Effect of early shearing during gestation on the productive and reproductive behavior of female sheep offspring in their first 18 months of age

The research has shown the interesting contributions of shearing in mid-gestation on the performance of lambs from birth to weaning. Other studies have reported that shearing at early pregnancy influences the development of the placenta and lamb live weight at birth. However, there was a lack of information on the effect of early-prepartum shearing on the behavior of the offspring from weaning onward. This study evaluated the effect of shearing ewes at 50 days of gestation on the growth, reproductive behavior and response to a gastrointestinal parasite challenge in the female offspring from weaning to 18 months old. Fifty-seven Polwarth female lambs were used, 22 being singles and 35 twins born to ewes either shorn at 50 days of pregnancy (PS, n = 23) or shorn at 62 days postpartum (U, control, n = 34) resulting in four subgroups: single lambs born to PS ewes (n = 8), born to U ewes (n = 14), twin lambs born to PS ewes (n = 15) or born to U ewes (n = 20). All progeny were managed together under improved pasture with a minimum forage allowance of 6% live weight on dry basis. Body weight, body condition score and fecal eggs count were recorded every 14 days from weaning to 18 months of age. Concentrations of progesterone were measured weekly (from 4 to 10 months of age and from 14 to 18 months of age) to establish the onset of puberty. Ovulation rate at an induced and a natural heat (545 ± 1.0 and 562 ± 1.0 day old) was recorded. Prepartum shearing did not affect the age at puberty or the ovulation rate of female offspring, but those born as singles were more precocious ( P = 0.03) and heavier ( P = 0.02) at puberty than twin born lambs. Both the average value of parasite egg count ( P = 0.0 7) and the Famacha index ( P = 0.02) for the entire study period were lower in lambs born to prepartum shorn ewes than those born to postpartum shorn ewes. In conclusion, shearing at 50 days of gestation did not affect the growth or the reproductive behavior of female offspring. However, female lambs born from ewe shorn during gestation showed a better response to the parasitic challenge, and further research is required to confirm this.     

The effect of different types of stressors during mid- and late pregnancy on lamb weight and body size at birth

Mid-pregnancy shearing has consistently been shown to increase lamb birth weight, which can lead to an increase in lamb survival rates. However, shearing ewes during the winter months and under outdoor pastoral farming conditions can expose the recently shorn ewe to a greater risk of hypothermia. The aim of this study was to determine if exposure of ewes to repeated stressors, in mid- and late pregnancy, would result in an increase in lamb birth weight. This information may assist in the elucidation of the mechanism for the birth weight response to mid-pregnancy shearing, which in turn could assist in the design of management options to increase lamb birth weight without placing the ewe at risk. One hundred and forty-four twin-bearing Romney ewes were allocated to one of six mid-pregnancy treatments: control, isolation on 2 or 10 occasions, sham-shearing on 10 occasions, intramuscular cortisol injection on 10 occasions or shearing. Isolation, sham-shearing and cortisol treatments were conducted twice a week beginning, on average, day 74 of pregnancy and shearing occurred on day 76. During pregnancy, ewe treatment had no effect on ewe live weight. However, average ewe body condition scores were higher in the shorn group than in the sham-shorn or cortisol groups (P < 0.05). Intramuscular injections of cortisol had a greater effect on ewe plasma cortisol concentrations than all other treatments (P < 0.05). Shearing produced a greater plasma cortisol response than isolation × 10 and sham-shearing (P < 0.05). Ewe plasma cortisol responses decreased during the 5 weeks of isolation and sham-shearing but cortisol injections produced a greater response during the fifth treatment than the first or ninth treatments (P < 0.05). Lambs born to shorn ewes were heavier and had a longer crown rump, forelimb and hind limb lengths than all other lambs (P < 0.05). In addition, lambs born to ewes in the cortisol treatment were lighter than lambs born to control, isolation × 2, isolation × 10 and shorn ewes (P < 0.05). The plasma cortisol concentrations observed for ewes injected with cortisol were far greater than those observed in all other groups, which is likely to explain the low birth weights of lambs born to ewes in that group. These results indicate that the mechanism by which mid-pregnancy shearing increases lamb birth weight is unlikely to be repeated stressors.     

