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PubMed1986

Influence of feeding time and diet on time of parturition in multiparous ewes.

Three hundred three pregnant ewes were randomly allotted to treatments in a 2 (diet) X 2 (feeding time) factorial arrangement 10 d before the first lambs were due in two lambing seasons to study the effect of time of feeding and diet on time of lambing. Behavioral activities were observed to determine if there was a relationship to time of parturition. All ewes were fed .5 kg ground whole corn per day plus either: alfalfa hay fed at 2200 each day, alfalfa hay fed at 1000 each day, alfalfa haylage fed at 2200 each day or alfalfa haylage fed at 1000 each day. Lambing data from 1983 and 1984 were combined across years because no treatment X year interactions (P greater than .05) were detected. Average time of day for lambing did not differ (P greater than .05) among treatments. In general, no differences due to treatments were observed in lambing time or behavioral activities studied. When data were pooled across treatments, two peak lambing times were observed. These peak times for lambing were from 0300 to 0700 (22.1%) and from 1500 to 1900 (22.5%). During these two 4-h periods (8 h total) 44.6% of the ewes gave birth.

Animal Husbandry↗

PubMed1988

Aggressive behavior of sows at parturition.

Sows, especially primiparous, may show aggressive behavior at parturition against their own piglets, resulting in wounding or death of the piglets. Frequency, environmental influences and heritability of aggressive behavior were studied in two data sets. The first (923 first litters) was collected at an experimental farm and the other (925 first litters) came from a pig breeding organization. Frequency of aggressiveness ranged, depending on its definition, from 7 to 12%. Fixed effects of year, season and feeding level of the gilt during the rearing period did not affect the frequency of aggressiveness. A regression of aggression on postpartum sow weight was found, suggesting that low weight at first farrowing might predispose sows to aggressive behavior. Coefficients for backfat and litter size were positive but nonsignificant. Heritability of aggressiveness on the underlying normal scale, estimated from the paternal half-sib component of variance, averaged .12 for the first data set, and .25 for data set II. Estimates from daughter-dam regression were .49 and .87 for the two data sets, respectively. A simulation study indicated that this difference might be due to maternal effects. A simple application would be to select boars and gilts from non-aggressive sows only. Response to selection would be rather slow if the frequency of aggressive behavior is low. At frequencies that are too high from an economic point of view, estimation of breeding values, combining own performance and(or) data from relatives, is required.

Aggression↗

PubMed1983

Parturition and pelvic fracture. Follow-up of 34 obstetric patients with a history of pelvic fracture.

Thirty-four women with a history of pelvic fracture gave birth. Ten had experienced increasing or recurrent pain during the course of their pregnancy. Twenty-seven women gave birth without complications, including 13 patients with displaced pelvis. In only one patient was cesarean section carried out on suspicion of disproportion. Cesarean section was carried out in another case because of resymphysiolysis and in one because of other complications to the pregnancy. Two underwent vacuum extraction because of secondary inertia, but subsequently they gave birth by the vaginal route without complications. In connection with pregnancy and birth, 2 patients had resymphysiolysis. They were the only patients of 8 with symphysiolysis who had undergone osteosynthesis, and both had had the material removed before pregnancy. It is concluded that separation of the symphysis in a pelvic fracture is a more serious complication in subsequent parturition than is displacement of the bony birth canal.

Adult↗

PubMed1998

New peptides, hormones and parturition.

This brief review emphasizes the importance of three novel discovered factors produced by fetal membranes, placenta and/or by the fetus itself in regulating uterine contractility. We have shown that, as reported for other hormones and substances, nitric oxide and endothelin may influence myometrial activity in an autocrine/paracrine manner interacting with other well-known agents such as prostaglandins, oxytocin and hormones. We also demonstrated that different isoforms of nitric oxide synthase (NOS) may play different roles throughout gestation and during labor. We have suggested that another peptide produced by trophoblast cells, adrenomedullin, may affect, directly or indirectly, myometrial contractility during pregnancy, although much remains to be learned about the mechanisms controlling adrenomedullin expression by the feto-placental tissues cells during pregnancy. Continued research is necessary to better define the complex interactions that result in parturition, both at term and preterm, and to allow a more rational approach to management of the premature labor, exploring new possible pharmacological solutions.

