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Biomedical subjects

M A Taverne

Publications and source records attributed to M A Taverne.

At least 37 records · Page 2Linked to original sources
PubMed1997

Induction of hydrometra in goats by means of active immunization against prostaglandin F2 alpha.

Hydrometra is a pathological condition of the uterus which is characterized by accumulation of aseptic fluid in the presence of a persistent corpus luteum. It forms a major cause of subfertility in goats. Active immunization against prostaglandin F2 alpha (PGF2 alpha), the luteolytic hormone in this species, was used to explore the possibility for artificial induction of this pseudopregnant condition. During the breeding season, 11 goats (group I) were immunized with 5 mg PGF2 alpha-ovalbumin conjugate in Freund's complete adjuvant, 4 goats were control-immunized (group CI) and 5 goats remained untreated (group C). Jugular blood samples were taken twice a week (monday and thursday) for measurements of plasma progesterone and binding of 3HPGF2 alpha. In conjunction with blood sampling, transcutaneous ultrasonographic examination of the uterus took place to detect the presence of fluid in the uterus. Before and immediately after immunization, the mean (+/-SD) duration of luteal phases (progesterone concentrations > or = 1 ng ml-1) was 16.7 +/- 1.6 (n = 39), 17.8 +/- 1.3 (n = 23) and 16.9 +/- 1.1 (n = 18) days in animals of group I, CI and C respectively. Ten goats of group I developed an antibody titre. Persistence of luteal function (mean duration +/-SD: 150.3 +/- 23.5 days) occurred in 6 of these animals and in 1 goat of group CI. Accumulation of fluid in the uterus in group I was first observed between day 31 and 38 of the prolonged luteal phase. Discharge of uterine fluid occurred as soon as the plasma progesterone concentration reached a level lower than 0.5 ng ml-1. It is concluded that immunization against PGF2 alpha is an effective method to induce pseudopregnancy in goats, providing a model for studies on luteal maintenance and uterine function in the absence of a conceptus.

Animals↗
PubMed1997

Noninvasive monitoring of fetal heart rate during the last ten days of gestation in sows.

OBJECTIVE: To develop and evaluate a noninvasive technique for monitoring and analyzing porcine fetal heart rate (FHR) during late gestation. ANIMALS: 8 fetuses of 8 pluriparous sows in late gestation. PROCEDURE: With the sow positioned in lateral recumbency, the most caudal fetus was identified, using real time ultrasonography, and its heart rate was recorded for 60 minutes by use of Doppler cardiography. The same fetus was identified and monitored repeatedly during the last 10 days of gestation, excluding the 24 hours before delivery. Visual inspection and computerized analysis of the recordings were performed. RESULTS: 66 one-hour recordings were obtained from 8 fetuses, 1 in each of 8 sows. Mean signal loss was 37.5%. Episodes of low FHR and low FHR variation (FHR pattern A) alternated with episodes of high FHR and high FHR variation (FHR pattern B). This cyclic alternation between 2 distinct. FHR patterns was observed in 46 of 66 (69.7%) recordings, and suggests the presence of different behavioral states in fetal pigs. Basal FHR decreased toward parturition in 7 fetuses, but increased in 1 fetus with abdominal ascites. Basal FHR and long-term FHR variation were negatively correlated (r[S] = -0.73; P < 0.001). CONCLUSION: Noninvasive monitoring of FHR is possible and feasible during late gestation in pigs. This method permits longitudinal studies under pathophysiologic conditions and the evaluation of the effects of endogenous and exogenous influences on porcine FHR.

Animals↗
PubMed1996

Characteristics of fetal heart rate changes during the expulsive stage of bovine parturition in relation to fetal outcome.

OBJECTIVE: To characterize fetal heart rate (FHR) patterns of nonacidotic (N-AC) and acidotic (AC) calves during the expulsive stage of parturition. ANIMALS: 32 calves born to heifers, either unassisted or by moderate traction. PROCEDURE: Cardiotocograms (CTG) evaluated qualitatively (visual) and quantitatively by a moving window technique (width 10, shift 5 minutes) for baseline FHR, variability, and periodic alterations (accelerations and decelerations). RESULTS: Significant differences were apparent between increase in baseline FHR of N-AC and AC calves; change in FHR (delta-FHR), taking into account individual FHR, is a more discriminating parameter. The predominant reaction to uterine contraction is a decrease in FHR; variable decelerations were the most common type in both groups, and late decelerations were seen only in AC calves. Additional characteristics of variable decelerations were more frequently seen in AC calves. CONCLUSIONS: CTG parameters during expulsion can discriminate between AC and N-AC calves, but specific characteristics are not exclusively restricted to AC or N-AC calves. CLINICAL RELEVANCE: CTG recordings during bovine parturition in cattle provide information on the fetal condition and can be used in the future to study the effects of medication and manipulations to the fetus.

