Tocodynamometry detects preterm labor in the bitch before luteolysis.

Preterm labor (PTL), myometrial activity, and accompanying cervical changes can lead to the loss of pregnancy via resorption or abortion before term gestation. Idiopathic PTL has no metabolic, infectious, congenital, traumatic, or toxic cause identified; however, hypoluteoidism has been hypothesized to cause PTL in the bitch, based on progesterone measurements at the time of clinical pregnancy loss. This study documents the use of tocodynamometry to detect PTL in 5 bitches; progesterone measurements in these bitches were normal for pregnancy at the time PTL was diagnosed.

Immunology of infective preterm delivery in the mare.

Placentitis is reported to be the cause of 9.8-33.5% of abortions, stillbirths and perinatal losses in horses. Bacterial infections are responsible for 53% of placentitis cases with Streptococcus equi ssp. zooepidemicus being isolated in 28% of these cases. Clinically, mares may have a vaginal discharge, show udder development, lactate prenatally and deliver a premature or dead foal. Major aspects of the pathogenesis of infectious preterm delivery that may require more effective therapeutic targeting are myometrial contraction, immunological aspects of preterm delivery, and the effects of proinflammatory cytokine signalling on activation of the fetal hypothalamic-pituitary-adrenal axis. This article focuses on current knowledge of inflammatory signalling secondary to equine placentitis, and the interplay among inflammation, loss of myometrial quiescence and activation of the fetal hypothalamic-pituitary-adrenal axis.

Benign placental mass with fetal growth retardation in a bull mastiff.

A 4-year-old bull mastiff presented due to premature labour. The referring veterinarian elected to perform a caesarian delivery and at the time of surgery a 4×4×2 cm round, smooth, red to tan, lobulated soft mass was identified attached to the allantoic surface of the zonary placenta of one pup. Microscopically, this mass was composed of loosely arranged confluent undulating cords of polygonal to columnar epithelioid cells separated by a fine fibrovascular stroma resembling the placental labyrinth. The labyrinthine structure and epithelioid nature of the cells suggested that the mass was of trophoblastic origin. Due to the non-invasive nature of the mass and relatively low mitotic activity, this proliferative trophoblastic mass was considered to be benign. The absence of morphological features supporting malignant behaviour and the recapitulation of the normal labyrinthine architecture led to the diagnosis of a trophoblastic hamartoma. To the authors' knowledge this is the first report of a placental hamartoma in the dog.

Treatment strategies for mares with placentitis.

Equine placentitis, and resultant preterm labor, are important sources of fetal and neonatal loss. The primary cause of equine placentitis is infection of the placenta with Streptococcus equi subspecies zooepidemicus, which ascends through the caudal reproductive tract. Current treatment protocols for mares affected with placentitis are empirical. This paper reviews treatment approaches for resolving placentitis and preterm labor in both equine and non-equine species. Specific therapies reviewed include antimicrobial, anti-inflammatory, tocolytic, and progestin agents.

Equine abortion and premature birth associated with Cellulosimicrobium cellulans infection.

During the 2002 and 2003 foaling seasons, Cellulosimicrobium (Cellumonas) cellulans (formerly Oerskovia xanthineolytica) was the principal microorganism isolated from fetal tissues or placentas from cases of equine abortion, premature birth, and term pregnancies. Significant pathologic findings included chronic placentitis and pyogranulomatous pneumonia. In addition, microscopic and macroscopic alterations in the allantochorion from 4 of 7 cases of placentitis were similar to those caused by Crossiella equi and other nocardioform bacteria. This report confirms a causative role of C. cellulans infection in equine abortion.

Serological survey of leptospirosis in sows with premature birth and stillbirth in Chiba and Gunma prefectures of Japan.

