Effects of a protracted induction of parturition on the incidence of retained placenta and assessment of uterine artery blood flow as a measure of placental maturation in cattle

The curse of the firstborn: Effects of dam primiparity on developmental programming in ruminant offspring

The first parity, or first pregnancy, of ruminant females has negative effects on offspring during fetal, perinatal, and pre-weaning periods which ultimately lead to diminished pre-weaning productivity. Offspring born to primiparous ruminant females can have decreased fetal and pre-weaning growth, resulting in lower body weights at birth and weaning in cattle, sheep, and goats. Moreover, mortality is greater during both neonatal and pre-weaning periods. Insults during these critical developmental windows likely also have long-term consequences on first-parity offspring through developmental programming, but less research has been done to investigate effects in the post-weaning period. Many potential physiological, metabolic, and behavioral mechanisms exist for the outcomes of dam primiparity. Although competition for nutrient partitioning between maternal and fetal growth or lactation is often cited as a major contributor, we hypothesize that the most important mechanism causing most first-parity outcomes is the relative physiological inexperience of reproductive tissues such as the uterus and mammary gland during the first pregnancy and lactation, or a "first use theory" of tissues. More research is necessary to explore these areas, as well as if primiparous dams respond differently to stressors than multiparous dams, and if stress during the first parity affects subsequent parities.

Twelve-oxoeicosatetraenoic acid-induced fetal membrane release improves postpartum ovarian function, milk production, and blood plasma biochemical parameters in cows

OBJECTIVE

We aimed to determine the effects of 12-oxoeicosatetraenoic acid (12-KETE)-induced placenta release on the performance of mother cows (milk yield, ovarian function, and blood plasma biochemical properties).

METHODS

Experimental treatments were as follows: i) natural delivery including natural placental release (control cows); ii) induced calf delivery with placental retention (RP cows); and iii) induced calf delivery and 12-KETE-induced placental release (KE cows). Delivery in pregnant KE cows was induced with dexamethasone and prostaglandin. These cows were injected with 12-KETE after calf discharge, resulting in the release of the fetal placenta. RP cows were not treated with 12-KETE after inducing delivery, resulting in placental retention.

RESULTS

The milk yield in RP cows during the first 50 days after delivery was significantly lower than that in control cows (p<0.05), whereas KE cows exhibited a similar milk yield to that of control cows. The postpartum plasma progesterone levels of control cows increased 14 days after delivery on average; however, its increase was delayed by 10 days in RP cows. Meanwhile, the 12-KETE treatment (KE cows) brought the timing of progesterone increase forward to the normal level (control cows). Among the 20 biochemical parameters examined, the total cholesterol levels in blood plasma 14 days after delivery were lower in RP cows than that in the other two treatment groups (control cows and KE cows) (p<0.05). In addition, the plasma level of haptoglobin tended to be low in cows that discharged their placentas shortly after delivery.

CONCLUSION

These findings indicate that 12-KETE treatment can alleviate the disorder caused by placental retention.

Status of Oxidative Stress during Low-Risk Labour: Preliminary Data

Pregnancy and childbirth are associated with the forming of reactive oxygen species that generate oxidative stress. Oxidative stress is a factor that may adversely affect the development of the fetus and the course of labour. Monitoring the parameters of oxidative stress can be used to assess the risk of health issues in the course of pregnancy and the condition of the newborn. Therefore, the analysis of oxidative stress in the physiological course of labour is the basis for understanding the role of oxidative stress in the pathogenesis of miscarriages and neonatal health circumstances. The study aimed to assess oxidative stress of mother-child pairs in the venous blood and umbilical cord blood at the time of physiological labour. One hundred and sixty-eight mother-child pairs were recruited to donate the mother’s venous blood in the first stage of labour and the venous umbilical cord blood after the newborn’s birth. Total antioxidant status (TAS), the activity of superoxide dismutase (SOD) with cofactors (Zn, Cu, Mn) and the activity of glutathione peroxidase (GPx) were analysed in venous blood plasma and umbilical cord blood. TAS value (p = 0.034), GPx activity (p < 0.001) and Zn concentration (p = 0.007) were significantly lower in maternal blood plasma as compared to neonatal umbilical cord blood. However, the activity of SOD (p = 0.013) and the concentration of Cu (p < 0.001) were significantly higher in the blood of mothers than of new-borns. The concentration of Mn in the plasma of the mother’s blood and the umbilical cord blood of the newborns was similar. Our research indicates higher levels of antioxidant enzyme (GPx) and total antioxidant potential (TAS) in umbilical cord blood compared to maternal blood, which may suggest depletion of redox reserves in women’s blood during labour.

Cellular and molecular mechanisms involved in placental separation in the bovine: A review

Retention of fetal membranes (RFM), where the fetal placenta is not expelled within 8-12 hr after calving, lowers bovine productivity and fertility, resulting in significant economic loss to the dairy industry. Several risk factors that predispose an individual to RFM are known, but a unifying pathogenesis remains elusive due to its multifactorial etiology. Fetal membrane separation and expulsion after parturition involves structural and immunological changes of the bovine placentome that are governed predominantly by steroid hormones and the prostaglandin milieu of late pregnancy and parturition. Maturation of the placentome, a gradual and concerted event of late gestation, is likely initiated by the up-regulation of fetal major histocompatibility complex class I in the interplacentomal region-which increases the apoptosis of binucleate and other trophoblastic cells, the degradation of collagen in the extracellular matrix by matrix metalloproteinases, and an influx of phagocytic leukocytes. Shear force further distorts the crypt architecture of the mature placentomes when they are forced against the fetus during the second stage of labor. Cotyledon dehiscence from the caruncular crypts is completed following fetal expulsion as a result of acute shrinkage of the cotelydonary villi as well as reduced perfusion to the caruncle; the secundinae is expelled by uterine contractions. A better understanding of placentomal maturation, intra-partum, and immediate postpartum changes of the placentome should help develop strategies for the treatment and prevention of RFM. The present review proposes a model of placentome maturation and separation of fetal membranes in the dairy cow.

