Determination of early pregnancy and embryonic growth in goats by transrectal ultrasound scanning

Growth, haemato-biochemical, hormonal and disease characteristics in Black Bengal goats: a review

The goats have been considered one of the noteworthy animals to provide food security and could promote socio-economic upliftment under challenging climatic scenarios in the coming decades, particularly in the tropics. Black Bengal goat (BBG) is one of the recognised native meat-type breeds of hot-humid tropics with distinguished characteristics, including superior-quality meat, excellent skin and high prolificacy. Smaller body mass, lower metabolic rate and efficient utilisation of high-fibre forages enable BBG to adapt to a wide range of harsh climates in the tropics. The BBG can maintain physiological homeostasis efficiently in terms of electrolyte profile, endocrine functions and haemato-biochemical traits in different life phases, including the gestation period, even in high-saline coastal areas of hot-humid tropics. Crossbreeding to improve its growth rate has been attempted, but the prolificacy has been decayed. This review is intended to attract global attention to the adaptive potentialities of Black Bengal goats in terms of growth and production, haemato-biochemical, endocrinological, salt tolerance and disease characteristics that could be an asset of climate-resilient agricultural farming.

B-mode ultrasound and ecobiometric parameters to assess embryonic and fetal development and estimate gestational age in goats

The aim of this study was to monitor maternal-fetal ecobiometric parameters during physiological pregnancy in goats using ultrasound to predict gestational age by establishing mathematical equations. Twenty-five Saanen goats were included in the study. Assessments were performed weekly from the 21^st day of pregnancy until parturition. The abdominal, thoracic, biparietal, and eye socket diameters; distance from the neck to snout; crown-rump, humerus, radius-ulna, metacarpal, femur, tibia, metatarsal, and placentome lengths; kidney height and length; and heart area were measured. Heart rate was obtained using the pulsed Doppler mode. The variables were correlated with gestational age using Spearman's test, and the adjustment of these variables to simple and multiple regression models was done to determine the mathematical formulas for calculating the gestational age. The highest obtained coefficients of determination (R²) were for humerus length (96.2), heart area (95.6), and distance from the neck to the snout (95.3). Only the placentome length and fetal heart rate presented low determination coefficients (R² = 54.3, R² = 45.0). The results indicated significant correlations between measures of maternal-fetal structures and gestational age, and can be used as reference values for detection of abnormalities during fetal development.

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.

Uterine blood flow, fetal heart rate, gestational length, and fetal birth weight variability in response to maternal temperament in the goat

This prospective study was designed to investigate the effects of maternal temperament on uterine blood flow, fetal heart rate, gestational length, and fetal birth weight in a goat experimental model. Based on the arena test, behavioral testing related to fear-eliciting stimulus, goats were divided into nervous (n = 13) and calm (n = 11) groups. After mating, the perfusion of maternal uterine arteries (UTAs) and its related Doppler parameters, blood flow volume (BFV), time-averaged mean velocity (TAMEANV), acceleration (Acce), and resistance impedance (S/D), were evaluated biweekly from week two until the end of pregnancy. Fetal heart rate (FHR) was investigated during the pregnancy in addition to the gestation length (GL) and fetal birth weight (FBW). The UTA-BFV and TAMEANV, as well as Acce and S/D, were influenced by maternal temperament (p < .05). The FHR showed no significant changes between experimental animals of different temperaments (p = .81). Both GL and FBW were increased in calm rather than nervous goats (p < .05). These results indicated that the maternal nervous (temperament) have negative impacts on uterine artery Doppler indices, fetal growth, and gestational length in a goat experimental model.

Assessment of pregnancy-associated glycoprotein profile in milk for early pregnancy diagnosis in goats

Objective

This study was conducted to assess the level of pregnancy-associated glycoprotein (PAG) in whole and skim milk samples, and its suitability for early pregnancy diagnosis in goats.