In 1996 and 1997, the seroprevalence against Leptospira in parturient sows with premature birth or stillbirth from two herds was investigated. In three out of four sow serum samples obtained in Gunma Prefecture, the antibody titers to Leptospira interrogans serovar copenhageni (M20) were higher than 10,000 (the reciprocal of the serum dilution). Furthermore, the antibody titers to L. interrogans serovar canicola (Hond Utrecht IV) were significantly high in the three sows and the titers ranged from 1,000 to 3,000. In sows obtained in Chiba Prefecture, significantly high antibody titers to serovar copenhageni (M20) were confirmed in eight out of 40 sows, and antibody titers greater than 10,000 in six of them. Significantly high antibody titers to L. interrogans serovar icterohaemorrhagiae (RGA) and L. canicola (Hond Utrecht IV) were confirmed in four and 18 out of the 40 sows, respectively, compared with the titers to the other serovars. These findings may indicate the prevalence of leptospirosis in pig herds in both Gunma and Chiba Prefectures.

Non-enzymatic antioxidative defence mechanisms against reactive oxygen species in bovine-retained and not-retained placenta: vitamin C and glutathione.

Vitamin C and glutathione (GSH) are water-soluble antioxidants which take part in defence mechanisms against reactive oxygen species (ROS). They may also be involved in processes of releasing/retaining bovine fetal membranes. Hence vitamin C, reduced (GSH) and oxidised (GSSG) glutathione levels were determined in retained and not-retained bovine fetal membranes in order to describe the non-enzymatic antioxidative status. Placental samples were collected immediately after spontaneous delivery or during caesarean section before term and at term, and 6 groups were formed as follows: (A) pre-term caesarean section without retained placenta; (B) pre-term caesarean section with retained placenta; (C) term caesarean section without retained placenta; (D) term caesarean section with retained placenta; (E) spontaneous delivery without retained placenta and (F) spontaneous delivery with retained placenta. Homogenates of maternal and fetal placental tissues were prepared, and vitamin C, GSH and GSSG were measured spectrophotometrically. Vitamin C levels were significantly higher in the maternal part than in the fetal part of the placenta in all groups examined. In retained placenta cases the levels were significantly lower than in control cows, except in pre-term groups. GSH concentrations were significantly higher in placentas without retention than with retention. GSSG levels showed the opposite relationship and were significantly higher in samples with retention of fetal membranes than in controls. Further experiments on antioxidative as well as oxidative status in bovine placenta are necessary.

Antioxidative defence mechanisms against reactive oxygen species in bovine retained and not-retained placenta: activity of glutathione peroxidase, glutathione transferase, catalase and superoxide dismutase.

Glutathione peroxidase (GSH-Px), glutathione transferase (GSH-Tr), catalase (CAT) and superoxide dismutase (SOD)-the members of enzymatic antioxidative defence mechanisms against reactive oxygen species-may play an important role in proper or improper release of bovine fetal membranes. The aim of the following study was the determination of GSH-Px, GSH-Tr, CAT and SOD activity in order to define antioxidative status of bovine placenta during retention of fetal membranes (RFM) in cows. Placental samples were collected immediately after spontaneous parturition or during caesarean section before term and at term and divided into six groups as follows: A: caesarean section before term without RFM; B: caesarean section before term with RFM; C: caesarean section at term without RFM; D: caesarean section at term with RFM; E: spontaneous delivery at term without RFM; F: spontaneous delivery at term with RFM. The enzyme activities in placental homogenates were measured spectrophotometrically. GSH-Px activity was statistically significantly higher in fetal than in maternal placenta in all examined groups, increased towards parturition and was higher in caesarean section groups than spontaneous delivery groups. Statistically significantly higher activities were noticed in retained than not-retained placentae. GSH-Tr activity was significantly lower in fetal than in maternal placenta. In preterm groups, the activity was statistically significantly higher in retained than not retained placenta. In term groups, the opposite relationship was observed, higher values in caesarean section groups than spontaneous delivery were noticed. CAT activity was statistically significantly higher in fetal than in maternal part of placenta in all groups examined. The highest values in C and D groups and the differences between retained and not-retained placenta were observed. SOD exhibited the highest values in preterm placenta and alterations between retained and not-retained fetal membranes. In conclusion, the activities of GSH-Px, GSH-Tr, CAT and SOD are altered in cases of retained fetal membranes which may suggest the activation of antioxidative mechanisms caused by the imbalance between production and neutralization of reactive oxygen species.

