Clinical,ultrasonographic, and endocrinological studies on donkey pregnancy

Although donkey breeding has gained new interest in the past two decades, knowledge about donkey reproduction is still scarce, particularly on jenny pregnancy. The aim of this study was to describe the ultrasonographic and endocrine profiles of the physiological pregnancy in the jenny. The study was performed on 12 pregnancies of 7 Amiata donkeys from Day 10 after ovulation to delivery. Because three pregnancies, respectively at weeks 42, 44, and 45, were considered pathologic and treated pharmacologically, data collected from 2 weeks before diagnosis to the end of pregnancy were removed from the analysis. Average length of the normal pregnancies was 353.4 ± 13.0 days (range, 339–370 days). Timing, dimensions, and development during the first phases of embryonic growth, evaluated using transrectal ultrasound, were similar to that previously described in jennies and mares: first detection of embryonic vesicle was at 11.8 ± 1.3 days of gestation and diameter was 6.5 ± 1.9 mm, loss of spherical shape occurred at 18.5 ± 1.4 days, and embryo and heart beat were first seen at 22.0 ± 1.1 and 25 ± 1.1 days, respectively. The intrauterine growth in the second half of pregnancy, evaluated using the transrectal and transabdominal approach, also showed strong positive correlations, similar to that reported for the mare. The trends of the combined thickness of the utero-placental unit and the echogenicity of the amniotic and allantoic fluids are examples. The diameters (mm) of fetal chest, eye orbit, and aorta increased throughout pregnancy and were 40.6 ± 2.9, 8.7 ± 1.5, and 3.5 ± 0.7, respectively, at week 13, and 190.9 ± 12.0, 21.4 ± 1.5, and 30.6 ± 1.8 at the last evaluation before parturition. In contrast, heart rate decreased as pregnancy progressed. Regression analyses between these parameters and day of gestation were statistically significant (P < 0.001). All fetuses consistently showed some intrauterine activity. Maternal plasma progestagens and estrone sulfate concentrations followed a pattern similar to that seen in mares, although the prepartal progestagen peak was lower in jennies. This study provides a range of ultrasonographic and endocrine values for normal pregnancy in jennies.     

Developmental changes of amino acids in ovine fetal fluids

We recently reported an unusual abundance of arginine (4-6 mM) in porcine allantoic fluid during early gestation. However, it is not known whether such high concentrations of arginine are unique for porcine allantoic fluid or whether they represent an important physiological phenomenon for mammals. The present study was conducted to test the hypothesis that arginine is also the most abundant amino acid in ovine allantoic fluid. Allantoic and amniotic fluids, as well as fetal and maternal plasma samples, were obtained from ewes between Days 30 and 140 of gestation. Glycine was the most abundant amino acid in maternal uterine arterial plasma, representing approximately 25% of total alpha-amino acids. Alanine, glutamine, glycine, plus serine contributed approximately 50% of total alpha-amino acids in fetal plasma. Fetal:maternal plasma ratios for amino acids varied greatly, being less than 1 for glutamate during late gestation, 1.5-3 for most amino acids throughout gestation, and greater than 10 for serine during late gestation. Marked changes were observed in amino acid concentrations in amniotic and allantoic fluids associated with conceptus development. Concentrations of alanine, citrulline, and glutamine in allantoic fluid increased by 20-, 34-, and 18-fold, respectively, between Days 30 and 60 of gestation and were 24.7, 9.7, and 23.5 mM, respectively, on Day 60 of gestation (compared with 0.8 mM arginine). Remarkably, alanine, citrulline, plus glutamine accounted for approximately 80% of total alpha-amino acids in allantoic fluid during early gestation. Serine (16.5 mM) contributed approximately 60% of total alpha-amino acids in allantoic fluid on Day 140 of gestation. These novel findings of the unusual abundance of traditionally classified nonessential amino acids in allantoic fluid raise important questions regarding their roles in ovine conceptus development.     

