Stress Of Parturition Research Articles

Comparison of Telomere Length in Age-Matched Primiparous and Multiparous Brahman Cows.

Physiological and psychological stressors have been associated with the attrition of telomeres, which are the protective caps of chromosomes. This study compares the telomere length (TL) in 4-year-old Brahman cows grouped by the first parity (n = 8) and the second parity (n = 11). The cows were bled via jugular venipuncture, weighed, and had their body condition scores recorded at Day -28 prior to calving and at Day + 7 and Day + 28 post-calving. The duration of labor (Dlabor) and parturition ease were recorded. The peripheral leukocytes were isolated, the leukocyte blood count with differential was recorded, and the genomic DNA was extracted. The relative quantity of telomere products, which is proportional to the average TL, was determined via multiplex quantitative PCR using the ratio (T/S ratio) of bovine telomere and β-globulin DNA. Standards of the bovine telomere (1012-107 dilution series) and β-globulin (109-104 dilution series) genes were utilized to produce relative copy numbers. The samples were assayed in triplicate and were included if the triplicate Cq difference was less than 0.25 cycles. The parity was the fixed effect, and the random effects included the sire and day repeated with the cow as the subject. Statistical significance was not observed in the leukocyte number or type (p > 0.1). A reduction in the TL of approximately 9225 telomeric copies was found between Parity 1 and Parity 2 (p = 0.02). A trend was found between the TL and Dlabor (p = 0.06). The stress of parturition and raising the first calf of a cow's life may be responsible for TL attenuation. Parity may be considered a stressor of cow longevity.

Effect of Supplementation of Rumen Bypass Fat on Live Body Weight, Milk Yield, Milk Composition and Body Condition Score of Graded Murrah Buffaloes

Background: During early lactation, the nutrient requirement of cows and buffaloes will be increased and at the same time, the feed intake is lowered due to stress of parturition. During this condition, depletion of body nutrient store occurs and the animal becomes weak day by day due to negative energy balance. Therefore to overcome the negative energy balance due to low feed intake, an alternate energy-dense ingredient is required. The bypass fat overcomes the negative energy balance and maintains animal body weight as well as milk production. Hence, undertook the present investigation. Methods: The present research was carried out in 10 graded Murrah buffaloes to study the effect of supplementation of rumen bypass fat on live body weight, milk yield, milk composition and body condition score during early lactation. The body weight, milk yield, milk composition and body condition score were recorded at weekly intervals before and after supplementation of rumen bypass fat. Result: Highly significant increase in live body weight, body condition score and milk production was observed, whereas a non-significant to a significant increase in milk fat and protein was recorded. The present study found a significant decrease in milk SNF and a highly significant decrease in milk density percentage. Non-significant effect on milk lactose was recorded. Therefore, it is concluded that supplementation of bypass fat could improve live body weight, body condition score and milk production in graded Murrah buffaloes.

Supplementation of antioxidant micronutrients reduces stress and improves immune function/response in periparturient dairy cows and their calves

