The use of ultrasonography for pregnancy diagnosis in the bitch

Twenty-three Greyhound bitches housed at 3 breeding kennels were examined for pregnancy via transabdominal palpation and ultrasonography. Pregnancy was timed from the calculated day of ovulation (day of ovulation = day when first pup was whelped--63), and from a single breeding date (day 0). Starting on day 10 after ovulation, 9 bitches were monitored every 3 days by ultrasonography only, to determine gestational vesicle sizes during gestation and the time when fetal movements and heartbeats could be first detected. The other 14 bitches were examined by ultrasonography and transabdominal palpation on the same day every week, starting on postovulation day 19, to compare the effectiveness of the 2 methods of pregnancy determination. Parturition was the final determinant of pregnancy status. The earliest correct diagnosis of pregnancy was at 18 days after ovulation, but fetal movements and heartbeat could not be identified until days 28 and 35, respectively. Estimation of fetal numbers by ultrasound or palpation was not reliable when there were more than four in the litter. Pregnancy and nonpregnancy were correctly determined by both methods in an increasingly greater number of bitches as gestation progressed, but ultrasonography was more accurate at all stages; on days 19 to 22, 26 to 30, 34 to 38, and greater than 40 after ovulation, correct diagnoses were made in 33%, 42%, 50%, and 75% of the bitches by palpation and in 42%, 67%, 75%, and 83% of the bitches by ultrasonography. The most common error was failure to detect pregnancy by palpation or ultrasonography in bitches with small litters and tense abdominal muscles.(ABSTRACT TRUNCATED AT 250 WORDS)     

Transabdominal Ultrasonography for Pregnancy Diagnosis and Estimation of Gestational Age in Dromedary Camels

The objective of this study was to evaluate the use of transabdominal ultrasonography as a method for pregnancy diagnosis and establish some foetal biometrics guidelines of pregnancy staging. Transabdominal ultrasonography was performed weekly on six pregnant camels from the 4th to the 19th week and at 2‐week intervals from the 20th to the 52nd week of gestation. Six areas were selected for examination: caudal abdominal (CAA), inside the thigh, above the base of the udder; middle abdominal (MIA), from the base of the udder to the umbilicus; and cranial abdominal (CRA), from the umbilicus to the xiphoid cartilage. Several foetal parameters including orbital diameter (ORD), biparietal diameter (BPD), abdominal diameter (ABD), chest depth (CHD) and ruminal diameter (RUD) were measured using standardized scan plans. The relationships between the gestational age and the foetal parameters were evaluated. From the 6th to the 12th week, the conceptus was always observed through the left CAA approach. Between the 13th and 27th week, the foetus was entirely visualized by the MIA examination. From the 28th to the 52nd week, the conceptus was mainly detected through the left CRA approach. The foetal parameters were measured frequently during mid‐ and late gestation. All regression and correlation coefficients were highly significant (p < 0.0001). In conclusion, transabdominal ultrasonography was shown to be a reliable technique for pregnancy diagnosis and estimation of gestational age in dromedary camels.     

Accuracy of early fetal sex determination by ultrasonic assessment in goats

The objective of this study was to determine the accuracy of early fetal sex determination by ultrasonic assessment of the relative location of the genital tubercle (GT) in goats at different stages of pregnancy as well as by the identification of fetal external genitalia. Pregnant animals were divided into three experimental groups (EI: n=21, EII: n=28, EIII: n=33). In EI, fetuses (n=27) were transrectally monitored daily from days 40 to 60 of pregnancy with a linear transducer (6.0 and 8.0MHz). In EII, fetuses (n=40) were examined once between days 45 and 70 of pregnancy by transrectal ultrasonography. In EIII fetuses (n=52) between days 100 and 120 of pregnancy, were submitted to a single transabdominal ultrasonography using a convex transducer (5.0 and 7.5MHz). Regardless of fetal sex diagnosis, 15/15 (EI), 13/16 (EII) and 9/14 (EIII) of single pregnancies and 10/12 (EI), 20/24 (EII) and 21/38 (EIII) of twin pregnancies were correctly identified. The accuracy of sex identification among EI (92.6%), EII (82.5%) and EIII (57.7%) was not statistically different (P>0.05). Identification of the GT in male fetuses was possible from day 45 onward. Changes in the GT position were not observed between days 53 and 60 of pregnancy. Accuracy of fetal sexing under field conditions is high in goats when ultrasound imaging is properly timed during pregnancy and when it is performed with proper equipment by experienced operators.     