Effects of shearing at housing, grass silage feed value and extended grazing herbage allowance on ewe and subsequent lamb performance

The study involved 120 crossbred ewes (sixty 1.5 years old animals and sixty 2.5 years old animals; initial liveweight 67.6 kg, condition score 3.7), that were mated in October. They were assigned to six treatments (two shearing treatments (shorn and unshorn) × two silage feed values (low and medium) and two extended grazed herbage allowances (1.0 and 1.8 kg dry matter (DM)/day)) designed to evaluate the effects of shearing at housing, grass silage feed value and extended-grazed herbage allowance on their performance and the performance of their progeny. Swards, which had silage harvested on 6 September, received fertiliser N (34 kg/ha) for extended (deferred) grazing between 19 December and lambing in mid-March. The herbage was allocated at DM allowances of 1.0 or 1.8 kg/ewe daily until 1 February. For the final 6 weeks of pregnancy, daily herbage DM allowances were 1.5, 1.6, 2.0, 2.0 and 2.0 kg for weeks 6, 5, 4, 3 and 2 to parturition, respectively. Two grass silages (low and medium feed value) were offered from housing on 19 December to lambing in mid-March. At housing, half the ewes were shorn whilst the remainder remained unshorn. Each ewe received 23.4 kg concentrate prior to lambing. For the extended-grazed herbage and the low and medium feed-value silages, DM concentrations were 132, 225 and 265 g/kg, and metabolisable energy (ME) concentrations were 10.0, 10.0 and 10.7 MJ/kg DM, respectively. Treatment did not alter (P > 0.05) litter size or number reared. Grass silage feed value did not significantly alter silage DM intake, or ewe and subsequent lamb performance. Increasing herbage allowance in mid-pregnancy decreased herbage utilisation (P < 0.05) and increased herbage intake (P < 0.05). Shearing increased silage intake (P < 0.05), lamb birth weight (P < 0.01) and tended to increase lamb weaning weight (P = 0.07). Relative to the housed shorn ewes, extended grazing did not alter (P > 0.05) ewe or subsequent lamb performance. It is concluded that shearing ewes at housing increased lamb birth weight due to increased silage intake probably associated with cold stress immediately post shearing and reduced heat stress in late pregnancy. Based on differences in lamb weight at weaning 0.8 kg of grass silage DM intake had the same feed value as a daily extended herbage DM allowance of 1.8 kg per ewe throughout the study. Neither silage feed value nor herbage allowance in mid-pregnancy affected lamb birth weight or subsequent growth rate.     

Effects of late gestation shearing on BW,feed intake and plasma metabolite concentrations in Rambouillet ewes managed outdoors during winter

The majority of lambs in the United States are born from late winter to early spring and pregnant ewes are generally sheared in the last third of pregnancy. Although there are benefits to shearing before parturition, shorn animals may be more vulnerable to the cold, highly variable climatic conditions associated with these seasons. The objective of this study was to determine if late gestation shearing induces differences in individual BW, dry matter intake (DMI) and plasma metabolite concentration of finewool ewes managed outdoors during winter. Thirty-six mature, pregnant Rambouillet ewes (3.8±0.45 years; 76.8±11.4 kg) were managed in a drylot with ad libitum access to pelleted alfalfa in bunks capable of measuring individual daily DMI. The treatment group consisted of ewes sheared at ~5 weeks before the estimated parturition date (shorn; n=18). Unshorn ewes (n=18) remained in full fleece throughout the experiment and were shorn on the last day of the experiment ~2 weeks before the estimated parturition date. Blood was collected on days 0 (before shearing shorn group), 7, 14 and 21 (before shearing unshorn group) of the trial, and plasma was isolated and analyzed for non-esterified fatty acid (NEFA), β-hydroxybutyrate (BHB) and glucose (GLU) concentrations. There was no effect of shearing on ewe DMI or BW during the trial (P⩾0.35). Plasma NEFA and GLU concentrations were similar (P⩾0.36) between shearing groups, though plasma BHB concentration was 103.7 μmol/l greater (24.1%; P<0.01) in unshorn ewes. Lamb BW at birth was not affected (P=0.30) by ewe shearing treatment. Under conditions of this study, no differences in economically important aspects of sheep production were observed between shorn and unshorn pregnant ewes.     

Autoimmunization of ewes against pregnancy-associated glycoproteins does not interfere with the establishment and maintenance of pregnancy