BackgroundPeriparturient period induces stress in cows which fluctuates hormonal and metabolic function and causes immune suppression. Apart from impairing the health, production, and reproduction of cows, it also influences the well-being of newborn calves by decreasing the colostrum quality. Micronutrients are known for optimal health and production and their effects on parturition stress, immune response in both cow and its calf need to be explored. AimThe aim of this study was to see the effect of oral supplementation of micronutrients during the prepartum period on the health status of crossbred dairy cows and subsequently on their newborn calves. MethodsA total of 42 healthy multiparous cows were selected and randomly divided into five groups with seven cows in each group, i.e. control (Basal Diet, BD), VA group (BD + vitamin A, 105 IU), Zn group (BD + zinc sulphate, 60 ppm), VE group (BD + vitamin E, 2500 IU), and combined supplementation (CS) group (BD + combination of VA, Zn, and VE). The supplements were offered in compounded concentrate DM (100 g) to individual cows once daily before the morning feeding and the remaining portion was incorporated in the TMR. Feeding was started one month before the expected days of calving till calving. Blood samples were collected from cows at days -15, -7, -3, 0, +3, +7, and +15 relative to the day of calving. Blood samples from newborn calves and milk samples of cows were collected at days 0, +3, +7, and +15. Milk somatic cell counts (SCC) were estimated using a cell counter. Cortisol was estimated by ELISA kit in blood and milk plasma of cows and in the blood plasma of their calves. Total immunoglobulins (Ig) were estimated in milk of cows and serum of calves using zinc sulphate turbidity method. Blood neutrophils from cows and calves were studied for phagocytic activity (PA) using nitro blue tetrazolium (NBT) assay.Data were analysed by repeated-measures two-way ANOVA using the mixed procedure of SAS, and the pairwise comparison was performed using a multiple comparison test (Tukey). ResultsCombined supplementation of micronutrients decreased (P < 0.05) maternal blood plasma (control vs. CS group, 5.98 ± 0.20 vs. 3.86 ± 0.23 ng/mL) and milk plasma (3.96 ± 0.13 vs. 2.71 ± 0.10 ng/mL) cortisol, milk SCC (3.05 ± 0.11 vs. 2.12 ± 0.10 × 105 cells/mL) and increased (P < 0.05) total milk Ig concentration (18.80 ± 0.11 vs. 23.04 ± 0.57 mg/mL) and the PA of blood neutrophils (0.84 ± 0.03 vs. 1.07 ± 0.03). Similarly, lower blood cortisol concentration (9.69 ± 0.35 vs. 6.02 ± 0.18 ng/mL) and higher (P < 0.05) total Ig (23.26 ± 0.11 vs. 30.34 ± 0.70 mg/mL) and PA of blood neutrophils (0.37 ± 0.02 vs. 0.52 ± 0.02) were observed in the calves born to CS group of cows as compared to the control. Highest (P < 0.05) positive effects (lower stress levels and higher immune response) of treatment were noticed in CS group followed by VE group and then Zn group. However, VA group didn’t differ from the control group. ConclusionOur results indicate that micronutrient interventions during the prepartum period can improve the health status of dairy calves and subsequently the well-being of their calves.

PSXIII-13 Comparison of telomere length in age-matched primiparous and multiparous Brahman cows

Abstract Telomeres are comprised of G-rich nucleotide sequences (5’-TTAGGG-3’) at the chromosome termini that are responsible for protecting chromosomes; however, attrition of these sequences has been observed in conditions of physiological and psychological stress. The purpose of this study was to compare telomere length (TL) in 4-yr-old Brahman cows grouped by first parity (n = 8) and second parity (n = 11). Cows were bled by jugular venipuncture, weighed, and had BCS recorded d+28 prior to calving and d-7 and d-28 post calving. Cows were observed for duration of labor (Tlabor) and calving ease (CE) at the time of parturition. Calf birth weight (CBW) and gender (CG) were recorded. Peripheral leukocytes were isolated, complete blood counts (CBC) were recorded, and genomic DNA was extracted utilizing silicone membrane spin column kits. The relative quantity of telomere products, which is proportional to the average TL, was determined by multiplex quantitative PCR analysis using the ratio of bovine telomere and β-globulin DNA. An absolute standard of bovine telomere (1012–107 dilution series) and β-globulin (109-104 dilution series) genes was utilized to produce relative copy number. All samples were run in triplicate and samples were included if triplicate Cq difference was less than 0.25 cycles. Parity was the fixed effect of interest and random effects included sire and day repeated with cow as the subject. No differences in CBC were seen. Tlabor, CE, CG, and CBW did not impact TL (P &amp;gt; 0.1). A trend was observed for day-parity interaction (P = 0.0918). TL between parity differed most on d-28 (P = 0.1046; parity one 127292 ± 6483; parity two 111045 ± 5376). The stress of parturition and raising the first calf of a cow’s life may be responsible for slight attenuation in TL.

Predicting intrapartum fetal compromise at term using the cerebroplacental ratio and placental growth factor levels (PROMISE) study: randomised controlled trial protocol

IntroductionIntrapartum complications are a major contributor to adverse perinatal outcomes, including stillbirth, hypoxic–ischaemic brain injury and subsequent longer term disability. In many cases, hypoxia develops as a gradual process due...