Methods

A two-step sandwich enzyme-linked immunosorbent assay (ELISA) system for estimation of milk PAG was developed and validated, which employed caprine-PAG specific polyclonal antisera. Whole and skim milk samples (n = 210 each) from fifteen multiparous goats were collected on alternate days from d 10 to d 30, and thereafter weekly till d 51 post-mating. PAG levels in milk samples were estimated by ELISA and the pregnancies were confirmed at d40 post-mating by transrectal ultrasonography (TRUS).

Results

The level of PAG in whole and skim milk samples of both pregnant and non-pregnant goats remained below the threshold values until d 24 after mating. Thereafter, PAG concentration in whole and skim milk increased steadily in pregnant goats, whereas it continued below the threshold in non-pregnant does. The PAG profiles in whole and skim milk of pregnant goats were almost similar and exhibited strong positive relationship (r = 0.891; p<0.001). Day 26 post-mating was identified as the first time-point for significantly (p<0.05) higher milk PAG concentration in pregnant goats than to non-pregnant goats. When compared to TRUS examination for pregnancy diagnosis, the accuracy and specificity of PAG ELISA using whole and skim milk samples were 94.5% and 95.4%; and 95.3% and 100%, respectively. The high values of area-under-curve (0.904 [whole milk] and 0.922 [skim milk]), demonstrate outstanding discrimination ability of the milk assays. Among the sampling dates chosen, d 37 post-mating was identified as the best suitable time point for collection of milk samples to detect pregnancy in goats.

Conclusion

The PAG concentration in whole and skim milk of goats collected between days 26 and 51 post-breeding can be used for the accurate prediction of pregnancy and may be useful for assisting management decisions in goat flocks.

Follicle stimulating hormone receptor gene polymorphism and its association with fecundity in goats

Pluriparous goats (73) in between second to fifth parity with history of breeding 30 days before were selected for present study. A real time B-mode ultrasonography machine equipped with a linear array 7.5 MHz transrectal scanner was used for diagnosis of early pregnancy and twinning in goats. Out of 73 goats, 40 were detected pregnant with 22 goats with single embryo and 18 goats with twin embryos. Genomic DNA was extracted from the blood of all pregnant goats and polymerase chain reaction (PCR) with FSHR gene specific primers was carried out. The PCR product for FSHR gene was digested by restriction enzyme MSCI. Two genotypes AA and AB having amplification size (214 bp, 90 bp) and (214 bp, 90 bp and 304 bp) were detected, respectively. In AA genotype, 21 single and 9 twins were observed while 1 single and 9 twin embryos were observed in AB genotype. The percentage of single and twins was 70% and 30% in AA genotype, and 10% and 90% in AB genotype. In AA genotype, the average litter size was 1.3 while in AB genotype it was 1.9 and the difference was statistially significant. The AB genotype for the FSHR gene is responsible for more twining percentage.

Reference values for fetal heart rate in cattle in the first trimester of pregnancy

The aim of this study was to create a fetal heart rate (FHR) reference curve for singleton bovine fetuses in the first trimester of gestation and to determine its possible relationship with the outcome of pregnancy. Forty-eight Holstein-Friesian cows with one fetus and five cows with twins were used. Fetal heart beatings were recorded on videotape during transrectal scanning with a 5 and/or 7.5 MHz linear array transducer on a weekly basis between Days 40 and 95 of gestation. FHR was calculated by averaging the results of five counts of the same record by the same observer. For singleton pregnancies, a reference curve was created using the mean, the standard deviation (SD) and the 5th and 95th percentiles. The FHR increased from Days 40-46 (173 beats/min) to Days 61-67 (183 beats/min). After a peak, the FHR decreased slowly until Days 89-95 (175 beats/min), while the SD increased. There was no significant difference between singleton and twin fetuses. in the aborted and lost fetuses in twin gestation due to fetal reduction, both bradycardia and tachycardia were detected compared to the singleton pregnancy reference curve.

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.

