Evaluation of a long-acting recombinant bovine FSH for multiple ovulation and embryo transfer in dromedary camels

The present study was conducted to test a new super-agonist recombinant bovine FSH (rbFSH) to induce superovulation (SOV) in dromedary camels. In experiment I, a single IM injection of 40, 60, 80, 100, or 120 µg rbFSH was administered (4 donors per group) to determine the effective dose resulting in acceptable multiple ovulation and embryo yield. Administration of 40 µg was ineffective, while 100 and 120 µg were associated with increased numbers of developed follicles, corpora lutea, and recovered embryos compared to administration of 60 and 80 µg. In experiment II, donors were divided into treatment groups to compare rbFSH with two conventional protocols for SOV. Donors received a single dose of 2000 IU eCG in combination with 400 mg porcine follicle-stimulating hormone (pFSH; Folltropin-V®; Group 1, n = 29) or 500 µg of pFSH with 100 µg of pLH (Stimufol®; Group 2, n = 16). Group 3 (n = 19) received a single dose of 100 µg rbFSH. No difference was found in the size and number of follicles per donor. Response time, ovulation rate, and the number of corpora lutea and recovered embryos per donor were similar in all groups. The number of medium-sized and transparent embryos decreased while the number of small-sized and semi-transparent embryos increased in Group 3 (rbFSH) compared to the other two groups. The pregnancy rate of the recipients at 10 days post-ET, at two months of gestation, and the rate of early pregnancy loss (EPL) did not differ among the groups. In conclusion, a single IM administration of 100 µg rbFSH induces a successful superovulation in dromedary camels and has the advantage of reducing stress associated with multiple FSH administration of the conventional protocols.

Comparison between trans-vaginal and recto-vaginal techniques for transferring embryos in the dromedary camels

The present study was conducted in two breeding seasons to compare the effect of two non-surgical techniques for embryo deposition intrauterine, trans-vaginal (TV) versus recto-vaginal (RV) techniques, on the pregnancy rate and early pregnancy loss (EPL) in dromedary camels. Embryos were collected from 70 donors and transferred to 210 recipients by TV (n = 256 transfers) or RV technique (n = 186 transfers). Pregnancy diagnosis was conducted on Day 10 after embryo transfer (ET) by using the progesterone-ELISA test and by trans-rectal ultrasonography at Day 60 of gestation. EPL was calculated as the recipients that were diagnosed pregnant on Day 10 post-ET and lost their pregnancy between Days 20-60 of their gestation. Using the RV technique in ET of a single embryo showed higher pregnancy rates at Day 19, especially with the embryos of folded, semi-transparent shapes, or those collected after superovulation with the recovery of >4 embryos per flush. While, the pregnancy rates at 60 days showed increases after ET with the RV technique of single, folded, transparent, and semi-transparent, medium-size embryos and/or those collected after superovulation with any number of the recovered embryos than those transferred by the TV technique. The rate of EPL was increased when the TV technique was used for ET of single, spherical, folded, semi-transparent, medium-sized embryos and those collected without or with the superovulation and recovery of >4 embryos per flush. In conclusion, using the RV technique to deposit the embryos intrauterine improves the pregnancy rate and reduces EPL compared to the TV technique.

Factors affecting outcomes of embryo transfer in dromedary camels: a retrospective study