Acidosis↗
PubMed1995

Serum prolactin concentration in pseudopregnant and normally reproducing goats.

Previous experiments with bromocriptine suggested that prolactin plays a role in the aetiology of pseudopregnancy in goats. Serum prolactin concentration was measured in a herd of white Dutch dairy (Saanen) goats when hydrometra (a typical characteristic of pseudopregnancy) was diagnosed by ultrasound, during the spontaneous development of pseudopregnancy, and in normally reproducing goats during the breeding season. In the normally reproducing does the prolactin concentration decreased at the beginning of the breeding season. In 12 of 14 pseudopregnant goats the prolactin concentration was within the range observed in the normally reproducing goats on the day that hydrometra was diagnosed. In two goats the prolactin concentration was low during the first few weeks of pseudopregnancy and in a third it fluctuated. There was no correlation found between the concentration of prolactin and the development or the presence of a persistent corpus luteum. These results suggest that prolactin does not play a crucial role in the aetiology of pseudopregnancy in the goat.

Anestrus↗
PubMed1995

Serum amyloid-A (SAA) and haptoglobin (Hp) plasma concentrations in newborn calves.

The concentrations of 2 major bovine acute-phase proteins, haptoglobin (Hp) and serum amyloid-A (SAA), were measured in plasma obtained shortly after birth from 22 healthy calves. In a separate group of diseased calves (n = 8), Hp and SAA concentrations were measured to determine whether newborn calves (up to 4 d old) are able to produce SAA and Hp. In blood samples taken directly after birth, the Hp plasma concentrations were all below the limit of detection. The mean SAA concentration was independent of weight (r = 0.063), degree of acidosis (r = -0.125), sex (p > 0.05), and were not different in calves born after different types of obstetrical help (p > 0.05). In the group of diseased calves, an increased Hp concentration was measured in only 2 of 8 animals, whereas the mean SAA concentration was significantly higher (p < 0.05) than in the healthy newborn calves. These data suggest that prenatal stress due to parturition does not form a stimulus for the production of acute-phase proteins in the fetal calf. The low Hp plasma concentrations might indicate that either it takes a few days to establish a detectable concentration of this protein, or that Hp production is not fully developed in newborn calves.

Journal Article↗
PubMed1995

Effect of uterus position relative to the pelvic inlet on the accuracy of early bovine pregnancy diagnosis by means of ultrasonography.

A 5-MHz sector transducer (experiment 1) and a 7.5 MHz linear-array transducer (experiment 2) were used for early pregnancy diagnosis in two Hungarian dairy herds under field conditions. In the first experiment, ultrasound scanning was conducted three times at 3 or 4-day intervals between 24 and 33 days after artificial insemination (AI), while in the second experiment, it was performed two times at 7-day intervals between 27 and 38 days post-insemination. Significantly more incorrect non-pregnancy diagnoses were made between 24 and 33 days (first experiment) and between 27 and 38 days (second experiment) after AI in cows in which the uterus was located far cranial to the pelvic inlet than in animals in which the uterus was located within or close to the pelvic inlet at the first ultrasonographic examination.

Animals↗
PubMed1994

The interval between birth and sternal recumbency as an objective measure of the vitality of newborn calves.