Transrectal ultrasound evaluation in tropical dairy goats: an indispensable tool for the diagnosis of reproductive disorders

In Brazil, great milk productivity was achieved after the implementation of a genetic improvement program. However, reproductive efficiency is still far from optimal, possibly due to the high number of undiagnosed disorders that may affect fertility. The aim of this study was to evaluate occurrences of the main reproductive disorders in dairy goats in southeastern Brazil. Data were collected between January 2015 and May 2017 from 23 commercial herds of different breeds, with goats ranging from 8 months to 12 years of age. Transrectal ultrasound exams were performed in 2680 goats. A total of 14.8% of the does showed a disorder in the reproductive tract: hydrometra (10.0%), ovarian follicular cysts (2.3%), gestational loss (1.5%), and hydrosalpinx (1.1%). This was the first study evaluating reproductive disorders in live animals that used a high number of Brazilian dairy goats. Considering that all these diseases affect fertility to different degrees, the performance of transrectal ultrasonography exams twice a year is strongly suggested, in order to guide precocious treatment or discard the animal as soon as possible, thus reducing economic losses in dairy goat farming.

Early and efficient pregnancy diagnosis in ewes: expression profile of ISG15 mRNA in peripheral blood leucocytes compared to transrectal ultrasonography

The objective of this study was to compare the measurement of one of interferon-tau stimulated genes (ISGs; ISG15) expression in peripheral blood leukocytes (PBLs) with transrectal ultrasonography (TUSG) for early pregnancy detection in ewes. Ewes (46) were examined 18 and 25 days after mating by TUSG. PBL samples were collected from 16 pregnant ewes on the day of mating (d0) and on days 15 and 18 after mating. Total RNAs were extracted from PBLs and converted to cDNA. ISG15 mRNA expression was detected using qPCR in triplicate. All pregnancies were confirmed by birth. In TUSG examinations on day 18, the embryonic vesicle and embryonic vesicle plus the embryo were visible for 14 and 32 ewes, respectively, of the 46 total. Both the embryonic vesicle and embryo were detected in 42 ewes on day 25. Four ewes out of 46 with a visible embryonic vesicle on day 18 were detected as non-pregnant on day 25. While significant differences in ISG15 mRNA expression levels of PBLs were detected in 13 of 16 ewes on day 15, ISG15 mRNA levels for all ewes were significantly different on day 18, compared with levels on the day of mating. The results suggested that profiles of ISG15 mRNA can provide pregnancy detection earlier than TUSG.

Effects of pH during liquid storage of goat semen on sperm viability and fertilizing potential

A specific problem in goat semen preservation is the detrimental effect of seminal plasma on sperm viability in extenders containing yolk or milk. Thus, the use of chemically defined extenders will have obvious advantages. Although previous studies indicate that the initial pH of an extender is crucial to sustain high sperm motility, changes in extender pH during long-term semen storage have not been observed. Monitoring extender pH at different times of semen storage and modeling its variation according to nonlinear models is thus important for protocol optimization for long-term liquid semen preservation. The present results showed that during long-term liquid storage of goat semen, both sperm motility and semen pH decreased gradually, and a strong correlation was observed between the two. Whereas increasing the initial extender pH from 6.04 to 6.25 or storage with stabilized pH improved, storage with artificially lowered pH impaired sperm motility. Extender renewal improved sperm motility by maintaining a stable pH. Sperm coating with chicken (Gallus gallus) egg yolk improved motility by increasing tolerance to pH decline. A new extender (n-mZAP) with a higher buffering capacity was formulated, and n-mZAP maintained higher sperm motility, membrane integrity and acrosome intactness than the currently used mZAP extender did. Goat semen liquid-stored for 12 d in n-mZAP produced pregnancy and kidding rates similar to those obtained with freshly collected semen following artificial insemination. In conclusion, maintenance of a stable pH during liquid semen storage dramatically improved sperm viability and fertilizing potential.

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.

