Pregnancy diagnosis in pigs: a field study comparing linear-array real-time ultrasound scanning and amplitude depth analysis

Between days 24 and 32 after mating/insemination, 881 pigs (785 pregnant and 96 not-pregnant) were tested for pregnancy on a commercial farm with a linear-array real-time ultrasound scanner. 5-7 Days later, 785 of these animals (708 pregnant and 77 not-pregnant) were tested again with A-mode equipment by farm employees. Confirmation of pregnancy was based on recorded farrowings or abortions; confirmation of non-pregnancy was based on return to oestrus and rebreeding, recorded non-farrowing, or inspection of the uterus of culled animals at the slaughterhouse. From the number of correct positive (a), incorrect positive (b), correct negative (c) and incorrect negative (d) diagnoses, a sensitivity (a/a + d) of 100% versus 97.5%, a specificity (c/c + b) of 90.6 versus 55.8%, a positive predictive value (a:a + b) of 98.9% versus 95.3% and a negative predictive value (c:c + d) of 100% versus 70.5% were calculated for the real-time ultrasound technique versus A-mode technique. It was concluded that real-time ultrasound scanning provides a very accurate technique for pregnancy diagnosis in pigs, enabling immediate decision making on treatment or culling of animals diagnosed as non-pregnant.     

Accuracy of pregnancy diagnosis and prediction of foetal numbers in sheep with linear-array real-time ultrasound scanning

Pregnancy diagnosis was carried out in sheep by means of transabdominal linear-array real-time ultrasound scanning. Animals were restrained standing, and the transducer was placed on the hairless area of the ventral abdominal wall just in front of the udder. Of a total of 818 tests, 724 were performed between days 29 and 89 of pregnancy, 598 animals subsequently lambed and 126 were non-lambing animals. Only 8 of these tests were wrong: 3 false positive and 5 false negative diagnoses. Sensitivity, specificity, positive- and negative predictive values for these tests were 99.2%, 97.6%, 99.5%, and 96% respectively. There was evidence to indicate that the three false positive tests were caused by foetal mortality or unobserved abortions that took place after testing. Only 2 of the 5 false negative tests were carried out after day 39 of gestation. Counting of foetal numbers (1, 2 or 3) was performed in only some animals (n = 210) between days 45 and 77 of gestation. Three groups of animals (A: 89 ewes; B: 27 PMSG-treated ewes; C: 94 ewes) were analyzed separately. Overall accuracy of all predictions was 83.1%, 37.0% and 78.7% for the 3 groups respectively. Animals in group B produced only 3 or more lambs. Sensitivity of the countings of singles, twins and triplets or more were 90.4%, 90.4% and 50% respectively for the animals from group A and 91.9%, 86% and 21.4% for the animals from group C.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pregnancy diagnosis in the dog: a comparison between abdominal palpation and linear-array real-time echography

This paper presents quantitative results of canine pregnancy diagnoses performed by abdominal palpation and/or linear-array real-time echography. Each animal was first palpated by an experienced clinician and then another investigator performed ultrasound scanning using a 3 MHz transducer. In other dogs echography was undertaken only when the result of abdominal palpation was negative or doubtful or when the owner requested ultrasound scanning. Using all tests performed between days 20 and 49 of pregnancy (day 0 = day of first mating or insemination), the results of abdominal palpation (n = 116) versus real-time scanning (n = 135) were: sensitivity: 89.0% v 92.9%; specificity: 93% v 96.0%; positive predictive value: 95.6% v 97.5%; negative predictive value: 83.3% v 88.9%. Results of ultrasound tests performed in 97 other dogs were: sensitivity: 92.4%; specificity: 97.7%; positive predictive value: 98.0% and negative predictive value: 91.4%. Almost identical figures were found when only the tests performed between days 25 and 35 of pregnancy were included. It was concluded that real-time ultrasound scanning is an accurate method for discriminating between pregnant and non-pregnant bitches; sensitivity and specificity of the abdominal palpation technique executed by an experienced clinician approach that of ultrasound scanning; small litter size and lack of knowledge of conception date are the main sources of false negative diagnoses.     