Pregnancy-associated glycoproteins (PAGs) are a large grouping of placental proteins that belong to the aspartic peptidase gene family. Although useful to detect pregnancy in ruminant species, the function of these molecules is unclear. Several PAGs expressed by trophoblast binucleate cells can enter the maternal circulation, suggesting that they could have a systemic role in altering maternal physiology. The objective of this work was to examine whether these circulating placental antigens were important in pregnancy by actively immunizing ewes against them. PAGs were purified by pepstatin-affinity chromatography and conjugated to the immunogenic protein, keyhole limpet hemocyanin (KLH). Ewes were immunized with PAG-KLH conjugate (n = 22) or with KLH alone (n = 9), and bred to intact rams. Blood samples, collected on Day 0 (day of estrus), Day 10, Days 15 to 25 and weekly throughout pregnancy, were analyzed for PAG by an ELISA. On Day 30, pregnancy was confirmed by ultrasound. Ewes immunized against PAG-KLH produced a range of reactive anti-PAG titers, whereas all immunized ewes had high anti-KLH immunoreactivity. PAGs became detectable in the anti-KLH (control) ewes at Day 21.6 ± 2.2 of pregnancy. Those ewes immunized against PAGs (n = 7), that had very low immunoreactivity toward PAGs, had measurable PAG by Day 22.9 ± 1.3, and their PAG serum profiles throughout pregnancy did not differ from the controls. Those exhibiting moderate to high anti-PAG immunoreactivity (n = 15), had significantly lower PAG concentrations than controls, with antigen not becoming detectable until Day 48.1 ± 15.6. The decrease in circulating PAG in the immunized animals did not correlate with changes in pregnancy rates, lamb number or lamb birth weight. These results suggest that while PAGs may play a role in maintaining pregnancy, their major contribution is likely to be at the fetal-maternal interface. Their actions at extra-placental sites are presumably of more secondary importance.     

Maternal serum progesterone concentration during pregnancy and lamb birth weight at parturition in Javanese Thin-Tail ewes with different litter sizes

Pregnant ewes, (N=38), with similar body weight and age (19, 13 and 6 carrying 1, 2 and 3 fetuses, respectively) were used to study the relationship between maternal serum progesterone concentration during pregnancy and lamb birth weight at parturition. Average maternal serum progesterone concentration in the ewes carrying 1, 2, and 3 fetuses was: 5.3±0.3, 6.2±0.7 and 6.6±0.5 ng/ml, during weeks 0 to 7 of gestation; 16.9±1.4, 25.3±1.5, and 26.8±2.5 ng/ml, during weeks 8 to 20; and 13.2±1.0, 18.7±1.0, and 19.8±1.7 ng/ml, during the entire gestation period respectively. Total lamb birth weight in ewes carrying 1, 2, and 3 fetuses was 1.9±0.1, 3.2±0.2, and 4.2±0.4 kg, respectively. In the respective litter sizes, ewes with higher mean serum progesterone concentration during the whole pregnancy gave birth to lambs with higher birth weight (r²=0.76, 0.42 and 0.46, for ewes carrying 1, 2 and 3 fetuses, respectively). The results of the study indicated that prenatal growth could probably be improved by increasing endogenous secretion of maternal progesterone during pregnancy.     

Placental weight mediates the effects of prenatal factors on fetal growth: the extent differs by preterm status

Objective:

Elevated pre‐pregnancy BMI, excessive gestational weight gain (GWG), and gestational diabetes mellitus (GDM) are known determinants of fetal growth. The role of placental weight is unclear. We aimed to examine the extent to which placental weight mediates the associations of pre‐pregnancy BMI, GWG, and GDM with birth weight‐for‐gestational age, and whether the relationships differ by preterm status.

Design and Methods:

We examined 1,035 mother‐infant pairs at birth from the Boston Birth Cohort. Data were collected by questionnaire and clinical measures. Placentas were weighed without membranes or umbilical cords. We performed sequential models excluding and including placental weight, stratified by preterm status.

Results:

We found that 21% of mothers were obese, 42% had excessive GWG, and 5% had GDM. Forty‐one percent were preterm. Among term births, after adjustment for sex, gestational age, maternal age, race, parity, education, smoking, and stress during pregnancy, birth weight‐for‐gestational age z‐score was 0.55 (0.30, 0.80) units higher for pre‐pregnancy obesity vs. normal weight. It was 0.34 (0.13, 0.55) higher for excessive vs. adequate GWG, 0.67 (0.24, 1.10) for GDM vs. no DM, with additional adjustment for pre‐pregnancy BMI. Adding placental weight to the models attenuated the estimates for pre‐pregnancy obesity by 20%, excessive GWG by 32%, and GDM by 21%. Among preterm infants, GDM was associated with 0.67 (0.34, 1.00) higher birth weight‐for‐gestational age z‐score, but pre‐pregnancy obesity and excessive GWG were not. Attenuation by placental weight was 36% for GDM.

Conclusions:

These results suggest that placental weight partially mediates the effects of pre‐pregnancy obesity, GDM, and excessive GWG on fetal growth among term infants.     