Ultrasonographic Doppler Use for Female Reproduction Management

Transrectal color Doppler ultrasonography is a useful technique to get new information about physiologic and pathophysiologic alterations of the uterus and ovaries in female cattle. During all reproductive stages characteristic changes in uterine blood flow are observed. Cows with puerperal disturbances show delayed decrease in uterine blood flow in the first few weeks postparturition compared with healthy cows. Measurement of follicular blood flow is used to identify normally developing follicles and predict superovulatory response. Determination of luteal blood is more reliable than B-mode sonography to distinguish between functional and nonfunctional corpora lutea. Color Doppler ultrasonography is a promising tool to improve reproductive management in female cattle.

The effect of parturition induction treatment on interval to calving, calving ease, postpartum uterine health, and resumption of ovarian cyclicity in beef heifers

The aim of this study was to compare the effects of two parturition induction protocols with a nontreated control group, on interval to calving, calving ease, postpartum uterine health, and ovarian cyclicity in beef heifers. At Day 285 of gestation, 81 crossbred recipient beef heifers carrying purebred Simmental fetuses, were blocked by live-weight, body condition score, expected calving date and fetal sex, and assigned to one of three groups: (1) control (CON; no induction treatment, n = 29); (2) induction with corticosteroids (CORT; n = 27); or (3) induction with corticosteroids plus prostaglandin (CORT + PG; n = 25). Interval from induction to calving in hours and calving ease on a scale of 1 to 5 were recorded. Vaginal mucus samples were collected on Day 21 and Day 42 after calving (Day 0) by means of a Metricheck and scored on a scale of 0 to 3. Reproductive tract examinations were conducted on Day 21 and Day 42 after calving, and uterine cytology samples were obtained on Day 21. A positive cytologic sample was defined as greater than 18% neutrophils in the sample obtained via a cytobrush technique. Cows were considered to have resumed ovarian cyclicity if the presence of the CL was confirmed. Data were analyzed using the Mixed (normally distributed data) and Genmod (nonparametric data) procedures of SAS (v. 9.3). The interval from treatment to calving was longer (P < 0.0001) for CON (161.9 ± 15.12 hours) animals compared with CORT (39.7 ± 11.64 hours) or CORT + PG (32.6 ± 12.10 hours), which did not differ. Treatment did not affect calving difficulty score. There was also no difference in incidence of retained placenta between the three groups. At Day 21 postpartum, cytology score tended to be higher for both induced groups (48%) compared with the control animals (24%), but this was not the case for vaginal mucus score (CON 52%, CORT 70%, and CORT + PG 52%). A higher proportion of CON had an involuted uterus by Day 21 postpartum (69%) compared with both induced groups (CORT 48%, CORT + PG 32%). Day 21 ovarian cyclicity was higher in both CON (52%) and CORT (59%) compared with CORT + PG (29%). By Day 42, there was no difference in ovarian cyclicity or uterine involution between CON and CORT; however, a positive relationship was observed between uterine involution score on Day 21 and return to cyclicity on Day 42 in these two groups. There was a negative relationship between uterine involution score and return to cyclicity in the CORT + PG group, and these animals were slower (P < 0.05) to resume cyclicity by Day 42 with a larger proportion animals having evidence of having resumed postpartum ovarian cyclicity in both CON (P = 0.03) and CORT compared with CORT + PG on Day 42. In conclusion, the use of corticosteroid-based treatments is an effective strategy to advance parturition in full term dams and does not have a negative effect on calving progress or dam health. However, when prostaglandin is also included in the protocol, these treatments may lead to greater delay in uterine involution with increased chance of uterine infection and slower resumption of ovarian cyclicity.

Plasma steroid dynamics in late- and near-term naturally and artificially conceived bovine pregnancies as elucidated by multihormone high-resolution LC-MS/MS

The plasma levels of corticosteroids and sex steroids during pregnancy are key indicators of mammalian placental function and the onset of parturition. Steroid hormones are believed to be disturbed in pregnancies produced using assisted reproductive technologies (ARTs) due to placental dysfunction and the frequently observed lack of parturition signals. To elucidate the plasma steroid dynamics, a liquid chromatography-tandem mass spectrometry method was developed and used to determine the levels of corticosteroids (corticosterone, 11-deoxycortisol, and cortisol) and their direct precursors (progesterone and 17α-OH-progesterone) as well as sex steroids (androstenedione, estrone, estrone sulfate, testosterone, and 17β-estradiol) in bovine plasma. The levels of these 10 steroids in recipient cows carrying naturally conceived (control), in vitro fertilized (IVF), or cloned (somatic cell nuclear transfer) conceptuses were compared during late-term pregnancy (30 days before parturition), during near-term pregnancy (1 day before parturition), and on the day of parturition (day 0). Significant differences were observed among the corticosteroid levels: higher levels of corticosterone, 11-deoxycortisol, and cortisol were detected in cloned pregnancies at day 30; lower levels of corticosterone were observed in ART-derived pregnancies at days 1 and 0; and estrone and estradiol levels were higher in IVF pregnancies throughout the final development. These results suggested an upregulation of the P450C11 and P450C21 enzymes 30 days before parturition in somatic cell nuclear transfer pregnancies and an overactivation of the aromatase enzyme in IVF pregnancies. Taken together, the monitoring of multiple steroid hormones revealed that the pregnancies obtained using ART exhibited plasma steroid concentration dynamics compatible with the dysregulation of steroidogenic tissues.