Presence of the major progesterone-induced proteins of the sheep endometrium in fetal fluids

Allantoic and amniotic fluids were collected on Days 60 (n = 3), 100 (n = 4), and 140 (n = 3) of pregnancy. The presence of uterine milk proteins (UTM-proteins) in these samples was evaluated by Ouchterlony immunodiffusion and enzyme-linked immunoabsorbant assay (ELISA). Eight of ten samples of allantoic fluid and three of ten samples of amniotic fluid produced one or two immunoprecipitin bands against antiserum to UTM-proteins. Each band fused with immunoprecipitin bands from UTM-proteins purified from uterine fluid. Data from a semi-quantitative ELISA indicated that allantoic fluid from all ewes and amniotic fluid from six of ten ewes contained immunoreactive UTM-proteins. Concentrations of UTM-proteins in these fluids were not statistically affected by day of gestation (p greater than 0.10), but tended to decline as gestation advanced. Greater concentrations of UTM-proteins were detected in allantoic fluid than in amniotic fluid (p less than 0.05). The physical characteristics of the immunoreactive material in allantoic and amniotic fluids were examined by polyacrylamide gel electrophoresis and Western blotting. The immunoreactive material was found to possess pIs and molecular weights identical to UTM-proteins. These results indicate that fetal fluids contain material that reacts with antiserum to UTM-proteins and has physical properties similar to UTM-proteins. It is likely, therefore, that the UTM-proteins are transported across the placenta during gestation, perhaps to serve some function in the fetal compartment.     

Suppression of lymphocyte reactivity in vitro by porcine allantoic and amniotic fluids

Porcine allantoic and amniotic fluids from early, mid and late pregnancy were analyzed for protein constituents and ability to suppress phytohemagglutinin (PHA)-induced lymphocyte transformation. All fetal fluids contained alpha-fetoprotein as evaluated by polyacrylamide gel electrophoresis (PAGE), with the highest concentrations appearing in mid-pregnancy amniotic fluids. In addition, allantoic fluids from mid-pregnancy contained proteins assumed to be secreted by the uterus. Both allantoic and amniotic fluids from mid-pregnancy were suppressive to PHA-induced lymphocyte transformation (P<.01). Thus it was concluded that substances, potentially able to suppress the immune response locally, exist within porcine fetal fluids, but it was not determined whether this material is of solely fetal or maternal origin, or a combination.     

Maternal age and parity influence ultrasonographic measurements of fetal growth in Dutch Warmblood mares

Ultrasonographic examination of the equine fetus in mid-late gestation is usually performed only if there are concerns about fetal or maternal health. Even then it is difficult to determine whether development is ‘normal’ for gestational age because the reference values include considerable error margins. This study examined maternal factors that influence fetal growth with the aim of producing more precise late gestation fetal growth curves for Dutch Warmblood horses. Fetal development was monitored at 2-week intervals from day 100 of gestation until term in 32 mares ranging from 4 to 18 years in age; seven of the mares were primiparous. Transrectal and/or transabdominal ultrasonographic measurement of the fetal eye orbit, cranium, aorta, heart rate and of the combined thickness of uterus and placenta (CTUP) were performed using a portable ultrasound machine equipped with 6 MHz linear and 3.5 MHz curved array probes.During days 100–250 of gestation, the CTUP was thicker in primiparous than multiparous mares (p < 0.05). After day 220 the maximum cross-sectional area, but not diameter, of both the eye orbit and cranium were also greater in primiparous than multiparous mares (p < 0.05). Fetal aorta diameter was not influenced by parity but was affected by maternal age, being smaller in mares ≥15 years of age than younger animals (p < 0.05). Only biparietal cross-sectional surface area and aorta diameter increased linearly throughout late gestation. However, even allowing for the effects of parity and maternal age, the late gestational variation in fetal size is such that serial measurements may be required to definitively identify abnormal development.     

The influence of gestational age and onset of labour on determinants of fetal-maternal fluid and electrolyte balance in sheep.