Frustrating case presentations in canine theriogenology.

The practice of small animal theriogenology is rewarding, but frustrations exist concerning technologic advances as compared with other species. Reproductive clinicians striving to practice good quality medicine readily identify topics of common concern: causes that are not identified or therapeutics that are not available or applicable. Improved collaboration among theriogenologists specializing in small animal practice is evidenced by growing attendance at national and international scientific meetings, increased scientific publications, and internet communications.

Synthetic mimics of surfactant proteins B and C: in vitro surface activity and effects on lung compliance in two animal models of surfactant deficiency.

Synthetic surfactant peptides SP-B1-78 and SP-C1-31 in a standard phospholipid mixture have been employed to examine the correlation between in vitro surface activity and in vivo function of synthetic surfactant preparations in the isolated rat lung and premature rabbit models of respiratory distress syndrome. Monolayer techniques showed that SP-B peptides have a high propensity for association with a phospholipid structure. By dynamic respreading, synthetic SP-B and SP-C showed rapid spreading and attained low surface tensions. Used as replacement surfactants in two animal models, these synthetic surfactant preparations partially restored lung compliance in lavaged rats and premature rabbits better than a pure phospholipid preparation and to a degree comparable to clinical surfactant, measured by pressure/volume curves. Our data confirm that in vitro functional determinations of synthetic surfactant peptides are instrumental in the preparation of replacement surfactants, and that dispersions thus selected represent viable therapeutic alternatives to current treatments for respiratory distress syndrome.

Prophylaxis of respiratory distress syndrome in premature calves by administration of dexamethasone or a prostaglandin F2 alpha analogue to their dams before parturition.

OBJECTIVE: To investigate effects of preterm induction of calving by administration of flumethasone and dinoprost on the lecithin-to-sphingomyelin ratio in amniotic fluid and on neonatal respiratory distress after birth. ANIMALS: 45 dairy cows and their newborn calves. PROCEDURE: Amniotic fluid from 45 cows was obtained and tested between days 258 and 270 of gestation. Cows were then given flumethasone (10 mg; n = 15), dinoprost (25 mg; n = 15), or saline solution (n = 15). Thirty hours later, left flank cesarean section was performed, amniotic fluid was collected, and the calf was delivered. Blood for determination of progesterone was withdrawn at amniotic fluid sample collections and before induction of calving. Blood for analysis of pH and base deficit was collected from calves during cesarean section and repeatedly after birth. Phospholipids in amniotic fluid were measured by thin-layer chromatography, and progesterone was determined by radioimmunoassay. Base deficit and pH were measured, using a blood gas analyzer. RESULTS: Before treatments, a corpus luteum was present in all cows and the lecithin-to-sphingomyelin ratio in amniotic fluid did not differ between groups. Thirty hours after injections of flumethasone and dinoprost, progesterone concentration had decreased (P < 0.05) and the lecithin-to-sphingomyelin ratio was significantly (P < 0.05) higher than values in controls. In calves delivered after flumethasone or dinoprost treatments, the degree of acidosis was significantly (P < 0.05) less than that in controls. CONCLUSIONS: Flumethasone and dinoprost, given to pregnant cows, accelerate fetal lung maturation and improve respiratory function after birth.

Studies on pathogenesis, tissue infection and congenital transmission in cows experimentally infected with Sarcocystis cruzi by various routes.