Adrenomedullin↗

PubMed2002

Blood and milk neutrophil chemiluminescence and viability in primiparous and pluriparous dairy cows during late pregnancy, around parturition and early lactation.

Extensive studies have shown the polymorphonuclear leukocytes (PMN) dysfunction inextricably links to parturition. To investigate the effect of parity on PMN function, phorbol 12-myristate 13-acetate (PMA) stimulated luminol-amplified chemiluminescence (CL) and viability of blood and milk PMN were investigated in primiparous and pluriparous dairy cows during periparturient period. The CL kinetics of blood and milk PMN and hematological profiles were also assessed. Milk PMN CL was always lower than blood PMN CL. Blood and milk PMN CL and milk PMN viability were significantly higher in primiparous cows throughout the study. Blood PMN CL in pluriparous cows showed a sharper decrease. Both in pluriparous and in primiparous cows, minimal blood PMN CL appeared at periparturient day (PPD) 2. After PPD 7, blood PMN CL recovery rate was faster in primiparous cows. Milk PMN CL was minimal at PPD 2 in both groups. Whereas no changes were observed in blood PMN viability, the viability of milk PMN in primiparous cows was substantially higher than in pluriparous cows. The number of circulating eosinophils and immature neutrophils was substantially higher in primiparous cows throughout the study. The CL kinetics of blood PMN at PPD -2 and 2 and of milk PMN at PPD 2 exhibited different responses to PMA, with higher intensity and durability, peaking and subsiding more slowly in primiparous dairy cows. The pronounced reduction in PMN CL and viability in milk PMN of pluriparous cows may be involved in the underlying mechanisms that make these animals more susceptible to periparturient infectious diseases.

Animals↗

PubMed1976

Bovine plasma corticoids during parturition.

Concentrations of adrenal corticoids in plasma were determined by a competitive protein-binding technique using jugular blood samples taken three times daily and more frequently during labor from 21 cows before and after parturition. The prepartum value was 6 ng/ml with a sharp rise during the last 16 h before calving. The average value at the time of calving was 19.2 ng/ml with a significant drop 1 h after calving to 11.2 ng/ml and a return to basal concentrations by 3 days postpartum. Evidence that labor is responsible for the increased corticoid is given. Maternal cortisol at calving was correlated with the time taken to calve .23, calf cortisol .04, cow:calf weight ratio -.07, and calf weight .14.

Animals↗

PubMed1983

Interrelationships of parturition problems, production of subsequent lactation, reproduction, and age at first calving.

Data of 22,691 observations on parturition related problems (dystocia, calf mortality, milk fever, retained placenta, and mastitis) were collected from 27 cooperating California dairy herds. Age at first calving did not affect calving difficulty; thus, an optimal age for first calving was not identified. Decisions on breeding virgin heifers should be based on size of cow because of the effect of size of cow on difficulty at first parity. Small calves experienced greatest mortality at parities greater than one; however, large calves had greater mortality at first parity. Greater mortality for large calves at first parity was partially due to the increased difficulty associated with larger calves. Calving difficulty resulted in impaired reproductive performance (more days open, more services, and more days to first breeding) and decreased 30-day milk production but had no effect on 90-day milk production and 305-day mature-equivalent milk production. Dystocia, milk fever, and retained placenta occurred as a complex. Incidence of dystocia and calf mortality decreased with parity, and all other problems increased with parity.

Age Factors↗

PubMed1991

Mastitis prevalence in primigravid heifers at parturition.

Prevalence of intramammary infection was determined for 382 primigravid heifers within 3 d postpartum on 11 Vermont dairy farms. Data collected during a 5-yr period are summarized. Duplicate quarter milk samples were cultured on tryptose-blood agar plates containing .1% esculin. Intramammary infections were diagnosed in 45.5% of the heifers and 18.7% of quarters. Staphylococcus species were the most prevalent bacteria isolated: they appeared in 25.4% of the heifers and 12.1% of quarters. Only 2.6% of the heifers were diagnosed with Staphylococcus aureus; 22.8% had udder infection caused by other staphylococcal species. Environmental mastitis pathogens, coliforms, and streptococci other than Streptococcus agalactiae were isolated from 14.9% of the heifers and 4.8% of quarters. The prevalence of mastitis among these primigravid heifers at parturition indicates a need to improve methods of diagnosis and control programs.

Animals↗

PubMed1991

Dry matter intake from parturition to midlactation.