Our aim was to compare the effects of gestational age and the timing of the onset of labour on factors influencing fetal fluid and electrolyte balance and urine production in fetal sheep. We measured the volume and composition of fetal urine and amniotic and allantoic fluids, as well as fetal and maternal plasma composition and micturition episodes in sheep during late gestation until the onset of labour. We found that daily fetal urine production and urethral urine flow per micturition episode increased significantly in relation to the onset of labour but not to gestational age (P < 0.05). In the 2 days preceding the onset of labour fetal urine and amniotic fluid K+ concentrations and urine osmolality increased significantly and the Na+/K+ ratio in allantoic fluid decreased significantly (P < 0.05). There was also a significant fall in fetal arterial SaO2 (P < 0.05) but no significant changes occurred in fetal plasma electrolyte composition, osmolality or AVP concentrations. Fetal plasma cortisol and prolactin concentrations and amniotic and allantoic fluid prolactin concentrations increased significantly and progressively in association with both advancing gestation and the onset of labour whereas maternal plasma prolactin concentrations increased significantly only in the 2 days before the onset of labour (P < 0.05). We conclude that some developmental aspects of fetal fluid and electrolyte balance, including renal function, are more closely related to the timing of parturition than to gestational age per se.     

Ultrasonic evaluation of uterine involution in Bulgarian Murrah buffalo after administration of oxytocin

The aim of this study was to determine the time taken for complete uterine involution in Bulgarian Murrah buffaloes following normal parturition and oxytocin stimulated milking; and to establish the time course of the change in size of the uterine horns, the cervix and caruncles between parturition and involution by means of ultrasonography. There were 17 animals in the study aged 3-6 years and average parity of 2.17 ± 0.18. They were administered 20 IU oxytocin 15 min before each milking. Rectal palpation and transrectal ultrasonography were performed at 3 d intervals from Days 1 to 34 post partum. The involution of the non-gravid and gravid uterine horns, and the cervix was complete by Days 22 and 25 post partum when their diameters were 2.7 ± 0.4 cm, 2.8 ± 0.3 cm and 3.12 ± 0.4 cm, respectively. Caruncles underwent rapid regression until Day 10 post partum. It was not possible to determine the dimensions of the caruncles after that time. The cumulative percentage of animals whose uterus was located in the pelvic cavity increased from 24% at Day 10 post partum to 100% at Day 34 post partum. The combination of rectal palpation and transrectal ultrasonography provided a reliable method of evaluating changes in the uterus over time and determining the time of uterine involution. The present study showed that complete uterine involution, with the uterus located in the pelvic cavity, was achieved by Day 34 after parturition in all 17 Bulgarian Murrah buffaloes treated with oxytocin before milking.     

Conjugated and unconjugated oestrogens in fetal and maternal fluids of the cow throughout pregnancy.

The changes in concentration of oestrone, oestradiol (-17alpha and -17beta), oestrone sulphate and the oestradiol sulphates have been measured in allantoic and amniotic fluids and in maternal peripheral plasma throughout gestation. Oestrone sulphate was the major oestrone present in all of the fluids. It was measurable in allantoic fluid before Day 52 and reached a peak concentration of 475 ng/ml around Day 133. A lower peak occurred in the amniotic fluid around Day 110. The changes in oestradiol sulphates in allantoic fluid were similar to those of oestrone sulphate but at a much lower level. Considerable fluctuation was observed in the oestradiol sulphate concentrations in amniotic fluid. The ratio of oestradiol-17alpha sulphate to oestradiol-17beta sulphate was considerably higher in amniotic fluid than in allantoic fluid. Consistent changes in the levels of oestrone and the oestradiols were found in amniotic fluid but not in allantoic fluid during the second half of pregnancy. In maternal peripheral plasma oestrone sulphate was measurable before Day 72. In the limited number of samples analysed no difference in oestrogen concentration due to the sex of the fetus was evident in any of the fetal or maternal fluids.     