The present study aimed to use a comprehensive approach for evaluating 12 factors related to embryo quality (shape, size and transparency), donors (age, ET type, number of recovered embryos and day of uterine flushing), recipients (age), males (age and individual variations), and environment (season and year) which could affect the outcome of ET in terms of pregnancy (PR) and pregnancy losses in dromedary camels. During three breeding seasons, 116 donors females were mated repeatedly at 12 to 14-day intervals by fertile camel males (n=33) without stimulation of the ovaries (WSPO). Superovulation (SPO ET) regimen was applied for each donor female twice or thrice per season. In the occasions of applying superovulation regimen, donor females having an ovulatory follicle were mated instead of GnRH administration and superovulation regimen was applied 4 days post-mating (MIX ET). The uteri of all donor females were flushed at Day 8 or 9 post-mating and a total of 2095 embryos were recovered and transferred individually to 924 recipient females. Pregnancy diagnoses were conducted at Day 10 after ET (Days 18 to 19 of gestation) by using progesterone assay and by transrectal ultrasonography (TRU) at Days 30 and 60 of gestation. By using logistic regression analysis, transparency of embryos and age of recipient females had significant effects on PR at Days 18 to 19 (P< 0.01), 30 (P < 0.01) and 60 (P < 0.01; P < 0.05, respectively) of gestation. The shape of embryos had significant effects on the PR at Days 30 (P < 0.05) and 60 (P < 0.01) of gestation. Type of ET and the breeding season (year) had significant (P< 0.05) effects on the PR at Day 30, while day of flushing had the same effect on PR at Day 60. Regarding the pregnancy losses, transparency and shape of the embryo, type of ET, breeding season had significant (P<0.05) effect on the late embryonic mortalities (LEM) and shape and season of year had significant (P<0.01 and P< 0.05, respectively) effect on LEM/early fetal mortalities (EFM). Regarding male individual factor, there was a tendency for a significant (P =0.055) effect of camel males on the PR at Days 18 to 19 and rate of LEM. In conclusion, transferring a spherical, transparent or a large-sized embryo (> 750 µm) into recipient females aging between 8 and 11 y could greatly improve the PR from Days 18 to 60 of gestation. Also, embryo recovered from donor females with Mix ET type or embryos sired by certain camel male or at Day 8 post mating of the donor could improve the two-month PR. In addition, transferring a transparent or spherical-shaped embryo or embryos recovered from donor females with SPO or Mix ET could reduce the pregnancy losses during the first two months of pregnancy.

Factors affecting pregnancy rates and pregnancy losses after embryo transfer in dromedary camels

The present study was conducted to estimate incidence of late embryonic and early fetal mortalities (LEM/EFM) after embryo transfer (ET) and to investigate factors that could affect proportions of LEM/EFM in dromedary camels. The uteri of 180 donors were flushed at Day 9 post-mating and 1309 ETs were conducted in 886 recipient females in two breeding seasons (2014-2015 and 2015-2016). Pregnancy diagnosis was conducted at Day 10 after ET (Day 19 of gestation) by using the progesterone-ELISA test and by transrectal ultrasonography at Day 60 of gestation. Pregnancy rates at Days 19 and 60 and proportions of LEM/EFM were 54.5%, 34.1%, and 37.5%, respectively. Using logistic regression analysis for evaluations, shape of embryos had an effect (P < 0.01) on pregnancy rates at Days 19 and 60. Also, number of recovered embryos per uterine flushing and breeding season (year) had an effect (P < 0.05) on pregnancy rates at Day 19 and 60, respectively. Regarding rate of LEM and EFM, size of embryos and year of ET had effects (P < 0.01 and P < 0.05, respectively) on the values for these variables. In conclusion, there is a marked occurrence of LEM/EFM in recipient females between Days 20 and 60 of gestation in dromedary camels. The pregnancy rate after ET might be affected by the shape and number of recovered embryos and the year. In addition, the rate of LEM/EFM after ET might be affected by the year and size of the embryos.

Passive immunization against inhibin increases testicular blood flow in male goats

The present study investigated whether or not passive immunization against inhibin modulates testicular blood flow in goats. Male Shiba goats were injected with either 10 ml of inhibin antiserum (INH group; n = 5) or 10 ml of normal castrated goat serum (NGS group; n = 4). Concentrations of FSH, LH, testosterone (T), and estradiol (E2) in the plasma were measured by radioimmunoassay. Blood flow within the supratesticular (STA) and marginal testicular arteries (MTA) were measured by color pulsed-Doppler ultrasonography, and Doppler indices (resistive index; RI and pulsatility index; PI) were recorded. Results revealed significant increases in concentrations of FSH and E2 in the INH group compared to those in the NGS group (P < 0.05). Animals in the INH group had greater (P < 0.05) FSH concentrations than those in the NGS group in the period between 60 h and 144 h after treatment than at any other time. Estradiol concentrations were greater (P < 0.05) in the INH group than in the NGS group at 6 h (12.15 ± 2.09 pg/ml vs 5.49 ± 1.17 pg/mL), 12 h (8.27 ± 1.29 pg/mL vs 3.05 ± 0.38 pg/mL), and 36 h (9.35 ± 1.31 pg/mL vs 5.09 ± 0.46 pg/mL) after treatment than at any other time. Concentrations of LH and T did not significantly change between the two groups. Goats in the INH group had lesser (P < 0.05) RI of the STA than those in the NGS group and RI values were lesser at 24 h (0.37 ± 0.031 vs 0.49 ± 0.004) and 120 h (0.38 ± 0.028 vs 0.55 ± 0.048) after treatment than at any other time. Furthermore, values of RI and PI of the MTA were significantly lesser (P < 0.05) in the INH group compared to those in the control group at 48 h (RI of MTA: 0.21 ± 0.014 vs 0.37 ± 0.039; PI of MTA: 0.24 ± 0.016 vs 0.46 ± 0.058) after treatment than at any other time. In conclusion, passive immunization against inhibin has a stimulatory effect on testicular blood flow in goats by inducing decreases in the RI values of the STA and MTA.