Cortisol modulates inflammatory responses in LPS-stimulated RAW264.7 cells via the NF-\u03baB and MAPK pathways

BackgroundThe uteruses of most dairy cattle are easily infected by bacteria, especially gram-negative bacteria, following parturition. Macrophages are important cells of the immune system and play a critical role in the inflammatory response. In addition, cortisol levels become significantly increased due to the stress of parturition in dairy cattle, and cortisol is among the most widely used and effective therapies for many inflammatory diseases. In this study, we assessed the anti-inflammatory effects and potential molecular mechanisms of cortisol using a Lipopolysaccharide (LPS)-induced RAW264.7 macrophage cell line.ResultsCortisol significantly suppressed the production of prostaglandin E2 (PGE2) and decreased the gene and protein expression of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in a dose-dependent manner. Moreover, cortisol inhibited the mRNA expression of pro-inflammatory cytokines including tumor necrosis factor alpha (TNFα), interleukin-1β (IL-1β), and interleukin-6 (IL-6) and decreased IL-1β secretion in an LPS-treated RAW264.7 macrophage cell line. Moreover, we found that cortisol suppressed nuclear factor-kappa B (NF-κB) signaling in RAW264.7 macrophages stimulated with LPS. This suppression was mediated by the inhibition of IκBα degradation and NF-κB p65 phosphorylation. In addition, cortisol also suppressed the phosphorylation of mitogen-activated protein kinases (MAPK) such as extracellular signal-regulated kinase (ERK1/2), p38 MAPK, and c-Jun N-terminal kinase/stress-activated protein kinase (JNK).ConclusionsThese results suggest that high cortisol levels can attenuate LPS-induced inflammatory responses in the RAW264.7 macrophage cell line by regulating the NF-κB and MAPK signaling pathways.

Effect of Poly-herbal mixture and butyric acid feeding on immune parameters of postpartum Murrah buffaloes

The present study was conducted in 24 Murrah buffaloes to study the effect of supplementation of poly-herbal mixture and butyric acid with the objective to reduce parturition stress and to improve immunity. In this study, control group i.e T0 (n=6) was offered ration as per NRC requirement plus 10 % and the rest of three supplemented groups T1, T2 and T3 (n=6 for each group) were offered ration as per control group along with three different supplementations, (T1= poly-herbal supplementation for seven day post partum, T2= poly-herbal supplementation for seven day post partum + 200 ml butyric acid supplementation (30 day prepartum and 30 day postpartum) and T3= 200 ml butyric acid supplementation (30 day prepartum and 30 day postpartum). Total leukocyte count (TLC) values in all groups showed decreasing trend as observed on 1st, 2nd and 5th days of postpartum. On the 1st day of postpartum, blood neutrophil percentage was found significantly lower (p&lt;0.05) in T2 and T3 group as compared to T0 group. On the 5th day of postpartum, blood neutrophil percentage were found significantly lower (p&lt;0.05) in T1, T2 and T3 groups as compared to T0 group. On day one postpartum, the phagocytic activity (PA) and myeloperoxidase activity (MA) was significantly higher (p&lt;0.05) in the T2 and T3 group of buffaloes in comparison to T0 group. On the 5th day of postpartum PA and MA were found to be significantly higher (p&lt;0.05) in the T1, T2 and T3 group of buffaloes in comparison to T0 group. These results indicate that supplementation of poly-herbal, poly-herbal + butyric acid and butyric acid during the transition period reduces the stress and improves immunity in Murrah buffaloes. Out of all the supplemented groups, maximum improvement was observed in the poly-herbal+butyric acid supplemented group.

ITRAQ quantitative analysis of plasma proteome changes of cow from pregnancy to lactation

Dairy cows undergo tremendous changes in physiological, metabolism and the immune function from pregnancy to lactation that are associated with cows being susceptible to metabolic and infectious diseases. The objective of this study is to investigate the changes of plasma proteome on 21 d before expected calving and 1 d after calving from dairy cows using an integrated proteomic approach consisting of minor abundance protein enrichment by ProteoMiner beads, protein labeling by isobaric tags for relative and absolute quantification, and protein identification by liquid chromatography coupled with tandem mass spectrometry. Nineteen proteins were changed around the time of calving. These proteins were associated with response to stress, including acute-phase response and defense response, based on the proteins annotation. In particular, three up-regulated proteins after calving including factor V, α2-antiplasmin and prothrombin were assigned into the complement and coagulation pathway. These results may provide new information in elucidating host response to lactation and parturition stress, and inflammatory-like conditions at the protein level. Differential proteins may serve as potential markers to regulate the lactation and parturition stress in periparturient dairy cows.