Six years of data from the Purina Research Center were summarized to quantitate relationships among DMI, DIM, BW, and 4% FCM. Cows were fed individually and housed in a tie-stall barn from parturition to 21 wk postpartum. Best overall equation predicting DMI was kg DMI = .008037 x kg BW + .3134 x kg 4% FCM + .2286 x DIM - .002176 x (DIM)2 + .00000705 x (DIM)3, R2 = .64, CV percentage = 11.1. Data were best fit when separate equations were developed for each week postpartum up to 6 wk and then for periods including 6 to 8, 9 to 13, and 14 to 20 wk. The commonly used equation, kg DMI = .02 x kg BW + .33 x kg 4% FCM, overestimated DMI until wk 10 but underestimated DMI thereafter. The NRC multifactor DMI estimates could be lower or higher than equations developed up to wk 8, depending on values chosen within range of several factors. At wk 8 and beyond, NRC estimates were lower than equations developed, even when highest level within range of several factors was chosen. Calculated energy balances resulted in greater and extended energy deficit for cows in their second or later lactation compared with first lactation. Loss of BW alone was a poor indicator of energy status in early lactation.

Animal Feed↗

PubMed1994

Effect of hormonal treatment on fertility in dairy cows with dystocia or retained fetal membranes at parturition.

Holstein cows (n = 445) that had experienced dystocia, retained fetal membrane, or both at parturition were used to determine the effects of GnRH, PGF2 alpha, or both on various reproductive measurements. Cows affected with these conditions were assigned randomly to each of four treatment groups. One group of cows was untreated, and three groups received GnRH once at 12 d postpartum, or GnRH at 12 plus PGF2 alpha at 26 d postpartum, or PGF2 alpha given at 12 and 26 d postpartum. Another group of 191 cows that calved normally were untreated. Conception rate after first AI was higher for cows treated with PGF2 alpha at 12 and 26 d postpartum. Cows affected with dystocia, retained fetal membranes, or both and treated early postparum with GnRH alone or followed 14 d later with PGF2 alpha did not have improved reproductive performance. Cows calving during the summer months of June through September experienced a reduction in the reproductive traits examined.

Animals↗

PubMed1999

Effects of induced parturition and estradiol on feed intake, liver triglyceride concentration, and plasma metabolites of transition dairy cows.

The effect of induced parturition and estradiol on feed intake, liver triglyceride, plasma metabolites, and milk yield was evaluated in fifty-six Holstein cows and heifers. Cows were assigned to treatments on d 260 of gestation and were on trial until d 10 postpartum for measurement of dry matter intake (DMI), plasma metabolites, and liver triglyceride and until d 31 postpartum to measure milk yield. Fourteen animals per group (9 cows and 5 heifers) received either a placebo, 1 mg of fenprostalene, 50 mg of estradiol-17 beta benzoate, or both on d 276 of gestation. Cows that received fenprostalene consumed more dry matter (DM) for the last 8 d prepartum than did cows that did not receive fenprostalene (9.6 kg/d vs. 8.5 kg/d, respectively) but consumed less DM for the first 10 d postpartum (10.9 kg/d vs. 13.1 kg/d, respectively). Cows injected with estradiol-17 beta benzoate tended to consume less DM postpartum than did cows not injected with estradiol-17 beta benzoate (11.3 kg/d vs. 12.7 kg/d, respectively). There was no effect of treatment on milk yield; however, a fenprostalene by day interaction resulted from lower milk yield on d 3, 4, 5, 7, and 10 relative to calving in cows that received fenprostalene. Administration of fenprostalene resulted in a delay in the peak plasma nonesterified fatty acid (NEFA) concentration until 2 d after calving. Plasma glucose concentrations were greatest 1 d prior to calving for cows that received fenprostalene, whereas plasma glucose concentrations peaked on the day of calving for cows that did not receive fenprostalene. Liver triglyceride increased over time; however, there was no effect of treatment on liver triglyceride. Calving induction improved DMI for the last 8 d prepartum, but a concomitant decrease in liver triglyceride after calving did not result. Estradiol-17 beta benzoate had no effect on plasma metabolites or liver triglyceride, indicating that the physiological rise in estradiol prior to calving does not have a primary role in lipolysis or hepatic fatty acid metabolism in the dairy cow.