Altered secretion of pregnancy-associated glycoproteins during gestation in bovine somatic clones

Somatic nuclear transfer (NT) in cattle is often accompanied by severe placental anomalies, hypertrophy, and hydrallantois, which induce a high rate of pregnancy losses throughout gestation. These placental deficits are associated with an abnormal increase of the maternal plasma levels of pregnancy-associated glycoprotein (PAG), produced by the trophoblastic binucleate cells (BNC) of the placenta. The objective of this study was to analyze the origin of the abnormally elevated PAG concentrations in the peripheral circulation of NT recipients during pathological pregnancies. Concentrations of PAG were measured both in maternal blood, in chorionic and cotyledonary tissular extracts from control recipients (after artificial insemination, AI, or in vitro fertilization, IVF) and clone recipients on Day 32, Day 62, and during the third trimester of gestation. Three different radioimmunoassay (RIA) systems were used. One homologous RIA for PSP60, similar to bovine PAG-1 (PAG_67kDa), and two heterologous RIA with PAG_67kDa as standard and tracer, and antisera anti-caprine PAG (AS#706 and AS#708). Circulating and tissular concentrations of bovine placental lactogen (bPL), a glycoprotein also produced by BNC, were determined by RIA at the same stages. The number of BNC in the placental tissues was determined by cell counting after immunostaining with anti PSP60 antibody on tissue sections from control and NT pregnancies. Maternal plasma PAG concentrations were not different among groups on Day 32, but they were significantly higher in NT than in control pregnancies on Day 62 with all three RIA and during the third trimester with two RIA (RIA-PSP60 and RIA with AS#708). Circulating bPL concentrations were undetectable on Days 32 and 62 and were not different in the third trimester between NT and control pregnancies. Tissular amounts of PAG on total proteins were not different between the two groups at all stages studied. No difference was determined in the percentage of PSP60-positive BNC in placental tissues between controls and NT on Day 62 and during the third trimester of pregnancy. Western blots of tissular extracts from placenta showed no major molecular weight changes of PAG in NT pregnancies compared to controls. No differences in maternal circulation concentrations or tissular content of bPL were observed between control and NT pregnancies. In conclusion, the specific increase of PAG in maternal plasma concentrations during abnormal NT pregnancies do not result from a higher proportion of BNC, or an increased protein expression of PAG and could be due to changes in the composition of terminal glycosylation which result into a clearance decrease of PAG from the circulation.     

Influence of maternal nutrition on outcome of pregnancy: prospective cohort study

ObjectiveTo investigate the relations of maternal diet and smoking during pregnancy to placental and birth weights at term.DesignProspective cohort study.SettingDistrict general hospital in the south of England.Participants693 pregnant nulliparous white women with singleton pregnancies who were selected from antenatal booking clinics with stratified random sampling.ResultsPlacental and birth weights were unrelated to the intake of any macronutrient. Early in pregnancy, vitamin C was the only micronutrient independently associated with birth weight after adjustment for maternal height and smoking. Each ln mg increase in vitamin C was associated with a 50.8 g (95% confidence interval 4.6 g to 97.0 g) increase in birth weight. Vitamin C, vitamin E, and folate were each associated with placental weight after adjustment for maternal characteristics. In simultaneous regression, however, vitamin C was the only nutrient predictive of placental weight: each ln mg increase in vitamin C was associated with a 3.2% (0.4 to 6.1) rise in placental weight. No nutrient late in pregnancy was associated with either placental or birth weight.ConclusionsConcern over the impact of maternal nutrition on the health of the infant has been premature. Maternal nutrition, at least in industrialised populations, seems to have only a small effect on placental and birth weights. Other possible determinants of fetal and placental growth should be investigated.

Key messages

• Placental and infant birth weights were not associated with the intake of any macronutrient early or later in pregnancy
• After adjustment for the effects of maternal height and smoking, only vitamin C independently predicted birth weight. The expected mean difference in birth weight for infants with mothers in the upper and lower thirds of intake was about 70 g
• Vitamin C was the only nutrient that independently predicted placental weight, but again this relation was of doubtful clinical significance
• Among relatively well nourished women in industrialised countries, maternal nutrition seems to have only a marginal impact on infant and placental size. Other causes of variation in the size of clinically normal infants should now be investigated

     

Gestational Weight Gain as an Independent Risk Factor for Macrosomia in Women with Intermediate State Gestational Blood Glucose

