Ultrasonic Measurement of Fetal Parameters for Estimation of Gestational Age in Korean Black Goats

Assessment of fetal development during mid and late term pregnancies by standard B-Mode ultrasonography in Shetland ponies

Transrectal and transabdominal ultrasonography is an established method to monitor pregnancy, fetal growth and wellbeing in different species. Growth charts with multiple bio-morphometric parameters to estimate days of gestation and days before parturition exist in small companion animals, sheep and goats, riding type horses and large ponies but not in small horse breeds like Shetland ponies. The aim of this study was to apply fetal biometric assessment and detailed description of physiologic fetal development to mid and late term pregnancies in Shetland mares and to generate reference data for clinical practice and for future research. Fetal parameters were collected starting on day 101 of pregnancy in five Shetland mares. The fetal biometric parameters determined consisted of aortic diameter, eye diameter, combined rib and intercostal distance (CRID), stomach length and width and different heart morphology parameters in sagittal and frontal plane. Additionally, fetal activity and organ development in terms of differentiation and changes in echogenicity were recorded. Considering reliably assessable parameters, fetal CRID was the best predictor for gestational age with ± 13.6 days and fetal aortic diameter the most accurate for prediction of days until parturition with ± 16.2 days.

Ultrasonography of Pregnancy in Murciano-Granadina Goat Breed: Fetal Growth Indices and Umbilical Artery Doppler Parameters

The evolution of some fetal growth indices and arterial blood flow parameters in the umbilical cord of the embryos and fetuses of primiparous pregnant goats of Murciano-Granadina breed were analyzed by ultrasonography. Weekly ultrasonographic sessions took place from 18- to 125-days post-breeding. Fetal measures were carried out by ultrasound B-mode. This mode was used to take a series of measurements in the embryo/fetus throughout pregnancy: crown-rump length (CRL, from 24-days post-mating -dpm- to 61 dpm), trunk diameter (TD, 24-34 dpm), biparietal diameter (BPD, 28-125 dpm) and eye orbit diameter (EOD, 75-125 dpm). Spectral Doppler was used to study blood flow from umbilical artery. Different blood flow parameters were obtained as follows: Arterial Pulse, Peak Systolic Velocity (PSV), End Diastolic Velocity (EDV), Mean Velocity (MV), Systolic velocity/Diastolic velocity Ratio (S/D), Pulsatility Index (PI) and Resistance Index (RI). In this study, the umbilical cord was first noticed between 32- and 35-days post-breeding. However, these umbilical arterial blood flow parameters were not conclusive (positive S/D ratios and RI < 1) until 65-80 days of pregnancy. The explanation to these results could be that vascular development related to umbilical arteries elasticity and diameter is not good enough in early pregnancy. Therefore, these vessels have already acquired their appropriate characteristics in order to allow blood flow parameters and Doppler index measures from only 2.5 months of pregnancy. This is the first time that a detailed study of fetal growth indices and umbilical artery flow rates in fetuses from Murciano-Granadina goats has been performed throughout virtually the entire duration of gestation. In conclusion, the evolution of the fetal growth indices in this breed has determined that the umbilical artery velocimetric parameters (PSV, EDV, MV) increase significantly and the AP, S/D, PI and RI indices decrease significantly throughout the analyzed pregnancy period.

The use of ultrasonographic measurement of the heart size and fetal heart rate variation for gestational age determination in local Bulgarian goats

Background

Determination of gestational age in goats was performed using ultrasound measurements of different fetal biometric parameters. There are no data showing quadratic and exponential dependence between fetal heart parameters and gestational age.

Objectives

The objective of the present study was to test the significance of the defined indicators (fetal heart rate, longitudinal and transverse fetal heart axes) for determining gestational age in local Bulgarian goats.

Methods

A total of 24 pregnant local Bulgarian goats, aged between 2 and 5 years, body weight 42–50 kg were included in the study. Ultrasonographic examinations were performed weekly on gestational days 21, 28, 35, 42 and 49. After gestational day 49 until parturition, scans were performed biweekly. The data from the measurements were subjected to linear (y = a + bx), quadratic (y = aх² + bх + c) and exponential (y = axⁿ) correlation. Results: Average fetal heart rate values decreased with pregnancy progression. The coefficient of determination (R²) and standard error of estimate (SEE) of the heart rate indicator were 0.72, 0.75, 0.58 and 15.1, 14.4, 19.2 days, respectively, for the three correlations. Longitudinal diameter (long axis) had the following values for R² = 0.94, 0.96, 0.96 and for SEE = 7.0, 5.5, 5.5 days, for the linear, quadratic and exponential correlations, respectively, while the values of the fetal heart transverse diameter (short axis) were higher than those of the external one (R² = 0.95, 0.97, 0.97). Simultaneously, SEE is lower (SEE = 6.1, 4.9, 5.0 days) compared to that found for the long heart fetal axis.