Accuracy of B-mode ultrasonography for diagnosing pregnancy and determination of fetal numbers in different breeds of goats

A total of 150 does of different breeds were used to evaluate the accuracy of transrectal (TRU) and transabdominal ultrasonography (TAU) for pregnancy diagnosis and fetal number estimation and to study the effect of breed and age of goats on the accuracy of ultrasonography. All does were scanned by TRU at days 17-22, 24-29 and 31-36 and by TAU at days 39-44 and 46-51 after breeding. The sensitivity (Se) of TRU for detecting pregnant does increased significantly (81.6% vs. 97.7%; P<0.0005) from days 17-22 to 24-29. There was a significant (P<0.05) effect of breed of goats on the specificity (Sp) of TAU for diagnosing non-pregnancy between days 39 and 51. In addition, there was a significant (P<0.01) effect of breed of goats on the Se and Sp of TRU for determination of does carrying multiples and singles, respectively, between days 24 and 36. The sensitivity of TAU for diagnosing pregnant does tended to be significantly (P=0.06) higher in young does (1.5-2 yr) than in older does (>2-9 yr) at days 39-44. The accuracy of TRU for determination of does carrying singles was significantly (P<0.05) higher in young does than that in older ones at days 24-29. In conclusions, TRU could be accurately used for early pregnancy diagnosis and fetal number estimation at days 24-29 and days 31-36, respectively, with accuracy similar to that of TAU at days 39-51. Furthermore, breed and age of does might influence the accuracy of ultrasonography for pregnancy diagnosis and fetal numbers estimation.

Effects of prostaglandin administration 10 days apart on reproductive parameters of cyclic dairy nulliparous goats

This study reported the effects of prostaglandin (PGF2a) administration 10 days apart on reproductive parameters of cyclic artificial inseminated (AI) nulliparous Alpine (n=9) and Saanen (n=9) goats. Animals received two doses of 22.5mg PGF2a 10 days apart. After 1st and 2nd PGF2a administrations, estrus was monitored at 12 h intervals, with a buck teaser. Plasma progesterone concentration (ng/mL) was determined from blood sampled on day 0 (1st PGF2a) and the following 5, 10 (2nd PGF2a), 15, 20, 25 and 30 days. After the onset of the second estrus, females were transrectally (5 MHz probe) scanned at 4 hour intervals until at least 8h after ovulation. Pregnancy was checked through transrectal ultrasound on days 20, 25, 30, 35 and 90 after insemination. All parameters studied did not differ between breeds (P>0.05). Estrous response and interval to estrus, respectively, after 1st (78.9% and 50.6±17.2h) and 2nd PGF2a (88.9% and 50.0±14.8h) administration did not differ (P>0.05). Overall animals ovulating (100.0%), interval to ovulation after 2nd PGF2a (64.5±19.5h) and after estrous onset (18.0±9.1h), ovulation rate (1.3±0.5), diameter of ovulatory follicle (8.1±1.1mm) were recorded. Embryo loss occurred before day 30 of pregnancy. Estrus can be efficiently synchronized in nulliparous Alpine and Saanen goats with two doses of prostaglandin 10 days apart.

Influence of the preservation temperature (37, 20, 4, -196°C) and the mixing of semen over sperm quality of Majorera bucks

This study assessed the effect of different semen storage temperatures and the influence of semen pooling in semen viability. In experiment 1, semen samples (n = 30) of five Majorera bucks were individually processed [Individual semen (IS)] and after the first dilution (Tris-yolk extender), semen-diluted aliquots from each male were pooled semen (PS). Thereafter, semen samples (IS and PS) were preserved as fresh semen (37 and 20°C), chilled semen (4°C) and frozen semen. Sperm motility and the percentage of abnormal sperm cells and intact membrane acrosomes were defined. Semen preservation at 20 and 4°C did not modify the quality of spermatozoa for the first 24 h, but the conservation at 37°C caused a dramatic fall in the semen motility from 12 h onwards. Furthermore, the longevity of frozen-thawed semen was limited to 4-6 h. No differences were observed in semen parameters when PS was compared with semen from individual males in any of the preservation protocols assessed. In experiment 2, 120 goats were distributed in four experimental groups: in group fresh individual semen (FIS, n = 30) and group frozen-thawed individual semen (FTIS, n = 30), does were transcervically inseminated with fresh semen and frozen-thawed semen from each individual male, respectively, and in group fresh pooled semen (FPS, n = 30) and group frozen-thawed pooled semen (FTPS, n = 30), goats were transcervically inseminated with FPS and FTPS, respectively. The kidding rate was very close in the FIS and FPS groups (70.0% and 73.7%, respectively), and no significant differences were observed in the fertility rate between FTIS and FTPS. The results of this study confirmed that semen samples may be preserved satisfactorily for 24 h both at 20 and 4°C. In addition, the mixture of semen of different bucks did not significantly modify the semen parameters when compared with semen from individual males.