Objective: Macrosomia is closely associated with gestational diabetes mellitus (GDM) but its relationship with maternal intermediate state gestational blood glucose (ISGBG; normal fasting blood glucose and 7.8 mmol/L <1 hour blood glucose &lsqb;BG] <10 mmol/L or 6.7 mmol/L <2 hour BG <8.5 mmol/L) is unclear. Here, we analyzed the clinical characteristics and pregnancy outcomes and explored risk factors for macrosomia in women with ISGBG.Methods: A total of 847 women with normal glucose tolerance gestation, 330 with ISGBG, and 99 with GDM were included. Maternal and fetal clinical data were collected and 3-point BG following oral glucose tolerance test, fasting insulin, glycated hemoglobin, and blood lipids profile were measured.Results: The incidence rate of macrosomia among the neonates of women with ISGBG was as high as 10.9%. In the ISGBG group, prepregnancy body mass index (BMI), gestational weight gain (GWG) and the proportion of women with excessive GWG (eGWG) were significantly higher in women with macrosomia compared with those who delivered a normal weight neonate. In women with ISGBG, neonate weight was positively correlated with maternal prepregnancy weight (r = 0.183, P<.01), prepregnancy BMI (r = 0.135, P<.01), and GWG (r = 0.255, P<.01), and negatively correlated with high-density lipoprotein cholesterol (r = -0.172, P<.01). Nonetheless, only eGWG was an independent risk factor (odds ratio = 3.18, 95% confidence interval = 1.26 to 7.88, P<.05) for macrosomia. The risk of macrosomia in pregnant women with prepregnancy BMI <25 kg/m² or BMI ≥25 kg/m² and eGWG was 3.39 and 3.27 times, respectively.Conclusion: The incidence rate of macrosomia is increased in women with ISGBG and eGWG is the strongest independent risk factor. In order to reduce the risk for macrosomia, timely lifestyle intervention to promote appropriate weight gain during pregnancy deserves evaluation.Abbreviations: AUC = area under the curve; BG = blood glucose; 1 hour BG = 1 hour blood glucose after OGTT; 2 hour BG = 2 hour blood glucose after OGTT; BMI = body mass index; CI = confidence interval; eGWG = excessive gestational weight gain; FBG = fasting blood glucose; FINS = fasting insulin; GDM = gestational diabetes mellitus; HbA1c = glycated hemoglobin; HDL-C = high-density lipoprotein cholesterol; HOMA-IR = homeostasis model assessment of insulin resistance index; ISGBG = intermediate state gestation blood glucose; LDL-C = low-density lipoprotein cholesterol; Ln = natural logarithm; MLBW = mature low birth weight; NGTG = normal glucose tolerance gestation; OGTT = oral glucose tolerance test; OR = odds ratio; SD = standard deviation     

A Retrospective Study Examining Phentermine on Preconception Weight Loss and Pregnancy Outcomes

Objective: Obesity is a well-known risk factor for infertility. However, the use of weight loss medications prior to conception is underutilized. The objectives of our study are to describe weight loss, pregnancy rates, and live birth rates after short-term phentermine use in women with obesity and infertility.Methods: This was a retrospective analysis of 55 women (18 to 45 years old) who were overweight or obese, diagnosed with infertility, and prescribed phentermine for weight loss in an ambulatory endocrinology clinic at a single, tertiary level academic medical center. Main outcome measures were mean percent weight change at 3 months after starting phentermine, and pregnancy, and live birth rates from start of phentermine to June 30, 2017.Results: Median duration of phentermine use was 70 days (Q1, Q3 &lsqb;33, 129]). Mean ± SD percent weight change at 3 months after starting phentermine was -5.3 ± 4.1% (P<.001). The pregnancy rate was 60% and the live birth rate was 49%. There was no significant difference in pregnancy rates (52% versus 68%; P = .23) or live birth rates (44% versus 54%; P = .50) in women who lost ≥5% versus <5% of their baseline weight. The number of metabolic comorbidities was negatively associated with the pregnancy rate. Phentermine was generally well-tolerated with no serious adverse events.Conclusion: Phentermine can produce clinically significant weight loss in women with obesity during the preconception period. Higher pregnancy or live birth rates were not observed with a greater degree of weight loss with phentermine.     

Newborn Body Fat: Associations with Maternal Metabolic State and Placental Size

Background

Neonatal body composition has implications for the health of the newborn both in short and long term perspective. The objective of the current study was first to explore the association between maternal BMI and metabolic parameters associated with BMI and neonatal percentage body fat and to determine to which extent any associations were modified if adjusting for placental weight. Secondly, we examined the relations between maternal metabolic parameters associated with BMI and placental weight.

Methods

The present work was performed in a subcohort (n = 207) of the STORK study, an observational, prospective study on the determinants of fetal growth and birthweight in healthy pregnancies at Oslo University Hospital, Norway. Fasting glucose, insulin, triglycerides, free fatty acids, HDL- and total cholesterol were measured at week 30–32. Newborn body composition was determined by Dual-Energy X-Ray Absorptiometry (DXA). Placenta was weighed at birth. Linear regression models were used with newborn fat percentage and placental weight as main outcomes.

Results

Maternal BMI, fasting glucose and gestational age were independently associated with neonatal fat percentage. However, if placental weight was introduced as a covariate, only placental weight and gestational age remained significant. In the univariate model, the determinants of placenta weight included BMI, insulin, triglycerides, total- and HDL-cholesterol (negatively), gestational weight gain and parity. In the multivariable model, BMI, total cholesterol HDL-cholesterol, gestational weight gain and parity remained independent covariates.