Doppler evaluation of maternal and fetal vessels during normal gestation in the bitch

The aim of this work is to evaluate the haemodynamic characteristics of maternal and fetal vessels during normal pregnancy in bitches, using Colour and Pulsed wave Doppler ultrasonography, in order to obtain more information about maternal and fetal circulation. The blood waveforms of the uteroplacental arteries, aorta, caudal cava vein and umbilical cord of the fetuses were recorded weekly in 16 pregnant bitches. Also, the measurements of Peak Systolic, End Diastolic Velocities, Resistance and Pulsatility Indices were carried out. Uteroplacental blood flow was biphasic while the ones of the umbilical artery and aorta were first systolic and then diastolic. The cava showed a typical waveform of venous vessels. During gestation the EDV and PSV of fetal vessels increased (alpha<0.05) while the PI and RI of all vessels examined decreased (alpha<0.05) except for the IP of the Aorta. The Doppler ultrasonography was used to study the characteristics of maternal and fetal vessel flow and their progressive changes during pregnancy. This study can be considered a further contribution in diagnosing and monitoring high-risk pregnancies in Veterinary Medicine.     

Practical use of a combination of a dopamine agonist and a synthetic prostaglandin analogue to terminate unwanted pregnancy in dogs

The combination of a dopamine agonist, caber-goline, and a synthetic analogue of prostaglandin F_2a, cloprostenol, was used to induce termination of pregnancy from day 25 after the estimated luteinising hormone surge (day 27 ± 4 after the first mating) in five mature beagle bitches. Caber-goline was administered orally at 5 μg/kg daily and cloprostenol was injected subcutaneously at 1 μg/kg every other day. Treatment efficacy, in terms of pregnancy termination, was 100 per cent. Termination always took place by resorption of the fetuses. No side effects were observed. A mean of three injections of cloprostenol and nine days of cabergoline treatment was necessary to eliminate all signs of gestation. Termination was in each case accompanied by a decline in plasma progesterone (to less than 1 ng/ml) within 72 hours of initiation of treatment. In a control group of five, untreated bitches, plasma progesterone remained elevated throughout a corre-     

Ultrasonographic monitoring of nuclear transferred fetal weight during the final stage of gestation in Holstein cows

Dystocia or stillbirth accompanied by Large Offspring Syndrome (LOS) occurs rather frequently in Holstein nuclear transferred calves. In regard to prophylaxes, nuclear transferred Holstein fetuses were monitored with ultrasonography during the final stage of gestation. Fetal weight was estimated weekly based on the fetal metacarpal width using ultrasonography. Fourteen Holstein cows pregnant with Holstein nuclear transferred fetuses were the subjects of this experiment. The fetal weight was estimated by measuring the fetal metacarpal width during the last month of gestation according to the expected date of parturition. Measurements were performed on a weekly basis. The ultrasound-estimated metacarpal width and body weight of 13 of the fetuses in the last week of gestation (30.2+/-2.2 mm, 50.0+/-4.7 kg) were similar to the actual measurement immediately after birth (30.0+/-2.1 mm, 51.2+/-5.5 kg). These results indicate that ultrasonographic monitoring within a week of parturition to is accurate for estimating fetal weight. Prediction of LOS with ultrasonography contributes to reliable a diagnostic method that minimizes syndrome-related gyneco-obstetric complications at parturition with the aid of appropriate treatments.     

Morphometric analysis of growth retardation in fetal lambs following experimental infection of pregnant ewes with Border Disease virus

The onset of growth retardation was investigated in fetal lambs following experimental infection of pregnant ewes with Border Disease virus ( ) on day 53 of pregnancy. Fetuses from control and infected ewes were harvested at weekly intervals between day 60 and day 95 of gestation and morphometric studies were completed on tibial radiographs and tibial growth cartilage metaphyseal junctions. Mean tibial areas were significantly reduced (P<0·01) in fetuses from infected ewes at 35 and 42 days after infection and growth cartilage metaphyseal junctions were less mature in fetuses from infected ewes at 42 days after infection. Positive immunostaining for BDV antigen was demonstrated in the brains of all fetuses from infected ewes between 14 and 42 days after infection. Attempts to demonstrate BDV antigen in bone proved unsuccessful. It is concluded that intrauterine growth retardation is an early manifestation of BDV infection in lambs and that the process is initiated shortly following infection of the fetus.     