The use of ultrasonography for the study of the bovine reproductive tract. II. Non-pregnant,pregnant and pathological conditions of the uterus

Real time B mode ultrasonography, with a 5 MHz transducer and a linear array scanner, was used to examine the bovine uterus. Approximately 450 dairy cows were examined either on farms or immediately prior to slaughter. Normal and pathological changes of the uterus were noted and a comparison made between ultrasound characteristics, rectal findings and gross examination at slaughter.The normal uterus in estrus, diestrus and pregnancy was found to exhibit characteristic images. These included a distinct folding of the endometrium at the time of estrus; a lack of folding and increased echogenicity at mid-diestrus; slight distension with non-echoic fluid as early as 22 days of gestation; and definitive recognition of the conceptus by day 27 of gestation.In addition, observations were made of the pathological conditions of endometritis, pyometra, mucometra, mummified and macerated fetuses. Generally, images of inflammatory conditions of the uterus were characterized by a distended lumen filled to a varying degree with partially echogenic, ‘snowy’ patches. In conditions involving fetal remnants, the images allowed visualization of the fragments.This study demonstrated that ultrasonography was useful in examining the normal uterus, being particularly helpful in differentiating questionable palpation results when uterine pathology was present.     

Early pregnancy diagnosis and embryonic and fetal development using real time B mode ultrasound in goats

Real time B mode ultrasound scanning was used for the diagnosis of early pregnancy and monitoring of embryonic and fetal development in goats. Estrus in 8 cyclic cross-bred does was synchronized using a single injection of PGF2α followed by mating with a buck. All the does were subjected to weekly transrectal (from day 14 of mating) and transabdominal ultrasonography (from day 28) up to the 4th month of gestation and once during the 5th month of gestation. Of the 8 animals, 6 does were confirmed pregnant. The embryonic vesicle was detected on day 21 and day 28 and the embryo proper on day 28, day 35 using the transrectal and transabdominal methods, respectively. Heart beat was observed as early as day 21 of gestation and it was recordable by day 28 using the transrectal approach. However, via transabdominal scanning the detection and recording of the heart beat was possible only on day 35 of gestation. Singles and twins were differentiated on day 35 and day 42 by the transrectal and transabdominal approaches, respectively. Placentomes as a circular ‘C’ shape structure was detectable on day 42 with an average diameter of 0.97 cm, using the rectal probe. Using the abdominal probe, placentomes were detectable on day 50 (average diameter of 1 cm of gestation). Skeletal structures such as the skull, rib cage and vertebral column were first viewed on day 56 in both approaches. A significant (P < 0.001) high correlation (r = 0.99) was recorded between the gestational age and head, thoracic and placentome parameters. It may concluded that the earliest identification of an embryonic vesicle (day 21) by transrectal scanning and confirmation of its viability by fetal heart beat (day 28) were the most reliable ultrasonographic features for early pregnancy diagnosis in goats. Transabdominal ultrasonographic measurements of placentome, head and thoracic diameter may be of use in the assessment of fetal age.     

Early pregnancy diagnosis and embryonic and fetal development using real time B mode ultrasound in goats

Real time B mode ultrasound scanning was used for the diagnosis of early pregnancy and monitoring of embryonic and fetal development in goats. Estrus in 8 cyclic cross-bred does was synchronized using a single injection of PGF2α followed by mating with a buck. All the does were subjected to weekly transrectal (from day 14 of mating) and transabdominal ultrasonography (from day 28) up to the 4th month of gestation and once during the 5th month of gestation. Of the 8 animals, 6 does were confirmed pregnant. The embryonic vesicle was detected on day 21 and day 28 and the embryo proper on day 28, day 35 using the transrectal and transabdominal methods, respectively. Heart beat was observed as early as day 21 of gestation and it was recordable by day 28 using the transrectal approach. However, via transabdominal scanning the detection and recording of the heart beat was possible only on day 35 of gestation. Singles and twins were differentiated on day 35 and day 42 by the transrectal and transabdominal approaches, respectively. Placentomes as a circular ‘C’ shape structure was detectable on day 42 with an average diameter of 0.97 cm, using the rectal probe. Using the abdominal probe, placentomes were detectable on day 50 (average diameter of 1 cm of gestation). Skeletal structures such as the skull, rib cage and vertebral column were first viewed on day 56 in both approaches. A significant (P < 0.001) high correlation (r = 0.99) was recorded between the gestational age and head, thoracic and placentome parameters. It may concluded that the earliest identification of an embryonic vesicle (day 21) by transrectal scanning and confirmation of its viability by fetal heart beat (day 28) were the most reliable ultrasonographic features for early pregnancy diagnosis in goats. Transabdominal ultrasonographic measurements of placentome, head and thoracic diameter may be of use in the assessment of fetal age.     