Ultrasonographic imaging in small ruminant reproduction

CONTENTS

Ultrasonography is a simple, reliable and non-invasive imaging technique without secondary effects. Application of ultrasonography in veterinary practice, and specifically in small ruminants, has developed to become the most efficient diagnostic tool for managing reproduction. The objectives of current revision are to offer an overview, after a short reminder of equipment and techniques for imaging genitalia in small ruminants, of the uses and utility of ultrasonography for the evaluation of physiological and pathological conditions in males and females and for the application of assisted reproductive technologies.

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.

Follicular and Hormonal Dynamics during the Estrous Cycle in Goats

Transrectal ultrasonography of ovaries was performed daily in 6 goats for 3 consecutive estrous cycles. Blood samples collected daily were measured for concentrations of FSH, inhibin A, and estradiol-17beta. Follicular and hormonal data were analyzed for associations between the follicular waves and hormonal concentrations. During the interovulatory intervals, follicular growth and regression occurred in a wave like pattern (2-5 waves), and the predominant patterns were three and four follicular waves. In addition, there was no significant difference among the diameters of dominant follicles during the growth phase of the follicular waves. The number of 3 mm follicles peaked on days 0, 7, and 11 in interovulatory intervals that had three follicular waves and on days -1, 5, 11, and 15 in those that had four follicular waves. Plasma concentrations of FSH increased around the day of follicular wave emergence and declined with the growth of follicles. Circulating FSH increased again concomitant with regression of dominant follicles in the anovulatory wave, whereas FSH levels remained low in the ovulatory wave. Inhibin A was negatively correlated with FSH, while it was positively correlated with estradiol-17beta, suggesting that inhibin A is a product of healthy growing follicles and that it contributes to the suppression of FSH secretion. In conclusion, the growth of ovarian follicles in goats exhibits a wave-like pattern, and follicular dominance is less apparent in goats. Moreover, inhibin A may be a key hormone for regulation of the follicular wave through suppression of FSH secretion in goats.

A comparison of diagnosis of pregnancy in the goat via transrectal ultrasound scanning, progesterone, and pregnancy-associated glycoprotein assays

Real-time ultrasound scanning (US) via the transrectal route, progesterone (P4) assay, and pregnancy-associated glycoprotein (PAG) detection can be used to diagnose pregnancy at around 3 weeks after breeding. Although several studies have been carried out to evaluate each of these different methods individually, it is difficult to establish adequate comparisons due to differences, such as the breed of goat, age, and farming conditions, among others. The aim of the present paper is to compare the accuracy of diagnosis of pregnancy using transrectal US, P4 assay and PAG detection at the same time and on the same animals. Canary dairy goats (n=143) were synchronized with an 11-day fluorogestone acetate (FGA) intravaginal sponge followed by PGF2alpha and eCG 2 days before the FGA withdrawal. Blood samples were collected on Days 20, 22, 24, and 26 after mating to determine P4 and PAG concentrations. Transrectal US examinations were performed at the same time. There were 79 pregnant goats and another 64 non-pregnant. The US via the transrectal method and the determination of PAG concentrations provide very accurate pregnancy diagnosis at 24-26 days after breeding; on the contrary, P4 assay on plasma samples performed on Day 22 after breeding was accurate, in this case, in detecting pregnant animals but did not always detect the non-pregnant does.