Effect of a single injection of gonadotropin-releasing hormone (GnRH) and human chorionic gonadotropin (hCG) on testicular blood flow measured by color doppler ultrasonography in male Shiba goats

Although color Doppler ultrasonography has been used to evaluate testicular blood flow in many species, very little has been done in goat. Eight male Shiba goats were exposed to a single intramuscular injection of either gonadotropin-releasing hormone (GnRH group; 1 µg/kg BW) or human chorionic gonadotropin (hCG group; 25 IU/kg BW). Plasma testosterone (T), estradiol (E2) and inhibin (INH) were measured just before (0 hr) and at different intervals post injection by radioimmunoassay. Testis volume (TV) and Doppler indices, such as resistive index (RI) and pulsatility index (PI) of the supratesticular artery, were measured by B-mode and color Doppler ultrasonography, respectively. The results indicated an increase in testicular blood flow in both groups, as RI and PI decreased significantly (P<0.05), but this increase was significant higher and earlier in hCG group (1 hr) than in the GnRH group (2 hr). A high correlation was found for RI and PI with both T (RI, r= −0.862; PI, r= −0.707) and INH in the GnRH group (RI, r=0.661; PI, r=0.701). However, a significant (P<0.05) correlation was found between E2 and both RI (r= −0.610) and PI (r= −0.763) in hCG group. In addition, TV significantly increased and was highly correlated with RI in both groups (GnRH, r= −0.718; hCG, r= −0.779). In conclusion, hCG and GnRH may improve testicular blood flow and TV in Shiba goats.

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.

Relationship of progesterone, bovine pregnancy-associated glycoprotein-1 and nitric oxide with late embryonic and early fetal mortalities in dairy cows

The aim of the present study was to determine the relationship of progesterone (P4), bovine pregnancy-associated glycoprotein-1 (bPAG-1) and nitric oxide (NO) levels with late embryonic (LEM; day 28 to day 42) and early fetal mortalities (EFM; > day 42 to day 56) in dairy cows. Transrectal ultrasonography (6-8 MHz) was performed in 100 Holstein-Friesian cows at days 28, 42 and 56 after artificial insemination (AI; day 0) to diagnose pregnancy and to monitor the fate of the embryo. After ultrasound scanning of each cow, a milk sample was collected for assessment of P4 by an ELISA test and a blood sample was collected for assessment of bPAG-1, by using a double-antibody radioimmunoassay, and serum NO metabolites (nitrate + nitrite). Based on ultrasonographic examinations and bPAG-1-RIA, 41 of 100 inseminated cows were confirmed pregnant at day 28 after AI. Nine cows suffered of LEM, and 6 cows suffered of EFM and the overall pregnancy loss rate was 36.6% (15/41) between days 28 and 56 of pregnancy. By logistic regression analysis, there were no significant relationships between the level of P4 and bPAG-1 at day 28 after AI and the occurrence of LEM and EFM. Also, there were no significant relationships between the levels of P4 and bPAG-1 at day 42 and the occurrence of EFM. On the other hand, a significant relationship (P<0.05) was found between NO level at day 28 and the occurrence of LEM. In conclusion, measurement of the serum NO concentration at day 28 of pregnancy might help to predict the outcome of pregnancy by day 42 in dairy cows but further studies are needed to confirm this.