Dynamics of activities of matrix metalloproteinases-9 and -2, and the tissue inhibitors of MMPs in fetal fluid compartments during gestation and at parturition in the mare

During late gestation in the mare, rapid fetal growth is accompanied by considerable placental growth and further invasion of the endometrium by microvilli. This growth requires extensive remodeling of the extracellular matrix (ECM). In early pregnancy, we know that matrix metalloproteinase (MMP)-9 and -2 are involved in the endometrial invasion during endometrial cup formation. The present study investigated whether MMPs are found in fetal fluids later in gestation and during parturition, and if there was a difference in their activities between normal and preterm delivery. Amniotic fluids were collected from pony mares during the latter half of gestation, and amniotic and allantoic fluids from pony and thoroughbred mares at foaling. The fluids were analysed for the activity of MMP-9 and -2, and TIMPs using zymography techniques. There was an increase (P = 0.002) in activity of latent MMP-9 when approaching normal foaling, and a decrease (P < 0.001) during foaling. MMP-2 activity did not change through gestation, or during foaling. When comparing samples from pregnancies resulting in preterm deliveries with samples from foaling mares, the activity of MMP-9 was lower (P < 0.001) and MMP-2 activity was higher (P = 0.004) during foaling than preceding preterm delivery. The activity of MMP-9 was lower (P = 0.002) prior to preterm delivery than before delivery of a live foal at term, whereas no difference (P = 0.07) was demonstrated for latent MMP-2 activity when comparing the same groups. The activity of TIMP-2 was higher (P < 0.001) in the pre-parturient period before normal foaling than preceding preterm delivery. These results suggest that MMPs may have a role as markers for high risk pregnancy in the mare.     

The origin and fate of hyaluronan in amniotic fluid

The mechanisms which regulate the steady-state concentration and molecular weight of hyaluronan in the amniotic fluid of sheep at different gestational ages have been investigated. An attempt to trace the origin of the polysaccharide has been made by analyses of various fetal fluids (amniotic fluid, allantoic fluid, tracheal fluid, urine, and serum). The fate has been studied by injection of radioactively labelled hyaluronan into the amniotic cavity and following the tracer in fetal tissues and fluids. The concentration of hyaluronan in amniotic fluid varies considerably but is in the order of 5 mg/l at mid-pregnancy and decreases to 1 mg/l in late pregnancy. The polysaccharide has a Mr-distribution with a weight-average in the order of 10(6) at 10 to 13 weeks of gestation which decreases to 10(5) closer to term. Calculations show that urine contributes 0.1 and 0.5 mg of low-molecular (Mr = 10(4) hyaluronan per day in mid- and late pregnancy, respectively, and the lung 10-20% of that amount in the form of high-molecular weight polymer (Mr greater than 10(6). The hyaluronan disappears from the amniotic cavity by bulk flow due to fetal swallowing. It is taken up and degraded in the fetal intestine. Molecules of Mr = 10(3) can pass the intestinal barrier. Calculations show that about 0.5 mg and 1.0 mg of hyaluronan is eliminated per day from the amniotic fluid at 12 and 17 weeks of gestation, respectively. Thus, the higher rate of elimination and the relatively high urinary contribution in more mature fetuses explain the low concentration and Mr of amniotic hyaluronan in late gestation, whereas a slower elimination combined with a relatively larger contribution of high molecular weight hyaluronan both from lung and urine and possibly from other sources are responsible for the higher concentration and Mr of the compound in early pregnancy.     