The time from birth to attaining sternal recumbency (T-SR) was recorded for 219 newborn calves in order to evaluate its use as a parameter for diagnosing vitality. Calves were defined as vital if they received routine care without medical treatment and survived seven days from birth without any symptom of illness (n = 192). Those which did not fulfil these conditions were categorised as non-vital (n = 27). Ten calves were born spontaneously and the others were delivered either by caesarean section (n = 105), normal extraction (n = 78) or forced extraction (n = 26). The mean (+/- sd) T-SR values of the vital calves in these delivery groups were: 4.0 +/- 2.2, 4.5 +/- 3.1, 5.4 +/- 3.3 and 9.0 +/- 3.3 minutes, respectively. Jugular blood gas and pH measurements were performed at several fixed times after birth until pH and base excess had reached values of over 7.2 and more than -5.0 mmol/litre, respectively. Mean pH and base excess values of vital calves 10 minutes post partum were significantly higher and lower, respectively, than those of non-vital calves. Forcefully extracted calves had longer T-SR, more serious acidosis, recovered more slowly from acidosis, died more, and exhibited trauma more frequently. A T-SR of at least 15 minutes had a predictive value of 84 per cent for non-vitality, while 10 minute pH values of less than 6.9 had a lower predictive value, namely 68 per cent, for non-vitality. Correlations between T-SR values and 10 minute pH and base excess values were moderate, whereas correlations between T-SR values and PCO2 values were weaker still and much more dependent on the type of delivery. It is concluded that T-SR determination is a valuable, practicable and objective diagnostic tool for estimating the condition of newborn calves during the first 15 minutes of life. The diagnostic value of a single pH measurement on the jugular blood of a neonatal calf is doubtful.

Acidosis↗
PubMed1994

Evaluation of transvaginal ultrasound-guided follicle puncture to collect oocytes and follicular fluids at consecutive times relative to the preovulatory LH surge in eCG/PG-treated cows.

Holstein-Friesian cows (n=56) were synchronized with Syncro-Mate B, and those cows (n=47) developing a normal progesterone pattern were further treated im with 3,000 I.U. eCG at Day 10 and 22.5 mg PGF2alpha 48 h later. Blood samples were collected every hour from 30 until 49 h after PG administration. Cows (n=17, 36.2%) with fewer than 8 follicles larger than 8 mm in diameter at 28 to 30 h after PG treatment and animals without an LH peak (n=7, 23%) were excluded from the study. Transvaginal ultrasound-guided puncture of the follicles was carried out two times per cow, at 30 h after PG injection (4 to 5 follicles) and again at 1 to 5 (n=6), 12 (n=8) or 22 h (n=9) after the LH peak. No differences in the concentrations of progesterone and LH were observed among the 3 groups. An average of 18 follicles per cow was punctured (total of 415 punctures, n=23); 116 cumulus-oocyte-complexes and 370 follicular fluid samples were obtained producing average recovery rates of 28.0% and 89.2%. The number of cumulus-oocyte-complexes varied between puncture times; shortly before ovulation, at 22 h after the LH peak, the recovery rate was significantly 5 times higher than immediately after the LH peak. Overall, in 75 punctures the cumulus-oocyte-complex was accompanied by a pure follicular fluid sample (3.3 per cow). In conclusion, the transvaginal ultrasound-guided puncture of preovulatory-size follicles can be used to collect follicular fluids to study changes in the microenvironment of maturing oocytes upon superovulation. However, further research is required in order to obtain an equivalent number of accompanying cumulus-oocyte-complexes.

Journal Article↗
PubMed1994

15-Hydroxy-prostaglandin dehydrogenase activity in uterine tissues of late gestational and parturient cows.

15-Hydroxy-prostaglandin dehydrogenase activity (PGDH) was measured in endometrium, allanto-chorion, allanto-amnion and the placenta from six cows during late gestation and six parturient cows during caesarean section. Under saturated substrate conditions PGDH activity was lower than 138 pmol g wet tissue-1 min-1 in all uterine tissues in both groups. Human placental reference samples showed a PGDH activity of 16,800 +/- 1200 pmol per g wet weight min-1 (n = 4). Under subsaturational conditions enzyme activity was demonstrated in endometrium and both fetal membranes. These results indicate that PGF2 alpha catabolism in bovine uterine tissue on day 262 and during parturition, contributes little to changing plasma PGFM concentrations.

Allantois↗
PubMed1994

Ultrasonography of the uterus of the goat.

The use of a transabdominal or a transrectal scanning technique to visualize the uterus in goats is discussed. The results of sonographic imaging of normal (non-pregnant, pregnant, postpartum) and abnormal (endometritis, hydrometra, fetal death) uterine structures are reviewed. In the goat, special attention must be paid to distinguishing between the sonographic image of hydrometra and early pregnancy. A case of hydrometra that developed in the presence of three dead fetuses is reported. It is concluded that, under field conditions, transabdominal scanning of goats, performed between days 40 and 70 after mating, yields information about pregnancy, fetal viability, and single or multiple pregnancy, while at the same time making possible a reliable differential diagnosis of pregnancy and hydrometra.