Abortifacient Agents, Nonsteroidal↗

PubMedDate not supplied

Estrous length, pregnancy rate, gestation and parturition lengths, litter size, and juvenile mortality in the domestic cat.

Reproductive performance in a feline research colony of 14 queens is reported. Average estrous length in 38 cycles was 5.8 +/- 3.3 days, with a range of two to 19 days. Estrous length in 23 bred cycles was not shorter (p greater than 0.05) than in 15 nonbred cycles, suggesting that induction of ovulation does not decrease estrous length. Pregnancy rate in 23 bred cycles was 73.9%. Gestation length averaged 66.9 +/- 2.9 days with a range of 62 to 71 days (n = 15). Average parturition length was 16.1 +/- 14.3 hours (n = 7), with a range of four to 42 hours. Litter size ranged from one to five kittens, with an average of 3.7 kittens per litter (n = 15). Percent mortality by eight weeks of age was 29.1%, with 4.7% stillbirths.

Animals↗

PubMedDate not supplied

Prostaglandin Falpha, progesterone and oestrogens in relation to parturition in sheep.

Six hourly blood samples were collected from either the uterine vein or posterior vena cava of 8 conscious ewes over a period of about 1 week prior to and 2 days after parturition. In addition blood was also collected simultaneously from the jugular vein. Using sensitive radioimmunoassay techniques, these samples were analyzed for PGF2 alpha, progesterone and oestrogens. The results indicate that concentrations of PGF2 alpha in sheep blood started to rise before a fall in progesterone concentrations. A rise in total oestrogens also preceded the fall in progesterone concentrations. It was however not possible to show a temporal relationship between the rises in oesterogens and PGF2 alpha concentrations.

Animals↗

PubMed1975

Mechanism of action of glucocorticoids in induction of ovine parturition: effect on placental steroid metabolism.

Maternal plasma progesterone levels in sheep may fall dramatically druing the last few days of gestation and following the administration of glucocorticoids to the foetus. To investigate the mechanism of the fall, metabolism of [3H] progesterone in vitro by ovin placental tissue was studied in five ewes before and after intra-foetal administration of dexamethasone in a dosage sufficient to induce parturition, and in one ewe after the spontaneous onset of labour at 143 days of gestation. Manual separation of maternal and foetal placental tissues showed that, in 11 out of 12 cases, the foetal and not the maternal placenta produced progesterone from pregnenolone in vitro. Total activities of cholesterol side-chain cleavage enzyme and 3beta-hydroxysteroid dehydrogenase in the foetal placenta were not influenced by intra-foetal dexamethasone. Befre administration of dexamethasone, homogenates of foetal placenta converted [3H] progesterone to 20alpha-hydroxy [3H]pregn-4-en-3-one in the presence of NADPH. Within 12 h of administration of dexamethasone, and after the natural onset of labour at 143 days, large amounts of 17alpha, 20alpha-dihydroxyI1pregn-4-en-3-one were formed form [3H]progesterone. Intra-foetal dexamethasone treatment also induced the formation of 17alpha, 20alpha-dihydroxy[3H]pregn-4-en-3-one by miced foetal placental tissue incubated with [3H]pregnenolone. This change in steroid metabolism did not occur in foetal placental tissue from a sham-operated animal receiving no dexamethasone. Assay of progesterone in foetal placentae showed that the increased fromation of 17alpha,20alpha-dihydroxypregn-4-en-3-one was unlikely to be caused by a change in the specific activity of added 3H-labelled precursor, although the production of 17alpha, 20alpha-dihydroxypregn-4-en-3-one in vitro increased at a time when both foetal placental and utero-ovarian venous levels of progesterone were decreasing in response to dexamethasone treatment. These observations indicate that intra-foetal dexamethasone treatment induces a placental 17alpha-hydroxylase enzyme, which is also present in foetal placental tissue after the spontaneous onset of labour at term.

17-alpha-Hydroxypregnenolone↗

PubMed1975

Initiation of human parturition. III. Fetal membrane content of prostaglandin E2 and F2alpha precursor.