Pregnancy diagnosis in Swine: a comparison of two ultrasound instruments

This investigation was designed to assess the sensitivity, specificity and positive predictive values of amplitude-depth and Doppler pregnancy detectors when utilized for pregnancy diagnosis of mated sows. Mated sows (n = 38) were tested daily from 15 to 45 days after mating for pregnancy with the ultrasound instruments. The same procedure was performed with nonmated sows (n = 10) 15 to 45 days after estrus. Both instruments were unreliable for pregnancy diagnosis between 15 and 22 days after mating. Between 23 and 45 days after mating the Doppler pregnancy detector was more specific and had greater positive predictive values. In contrast the amplitude-depth pregnancy detector was more sensitive during the same time interval.

Serum estrone sulphate concentrations were determined in samples collected between 27 and 30 days after mating or estrus, as an alternate method of pregnancy diagnosis. Serum estrone sulphate concentrations were always equal to or greater than 0.5 ng/mL in the pregnant sows, while in the nonmated sows estrone sulphate concentrations were never more than 0.5 ng/mL serum.

     

Accuracy of pregnancy diagnosis and prediction of calving date in red deer using real-time ultrasound scanning

One hundred and sixty-two 18-month-old farmed red deer were used to test the accuracy of pregnancy detection and equations for predicting gestational age. Deer ranging from 30 to 110 days gestation were examined by rectal ultrasonography using a 5 MHz transducer while they were standing. Each scan was recorded on video tape for measurements of uterine diameter, amniotic sac diameters, crown-rump length, head length, head diameter, nose length, chest depth, chest width and placentome base-apex length and width. Fetal age was calculated from the mean of the age predictions derived from each dimension measured on individual deer, for 132 deer between 44 and 110 days gestation. All the hinds diagnosed as pregnant produced offspring, and all the hinds diagnosed as not pregnant failed to produce offspring. Between one and six fetal and uterine dimensions were measurable and the number measurable increased with fetal age. The mean error of calving date prediction in 132 deer was 0.97 days. The error of prediction when measurements were made between 44 and 60 days was 0.44 days, whereas between 61 and 80 days and between 81 and 110 days the errors were +0.95 and +4.72 days, respectively. The estimates of calving date were all within 13 days of the calving date.     

Prediction of calving date in beef cows by real-time ultrasonic scanning

Three hundred pregnant beef cows between 35 and 125 days of gestation were scanned ultrasonically and their calving dates were predicted from measurements of fetal parts. The mean difference between the actual and predicted calving dates was 0.9 day with a standard deviation of 9.0 days. The accuracy and precision of the prediction of calving date were sufficient to be of benefit in the management of cows in late pregnancy and at calving.     

Use of a high frequency transducer with real time B-mode ultrasound scanning to identify early pregnancy in cows

The reproductive tracts of 22 Friesian dairy cows were examined from seven to 35 days after insemination using a real time B-mode ultrasound scanner with a 7.5 MHz transducer. The earliest detection of pregnancy was at nine days when a vesicle was imaged within the lumen of the uterine horn. The early conceptus was seen at day 13 within the vesicle and these structures were followed ultrasonically until day 35. There was a sudden enlargement of the vesicle at day 19 and a heart beat was detected in the embryo at day 22. The allantois was imaged at day 23 and the amnion by day 29. The embryonic outline was clearly defined by day 33 when the body cavities could be discerned. This ability to determine pregnancy at an early stage should prove to be a useful technique in investigating the problems associated with early embryonic death in cattle.     

Pregnancy diagnosis in dairy goats and cows using progesterone assay kits

Early pregnancy diagnosis in dairy goats and cows was studied using enzyme immunoassays (EIA) to measure progesterone concentrations in whole milk samples collected approximately 3 weeks after mating. Two qualitative on-farm assay kits and 2 quantitative assay kits, all designed for use in the dairy cow, were tested for their accuracy with goats milk samples. Accuracy of diagnosis of goat pregnancy ranged from 83 to 88%, and of non-pregnancy from 80 to 100%. Pregnancy diagnosis with samples of cows milk using 2 quantitative kits gave accuracies of 66 to 68% for pregnancy, and 90 to 91% for non-pregnancy. Possible causes of error in the early diagnosis of pregnancy with milk samples are discussed.     