Effect of restraint stress on plasma concentrations of cortisol, progesterone and pregnancy associated-glycoprotein-1 in pregnant heifers during late embryonic development

The aim of the present study was to evaluate the effect of restraint stress, which is commonly practised in the field, on plasma concentrations of cortisol, progesterone (P4) and bovine pregnancy-associated glycoprotein-1 (boPAG-1) in pregnant heifers between Days 30 to 40 of gestation. Twelve Holstein-Friesian heifers between Days 30 (Day 0 of experiment) and 40 (Day 10 of experiment) of pregnancy in a Hungarian dairy farm were used in the present study. The heifers were exposed to an acute stressor consisting of immobilisation (restraint stress) in a crush for 2 h (Group 1, n = 6) on Day 2 (Hour 48) and for 2 × 2 h (Group 2, n = 6) on Days 2 and 3 (Hour 72) of the experiment. Transrectal ultrasonography (7.5 MHz linear-array rectal transducer) was performed daily from Day 0 to Day 10 of the experiment to detect embryonic heartbeat or the fate of the conceptus. Blood samples were withdrawn before each ultrasonographic examination. Additional blood samples were withdrawn by 1 and 2 h (at Hours 49 and 50 in Groups 1 and 2 and Hours 73 and 74 in Group 2) of the onset of applying the stressor. Plasma cortisol, P4 and boPAG-1 concentrations were measured by radioimmunoassay. Acute restraint stress significantly (P < 0.001) increased the plasma cortisol level in pregnant heifers at 1 h of the exposure to the stressor at Days 2 (48 h) and 3 (72 h) of the experiment. On the other hand, the restraint stress did not affect the concentration of P4 and boPAG-1 concentrations in both groups. In conclusion, restraint stress for 2 h during early pregnancy in heifers increased blood cortisol, but it did not affect the concentrations of P4 and boPAG-1 between Days 30 to 40 of gestation.

Accuracy of ultrasonography and pregnancy-associated glycoprotein test for pregnancy diagnosis in buffaloes

The aims of the present study were to evaluate and compare the accuracy of transrectal ultrasonography and pregnancy-associated glycoprotein radioimmunoassay (PAG-RIA) test for diagnosis of pregnancy in buffaloes. Two hundred and seventy-five buffalo cows and heifers were examined once for pregnancy diagnosis by transrectal ultrasonography using a 5 MHz linear-array transducer between Days 19 and 55 after mating. After ultrasound scanning, a blood sample was withdrawn from jugular vein of each animal for measuring pregnancy-associated glycoprotein using a heterologous double-antibody RIA. Based on palpation of the uterus per rectum at Days 75-90, 87 animals were designated pregnant and 188 as non-pregnant. The sensitivity of transrectal ultrasonography at Days 19-24 was 44.4%, reaching 100% from Day 31 after mating. The specificity of transrectal ultrasonography ranged between 92.5 and 100% from Days 19 to 55 after mating. The sensitivity of PAG-RIA test was 11.1% at Days 19-24 and reached 100% from Day 31 after mating. The specificity of PAG-RIA test ranged from 90 to 100% from Days 19 to 55 after mating. There were no significant differences between the sensitivity and specificity of the two tests in all examined periods. In conclusion, transrectal ultrasonography and PAG-RIA test are highly accurate tests for detecting pregnant buffaloes from Day 31 after mating onwards.

Measurement of Ovine Pregnancy-Associated Glycoprotein (PAG) During Early Pregnancy in Lacaune Sheep

This study describes ovine pregnancy-associated glycoprotein (ovPAG) concentrations in 20 Lacaune sheep during early pregnancy. Measurements were performed by using semi-purified ovPAG as standard, tracer and immunogens for antibody production in rabbits. Antisera R780 (against ovPAG(57+59kDa)) and R805 (against ovPAG5(58+61kDa)) were used respectively in RIA-780 and RIA-805. Blood samples were collected at days 0, 18, 20, 22 and 25 after artificial insemination. From day 18 after breeding onward, the mean ovPAG concentration was significantly higher (p < 0.001) in plasma samples from pregnant ewes (n = 17) than in non-pregnant ones (n = 3). The specific activity of the tracer was 11 760 Ci/mmol in RIA-780 and 14 900 Ci/mmol in RIA-805. The minimal detection limits for RIA-780 and RIA-805 were 0.2 ng/ml and 0.3 ng/ml, respectively. The intra-assay CV of samples with low (1.0 ng/ml), medium (2.5 ng/ml) and high (4.0 ng/ml) PAG concentrations were 3%, 6% and 9% for RIA-780 and 8%, 9% and 5% for RIA-805. The inter-assay CV in the same samples were 13%, 12% and 7% for RIA-780 and 13%, 11% and 5% for RIA-805. The recovery was higher than 95% in both assays. No cross-reaction was observed with members of aspartic proteinase family as well as with other tested proteins. In both RIA-780 and RIA-805, inhibition of the binding of the tracer by antisera was parallel between standard curve and serial dilutions of pregnant ewe samples. In conclusion, the two homologous RIA systems are suitable for early quantification of ovPAG concentrations in ewe plasma samples from day 18 after breeding.