Evaluation of false transrectal ultrasonographic pregnancy diagnoses in sheep by measuring the plasma level of pregnancy-associated glycoproteins

The present study was undertaken to investigate to what extent pregnancy diagnoses made by transrectal ultrasonography could be confirmed by measurements of plasma concentration of ovine pregnancy-associated glycoproteins (ovPAG). A total of 424 Awassi x Merino ewes were synchronized for estrus and examined by transrectal ultrasonography. In Experiment 1, the ewes (n = 156) were repeatedly scanned in a standing position on d 29, 36 and 50 of gestation. Similarly, the ewes (n = 268) in Experiment 2 were scanned on d 24, 29 and 34 of gestation, but these ewes were fasted for 12 h prior to the examination and the abdominal wall of each animal was lifted up by the hands of the assistant during the scanning. Blood samples were withdrawn after each transrectal ultrasonographic examination in both experiments. Ovine PAG concentrations were measured in plasma by a heterologous radioimmunoassay and the cut-off value for pregnancy was > or = 1 ng.mL-1. Based on the lambing performance, in Experiment 1, altogether 47 false negative and 38 false positive diagnoses were made by transrectal ultrasonography in 24 and 33 ewes, respectively between d 29 and 50 of gestation. In Experiment 2, altogether 8 false negative and 13 false positive diagnoses both were made in 7 ewes between d 24 and 34 of gestation. In both experiments, all ewes with false negative diagnoses had ovPAG concentrations higher than the threshold level for pregnancy diagnosis and all ewes with false positive diagnoses had ovPAG concentrations lower than the threshold of pregnancy. Furthermore, by the PAG-RIA test all lambed or aborted ewes (n = 63) were correctly diagnosed as pregnant and with three exceptions, all non-lambed ewes (n = 361) were correctly diagnosed as non-pregnant during the examined periods of both experiments.     

Real-time ultrasonography for determining pregnancy status and viable fetal numbers in ewes

The reproductive tracts of 26 estrus synchronized, bred ewes were scanned with a portable 5.0 MHz real-time ultrasound unit within 1 to 6 d postbreeding. Intrarectal scanning was performed on alternate days until Days 28 to 30 and twice weekly until Days 50 of gestation. Transabdominal uterine scans were conducted twice weekly from Days 25 to 65 and continued weekly until parturition. A total of 24 ewes (92%) became pregnant. A nonpregnant ewe was recognized 100% of the time by both methods of ultrasonic screening. Correct identification of a gravid ewe as pregnant was 100% from Days 51 to 150 of gestation using transabdominal real-time ultrasonography. There was a significant association (P < 0.005) between the number of lambs born and the number of fetuses observed using transabdominal real-time ultrasonography after Day 25 of gestation. Accurate differentiation of fetal numbers by transabdominal scanning was 100.0% for ewes carrying one lamb and 97.3% for ewes carrying two lambs at Days 51 to 75 of gestation. Fetal attrition was documented in one ewe at Day 49 of gestation. Hydrops allantois was diagnosed in another ewe at 110 d of gestation. A total of 37 lambs were born to 23 ewes in the project flock. No congenital abnormalities were noted in any of the lambs. Transabdominal real-time ultrasonography is a safe, rapid, accurate and practical method for assessing pregnancy status, fetal number and fetal viability in sheep.     

The effect of chlamydial infection on the initiation of premature labour: serial measurements of intrauterine prostaglandin E2 in amniotic fluid, allantoic fluid and utero-ovarian vein, using catheterised sheep experimentally infected with an ovine abortion strain of Chlamydia psittaci