Conclusions

For precise estimation of gestational age, use of longitudinal (long) and transverse (short) axes is recommended. Fetal heart rate is not an exact indicator but can be used as a reference for gestational age along with changes in the heart size and echogenicity.

Doppler ultrasound measurements of the blood flow velocity in the fetal heart and aorta in Bulgarian White milk goats

The aim of the present study was to determine the parameters characterising the blood flow velocity in the fetal heart and aorta in goats by Doppler ultrasonography. Twenty-four Bulgarian White milk goats, aged 4-6 years, weighing 45-51 kg were used in the study. Doppler ultrasound measurements of the blood flow velocity in fetal heart were done at the end of first, second and third trimesters of pregnancy, and in the fetal aorta - at the end of the second and third trimesters of pregnancy. Ultrasound investigations were carried out by transabdominal approach with linear and convex transducers, with frequency 8.0 MHz. Blood flow parameters that included maximum and minimum systolic velocity, end-diastolic velocity, pulsatility index, resistance index and systolic/diastolic ratio were measured by spectral Doppler ultrasonography. The results showed that the highest maximum systolic velocity in the fetal heart was observed at the end of the first pregnancy trimester. Statistically significantly (p < 0.05) lower values of this parameter were registered in the second and third pregnancy trimesters. A similar tendency was observed for minimum systolic velocity, end-diastolic velocity and systolic/diastolic ratio. The pulsatility index and resistance index had similar values for the three studied periods. Examination of the fetal aorta showed statistically significant differences (p < 0.05) of minimum systolic velocity, end-diastolic velocity, pulsatility and resistance index in the third, compared with the second trimester of pregnancy. The analysis of the results suggested that Doppler ultrasonography can be used to monitor fetal blood flow changes during the various stages of pregnancy.

Consideration of breed specific fetal trunk diameter for the estimation of gestation age using trans-abdominal ultrasonography in sheep

The study aim was to estimate gestational age (GA), expected parturition date (EPD) and growth rate by determining fetal trunk diameter (TD). Effects of fetal-dam pelvis alignment and in utero fetal position at time of ultrasonography (UG) on fetal numbers and sex determination were also studied. Trans-abdominal UG (3-6.5 MHz) was conducted on 37 ewes with known breeding dates from Days 25-120 of pregnancy. Errors in GA and EPD were studied using an equation in the same ewes at their successive breeding when date of breeding was unknown. There were four equations, Y = 1.28861X+32.656 (R² = 0.92), for Indigenous; Y = 1.2603X+38.075 (R² = 0.85), for Indigenous × Garole; and Y = 0.8932X+45.916 (R² = 0.99), for Garole fetuses; and the equation, Y = 1.3565X + 32.604 (R² = 0.94), independent of breed were computed to estimate GA and the relationship between GA and TD of different breeds. The error in estimated GA and EPD using these four equations was determined and there was comparison with the data collected using US and the previously described equations. Results indicate there was the greatest (P <  0.01) error for GA and EPD values using the US TD equation for all breeds. There was the least error in estimated EPD using the breed specific equations. Error in the sex determination was 4.8 % and fetal number determination was 16.7 % with singleton and 7.7 % twin fetuses. The results indicate there is a breed specific fetal TD that is useful for predicting GA in sheep.

Determination of gestational age by measuring defined embryonic and foetal indices with ultrasonography in Abaza and Gurcu goats

The aim of this study was to determine gestational age in Abaza and Gurcu goats by measuring certain embryonic and foetal indices with ultrasonography. A 5–7.5 MHz linear probe was used to obtain ultrasound measurements from 30 pregnant goats (10 Abaza and 20 Gurcu). Heart diameter (HD), biparietal diameter (BPD), crown-rump length (CRL), trunk diameter (TD) and placentome diameter (PD) were measured to determine gestational age. The mean of embryonic and foetal indices were calculated and linear regression was performed. Heart diameter measurements for Abaza and Gurcu goats were significantly different on days 45 (P= 0.048) and 60 (P= 0.019). Biparietal diameter values were significantly different on day 45 (P= 0.035). Crown-rump length measurements were significantly different at days 30 (P= 0.003) and 60 (P= 0.002). We determined that HD and TD were the best predictors of gestational age for Abaza goats (R2= 0.952, R2= 0.949, respectively), whereas HD and CRL were the best predictors of gestational age for Gurcu goats (R2= 0.933, R2= 0.942, respectively). Based upon our study results, these specific indices could be applied during ultrasonographic examinations of Abaza and Gurcu goats to confirm gestational age when the day of mating is unknown.