Evaluation of real time B-mode ultrasound scanning for detecting early pregnancy in cows

A real time B-mode ultrasound scanner with a 7.5 MHz rectal linear transducer was used in two trials to detect whether dairy cows, less than 25 days after insemination at standing oestrus, were pregnant. In the first trial 17 cows were inseminated on the same day, and their reproductive tracts were examined 14, 15, 16 or 17 days after insemination. All the cows were diagnosed accurately as either pregnant or not pregnant. In the second trial 22 cows were inseminated on the day of observed oestrus while 14 were observed at oestrus but not inseminated. The animals were kept as a mixed group and an experienced operator scanned the uterus of each cow on one occasion, without knowing either the dates of observed oestrus or which cows had been inseminated. The rate of correct diagnosis was only 33 per cent in cows up to 16 days after oestrus, but increased markedly after 17 days and was 100 per cent by day 20.     

Pregnancy diagnosis in sows: a comparison of the vaginal biopsy and Doppler ultrasound techniques.

Two pregnancy diagnosis techniques, vaginal biopsy and ultrasonic detection, were applied to 190 sows following service. Of 172 sows diagnosed pregnant by vaginal biopsy, five did not farrow. Of 18 sows judged not pregnant, one produced a litter. With the ultrasound technique, 175 sows were diagnosed pregnant, but 11 did not farrow. Of the remaining 15 sows considered not pregnant by the 39th day after service, four farrowed. The biopsy result was usually available up to 48 hours earlier than the ultrasound result. It was concluded that where laboratory facilities are available, the biopsy technique is the method of choice.     

Pregnancy diagnosis in thoroughbred mares using radioimmunoassay (RIA), enzyme immunoassay (kit) and ultrasound echography (scanning)

On the basis of progesterone determination on plasma or blood after RIA and the kit method respectively and consecutive scanning performed on a total number of 31 mares the following features were demonstrated: The overall material shows that in 20 mares (64.5%) embryonic vesicles were demonstrated. Of these mares 16 have conceived after service in the 1st estrous cycle and 3 mares in the 2nd estrous cycle. 18 mares were scanned in the time interval 13th-26th day after the latest service, while 2 mares were scanned on day 46 and 41 respectively. A total of 14 scanning positive mares were examined for progesterone by the RIA as well as by the kit method. For these mares (100%) agreement was found between the progesterone analyses as well as with the scanning results. For 19 mares (100%) there was agreement between kit and scanning results. 15 RIA progesterone determinations are in agreement with the scanning results. Progesterone values after the RIA method performed on 15 scanning positive mares were in average 8.40 +/- 2.79 ng/ml plasma. A total of 9 out of 10 scanning negative mares have been examined by the RIA as well as by the kit method. In 6 of these mares with 7 estrous cycles agreement has been found between progesterone analyses and the scanning results (77.8%). In 2 mares (no. 2 and 4) discrepancy has been found in the 2nd estrous cycle between RIA, kit and scanning results. For 1 mare (no. 7) discrepancy has been found in the 1st and 3rd estrous cycle between RIA and scanning.(ABSTRACT TRUNCATED AT 250 WORDS)     

Terbutaline pharmacokinetics in cows: preliminary data

The objective of this study was to determine the serum pharmacokinetics of terbutaline in healthy cows. In the initial experiment, terbutaline was administered once as an intravenous (i.v.) bolus to 6 near-term pregnant beef cows within 24 h after parturition at a low but therapeutically relevant dose, 5 microg/kg. A 2nd experiment was conducted in the same cows with a higher dose, 0.5 mg/kg, but an otherwise similar experimental design. The serum concentration of terbutaline was determined by means of high-performance liquid chromatography with fluorescence detection in both experiments. After i.v. administration of 0.5 mg/kg, the mean peak serum concentration, residence time, and half-life were 708.22 (standard deviation 509.6) ng/mL, 6.75 (3.6) min, and 6.93 (2.4) min, respectively. The results indicate that terbutaline is rapidly eliminated from the bloodstream after i.v. administration in cattle, falling below the assay's limit of detection 30 min after administration.     