PREGNANCY DIAGNOSIS WITH ULTRASOUND IN THE DOMESTIC CAT

Ultrasonographic examinations of seven pregnant cats with known breeding dates were made on successive days to establish the identifiable characteristics of pregnancy. Subsequent serial examinations were made to sonographically characterize normal feline prenatal development before 30 gestational days. An enlarged uterus, gestational sacs, and fetal poles were recognized as the features of early feline pregnancy and were first seen at 4, 11, and 15 days, respectively. Cardiac activity was detected earliest on gestational day 16, and recognizable feline fetal morphology appeared at day 26. Fetal membranes became apparent at as early as 21 days of gestation. Generalized fetal movements were first noted at day 28. Live and dead fetuses were compared in utero and marked differences were noted, with dead fetuses rapidly losing previously recognizable morphology. Determination of litter size in each cat could not be done accurately by ultrasound examination. It was concluded that the diagnosis and accurate dating of early pregnancy in the domestic feline may be accomplished with serial ultrasound evaluation.     

Evaluation of a bovine visual pregnancy test for the detection of pregnancy‐associated glycoproteins in sheep

As sheep produce similar pregnancy‐associated glycoproteins (PAGs) to cattle, a commercially available bovine visual pregnancy test based on the detection of PAGs (visual‐PAG‐test) was evaluated in sheep. The test was performed with whole blood (WhB), plasma (P) and serum (S) of 163 pregnant and 153 non‐pregnant ewes. Additionally, 11 pregnant ewes were tested weekly from day 14 to 49 of gestation and monthly from day 60 to day 149. Ten ewes were sampled weekly from the date of lambing until day 63 post‐partum (p.p.). The sensitivity in mid‐pregnancy (n = 163) was 98.16% (WhB), 99.39% (P) and 99.39% (S) compared to transabdominal ultrasonography as the gold standard while the specificity (n = 153) was 94.12% (WhB), 76.47% (P) and 93.46% (S), respectively. During early pregnancy, all 11 ewes were correctly identified as pregnant on day 42 (100%); however, the test sensitivity decreased to 54.6% (WhB) and 63.6% (S and P, respectively) at day 49. The ewes were again consistently identified as pregnant on day 63 (P) or on day 119 (S, WhB). The test was consistently negative from day 42 p.p. onwards in eight out of ten ewes. Two ewes remained consistently positive until the last sample on day 63 p.p. In conclusion, the test could be used to accurately select pregnant ewes at day 42 with a drop in sensitivity at day 49. The sensitivity of the visual‐PAG‐test was good in mid to late pregnancy, and early detection of pregnancy was possible in individual animals. In some ewes, the PAGs were however detectable for more than 63 days p.p.—the previous breeding history should therefore always be taken into account for correct interpretation of the test results.     

Altrenogest and progesterone therapy during pregnancy in bottlenose dolphins (Tursiops truncatus) with progesterone insufficiency

Progesterone production is essential for growth and development of the conceptus during pregnancy. Abnormal development of the corpus luteum (CL) after conception can result in early embryonic loss or fetal abortion. Routine monitoring of bottlenose dolphin (Tursiops truncatus) pregnancy after artificial insemination or natural conception with ultrasonography and serum progesterone determination has allowed for the establishment of expected fetal growth rates and hormone concentrations. Using these monitoring techniques, we revealed four pregnant dolphins (12-24 yr old) with abnormally low progesterone production indicative of luteal insufficiency. Once diagnosed, animals were placed on altrenogest (0.044-0.088 mg/kg once daily) alone or with oral progesterone (50-200 mg twice daily). Doses of hormone were increased or decreased in each animal based on how fetal skull biparietal and thoracic growth rates compared with published normal values. Hormones were withdrawn starting from day 358 of gestation in animals 1 and 2, with labor occurring 6 and 7 days after withdrawal and at 376 and 373 days of gestation, respectively. Both deliveries were dystocic, with each calf requiring manual extraction and fetotomy for calf 1. The fetuses in animals 3 and 4 died at 348 and 390 days of gestation, respectively. Induction of labor was attempted in both animals, after fetal death, by using a combination of rapid progesterone withdrawal and steroid and prostaglandin F2alpha administration. The calf of animal 4 had to be removed with manual cervical dilation and fetotomy All adult females survived the procedures. These data provide the first in vivo evidence that the CL is the primary source of progesterone throughout pregnancy in the bottlenose dolphin. Until further characterization of hormones required during pregnancy and at parturition has been accomplished, the exogenous progestagen supplementation protocol described here cannot be recommended for treatment of progesterone insufficiency in bottlenose dolphins.     