The cardiac biomarkers troponin I and CK-MB in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth, and goats with pregnancy toxemia

This study was designed to establish the reference range for the cardiac biomarkers cardiac troponin I (cTnI) and creatine kinase myocardial band (CK-MB) in nonpregnant and pregnant goats, goats with normal birth, goats with prolonged birth associated with dystocia, and goats with pregnancy toxemia. Fifty-seven does, categorized into three groups (G1 to G3), were used. These groups were comprised of 20 healthy does (G1), 19 does with prolonged birth (G2), and 18 does with pregnancy toxemia (G3). Six blood samples (T0 to T5) were collected from G1. The first blood sample (T0) was taken before insemination, the second (T1) at the first trimester, the third (T2) at the second trimester, the fourth (T3) at the last trimester, the fifth (T4) within 12 h of parturition, and the sixth blood sample (T5) was taken 10 days after parturition. A sample of blood was obtained from G2 and G3 upon admission to the hospital. At T0 to T3, no cTnI was detected in any of the 20 does in G1. At parturition (T4), seven of the 20 goats (35%) exhibited slightly elevated cTnI concentrations (range, 0.01 to 0.04 ng/mL). Ten days after parturition (T5), cTnI was not detected in any of the 20 goats. In 10 of the 19 goats (53%) with prolonged birth (G2), the cTnI was significantly elevated to a mean value of 0.094 ± 0.155 ng/mL, with a maximum value of 0.61 ng/mL. In 16 of the 18 goats (89%) with pregnancy toxemia (G3), the cTnI was significantly elevated to a value of 0.852 ± 1.472 ng/mL, with a maximum value of 5.219 ng/mL. Comparing the values of CK-MB in G1 (T0 to T5), G2 and G3 revealed nonsignificant differences. Only a slight elevation in the CK-MB levels in goats with prolonged birth (G2) was noted. We concluded that in healthy does, the cardiac biomarker cTnI is not elevated during normal pregnancy. The serum cTnI concentration may be elevated in a number of goats at normal vaginal or cesarean delivery. Finally, cTnI is significantly elevated in does with pregnancy toxemia and could be used as a prognostic indicator in such cases. The cardiac biomarker CK-MB is not a good indicator of parturition stress in does. Serum cTnI is elevated in goats with pregnancy toxemia, indicating some degree of cardiac dysfunction.

Chronic and acute clinical manifestations associated with systemic mineralization caused by ingestion of Nierembergia veitchii in sheep in southern Brazil

Enzootic calcinosis associated with Nierembergia veitchii ingestion occurs in sheep in southern Brazil, and has been described as a chronic disease. However, in recent years this plant has been associated with cases of acute disease and sudden death in sheep. Data from 12 sheep flocks affected by this toxicosis in southern Brazil, between 1990 and 2007, are described. Thirty-five sheep were necropsied. Twenty-four had a history of chronic disease with weight loss, stiff gait, tucked abdomen, kyphosis, and recumbency. Eleven sheep died suddenly with no prior history of severe illness. In all affected sheep, gross changes included poor body condition and widespread mineralization of several tissues, more prominent in blood vessels and heart valves. In addition, sheep that experienced sudden death had moderate to severe pulmonary edema. There was a distinct seasonal pattern to the clinical presentations, with chronic disease occurring in spring and summer and the acute cases dying in fall and winter. Stress of parturition or poor climatic/nutritional conditions may have precipitated the acute deaths.

Parturition and Hypocalcemia Blunts Calcium Signals in Immune Cells of Dairy Cattle

The stress of parturition in the dairy cow is associated with increased susceptibility to infectious disease. During the periparturient period the demands for calcium are increased; these increased demands for calcium can result in subclinical or clinical hypocalcemia. Periparturient cows also experience significant immune suppression. Because intracellular calcium signaling is a key early feature in immune cell activation, we have hypothesized that the increased demand for calcium in periparturient cows may adversely affect intracellular calcium stores of immune cells. This reduction in intracellular calcium stores in immune cells could blunt intracellular calcium release following an activating stimulus, contributing to the immune suppression seen in these animals. To test this hypothesis, peripheral mononuclear cells were obtained from 27 multiparous dairy cows spanning a period of 2 wk before and 2 wk after parturition. Following activation of these cells by anti-CD3 antibodies plus secondary antibodies, intracellular calcium release from intracellular stores was measured. The intracellular calcium released in response to the activation signal declined as calcium demand for lactation became more intense and recovered as plasma calcium normalized. Intracellular calcium stores in peripheral mononuclear cells, estimated by pretreating cells with pervanadate and ionomycin, significantly decreased at parturition and returned to normal levels as the cows’ blood calcium returned to normal levels. Hypocalcemia, which is common in periparturient dairy cows, is associated with decreased intracellular calcium stores in peripheral mononuclear cells. Our data suggest that this is the cause of a blunted intracellular calcium release response to an immune cell activation signal. It is concluded that intracellular Ca stores decrease in peripheral blood mononuclear cells (PBMC) before parturition and development of hypocalcemia. This suggests that systemic calcium stress precedes measurable hypocalcemia, particularly in cows that will develop milk fever. Therefore, PBMC intracellular Ca stores are a more sensitive measure of calcium stresses in transition cow. This decrease in PBMC intracellular Ca stores before parturition and the development of hypocalcemia contributes to periparturient immune suppression.