The initiation of premature labour by an ovine abortion strain of Chlamydia psittaci was studied in relation to Prostaglandin E2 (PGE2), which plays a major role in parturition. The local intrauterine concentration of PGE2 was monitored after experimental infection with C. psittaci, during late gestation, using a catheterised sheep model. Indwelling catheters were implanted into the amniotic and allantoic cavities of six control sheep, and into six sheep infected with an ovine abortion of C. psittaci. The release of PGE2 into the utero-ovarian vein of these sheep was also monitored. Infection with C. psittaci was associated with a premature rise in PGE2 in the amniotic fluid between days 122 and 135 of gestation (P less than 0.01). A premature increase in PGE2 was defected between days 127 and 136 of gestation (P less than 0.05) in the allantoic fluid of sheep infected with C. psittaci, but not in the control uninfected sheep. Chlamydial infection significantly decreased the secretion of PGE2 into the utero-ovarian vein. The mean concentration of PGE2 in the utero-ovarian vein of infected sheep was 68.8 +/- 5.2% of the PGE2 concentration of control sheep between days 122 to 141 of gestation (P less than 0.01). The release of PGE2 into the utero-ovarian vein increased between days 126 to 136 of gestation in infected and control sheep (P less than 0.01). The results from the catheterised sheep model indicated that C. psittaci infection is associated with a local intrauterine release of PGE2. The magnitude of this release was similar to the PGE2 release in control sheep prior to parturition.(ABSTRACT TRUNCATED AT 250 WORDS)     

Hormonal and physical changes associated with bovine conceptus development.

Conceptus (placental membranes, fetal fluids and fetus) development was characterized between Days 27 and 111 of gestation. Progestagens, oestrone, oestradiol, oestrone sulphate and prostaglandins (PG) F were measured in maternal plasma and allantoic and amniotic fluids. Protein concentrations are described for fetal fluids. The early increase in placental membrane weight from 1.12 g (27 days) to 58.45 g (50 days) was associated with oestrogen production presumably of conceptus origin. Oestrogens increased significantly in allantoic and amniotic fluids throughout the period studied with oestrone being the primary free oestrogen, rising from 2 pg/ml (Day 33) to 144 ng/ml by 111 days in allantoic fluid. Changes in plasma oestrogens of the maternal circulation were not detected until after Day 70 at which time oestrone concentration was greater than that of oestradiol. Fetal fluid concentrations of progestagens, oestrone sulphate and PGF were not related to maternal plasma levels and a sequestration of these hormones by the allantois is postulated.     

Perturbations in the biochemical composition of fetal fluids are apparent in surviving bovine somatic cell nuclear transfer pregnancies in the first half of gestation

Amniotic and allantoic fluid volumes and composition change dynamically throughout gestation. Cattle that are pregnant with somatic cell nuclear transfer (NT) fetuses show a high incidence of abnormal fluid accumulation (particularly hydrallantois) and fetal mortality from approximately midgestation. To investigate fetal fluid homeostasis in these pregnancies, Na, K, Cl, urea, creatinine, Ca, Mg, total PO(4), glucose, fructose, lactate, total protein, and osmolalities were measured in amniotic and allantoic fluids collected at Days 50, 100, and 150 of gestation from NT pregnancies and those generated by the transfer of in vitro-produced embryos or by artificial insemination. Deviations in fetal fluid composition between NT and control pregnancies were apparent after placental and fetal organ development, even when no gross morphological abnormalities were observed. Individual NT fetuses were affected to varying degrees. Elevated allantoic Na was associated with lower K and increased allantoic fluid volume or edema of the fetal membranes. Total PO(4) levels in NT allantoic and amniotic fluid were elevated at Days 100 and 150. This was not accompanied by hypophosphatemia at Day 150, suggesting that PO(4) acquisition by NT fetuses was adequate but that its readsorption by the kidneys may be impaired. Excessive NT placental weight was associated with low allantoic glucose and fructose as well as high lactate levels. However, the fructogenic ability of the NT placenta appeared to be normal. The osmolality of the fetal fluids was maintained within a narrow range, suggesting that the regulation of fluid composition, but not osmolality, was impaired in NT pregnancies.     

Biochemical characteristics of amniotic and allantoic fluid in late gestational mares

The purpose of this study was to determine certain clinically important parameters of amniotic and allantoic fluid. Amniocentesis was performed on 10 normal mares in late gestation (323.8±10.2 d) and fluid was collected from both amniotic and allantoic cavities. Compared to amniotic fluid, allantoic fluid had significantly higher values of specific gravity, sorbitol dehydrogenase, total bilirubin, gamma glutamyltransferase, creatinine, phosphorus, total protein, and globulin. However, allantoic fluid had significantly lower values for sodium, chloride and alkaline phosphatase than amniotic fluid.