Birth of a Live Foal after Transabdominal Ultrasound-guided Cardiac Injection of a 200-day Equine Twin Fetus

In horses, development of twins is often problematic and may represent a potential life-threatening condition for the mare and both of the embryos/fetuses. There have been many attempts at various stages of gestation to reduce twin fetuses to a singleton with variable success. Techniques have been described to perform transabdominal ultrasound-guided cardiac injection of a toxic substance into a twin fetus. The case discussed in this report is of a mare that presented at 200 days with twin fetuses. Procaine penicillin was injected directly into the heart of one fetus, using an ultrasound-guided approach. The ultimate outcome was birth of a live healthy filly, followed by the passage of a mummified fetus. This report is the first to describe the procedure in a mare at more than 168 days of gestation, leading to birth of a live foal that lived longer than 3 days.     

Timing of Early Foetal Loss for Single and Twin Pregnancies in Dairy Cattle

The incidence of early foetal loss is increasing under intensive management systems for dairy cattle. The aims of the present study were to determine whether there is any peak period of pregnancy loss during the early foetal period and to evaluate possible differences between single and twin pregnancies. The study population consisted of 1442 pregnant cattle from a single herd. Pregnancy was diagnosed by transrectal ultrasonography between 36 and 42 days after insemination, and then weekly until day 90 of gestation or until pregnancy loss. A total of 1310 cows (90.8%) bore single embryos and 132 (9.2%) carried twins. Pregnancy loss was registered in 139 (9.6%) cows before day 90 of pregnancy: 101 (7.7%) in single and 38 (28.8%) in twin pregnancies. The average time of pregnancy loss for all animals was 58.4 ± 12.6 days and ranged from 45 to 90 days. Seventy‐five per cent of the pregnancy losses were registered between 45 and 60 days of gestation. The average time of pregnancy loss for cows with singletons was 52.1 ± 4.1 days and ranged from 45 to 61 days and that for those with twins was 75.1 ± 12.4 days and ranged from 46 to 90 days. Seventy‐five per cent of the twin pregnancy losses were registered between 68 and 90 days of gestation. Our data show that the foetal loss in singleton pregnancies occurs earlier than in twin pregnancies. Assessment of normal development of gestation on days 60 and 90 after insemination is suggested.     

Ultrasonography of the reproductive tract and early pregnancy in red deer

Thirty-five farmed red deer hinds two years of age or older were observed during mating in April and May and the dates of oestrus and, or, matings were recorded. From immediately before the breeding season and at approximately weekly intervals from the start of mating until all deer were 42 days pregnant, rectal ultrasonographic scans were taken using a 5 MHz linear transducer while deer were held standing in a restraining device. Scans were recorded on video. The vagina and cervix were visible with the lumen appearing as a continuous or intermittent white line, respectively. The non-pregnant uterus was observed in most cases and was immediately anterior to the bladder. Structures resembling ovaries were seen only occasionally. By seven days gestation a 5 mm vesicle could be observed in a few deer, and by day 14, oedema of uterine horns was apparent in some cases. A comma-shaped fetal mass 6 mm long, fetal membranes and placentomes could be observed on day 24. The heart beat was observed on day 28 when the fetus was 10 mm long. Limb buds were observed on day 31 and by day 37 the head with nose and eyes was distinguishable. Fetal movements were first observed on day 42. The accuracy of pregnancy detection before day 20 was 35 per cent, between 21 and 30 days gestation 71 per cent and from 31 to 42 days 98 per cent.     

Ultrasonographic fetal well-being assessment, neonatal and postpartum findings of cloned pregnancies in cattle: A preliminary study on 10 fetuses and calves

Cloned pregnancies in cattle are considered to be at risk due to a variety of fetal or adnexal abnormalities. Data is lacking concerning the possibility of transabdominal ultrasonography in the assessment of these high risk pregnancies. Transabdominal ultrasonography has rarely been reported in the assessment of bovine cloned pregnancies. Ten Holstein heifers carrying 8-month-old cloned fetuses were assessed by transabdominal ultrasonographic examination during the 3rd trimester of pregnancy. Fetal heart rates (FHR), movements, adnexal appearance, and placentome size were recorded. The outcome of the pregnancies was also noted and potential indicators of fetal demise recorded. Survival rate 1 week after birth was 30%. Mean FHR was 113 beats per minute (range: 92 to 128 bpm) during the fetal ultrasonography. No correlation between FHR and fetal activity was found. Fetal hyperactivity and imaging of hyperechoic particles in both allantoic and amniotic fluids were possible signs of fetal distress. Despite the size of the fetus and the deep bovine abdomen, fetal transabdominal ultrasonography can be performed in cattle. This preliminary study points to the necessity of further larger studies for defining normal and abnormal findings in bovine late pregnancy.     