Conclusion

Maternal BMI and fasting glucose were independently associated with newborn percentage fat. This effect disappeared by introducing placental weight as a covariate. Several metabolic factors associated with maternal BMI were associated with placental weight, but not with neonatal body fat. Our findings are consistent with a concept that the effects of maternal BMI and a number of BMI-related metabolic factors on fetal fat accretion to a significant extent act by modifying placental weight.     

Maternal periconceptional undernutrition in Merinos d'Arles sheep: 1. Effects on pregnancy and reproduction results of dams and offspring growth performances

Maternal undernutrition during gestation can condition offspring adult health, with the periconceptional period pointed out as a key period. The aim of this study was to evaluate the effects of maternal periconceptional undernutrition on pregnancy and offspring growth performance in sheep.52 Merinos d'Arles ewes were fed to requirements (control group, C), whereas 64 ewes received 50% of their dietary needs from −15 to +30 days post-conception (restricted group, R). Thereafter, both groups were fed according to needs. Maternal body weight (BW), body condition score (BCS) and Non Esterified Fatty Acids (NEFA), progesterone, leptin and cortisol plasma concentrations were monitored weekly during the restriction period and the following month, then monthly until weaning. Lambs were weighed weekly until weaning at 22 kg BW, then monthly. Plasma leptin was monitored monthly in lambs.The BW, BCS, and leptin concentrations were significantly decreased, whereas NEFA and cortisol concentrations were increased in R dams. Maximum progesterone concentration was higher in R ewes that had a high (10-25%) vs. low (0-10%) BW loss during restriction (27.9 ± 2.59 vs. 20.8 ± 2.00 ng/mL, P < 0.05). Overall, gestation was significantly longer in the R group (151.0 ± 0.3 vs. 149.4 ± 0.4 days, P < 0.001). There was no difference between groups for pregnancy rates, prolificacy, birth weight and lamb mortality, but the proportion of male lambs was significantly higher in the R group, only for singletons (16/26 vs. 9/26, P < 0.05). Lamb growth was not significantly modified by treatment. Leptin concentrations at birth were significantly lower in R vs. C males (6.15 ± 0.13 ng/mL vs. 7.42 ± 0.36 ng/mL, P < 0.05), whereas in females, leptin concentrations were significantly higher in R vs. C lambs at 4 mo of age (7.31 ± 0.27 ng/mL vs. 6.41 ± 0.29 ng/mL, P < 0.05).These results indicate that maternal periconceptional undernutrition in a hardy breed does not significantly affect lamb birth weight and growth rates, in contrast to previous reports in other breeds, suggesting that caution must be taken when extrapolating programming data between breeds and breeding conditions.     

Neospora caninum and coxiella burnetii seropositivity are related to endocrine pattern changes during gestation in lactating dairy cows

Q fever is a zoonotic infection caused by Coxiella burnetii that is endemic worldwide. Domestic ruminants are a source of infection for humans. Given the suggestion that the bacterium recrudesces during pregnancy in cattle, this study was designed to determine whether C. burnetii infection affects hormonal patterns, such as progesterone, cortisol, pregnancy associated glycoproteins (PAG), and prolactin during gestation in lactating cows. Possible interactions with Neospora caninum were also explored. The study was performed on 58 gestating non-aborting cows. Blood samples for hormone determinations were collected on Days 40, 90, 120, 150, 180, and 210 of gestation. For antibody determinations, blood was collected at day 40 postinsemination and postpartum. By GLM repeated measures analysis of variance, we established the effects of production and reproductive variables as well as Coxiella and Neospora seropositivity related to changes on cortisol, PAG, progesterone, and prolactin levels. Coxiella antibody levels were significantly related to cortisol, PAG, and plasma progesterone concentrations, whereas Neospora seropositivity was linked to plasma progesterone concentrations. The interaction between Coxiella and Neospora seropositivity was correlated with cortisol and plasma progesterone levels, whereas the interaction seropositivity against C. burnetii-plasma cortisol concentration was related to plasma PAG levels. Finally, an effect of lactation number only was observed on plasma prolactin. Our findings suggest that both the N. caninum and C. burnetii infection or the presence of both modify endocrine patterns throughout gestation. Cows seropositive to both, Neospora and Coxiella, showed higher plasma progesterone levels than the remaining animals examined. Seropositivity to C. burnetii was associated with placental damage and diminishing PAG levels throughout the second half of gestation, along with increased plasma cortisol levels on Day 180 of gestation.     