High levels of human chromogranin A in umbilical cord plasma and amniotic fluid at parturition.

The human placenta is a neuroendocrine organ that produces several hypothalamic and pituitary hormones that are secreted during pregnancy and parturition into maternal and fetal circulation and amniotic fluid. Human chromogranin A (CgA) is a glycoprotein mainly localized to the adrenal medulla and released in response to several stressful events. During pregnancy, intrauterine tissues express and synthesize CgA mRNA and peptide and secret it into the biologic fluids of pregnancy, so we investigated whether maternal, umbilical, and amniotic human CgA levels are affected by the stress of parturition. We measured pregnancy CgA levels in maternal and umbilical cord plasma and in amniotic fluid at term (39-40 weeks), by enzyme-linked immunosorbent assay at elective cesarean (n = 16), after spontaneous vaginal delivery (n = 12), and longitudinally throughout labor and 2 hours postpartum. CgA levels were highest in umbilical cord blood (P <.001). Umbilical cord plasma and amniotic fluid CgA levels were significantly higher at spontaneous vaginal delivery than at cesarean (P <.001), and the levels were not changed in maternal plasma according to cervical dilatation and postpartum. The present findings showed that the stress of parturition increased CgA levels in umbilical cord plasma and amniotic fluid and was probably of fetal origin. Whatever the mode of delivery, CgA levels in infants were much more elevated than in mothers, providing evidence for an unusual and sustained high level of sympathoadrenal stimulation in full-term neonates.

The Effect of Piglet Expulsion in the Sow on Plasma Cortisol, Adrenocorticotropic Hormone and β‐endorphin

ContentsPrevious studies have shown an increase in plasma cortisol in gilts over farrowing irrespective of environment suggesting that factor(s) associated with parturition itself cause physiological stress. Factors involved in mediating the hypathalomo–pituitary–adrenal (HPA) axis at parturition are not well understood. This study examines the effect of piglet expulsion on the pituitary–adrenal axis by measurement of plasma cortisol, adrenocorticotropic hormone (ACTH) and β‐endorphin. The effect of farrowing environment in modulating the acute response to piglet expulsion is also investigated. Twelve second parity sows, with indwelling jugular catheters, were moved into either a farrowing crate or a straw‐bedded pen 5 days before their expected parturition date (EPD). Blood samples were taken from each sow during a prefarrowing baseline period and then rapid samples (2.5 mins) were taken for 10 min following the birth of two piglets. No effect of environment was found on any of the hormonal variables which reinforces the hypothesis that the physiological stress seen in parturient pigs is due to some intrinsic factor of parturition. Plasma cortisol, ACTH and β‐endorphin did not change significantly in the period following piglet expulsion suggesting that individual piglet expulsions do not play a major role in ‘parturition stress’. There was however, an increase in plasma cortisol, ACTH and β‐endorphin in response to increasing piglet number which is consistent with previous studies of general farrowing in which cortisol increased as farrowing progressed. Therefore this study reinforces the hypothesis that physiological stress increases with ongoing parturition although this does not appear to be a result of piglet expulsion. The potential role of other factors which may be involved in causing ‘parturition stress’ should be investigated.

Effects of parturition on corticotropin releasing hormone and products of the pituitary and adrenal in term fetuses at delivery.