Early Pregnancy Diagnosis by Means of Ultrasonography as a Method of Improving Reproductive Efficiency in Goats

Eighteen cyclic Shiba goats were used in this study. Estrus was synchronized with a single injection of 125 microg of a synthetic analogue of prostaglandin F(2)alpha (PGF(2)alpha) after detection of at least one corpus luteum by B-mode ultrasonography. Blood samples were collected from each animal on days 0, 7 and 21 post-mating for progesterone assay. Animals in estrus were either allowed to be mated by fertile bucks twice during estrus (group I; n=12) or not at all (group II; n=6). Ultrasonographic examinations were performed transrectally or transabdominally using a real-time B-mode scanner equipped with a 7.5 or 5 MHz transducer. All animals exhibited estrus 56.0 +/- 2.7 h after injection of PGF2alpha. The results show that the accuracy of the progesterone assay in diagnosing pregnancy on day 21 after mating was 80% for pregnancy and 100% for non-pregnancy, retrospectively. Ultrasonographic examinations showed that gestational sac and embryos heartbeats were detected on days 20.2 +/- 0.6 and 24.3 +/- 0.7 of gestation, respectively. Placentomes were detected on day 35.4 +/- 1.0 of gestation as small nodules (0.7 +/- 0.2 cm in size). At two months pregnancy, skeletal structures like skull, thorax and long bones were clear. Biparietal diameter of the skull and length of long bones could be used as an estimate of gestational age. The accuracy of detection of fetal number using real-time B-mode ultrasonography was 91.7% on day 60 of gestation. In conclusion, progesterone assay at day 21 post-mating (cut-off value, 1 ng/ml) can be used for pregnancy diagnosis in goats. However, B-mode transrectal ultrasonography was more efficient due to detection of embryo and confirmation of its viability by heartbeats. In addition, fetal number and gestational age could be determined only by ultrasonography.

Pregnancy-associated glycoproteins (PAG) detection in milk samples for pregnancy diagnosis in dairy goats

In ruminants, glycoproteins synthesized in the outer layers of the trophoblast enter the maternal bloodstream. The assay of their concentration in plasma or in serum can be used for pregnancy diagnosis and to indicate feto-placental health status. In this study, concentrations of the pregnancy-associated glycoprotein (PAG) were investigated in the milk of dairy goats. The mean concentrations of PAG in milk were significantly higher in pregnant than in non-pregnant goats throughout the sampling period. Positive milk PAG levels were found in all pregnant animals from Day 32 after breeding, but remained at negative values in nonpregnant ones. This study reports for the first time a pregnancy diagnosis based on milk concentrations of PAG, that could be of great use on the farm.

Advanced reproductive techniques in goats

The use of ultrasonography for pregnancy diagnosis and reproductive tract evaluation in the goat has become more common in the past decade. Pregnancy-specific hormone assays are commercially available for pregnancy determination in goats. Hormonal methods of synchronization of estrus for artificial insemination have been refined, but a number of factors still make pregnancy results variable. Caprine embryo transfer is widely used commercially. More advanced reproductive techniques such as in-vitro production of embryos and cloning have been accomplished in goats; success rates with these techniques will likely rapidly improve.

Early pregnancy diagnosis in goats by determination of pregnancy-associated glycoprotein concentrations in plasma samples

Different RIA systems available for measuring the concentrations of pregnancy-associated glycoproteins (PAGs) in dairy goats were compared in order to evaluate their accuracy in early pregnancy diagnosis. Plasma concentrations of PAGs were determined by 3 heterologous RIA systems with a bovine PAG standard and tracer in combination with antisera anti-ovine PAG (RIA 1), anti-caprine PAG55 + 62 (RIA 2), anti-caprine PAG55 + 59 (RIA 3), and by 2 homologous RIA systems that employed caprine PAG55 + 62 and caprine PAG55 + 59 and their specific antisera (RIAs 4 and 5, respectively). In all of the RIAs, the mean concentrations of PAGs were significantly higher (P < 0.01) in pregnant than in nonpregnant goats from Day 21 onwards after breeding. On Day 21, the accuracy rates of early pregnancy diagnoses were 56% (RIA 1), 96% (RIA 2), 99% (RIA 3), 95% (RIA 4) and 90% (RIA 5), whereas on Day 28 these rates were > 99% for RIAs 2, 3, 4 and 5. The RIAs for PAGs depend on proteins from the placenta being present in maternal plasma and require only a single sample of blood, to distinguish pregnant goats from those that fail to return to estrus for other reasons. The homologous and semi-heterologous assays are highly accurate as early as Day 21 of pregnancy.