A group of nine cows, naturally infected with Sarcocystis, were challenged with Sarcocystis cruzi: three intrarumenally with sporocysts, two intrarumenally with water (controls), two intravenously with merozoites grown in vitro and two intravenously with saline solution (controls). The animals intrarumenally challenged with sporocysts developed acute sarcocystiosis and produced stillborn calves, whereas those intravenously challenged with merozoites suffered from subclinical sarcocystiosis with premature births. No parasites were found in calves from cows challenged with sporocysts; however, a meront of Sarcocystis was found within a macrophage in the cerebrospinal fluid of a calf from a cow intravenously inoculated with merozoites of S. cruzi. This is the first time that merozoites of S. cruzi grown in vitro have been demonstrated to retain the ability to infect their natural intermediate host and complete their life cycle.

[The effect of subclinical and acute ante partum acidosis in cows on the course of pregnancy with regard to the steroid hormone profile]. / Einfluss subklinischer und akuter Azidose ante partum bei Kühen auf den Graviditätsverlauf unter Berücksichtigung der Steroidhormonprofile.

Experiment 1: In a field experiment in 19 of 87 cows being in day 260-265 of pregnancy subclinical metabolic acidosis was found. The control group included 10 healthy cows in the same stage of pregnancy. Blood samples from cows of both groups were collected once daily until day 2 post partum for determination of oestrogens, progesterone and cortisol. Dystocia was found in four and retained placenta in three cows having acidosis. These cows had lower oestrogens and markedly higher cortisol and progesterone concentrations during parturition. Course of pregnancy and delivery in control cows an without any difficulties and hormonal profiles in these cows were typical. Experiment 2: On day 265 of pregnancy experimental acute acidosis was evoked in five cows and five other cows served as control. Sampling of blood was the same as in experiment 1. Acidosis caused on day 269 in two cows premature birth with retained placenta. Moreover concentrations of studied steroids were atypical. In three other cows with acidosis course of pregnancy and delivery was without any trouble. Only cortisol was increased while progesterone and oestrogen values were in agreement with concentrations of control cows. Data suggest that metabolic acidosis can cause dystocia, premature birth and retained placenta. Furthermore, acidosis clearly affects the profile of steroid hormones.

Plasma bovine placental lactogen concentration throughout pregnancy in the cow; relationship to stage of pregnancy, fetal mass, number and postpartum milk yield.

This study characterized the peripheral plasma placental lactogen (bPL) profile throughout gestation and examined the relationship between the stage of gestation, fetal mass, number, and postpartum lactation with circulating levels of bPL in Holstein cows after nonsurgical embryo transfer. Cows (n = 12) were divided into two groups: Group 1 = single embryo recipient cows (n = 5); Group 2 = twin embryo recipient cows (n = 7). Blood was collected about every third day from Day 0 (Day 0 was defined as the first day of standing estrus), then daily for the last 10 d of gestation, and sampling was stopped 1 d postpartum. The cows were milked twice daily at 0800 and 1800 hr. Two twin-embryo recipient cows had abnormal pregnancies; therefore, their data were excluded from that of the group and reported separately. The time trend concentrations of plasma bPL were significantly affected by the stage of gestation (P < 0.01) but not fetal number (P < 0.21). In both groups bPL levels remained low during the first two trimesters, then increased rapidly (P < 0.01) to peak concentrations between Days 200 and 220, and stabilized at this elevated level until parturition. Postpartum milk yields were indistinguishable between the singleton and twin bearing cows. Calf birth weight and postpartum lactation were both correlated (P < 0.01) to peripheral bPL concentration in singleton cows, however, this relationship decreased with a subsequent increase in fetal number. Cows giving birth prematurely to stillborn calves or to a schistosomus reflexus calf exhibited a deviating pBL profile. These results indicate that peripheral bPL levels are positively associated with the stage of gestation but not with fetal number. Otherwise, the peripheral pattern of bPL is a valuable index for predicting feto-placental viability.

Production of premature delivery in pregnant rhesus monkeys by androstenedione infusion.