Comparison of accuracy of transabdominal ultrasonography, progesterone and pregnancy-associated glycoproteins tests for discrimination between single and multiple pregnancy in sheep

The aim of the present study was to evaluate and, compare the accuracy of transabdominal ultrasonographic (US) and the progesterone (P4-RIA) and ovine pregnancy-associated glycoprotein (ovPAG-RIA) tests for the discrimination between single and multiple pregnancy in sheep. One hundred pregnant AwassixMerino ewes were scanned by transabdominal ultrasonography (3.5 MHz linear-array transducer) at Days 43-56 and 81 of these ewes were scanned at Days 76-87 of gestation. The ewes were scanned in dorsal recumbency at the bare area of the inguinal regions (without pre-scanning shaving of the ventral abdominal wall). After each scan, blood samples were withdrawn from the jugular vein to estimate the levels of P4 and ovPAG by radioimmunoassay. At lambing, 61 ewes gave birth to single lambs and 39 ewes gave birth to multiples. The sensitivity of the transabdominal US, the P4-RIA and the ovPAG-RIA tests for determining ewes carrying multiples was 54, 64.1 and 64.1% at Days 43-56. At Days 76-87 of gestation these accuracies were 60.0, 66.7 and 76.6% for the US, P4-RIA and PAG-RIA tests, respectively. The specificity of the transabdominal US, the P4-RIA and the ovPAG-RIA tests for determining ewes carrying singles, was 78.6, 60.7 and 62.3% at Days 43-56 and 78.4, 64.7 and 70.6% at Days 76-87 of gestation, respectively. It is concluded that the accuracy of transabdominal ultrasonographic (without pre-scanning shaving of the ventral abdominal wall), the P4- and the ovPAG-RIA tests for determination of the fetal numbers in AwassixMerino crossbred ewes is too low to be used in the field.

Effect of the type and number of prostaglandin treatments on corpus luteum, the largest follicle and progesterone concentration in dairy cows

Lactating dairy cows (n = 72) with a mature corpus luteum (CL) (diameter of > or = 17 mm) determined by ultrasonography and having a follicle with a diameter of > or = 10 mm were randomly assigned to four groups. Cows were treated with cloprostenol i.m. once or twice, or with dinoprost i.m. once or twice with an 8-h interval. The ovaries of each cow were scanned daily by transrectal ultrasonography to measure the changes in the areas of CL and the largest follicle and to determine the occurrence of ovulation. Oestrus was verified twice daily. In addition, blood sample was withdrawn from each cow daily for measuring progesterone (P4) concentrations. Significant decreases in the percentage changes relative to areas of CL and P4 concentrations or increases in the percentage changes in the area of the largest follicle on day 0 were detected in each group during the experiment. However, the type of the drug and the number of the treatments had no significant effect on those parameters. Cows ovulated with or without showing oestrus (group A) and cows exhibiting no oestrus and ovulation (group B) were also evaluated. In contrast to the mean area of the CL and the mean concentration of P4 on day 0, the mean area of the largest follicles between the two groups on day 0 differed significantly. Significant decreases in the percentage changes relative to the area of the CL and P4 concentration or increases in the percentage changes relative to the area of the largest follicle during the experiment were detected in both groups; however, there were no group differences. Treatment of dairy cows with two injections of prostaglandins (cloprostenol or dinoprost) at an 8-h interval resulted in more cows being observed in oestrus within 5 days after treatment and having significantly higher pregnancy rate than those treated with a single prostaglandin injection.

Accuracy of transrectal ultrasonography for determination of pregnancy in sheep: effect of fasting and handling of the animals