Determination of the gestational age through ultrasound measurements of some uterine and foetal parameters in Bulgarian local goats

The aim of the current study was to determine the gestational age in goats through the measurement of some foetal and uterine structures. Twenty-four pregnant Bulgarian local goats were submitted to ultrasound foetometry by transrectal and transabdominal approaches. Ultrasound measurement of studied parameters was done at 7-day intervals during the first trimester of gestation (days 21-49) and at 14-day intervals between gestation days 49 and 133. Associations of foetometry data with foetal age were investigated by linear (y = a + bx), quadratic (y = ax²  + bx + c) and exponential (y = axⁿ ) equations. According to the results, some biometric parameters (uterine lumen diameter, crown-rump length, trunk diameter, biparietal diameter, foetal aortic diameter) exhibited a stronger correlation to gestational age (R²  ≥ 0.90) and lower standard error of the estimate (SEE ≤ 8) as compared to foetal eye orbit diameter, and outer and inner placentome diameters (R²  ≤ 0.90; SEE ≥ 8). Each of these biometric parameters could be measured in different periods of gestation, thus allowing for monitoring and determination of foetal age at almost all stages of pregnancy.

Ultrasonographic foetometry and maternal serum progesterone concentrations during pregnancy in Turkish Saanen goats

The objectives of the present study were (1) to generate reliable equations to estimate the gestational age of Saanen goats by measuring embryonic and foetal structures via B-Mode ultrasonography (USG), (2) determine the maternal serum progesterone (P₄) concentrations during pregnancy, and (3) compare the relationship between P₄ concentrations and gestational age, litter size, and birth weight of kids. Seven pregnant goats were used in this study. Ultrasonographic examinations were performed transrectally from Days 15 to 27 of pregnancy at 3-day intervals and transabdominally from Days 30 to 128 at 7-day intervals. Blood samples were collected daily between Day 15 and 24 of gestation, and weekly from Day 27 to 128 to determine the serum P₄ concentrations. Outer placentome diameter, biparietal diameter, occipito-nasal length, chest diameter, foetal heart rate, transversal heart diameter, orbit diameter, umbilical cord diameter, and kidney diameter were highly correlated with gestational age (P <  0.0001). Goats with twins had greater progesterone concentrations than those with a single foetus (P <  0.001). Furthermore, maternal serum progesterone concentrations detected on Days 51, 107, 114, and 128 of gestation were greater in goats carrying twins than those with a single foetus (P <  0.05). A negative correlation was evident between serum progesterone concentrations and birth weights of the kids (r = -0.78; P =  0.007). In conclusion, gestational age can be estimated using ultrasonographic foetometry, and litter size at specific times during pregnancy can be determined based on maternal serum progesterone concentration in Turkish Saanen goats.

Use of ultrasonographic fetometry for the estimation of days to kidding in dairy does

The objective of this study was to predict the number of days to kidding in dairy goats by ultrasonographic measurement of three consecutive ribs and intercostal spaces or trunk diameter of fetuses. Two groups of primiparous and multiparous goats were examined by transabdominal ultrasonography. Actual kidding date was used to compute the true number of days to kidding relative to the ultrasound examination day. Linear regression models were built to predict days to kidding based on fetal measurements, parity, and number of kids. The model using the width of three consecutive ribs and intercostal spaces (n = 29 goats) showed a curvilinear relationship between days to kidding and rib distance (R² = 0.60; P < 0.01). The trunk diameter model (n = 135 goats) showed a curvilinear relationship between days to kidding and trunk diameter with an effect of parity (R² = 0.81; P < 0.01).

Two-dimensional and three-dimensional ultrasonography for pregnancy diagnosis and antenatal fetal development in Beetal goats

Aim:

The objective of this study was to compare two-dimensional (2D) and three-dimensional (3D) study of the pregnant uterus and antenatal development of the fetus.

Materials and Methods:

2D and 3D ultrasound were performed from day 20 to 120 of gestation, twice in week from day 20 to 60 and once in week from day 60 to 120 of gestation on six goats. The ultrasonographic images were obtained using Toshiba, Nemio-XG (Japan) 3D ultrasound machine.

Results:

On the 20^th day of gestation, earliest diagnosis of pregnancy was done. First 3D ultrasonographic image of the conceptus, through transabdominal approach, was obtained on day 24. On 39^th day, clear pictures of conceptus, amniotic membrane, and umbilicus were seen. On 76^th day of gestation, internal organs of fetus viz heart, kidney, liver, urinary bladder, and stomach were seen both in 2D and 3D images. 3D imaging showed better details of uterine structures and internal organs of the fetus.

Conclusions:

Comparing 3D images with 2D images, it is concluded that 2D was better in visualizing fluid while 3D images were better to view details of attachment of fetus with endometrium.