Unesterified arachidonic acid is the obligatory precursor of the prostaglandins (PG), PGF2alpha and PGE2. In order to ascertain whether or not the human fetal membranes could represent a storage site for prostaglandin(s) precursor, the fatty acid content of human fetal membranes was measured. Approximately 20% of the fatty acids found in fetal membranes obtained from near-term, non-laboring women was arachidonic acid, whereas only 0.4% of the fatty acids of the parietal peritoneum of the mother is arachidonic acid. A small but significant decrease in the arachidonic acid concentration was found in the fetal membranes obtained from laboring women compared to that found prior to labor. On the other hand, the concentration of palmitic acid was increased in membranes obtained during labor while no significant changes in concentration in the remaining fatty acids were observed in membranes from laboring compared to non-laboring near-term gravidas. The significance of these observations in relation to the availability of prostaglandin precursor and the initiation of human parturition is considered.

Arachidonic Acids↗

PubMedDate not supplied

Prostaglandins and prostanoid receptors in human pregnancy and parturition.

Preterm labor occurs in up to 10% of all births but is associated with 85% of perinatal deaths in otherwise normal babies. Elucidation of the mechanisms involved in normal labor is an important prerequisite for the development of effective therapeutic strategies to prevent and treat preterm labor. Prostaglandins are important in human parturition. They have been used extensively for induction of labor. Prevention of their formation with prostaglandin synthase inhibitors can delay delivery in preterm labor. Nevertheless, the functional activity of prostaglandins in gestational tissues is complex. There are numerous classes of prostaglandins that act on many different prostanoid receptors. Receptor subtypes, even within the same class, are coupled to various second messengers and may thus be stimulatory or inhibitory. Alternate splicing leads to additional diversity. Within this complex background, the tissue-, gestation-, and labor-associated changes in prostaglandins and their receptors are reviewed.

Animals↗

PubMedDate not supplied

Estrogen receptor alpha and progesterone receptor A and B concentration and localization in the lower uterine segment in term parturition.

OBJECTIVE: To determine the localization and concentrations of estrogen receptor alpha and progesterone receptors A and B in the lower uterine segment during term parturition. METHODS: Biopsies were taken from 70 patients during nonelective cesarean delivery. The patients were at different stages of cervical dilatation (<2 cm, 2-3.9 cm, 4-6 cm, >6 cm) and different duration of labor (< or =6 hours, >6-12 hours, >12 hours). The receptor concentrations were determined with solid phase immunoassays, and their localization was investigated immunohistochemically. RESULTS: Estrogen receptor alpha concentration decreased significantly from 2.12 fmol/mg protein at less than 2 cm dilatation to 1.08 fmol/mg (4-6 cm) but tended to increase at greater than 6 cm. Progesterone receptor A and B concentration was 84.7 fmol/mg at less than 2 cm dilatation, decreased significantly to 36.6 fmol/mg (2-3.9 cm), and increased again with further dilation. Concentrations of both receptors did not depend on duration of labor. By immunohistochemistry only progesterone receptor A and B was found to be expressed by endothelial and smooth muscle cells of the vessels, stromal fibroblasts, smooth muscle cells in the myometrium, and glandular epithelial cells. Regardless of the extent of cervical dilatation, expression of progesterone receptors A and B was marked. CONCLUSION: A decrease in estrogen receptor alpha and progesterone receptor A and B concentration in the early phase of first stage labor may play a role in cervical dilation at term.

Estrogen Receptor alpha↗

PubMed1976

Maternal and fetal plasma cortisol levels at parturition.

Fetal adrenal function during pregnancy has a probable role in parturition. Ninety-five mothers and fetuses were evaluated to ascertain maternal or fetal plasma cortisol interrelationships under various clinical situations. When mode of delivery was evaluated, maternal cortisol levels showed no differences. However, the fetuses from vaginal delivery (mean, 43.7 mug/100 ml) had higher levels than those from cesarean section (mean, 34.7 mug/100 ml). Induction of labor showed a rise in maternal cortisol from preinduction levels (mean, 40.2 mug/100 ml) to delivery (mean, 49.6 mug/100 ml), probably reflecting the maternal stress of labor. The fetal cortisol level after induced labor (mean, 35.2 mug/ml) supporting the adrenal contribution to the initiation of labor. Gestational age of the fetus was significant in the fetal cortisol levels: 36 weeks or less (mean, 34.1 mug/100 ml); 37 weeks or more (mean, 44.5 mug/100 ml). This again supports the development of adrenal maturity. Fetal weight, postdatism, acute and chronic fetal distress, hypertensive disease in pregnancy, and race were evaluated without revealing any significant intergroup differences. Two anencephalic pregnancies were also studied.

Adrenal Glands↗