Animals↗
PubMed1994

Feasibility of continuous recording of fetal heart rate in the near term bovine fetus by means of transabdominal Doppler.

A transabdominal Doppler technique for the recording of fetal heart rate (FHR) was investigated in the bovine fetus. During the last 2 weeks of gestation recordings were made once or twice per week in eight cows by placing a 1.5 MHz Doppler transducer on the right ventral abdominal wall. Continuous FHR recordings with a duration of more than 30 min were obtained in 29 of the 35 sessions. Major displacements of the fetus were the main cause of recording failure. The overall mean baseline FHR was 105 +/- 1.5 bpm with a range of 90 to 125 bpm. The mean bandwidth of the baseline FHR was 10.8 +/- 0.7 bpm with a range of < 5 to 20 bpm. Periods with different bandwidths alternated. The alternation of bovine FHR patterns pointed to the existence of different fetal behavioural states. The mean number of accelerations of FHR was 7.1 +/- 1.0 per hour. Many of the accelerations coincided with visible or perceptible fetal body movements. Decelerations of FHR occurred less frequently (range 0 to 4 per h). A period of tachycardia accompanied by an increased number of fetal movements occurred in 3 of the 29 FHR recordings. This non-invasive technique appears to be suitable to study FHR patterns during gestation and to investigate the presence and characteristics of behavioural states in the bovine fetus. It also provides the possibility to study effects on the fetus of drugs administered to the dam.

Abdomen↗
PubMed1993

Relationship between prostaglandin-induced luteolysis and temporary inhibition of myometrial activity in late pregnant cows with ear implants containing progestagen.

The influence of luteolysis on myometrial activity in late pregnant cows was studied by measuring electromyographic (EMG) activity and concentrations of progesterone and 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) in maternal arterial plasma of five cows. Application of two ear implants containing progestagen at day 261 of gestation was followed by an injection of a luteolytic dose of a prostaglandin F2 alpha (PGF2 alpha) analogue (PG) on day 264. Calving was initiated by removal of the implants and a single injection of 5 mg flumethasone on day 270. All calves were born alive at a mean interval of 36 h. After 4 h of hyperactivity immediately following the injection of PG, myometrial activity was almost completely absent for 20 h; before luteolysis the total duration of EMG activity was 7.21 +/- 0.31 min h-1 (mean +/- SEM), during the 4 h after PG 23.61 +/- 3.40 min h-1, and during inhibition 2.70 +/- 0.87 min h-1. After the last period, EMG activity recurred and reached values of 14.52 +/- 3.07 and 11.17 +/- 2.87 min h-1, on days 265 and 269, respectively. Concentrations of progesterone in maternal plasma decreased from 4.17 to 1.14 ng ml-1 within 12 h after PG, whereas concentrations of PGFM in plasma remained low, varying from 15 to 30 pg ml-1. After removal of the implants and injection of flumethasone on day 270, EMG activity increased without an inhibitory phase and reached maximum values around the time of expulsion of the calves.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Peripartum acute-phase protein serum amyloid-A concentration in plasma of cows and fetuses.

Concentration of the acute-phase protein serum amyloid-A (SAA) was measured by means of an indirect ELISA method, in plasma of 3 pregnant cows and in plasma taken by cannula from another 4 pregnant cows and, by separate cannula, from their fetuses. Blood samples were taken daily from approximately 72 hours before until 72 hours after parturition. After parturition, SAA concentration increased significantly (P < 0.05) in maternal plasma. In fetal plasma, only a nonsignificant increase was found at time of delivery. The concentration of maternal SAA started to increase within the first 24 hours after delivery, reaching a peak value between 24 and 48 hours after delivery. In the aforementioned plasma samples from the 4 pregnant cows and their fetuses, the concentration of maternally derived cortisol increased nonsignificantly after parturition. The concentration of fetally derived cortisol was significantly (P < 0.05) increased at parturition (t = 0), compared with the initial fetal cortisol concentration at 120 hours before delivery. Peripartum concentration of maternal SAA increased and maternal cortisol remained low, whereas fetal SAA concentration remained low and fetal cortisol concentration increased. These findings indicate possible suppressive action of fetal cortisol on fetal SAA production. However, it might be argued that the main cause of the difference in SAA concentration is the difference in tissue damage between cows and fetuses at parturition.

Acute-Phase Proteins↗