Growth of the conceptus in alpacas

OBJECTIVE: To determine growth of the alpaca conceptus during early gestation, using ultrasonography. ANIMALS: 40 pregnant alpacas (20 multiparous, 20 nulliparous). PROCEDURE: Transrectal ultrasonography with a 5-MHz probe was performed 3 times weekly from days 7 through 45 after copulation (day of copulation = day 0). Blood samples were collected for progesterone assay on days of ultrasonography. RESULTS: Forty embryonic vesicles and embryos were identified and measured. Embryonic vesicles were first detected on day 12 after copulation and appeared spherical. Cumulative percentage of embryonic vesicles detected was 50, 82.5, and 100% on days 12, 14, and 16, respectively. Embryos were first detected by day 22 and heartbeats by day 24. Similarly, cumulative percentage of embryos detected was 17.5, 82.5 and 100% for 22, 24, and 26 days after copulation, respectively. Embryonic vesicles occupied both uterine horns beginning on day 19. A positive correlation existed between length and width of embryonic vesicles. Size of embryonic vesicles and embryos and progesterone concentrations did not differ between multiparous and nulliparous females. Five sets of twins were detected from days 21 through 33 after copulation, but the conceptus identified in the right uterine horn became nondetectable between days 28 and 33. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasonography was useful in detecting the earliest appearance of alpaca embryonic vesicles and determining the changes in growth from days 12 through 45 after copulation. Embryos were first detected by day 22. Transrectal ultrasonography was not harmful to animals and did not provoke embryonic death in this study.     

Transabdominal ultrasonographic determination of fetal gender in the horse during mid-gestation

Gender determination of the equine fetus using transabdominal ultrasonography was studied in 20 mares. One group of 10 research mares was scanned repeatedly every 2 weeks from 100 days gestation to parturition, while the second group of 10 client mares was subjected to echography once during mid-gestation. In males, the penis and/or prepuce was observed on 71 occasions from 102 days to 258 days gestation. On cross-sectional views, the male external genitalia had a round shape with parallel linear echogenic foci up to approximately 140 days gestation and then appeared triangular. Fetal testes were oval in shape in frontal view and had an homogeneous ultrasonographic appearance. Females were diagnosed on 23 occasions from 118 days to 227 days gestation based on the presence of the mammary glands and teats. Fetal ovaries appeared homogeneous with a characteristic circular echo from 100 days to 134 days gestation. Gender identifications (n = 98) based on the presence of the penis and/or prepuce in males and mammary glands and teats or fetal gonads in females were all correct, in agreement with the sex of the foals at birth. The optimal window of time was defined in both sexes as 100 to 220 days gestation. Thereafter, it was increasingly difficult to identify the anatomical structures cited above. Fetal sex was mainly determined using the transabdominal approach (87/98). However, the transrectal approach was useful in cases in which fetuses were either in posterior presentation or located very high in the mares abdomen. Good quality diagnostic scanners used typically in equine reproduction and equipped with a 5.0 MHz probe can be used for this procedure up to 160 days gestation, after which a 3.5 MHz transducer is often necessary due to increasing fetal size.     

Early fetal sexing of Saanen goats by use of transrectal ultrasonography to identify the genital tubercle and external genitalia

OBJECTIVE: To define the optimum period for sexing of Saanen goat fetuses by use of transrectal ultrasonography. ANIMALS: 82 Saanen goats pregnant with 124 fetuses. PROCEDURES: Fetal sexing was performed on the basis of the final location of the genital tubercle or identification of external genitalia. In experiment 1, fetuses (n = 78) were monitored every 48 hours from days 40 to 60 of gestation, whereas for experiment 2, 46 fetuses were examined only once between days 47 and 77 of gestation. RESULTS: For experiment 1, accuracy of fetal sexing was 20 of 20 (100%) for a single fetus, 39 of 42 (92.8%) for twin fetuses, and 10 of 16 (62.5%) for triplet fetuses. Diagnostic accuracy was significantly lower for triplet fetuses than that for single or twin fetuses. Final location of the genital tubercle was detected between 45 and 55 days of gestation (mean +/- SEM, 48.9 +/- 1.8 days). For experiment 2, accuracy of fetal sexing for a single fetus (24/24 [100%]) was significantly higher than the accuracy for twin fetuses (16/22 [72.7%]). Considering all fetuses that were born, accuracy of diagnosis was 69 of 78 (88.4%) for experiment 1 and 40 of 46 (86.9%) for experiment 2. Accuracy did not differ significantly between experiments. CONCLUSIONS AND CLINICAL RELEVANCE: Real-time ultrasonography after day 55 of gestation is a suitable method for determination of sex of Saanen goat fetuses by observation of the genital tubercle or identification of external genitalia.     