Transabdominal ultrasound for pregnancy diagnosis in Reeves' muntjac deer

Reeves' muntjac deer (Muntiacus reevesi) are a small cervid species native to southeast Asia, and are currently being investigated as a potential model of prion disease transmission and pathogenesis. Vertical transmission is an area of interest among researchers studying infectious diseases, including prion disease, and these investigations require efficient methods for evaluating the effects of maternal infection on reproductive performance. Ultrasonographic examination is a well-established tool for diagnosing pregnancy and assessing fetal health in many animal species(1-7), including several species of farmed cervids(8-19), however this technique has not been described in Reeves' muntjac deer. Here we describe the application of transabdominal ultrasound to detect pregnancy in muntjac does and to evaluate fetal growth and development throughout the gestational period. Using this procedure, pregnant animals were identified as early as 35 days following doe-buck pairing and this was an effective means to safely monitor the pregnancy at regular intervals. Future goals of this work will include establishing normal fetal measurement references for estimation of gestational age, determining sensitivity and specificity of the technique for diagnosing pregnancy at various stages of gestation, and identifying variations in fetal growth and development under different experimental conditions.

The accuracy of gestational age predicted from femur and humerus length in Saanen goats using ultrasonography

Serial transabdominal ultrasonographic scanning was performed to measure femur and humerus length of foetuses of Saanen goats to establish their gestational stage. Data were obtained from 38 goats that became pregnant after artificial insemination. Animals were restrained in a supine position on a special table designed for this purpose. Humerus and femur length were measured at weekly intervals starting from week 8 of gestation till the end of gestation. Real-time ultrasound scanner equipped with switchable frequency (5-7.5 MHz) micro convex probe was used in the present study. Humerus and femur length showed strong positive correlation with gestational age (r2 = 0.95). Measurements of humerus and femur of foetuses are useful indicators to predict gestational age at the 2nd and 3rd trimesters in Saanen goats. Measuring of only one bone length is quite enough. Incorporating of both measurements within a multiple regression equation did not improve predictive capacity of the bones. The results of the study were used to construct reference charts and gestational equations in Saanen goats utilizing humerus and femur measurements. In Sudan, this is the first study utilizing measurements of the femur and humerus and the first study comparing the length of the humerus and femur for predicting gestational age in Saanen goats.

Fetal age estimation of Hokkaido sika deer (Cervus nippon yesoensis) using ultrasonography during early pregnancy

In sika deer, the normal method of estimating fetal age, based on fetal weight, is not applicable during the early pregnancy period. The objective of the present study was to describe the growth and development of sika deer fetuses and to establish a method for fetal age estimation during early pregnancy using ultrasonography. Five captive female Hokkaido sika deer (Cervus nippon yesoensis) were observed for estrus and mated (day 0) with an intact male. At two- or three-day intervals, fetuses were observed by rectal ultrasonographic scans until 59-61 days of gestation. The straight crown-rump length (SCRL), curved crown-rump length (CCRL), head length (HL), trunk depth (TD) and heart rate (HR) of the fetuses were measured. Linear regression equations were computed for each measurement together with fetal age. Analyses were conducted after transformation to a natural logarithm for SCRL and CCRL. All equations were significant (P<0.001), with SCRL becoming measurable earlier (day 20) than the others and yielding the best correlation (Days= -2.08+14.15 LnX: X=SCRL, Ln=natural logarithm). Therefore, we concluded that a precise estimation of fetal age in early gestation is best performed using SCRL measurements.

Ultrasonographic fetometry and determination of fetal sex in buffaloes (Bubalus bubalis)

The aim of the current study was to establish ultrasonic biometric threshold of different fetal parts in buffaloes and to evaluate the feasibility and accuracy of ultrasonic fetal sex determination. Serial ultrasonographic examinations were carried out on twelve pregnant buffalo-cows, during which fetal parts were measured, and fetal sex and presentation were determined. The obtained results revealed that embryo and amniotic vesicle (AV) were detected by the forth and fifth week of pregnancy, respectively. Organization was observed by the seventh week, while ossification was indicated between the eighth and 10th week. High correlations were found between different studied parameters and gestational age, where the highest correlation was found with the crown-rump length (CRL) and amniotic vesicle diameter (AVD) at the early-gestation; the biparietal diameter (BPD) at the mid-gestation; and the eyeball diameter (EBD) at the mid- and late-gestation. The results also revealed that the best window for fetal sexing was found between the 10th and 18th week of gestations, with an overall accuracy of 97.1%. The final polarity with all fetuses in anterior presentation was adopted by the 30th week. In conclusion, the overall data indicated the feasibility and value of ultrasonographic fetometry in buffaloes for evaluation of fetal development, estimation of gestational age and determination of fetal sex.