Technical note: A novel technique to assess internal body fat of cattle by using real-time ultrasound

The objectives of this study were to describe a system to assess KPH fat by using real-time ultrasound (RTU) and to develop equations to predict total physical separable internal fat (IFAT) based on ultrasound measurements. Data for this study were obtained from 24 Angus steers fed either hay- or corn-based diets during the backgrounding phase. Steers were serially slaughtered in 3 groups: at weaning (baseline), then at 4 and 8 mo after weaning. A fourth group was composed of 4 steers from the hay-fed group that were slaughtered at approximately 10 mo after weaning. The RTU measurements were collected every 2 mo, with a preslaughter scan approximately 7 d before the slaughter time. The RTU measurements consisted of 12th- to 13th-rib backfat thickness, 12th to 13th ribeye area, percentage of intramuscular fat, and kidney fat depth, which was measured in a cross-sectional image collected between the first lumbar vertebra and the 13th rib. For kidney fat, the ultrasound probe was placed on the flank region approximately 15 cm from the midline of the animal. Images were stored in the ultrasound console, and measurements were taken between the ventral part of the iliocostalis muscle and the end of the KPH fat at the chute side. The relationship between carcass and ultrasound measurements in the depths of kidney fat (cKFd and uKFd, respectively) had an r(2) of 0.93, with a root mean square error (RMSE) of 1.14 cm. An allometric regression between carcass KPH weight (cKPHwt) and cKFd was identified, and the untransformed regression had an r(2) of 0.96. The linear regression between total IFAT and cKPHwt had an r(2) of 0.97, with an RMSE of 2.67 kg. Therefore, a system was developed to predict IFAT from uKFd measurements by combining these equations. Additionally, a single linear regression between IFAT and uKFd measurements was developed (r(2) = 0.89, RMSE = 5.32 kg). Even though the system of equations had a lower RMSE of prediction and greater r(2) compared with the single linear regression (4.80 vs. 5.10 kg and 0.91 vs. 0.89, respectively), there was no difference between these methods in predicting IFAT (P = 0.4936) by using a pairwise mean square error of prediction analysis. Our results indicated that uKFd measurements can accurately and precisely predict the cKFd of steers consuming either high concentrate or forage rations. The results also showed that cKFd is highly correlated with cKPHwt, which can be used to estimate total IFAT. More research is needed to further evaluate this technique with different feeding strategies, breeds, and sexes.     

Pregnancy toxaemia of beef cows in Orkney

Pregnancy toxaemia in beef cows is assessed based on approximately 30 isolated cases seen in Orkney during the period 1974 to 1977. Case histories of nine of these are included. A mortality rate of over 90 per cent was recorded. The importance of nutrition and early detection is emphasised.     

Pregnancy rates during experimentation in dairy cows

This study investigated pregnancy rates on day 16 in dairy cows following artificial insemination and blood sampling to monitor hormonal status. Collection of blood samples by jugular venepuncture coupled with single fixed time insemination resulted in a poor pregnancy rate (27.8%). Modification of the protocol to include double insemination and collection of blood samples from jugular cannulae inserted four days prior to insemination did not improve pregnancy rate (27.3%). Acclimatization of cows to the experimental facility, however, resulted in a dramatic increase in pregnancy rate (85.7%;P < 0.005). This improvement was not associated with any difference in plasma progesterone but was associated with a marked advancement in the decline in oestradiol at the end of the follicular phase, indicative of earlier ovulation. Non-pregnancy was associated with a delayed fall in oestradiol and reduced plasma concentrations of progesterone. The results support a role for inadequate progesterone in early embryo mortality but suggest that impaired ovulation is a more important problem in cows under the 'stress' of experimentation.