The Efficacy of the Vaginal Plug Formation after Mating for Pregnancy Diagnosis,and Embyonic Resorption In Utero in the Greater Cane Rat (Thryonomys swinderianus,Temminck)

The efficacy of the detection of vaginal plug formation after mating for pregnancy diagnosis, and the degree of embryonic resorption were studied in 67 wild greater cane rats (Thryonomys swinderianus) at Esiam in the Ekumfi District, Ghana, over a period of 3 months. Vaginal plug formation was first observed on day 59 of gestation, and could be used for pregnancy diagnosis on or after that date. However, the vaginal orifice subsequently opened a couple of times prior to day 105 of gestation and further checks for pregnancy after day 59 of gestation are suggested. Animals with unplugged vaginas 105 days after mating could, however, be considered as not pregnant. The mean (±SE) number of implantation sites and litter size in the greater cane rat were 7.2±0.18 and 3.4±0.29, respectively, the embryonic resorption rate being 42.7±6.66%. The significant positive correlation between the number of implanted embryos and the bled-out carcase weight suggests a positive role of maternal nutrition in increasing the litter size in the greater cane rat. The incidence of post-partum oestrus during the study period was 42.1%, which suggests that the greater cane rat can be re-bred immediately after parturition.     

Milk production correlates negatively with plasma levels of pregnancy-associated glycoprotein (PAG) during the early fetal period in high producing dairy cows with live fetuses

This study was designed to establish possible factors affecting plasma pregnancy-associated glycoprotein (PAG) concentrations during early pregnancy in high producing dairy cows with live fetuses. Blood samples were obtained on days 35, 42, 49, 56 and 63 of gestation from 80 lactating cows in two herds carrying live fetuses. Radioimmunoassay systems were used to determine PAG (RIA-497 and RIA-706) and progesterone concentrations. We evaluated the effects on PAG concentrations of herd, lactation number, sire of fetus, day of gestation, fetus number, plasma progesterone and milk production at each time point established, along with possible paired interactions. Mean milk production per cow approached 41kg during the study period. PAG concentrations were not affected by herd, lactation number or plasma progesterone concentration. Significant positive effects on PAG concentrations were shown by the gestation day, and the interaction between day of gestation and twin pregnancy. Significant differences between bulls and a significant negative correlation between milk production and PAG values on day 63 of pregnancy were also detected. Proportions of blood samples showing undetectable PAG levels and false negative diagnoses throughout the study period were significantly higher (P<0.001) using the RIA-497 system (2.5% and 5.3%, respectively) compared to RIA-706 (0% and 0.8%, respectively). Our findings suggest that PAG concentrations during the early fetal period are related to the day of gestation, milk production, number of fetuses and sire of fetus in high producing dairy cows. Under our working conditions, the RIA-706 method was better at detecting plasma PAG molecules than the RIA-497 system.     

Surgical resolution of an ectopic pregnancy in a captive gerenuk (Litocranius walleri walleri).

A full-term ectopic pregnancy was diagnosed in a multiparous, captive gerenuk (Litocranius walleri walleri) following prolonged gestation without parturition. Until 213 days of gestation, fetal viability was determined by transabdominal ultrasound of fetal heartbeat, physical palpation, and visual observations of fetal movements. Survey abdominal radiographs obtained at day 229 of gestation revealed a fully mineralized fetal skeleton in an inappropriate position for parturition. Surgical exploration revealed a full-term, nonviable, male calf contained within fetal membranes attached to the omentum. Histologic examination of the fetal membranes identified lesions compatible with placenta-cotyledon separation occurring prior to surgical removal. No congenital fetal abnormalities or infectious processes were identified. Visual observation of the reproductive tract at the time of surgery revealed no abnormalities or evidence of concurrent pregnancy.