The endocrine mechanism involved in term and preterm delivery in primates, including pregnant women, are poorly understood. In the term monkey, fetal plasma androgen concentration rises to two hundred times the maternal concentration which remains unchanged. Placental conversion of androgen to estrogen results in increased maternal plasma estrogen concentration at term in both pregnant nonhuman primates and women. In the present study, continuous infusion of androstenedione to 0.8 gestation monkeys resulted in the premature occurrence of labor-type myometrial activity and increases in maternal plasma estrogen, oxytocin and amnion fibronectin concentrations similar to those measured at normal-term labor. Androstenedione induction of these normal-term biochemical and endocrine changes accompanied by fetal membrane rupture, cervical dilatation and live delivery provides a rich opportunity to study the molecular and physiological mechanisms of both term and preterm labor in primates.

Effects of induced or delayed parturition and supplemental dietary fat on colostrum and milk composition in sows.

Two experiments were conducted to evaluate the effects of inducing premature parturition on the composition of colostrum and milk and the effects of dietary fat supplementation on colostrum and milk composition from premature and delayed farrowing sows. In Trial 1, eight sows were allowed to farrow naturally (d 114, NF sows) and eight sows were induced to farrow (IF sows) prematurely by injection of prostaglandin F2 alpha on d 112 of gestation. Average fat content of sow's milk during the first 12 h postpartum was lower for IF than for NF sows (P < .05), as was overall mean fat percentage (P < .05). In Trial 2, 53 sows were randomly assigned in a 2 (diets) x 5 (parturition treatments) factorial experiment. Dietary treatments fed during the last 2 wk of gestation and throughout lactation were control diet and added fat diet (control diet plus 10% corn oil). Parturition treatments included 1) natural farrowing (d 114), induction of parturition with prostaglandin F2 alpha on 2) d 110, 3) d 111, or 4) d 112 of gestation, and 5) delay of parturition with progesterone followed by injection of prostaglandin on d 115. The added fat diet increased milk fat percentage compared with the control diet (P < .01). Colostral fat percentage was reduced by induction of premature farrowing (d 110 or 111) in sows fed the control diet but was unaffected in sows fed added dietary fat (interaction, P < .05). Mean fat content of colostrum was not reduced in groups receiving the added fat diet that were induced to farrow prematurely.(ABSTRACT TRUNCATED AT 250 WORDS)

ACTH-induced preterm labour in the ewe is associated with increased mRNA and protein levels of myometrial gap junction protein, connexin-43.

The myometrial gap junction protein, connexin-43, is thought to be critical to the development of synchronous, high-amplitude contractions of the myometrium during labour. The purpose of this study was to determine the relationship between the temporal expression of myometrial connexin-43 mRNA and protein, the contractile patterns of the uterus and the changes in maternal plasma oestrogen and progesterone. On day 127 chronically catheterized fetal sheep were randomized to receive either ACTH (1 microgram over 15 min every 2 h) or saline (control) infusions. Using this model, ACTH induces labour in 110 +/- 5 h and produces similar endocrine profiles and changes in myometrial activity to that of term spontaneous labour. Myometrial tissue was obtained during autopsy at: 0 h (127 days: no infusion), 72 h saline, 72 h ACTH, 120 h saline, and during ACTH-induced labour (n = 4/group). Northern analysis demonstrated a significant (P < 0.05) increase in connexin-43 transcripts during labour (2.21 +/- 0.39; mean +/- S.E.M. relative to 18S) compared with 0 h (0.67 +/- 0.17) and 72 h ACTH (0.41 +/- 0.11). Connexin-43 protein (as determined by Western analysis) showed a similar pattern to that of the transcripts. These changes in myometrial connexin-43 expression were associated with significant increases in the rate of rise of intrauterine pressure, frequency and maximum amplitude of uterine contractions and the maternal plasma oestrogen to progesterone ratio. No changes in connexin-43 expression, contractile parameters or endocrine profiles occurred in control animals.(ABSTRACT TRUNCATED AT 250 WORDS)