Maternal BMI Associations with Maternal and Cord Blood Vitamin D Levels in a North American Subset of Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study Participants

ObjectiveObesity in pregnancy may be associated with reduced placental transfer of 25-hydroxyvitamin D (25-OHD). The objective of this study was to examine associations between maternal BMI and maternal and cord blood levels of 25-OHD in full term neonates born to a single racial cohort residing at similar latitude. Secondary objectives were to examine associations between maternal glucose tolerance with maternal levels of 25-OHD and the relationship between cord blood 25-OHD levels and neonatal size.MethodsThis study was conducted among participants of the Hyperglycemia and Adverse Pregnancy Outcomes (HAPO) Study meeting the following criteria: residing at latitudes 41–43°, maternal white race, and gestational age 39–41 weeks. Healthy pregnant women underwent measures of height, weight, and a 75-g fasting oral glucose tolerance test (OGTT) at approximately 28 weeks gestation. Maternal and cord blood sera were analyzed for total 25-OHD by HPLC tandem mass spectrometry. Statistical analyses included ANOVA and linear regression models.ResultsMaternal and cord blood (N = 360) mean levels (sd) of 25-OHD were 37.2 (11.2) and 23.4 (9.2) ng/ml, respectively, and these levels were significantly different among the 3 field centers (ANOVA p< 0.001). Maternal serum 25-OHD was lower by 0.40 ng/ml for BMI higher by 1 kg/m² (p<0.001) in an adjusted model. Maternal fasting plasma glucose, insulin sensitivity, and presence of GDM were not associated with maternal serum 25-OHD level when adjusted for maternal BMI. Cord blood 25-OHD was lower by 0.26 ng/ml for maternal BMI higher by 1 kg/m² (p<0.004). With adjustment for maternal age, field center, birth season and maternal serum 25-OHD, the association of cord blood 25-OHD with maternal BMI was attenuated. Neither birth weight nor neonatal adiposity was significantly associated with cord blood 25-OHD levels.ConclusionThese results suggest that maternal levels of 25-OHD are associated with maternal BMI. The results also suggest that interpretation of neonatal 25-OHD levels may need to incorporate specific maternal factors in addition to season of birth and latitude.     

Relationships between calf birth weight, prepartum concentrations of plasma energy metabolites and resumption of ovulation postpartum in Limousine suckled beef cows

The aim of this study was to determine the relationship between energy status before calving and calf birth weight and their potential effects on interval between calving and first ovulation. Sixty-nine Limousine, suckled beef cows were sampled weekly over a 3-yr period during the last 2 m.o. of pregnancy to determine the concentrations of nonesterified fatty acids (NEFA), beta-3-hydroxybutyrate (beta-OHB), glucose and glycerol. After parturition, progesterone concentrations were measured weekly to determine time of resumption of ovulation. Cows were allotted to 3 groups according to calf birth weight (Heavy: > 44 kg, n = 37; Medium: 39 to 43 kg, n = 56; and Light: < 38 kg, n = 45) and to postpartum ovarian resumption of cyclicity (Late: > 11 wk, n = 41; Mid: 7 to 10 wk, n = 57; and Early: < 6 wk, n = 40). Puerperium glycaemia of the dams was steady state (0.66 +/- 0.03 g/L) and was not related to calf birth weight. Plasma NEFA, beta-OHB and glycerol values were higher (P < 0.05) in Heavy than in Medium and Light group dams during the last 4 wk of pregnancy. Interval between calving and first ovulation was significantly longer for primiparous than for multiparous cows (respectively, 9.9 +/- 2.0 and 7.7 +/- 1.4 wk; P < 0.05). Calf birth weight was not related to time of first ovulation. Late primiparous cows had higher NEFA plasma concentrations than Mid and Early group primiparous cows during the last 4 wk of pregnancy, whereas NEFA plasma concentrations were not related to interval between calving and first ovulation in multiparous cows. Thus, lipomobilization increased with calf birth weight during the last 4 wk of pregnancy. High level of body reserves mobilization was associated with delayed first ovulation in primiparous but not in multiparous cows.     

Association of naturally acquired IgG antibodies against Plasmodium falciparum serine repeat antigen-5 with reduced placental parasitemia and normal birth weight in pregnant Ugandan women: A pilot study