The present study was performed to investigate the effect of previous fasting and lifting of the abdomen of the ewes during transrectal ultrasonographic scanning on the results of early pregnancy diagnosis. Ewes of four flocks (A, B, C and D; all Awassi x Merino ewes, n = 1247 ) aged 0.7-10 years were used in this study. These ewes were estrus synchronized and artificially inseminated. From 2 weeks later onwards, fertile rams were kept with the ewes of flocks A, B and C ( n=949 ) for natural breeding, while ewes of flock D ( n=298 ) were re-inseminated 17 days later. Transrectal ultrasonography (5 MHz) was carried out in ewes of flocks A, B and C on four separate occasions but only once in ewes of flock D. For final analysis, animals were divided over two groups: ewes of Group 1 ( n=949 scans) were scanned in a standing position within the milking parlor. Animals of Group 2 ( n=764 scans) were scanned by the same operator and with the same scanning technique, but these ewes were fasted for 12h prior to scanning and the abdominal wall was lifted, just in front of the udder during scanning. The sensitivity of the test for diagnosing pregnancy at Days 18-24, 25-30, 31-40 and 41-50 was 21.8, 32.3, 63.3 and 50% in Group 1, and 46, 92.5, 92.3 and 96.8% in Group 2, respectively. Only within Group 1, the sensitivity of the test was higher in young ewes (0.7-2 years) than in older ones (>2-10 years). Significant differences were observed at scan periods Days 18-24 and Days 41-50 of gestation. It is concluded that, fasting prior to scanning and lifting the abdomen during scanning significantly improve the accuracy of transrectal ultrasonographic pregnancy diagnosis in Awassi x Merino ewes.

Evaluation of false transrectal ultrasonographic pregnancy diagnoses in sheep by measuring the plasma level of pregnancy-associated glycoproteins

The present study was undertaken to investigate to what extent pregnancy diagnoses made by transrectal ultrasonography could be confirmed by measurements of plasma concentration of ovine pregnancy-associated glycoproteins (ovPAG). A total of 424 Awassi x Merino ewes were synchronized for estrus and examined by transrectal ultrasonography. In Experiment 1, the ewes (n = 156) were repeatedly scanned in a standing position on d 29, 36 and 50 of gestation. Similarly, the ewes (n = 268) in Experiment 2 were scanned on d 24, 29 and 34 of gestation, but these ewes were fasted for 12 h prior to the examination and the abdominal wall of each animal was lifted up by the hands of the assistant during the scanning. Blood samples were withdrawn after each transrectal ultrasonographic examination in both experiments. Ovine PAG concentrations were measured in plasma by a heterologous radioimmunoassay and the cut-off value for pregnancy was > or = 1 ng.mL-1. Based on the lambing performance, in Experiment 1, altogether 47 false negative and 38 false positive diagnoses were made by transrectal ultrasonography in 24 and 33 ewes, respectively between d 29 and 50 of gestation. In Experiment 2, altogether 8 false negative and 13 false positive diagnoses both were made in 7 ewes between d 24 and 34 of gestation. In both experiments, all ewes with false negative diagnoses had ovPAG concentrations higher than the threshold level for pregnancy diagnosis and all ewes with false positive diagnoses had ovPAG concentrations lower than the threshold of pregnancy. Furthermore, by the PAG-RIA test all lambed or aborted ewes (n = 63) were correctly diagnosed as pregnant and with three exceptions, all non-lambed ewes (n = 361) were correctly diagnosed as non-pregnant during the examined periods of both experiments.

Early pregnancy diagnosis in sheep by progesterone and pregnancy-associated glycoprotein tests

The aim of this study was to compare the accuracy of the progesterone (P4) and pregnancy associated glycoprotein (PAG) tests for determination of early pregnancy in sheep. Estrus was synchronized in 182 Awassi x Merino ewes and blood samples were collected at Days 0 (day of the insemination), 18, 22, 29, 36, and 50 after artificial insemination (AI). Plasma P4 concentrations at Days 0 and 18 were determined by double antibody radioimmunoassay, while PAG concentrations at Days 22, 29, 36 and 50 were determined by a heterologous, double-antibody radioimmunoassay (RIA) using the bovine PAG 67 kDa subunit as tracer and standard and rabbit antiserum raised against a mixture of caprine 55 and 59 kDa PAG subunits as the first antibody. The discriminatory value for diagnosis of pregnancy by the P4 and the PAG-RIA tests was > or = 1 ng/ml. Based on lambing data, the accuracy for diagnosing pregnant (sensitivity) and non-pregnant ewes (specificity) and predictivity of both tests were calculated. The sensitivity, specificity, positive and negative predictive values for P4 and PAG tests were 100, 95.4, 81.6, and 100% at Day 18 (P4) and 93.5, 100, 100 and 98.7% at Day 22 (PAG), respectively. For diagnosis of non-pregnant ewes the PAG test had significantly higher specificity than the P4 test (P < 0.05). It is concluded that ovine pregnancy can be reliably diagnosed at Day 22 after AI by using a heterologous radioimmunoassay of PAG.