct genetic effect explained the highest proportion of variability, and it corresponded with moderate direct heritability (0.48), while maternal heritability was much lower (0.06). We estimated conventional and genomic breeding values with the genomic matrix based on 39 145 single nucleotide polymorphisms in 13 844 animals. Genomic breeding values were weakly (&amp;lt; 0.25) but significantly correlated with breeding values for type, production and fitness traits. Pearson correlations between breeding values indicated a negative association of direct gestation length with milk production, longevity and fertility of bulls, and a positive association of maternal gestation length with most of the type traits related to the body composition. Genetic trends for male and female parts of the population showed a tendency to the shortening of gestation, which should be of concern, as short gestation could be reflected in a negative indirect response in other correlated traits, such as the incidence of stillbirth, the health status of cows after calving, culling, or conception rate.

Recurrent Preterm Birth Reduction by 17-Hydroxyprogesterone Caproate in Dichorionic/Diamniotic Twin Gestation.

The study aimed to evaluate the impact of 17-hydroxyprogesterone caproate (17-OHPC) on recurrent preterm birth (PTB) in women with a prior PTB and a current dichorionic/diamniotic twin gestation. We combined individual patient-level data from two prospective randomized placebo-controlled trials of prophylactic 17-OHPC in twin gestation and compared the rates of recurrent spontaneous PTB in those women with a prior singleton PTB randomized to placebo or 17-OHPC (250 mg weekly). Only 7.4% of women with dichorionic/diamniotic twin gestation experienced a prior PTB. Among these 66 women, spontaneous delivery prior to 34 weeks occurred significantly less often (p = 0.03) in those randomized to 17-OHPC (20.6%) than in those randomized to placebo (46.9%). However, mean gestational length was not significantly different, and there was no statistically significant difference in composite neonatal outcome. 17-OHPC may be beneficial to women with a prior PTB and a current dichorionic/diamniotic twin gestation. These findings along with those reported by the Maternal Fetal Medicine Units Network in singletons suggest a common mechanism of action and a specific target population, those with a prior PTB, that may benefit from 17-OHPC treatment. A large prospective trial is needed to validate these findings. · 17-OHPC reduces recurrent PTB in women with dichorionic/diamniotic twins.. · PTB risk and response to 17-OHPC may differ according to the type of twinning.. · 17-OHPC may affect a common pathway in twins and singletons with a prior PTB..