Plasmodium falciparum infection during pregnancy contributes substantially to malaria burden in both mothers and offspring. Analysis of naturally acquired immune responses that confer protection against parasitemia and clinical disease is important to guide vaccine evaluation as well as identify immune correlates. Unfortunately, few studies have addressed the relationship between immune responses to malaria vaccine candidate antigens and protection against adverse effects on pregnant women and newborn birth weight. This study examines the relationship of maternal antibody responses to serine repeat antigen-5 (SE36) and merozoite surface protein-1 (MSP1₁₉ and MSP1₄₂) with placental parasitemia and birth weight. In a peri-urban setting in Uganda, pregnant women without placental parasites have high median ODs for antibodies against SE36 (P < 0.001). Naturally acquired anti-SE36 IgG was most prevalent in women without placental parasitemia (P < 0.001). Furthermore, pregnant women with significantly high levels of anti-SE36 IgG delivered babies with normal birth weights (P < 0.001). That antibody to SE36 was associated with both a reduced risk of placental parasitemia and resulting normal birth weight in newborns suggests some protective role. In contrast, although antibody to MSP1₄₂ was also associated with reduced placental parasitemia and immune responses to both MSP1₁₉ and MSP1₄₂ may be of importance, there was no association between anti-MSP1₁₉ antibodies and infant birth weight outcomes. This study highlights the need for conducting further studies to investigate the association of antibodies against SE36 and outcomes of malaria infection in pregnant women.     

Oleic acid stimulates system A amino acid transport in primary human trophoblast cells mediated by toll-like receptor 4

Obese women have an increased risk to deliver large babies. However, the mechanisms underlying fetal overgrowth in these pregnancies are not well understood. Obese pregnant women typically have elevated circulating lipid levels. We tested the hypothesis that fatty acids stimulate placental amino acid transport, mediated via toll-like receptor 4 (TLR4) and mammalian target of rapamycin (mTOR) signaling pathways. Circulating NEFA levels and placental TLR4 expression were assessed in women with varying prepregnancy body mass index (BMI). The effects of oleic acid on system A and system L amino acid transport, and on the activation of the mTOR (4EBP1, S6K1, rpS6), TLR4 (IĸBɑ, JNK, p38 MAPK), and STAT3 signaling pathways were determined in cultured primary human trophoblast cells. Maternal circulating NEFAs (n = 33), but not placental TLR4 mRNA expression (n = 16), correlated positively with BMI (P < 0.05). Oleic acid increased trophoblast JNK and STAT3 phosphorylation (P < 0.05), whereas mTOR activity was unaffected. Furthermore, oleic acid doubled trophoblast system A activity (P < 0.05), without affecting system L activity. siRNA-mediated silencing of TLR4 expression prevented the stimulatory effect of oleic acid on system A activity. Our data suggest that maternal fatty acids can increase placental nutrient transport via TLR4, thereby potentially affecting fetal growth.     

Effects of grass and maize silage feed value,offering soybean meal with maize silage,and concentrate feed level in late pregnancy,on ewe and lamb performance

In many countries, daily herbage accumulation on pasture declines towards zero during the winter period; thus, many pregnant ewes are housed and offered conserved forages supplemented with concentrate prior to parturition. The effects of forage type and feed value (FV), offering soybean meal with maize silage during mid and late pregnancy, and concentrate feed level in late pregnancy on the performance of ewes and their progeny (to slaughter) were evaluated. Ewes (n = 151) were assigned to one of nine treatments from mid-pregnancy until lambing. Medium FV and high FV grass silages (metabolisable energy concentrations of 10.7 and 12.0 MJ/kg DM) were offered ad libitum supplemented with either 15 or 25 kg concentrate/ewe during late pregnancy. Low and high DM maize silages (starch concentrations of 80 and 315 g/kg DM) were offered ad libitum either alone or with soybean meal (200 g/d) and supplemented with 15 kg concentrate during late pregnancy. A final treatment consisted of high FV grass silage supplemented with 5 kg soybean/ewe over the final 4 weeks of pregnancy. Ewes and lambs were put to pasture in a rotational-grazing system within 3 days of lambing. There were no interactions (P > 0.05) between grass silage FV and concentrate feed level for ewe or lamb traits. Increasing grass silage FV increased food intake (P < 0.001) during late pregnancy, ewe BW and body condition score (BCS) at lambing (P < 0.001), lamb BW at birth (P < 0.001) and weaning (P < 0.05), and reduced age at slaughter (P = 0.06). Increasing concentrate feed level increased metabolisable energy (P < 0.05) intake during late pregnancy but had no effect (P > 0.05) on ewe or lamb performance. Increasing maize DM at harvest and offering soybean meal with maize silage increased food intake (P < 0.001) and ewe BW and BCS at lambing (P < 0.05 or P < 0.01). Offering soybean meal with maize silage increased lamb BW at birth (P < 0.01) and reduced age at slaughter (P < 0.05). Reducing supplementation of high FV grass silage to 5 kg of soybean meal had no effect (P > 0.05) on animal performance. Replacing grass silage with maize silage did not affect (P > 0.05) BW gain of lambs. It is concluded that increasing the FV of the grass silage offered during pregnancy had the greatest positive impact on ewe and lamb performance.