Corticotropin releasing hormone (CRH), a hypothalamic hormone which regulates pituitary-adrenal function, is also produced by the human placenta. We studied umbilical cord concentrations of CRH to determine whether placental secretion of this hormone into the fetal compartment is altered during parturition. We also measured adrenocorticotropic hormone (ACTH), cortisol and dehydroepiandro-sterone sulfate (DHEAS) to determine whether levels of these pituitary and adrenal hormones were correlated to CRH in the fetal plasma. Blood was obtained from umbilical cords of 111 healthy term fetuses at delivery. Concentrations of CRH, ACTH, cortisol and DHEAS were measured by radio-immunoassay. Hormone levels were analyzed according to the presence of labor and delivery mode. In addition correlations between different hormones were determined. Fetal plasma CRH levels were similar for all conditions of labor and delivery as were levels of DHEAS. Fetal plasma ACTH and cortisol were increased after vaginal delivery. There were no significant correlations between placental CRH, ACTH and cortisol levels. However, an inverse correlation between fetal plasma CRH and DHEAS levels was found (r = -0.41, p < 0.001). Increases in ACTH during parturition are likely due to stimulated release by the fetal pituitary. Our data suggest that placental CRH does not mediate this acute response to the stress of parturition. We hypothesize that continuous stimulation of the pituitary and adrenal by circulating CRH during development may occur and the inverse correlation between fetal plasma CRH and DHEAS may be due to this chronic regulatory effect.

Beta-endorphin in sows during late pregnancy: effects of cloprostenol and oxytocin on plasma concentrations of beta-endorphin in the jugular and uterine veins.

Beta-endorphin was measured in the plasma of pigs during late pregnancy and at different stages of the oestrous cycle. In pregnant animals, beta-endorphin secretion from uteroplacental tissues into the maternal circulation and the possible effects of oxytocin and the prostaglandin F2 alpha (PGF2 alpha) analogue cloprostenol on beta-endorphin release were determined. Plasma beta-endorphin concentrations in pregnant sows were significantly higher than in non-pregnant pigs. However, there were no significant changes in beta-endorphin values throughout the oestrous cycle. Because the increase in plasma beta-endorphin concentrations had occurred before luteolysis and onset of labour it could not be attributed to the stress of parturition. The surgical intervention of a laparotomy increased beta-endorphin release into peripheral plasma. Cloprostenol but not oxytocin caused an immediate increase in plasma beta-endorphin concentrations. At parturition, endogenous PGF2 alpha may be involved in the regulation of beta-endorphin secretion. Concentrations of beta-endorphin in the jugular and uterine vein plasma were not significantly different, and so it would appear that beta-endorphin in the plasma of pregnant sows is not of uteroplacental origin. In conclusion, changes in the concentration of beta-endorphin in peripheral plasma, associated with pregnancy but not the oestrous cycle, exist in pigs. Hence a physiological function of peripheral opioid peptides in the periparturient sow is feasible.

Neonatal Adaptation to Stress of Parturition and Dystocia

The fetal animal undergoes a tremendous transition from intrauterine to extrauterine life at parturition. In this article, the maternal-fetal interactions of parturition are discussed with the aim of examining the normal stress reactions of parturition. Dystocia is discussed from the standpoint of additional distress of the newborn, with an aim toward the development of rational therapeutic support.

Prostaglandin-Induced Mid-Pregnancy Abortion Increases Plasma and Amniotic Fluid Levels of β-Lipotropin and β-Endorphin

The continuous and progressive rise of beta-endorphin (B-EP), beta-lipotropin (B-LPH) and cortisol plasma levels during labor in term-pregnant women represents one of the most relevant maternal hormonal responses to the stress of parturition. The aim of the present study was to evaluate the changes of these hormones, both in plasma and amniotic fluid (except cortisol), in a group of pregnant women undergoing prostaglandin-induced therapeutic abortion at the 2nd trimester of pregnancy. B-EP, B-LPH and cortisol were measured by radioimmunoassay. Both plasma and amniotic fluid samples were purified through extraction and chromatography (Sephadex G-75 columns). The prostaglandin derivative, 16-phenoxy-PGE2-methylsulfonylamide (sulprostone, Schering, Berlin) (500 micrograms, i.m., every 4 h), caused a rapid and significant rise of plasma B-EP, B-LPH and cortisol levels in all subjects. The relative increase of the 3 hormones was less relevant after the 2nd and absent after the 3rd injection of PGE2. The amniotic fluid concentrations of B-EP and B-LPH were also raised 2 h after the 1st injection. These data indicate that sulprostone-induced abortion activates both maternal and fetoplacental release of opioids independently of the trend of uterine contractions. The pattern of pro-opiomelanocortin-related labor differs from spontaneous labor and can probably be linked to a direct effect of the drug.

Opiate antagonism reduces placentophagia and pup cleaning by parturient rats

Since endogenous opiate mechanisms are activated during parturition, the present study examined in rats the effects of opiate antagonism on maternal care during and shortly after parturition. Endogenous opiate mechanisms were blocked in late pregnant rats by (1) naltrexone pellet implants (Experiment 1); (2) acute naloxone injections of 10 mg/kg (Experiment 2) or 0.1 mg/kg (Experiment 7); or (3) induction of opiate tolerance (Experiment 3). All methods resulted in a significant decrease in placentophagia and/or in cleaning pups of umbilical cords and birth fluids (Experiment 6). Other aspects of maternal care appeared relatively unaffected and 24 hr pup survival rates were lowered only by induction of morphine tolerance (probably via its effects on the young). In nonpregnant females, naloxone produced a small but significant decrease in placentophagia (Experiment 4) whereas morphine-tolerant nonpregnant females consumed placentas as readily as controls (Experiment 5). Thus the inhibition of placentophagia produced by opiate antagonism may be specific to conditions associated with parturition. These findings suggest that endogenous opiates support placenta eating and pup cleaning during and immediately after birth. Mediation may be via opiate effects on ingestive behavior, and/or via a reduction in the stress of parturition which otherwise can interfere with the female's ability to perform these tasks.

Performance of Crosses among Hereford, Angus and Simmental Cattle with Different Levels of Simmental Breeding. II. Effect of Calf Breed on Cow Productivity

Hereford cows were randomly bred to Hereford, Angus, Simmental X Hereford and Simmental sires. Each sire breed group was represented by nine or 10 sires. These matings produced approximately 100 calves in each sire breed group over 4 yr. The objective of this study was to determine the effect of calf breed on characteristics of the cow such as milk production, reproduction, measures of condition, weight and changes in condition and weight during lactation. All of the cows were contemporary Herefords that were raised and managed under similar environmental conditions. Hence, any detection of an important effect of calf breed on cow productivity should be a reflection of different levels of maternal requirement imposed on the cow by the different calf breed groups. Cows that raised crossbred calves gained less weight from precalving to weaning, had lower condition scores at weaning, had smaller gains in weight change per unit of height and experienced a lower pregnancy rate. All results consistently showed that crossbred calves challenged the maternal ability of their dams to a greater degree than the straightbred calves and that among the crossbred calves, those by Simmental sires challenged their dams the most. It appeared that calf breed group effects on cow traits were at least partially mediated through calf growth rate, but not through parturition stress. Therefore, benefits realized from crossbreeding need to be weighted against possible unfavorable results.

Effect of Segmental Epidural Analgesia on Changes in Peripheral Blood Leucocyte Counts, Lymphocyte Subpopulations, and in vitro Transformation in Healthy Parturients and Their Newborns

Changes in the peripheral blood leucocyte count, lymphocyte subpopulations, and in 'in vitro' responses of lymphocytes to phytohaemagglutinin and tuberculin after induced labour were investigated in 10 normal parturients and their newborns. Every other parturient was given segmental epidural analgesia at level T 10-12 for pain relief during the first stage of labour. The remaining mothers served as controls. The results of blood samples taken from the mothers before induction of labour and from the newborns immediately after delivery served as basal values against which the results of samples drawn on the 1st and on the 5th day following delivery were compared. A significant (p less than 0.05) increase from the basal values in the total leucocyte count after delivery was found only in those mothers not given epidural analgesia and in their newborns. Similarly, a significant (p less than 0.01) decrease in the T cell count characterized by both E rosette formation and acid alpha-naphthyl acetate esterase staining was found in the peripheral blood only in the mothers (but not the newborns) without epidural analgesia. The differences between the research groups were not, however, significant. The lymphocyte response to phytohaemagglutinin on the 1st and on the 5th day after delivery was also significantly (p less than 0.05) lower in the newborns of the mothers not given epidural analgesia than in those of the mothers given it. The present results show that the depression induced by the stress of parturition in some parameters of cell-mediated immunity of mothers and newborns can be at least partly prevented by using segmental epidural analgesia.