34 research outputs found

    Comparison of the ability of three radioimmunoassay to detect pregnancy-associated glycoproteins in bovine plasma

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    Pregnancy-associated glycoproteins (PAGs) constitute a large family of glycoproteins that are synthesized in the superficial layer of the ruminant placenta according to a spatial and temporal expression pattern. When PAGs are released in the maternal blood they can be used for pregnancy diagnosis, pregnancy follow-up and for the monitoring of the trophoblastic function. Three different radioimmunoassay systems (RIA 1, RIA 2 and RIA 3) using antisera produced against PAG I67 (RIA 1), PAG55+62 (RIA 2) and PAG55+59 (RIA 3) were used in this investigation in order to measure the PAG concentration in plasma samples withdrawn from pregnant cows and heifers during different periods following artificial insemination (AI). These systems were able to detect PAG molecules in the maternal blood as early as 21 days after AI in different concentrations (RIA 1: 0.43 +/- 0.24 ng/ml, mean +/- SD; RIA 2: 0.48 +/- 0.24 ng/ml; RIA 3: 0.64 +/- 0.37 ng/ml). On days 32 and 42 RIA 2 (4.30 +/- 1.32 ng/ml and 5.56 +/- 1.95 ng/ml) and RIA 3 (4.17 +/- 1.15 ng/ml and 5.60 +/- 1.89 ng/ml) presented significantly (p /= 0.929) were determined between the three systems. Additionally the three individual PAG profiles presented in this study showed that PAG molecules secreted in the maternal blood between 21 and 50 days after AI were better recognized by the RIA 2 and RIA 3 systems. This study clearly indicated that the ability of a RIA test to recognize PAG molecules in the maternal blood can be improved by carefully selecting the antiserum

    Effect of number of lambs, their sex and birth weignt on ovine pregnancy associated glycoprotein (ovPAG) concentrations

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    peer reviewedEarly pregnancy detection and prediction of the number of lambs would be profitable for sheep breeders, as this enables nourishment of pregnant ewes to their individual needs. Nonpregnant ewes can be separated and sold before winter. Prediction of sex is interesting for the curiosity of impatient breeders. Early pregnancy detection (before 45 days after mating) by means of ovine pregnancy-associated glycoproteins (ovPAGs) has proved to be a more reliable test than the commonly used transrectal ultrasound. The concentration of ovPAG has been claimed to be related to the number of lambs, their sex and birth weight, but contradictory results were obtained in different small-scale studies. In this study the correlation between number of lambs, their sex and birth weight and the ovPAG concentration in the serum of the ewes was examined. In a field trial, 160 and 70 ewes of the Texel and Suffolk breed, respectively, housed on 6 different farms, were synchronized by means of intravaginal sponges impregnated with 40 mg cronolone (Chronogest®, Intervet, Boxmeer, The Netherlands). At the moment of synchronisation (T0) and at 25 (T25), 35 (T35) and 45 (T45) days after mating or artificial insemination, blood samples were taken by jugular vein puncture. A heterologous radioimmunoassay (RIA) was used to determine the ovPAG concentration. In the heterologous RIA boPAG molecules were used as tracer, and ovPAG molecules as standard, while rabbit antibodies against ovPAG were used as antiserum. At parturition, number, sex and birth weight of the lambs were registered and their effect on ovPAG concentrations was statistically evaluated. No significant difference in ovPAG concentration was found between ewes pregnant of a single male or female lamb (P = 0.29). ovPAG concentrations were affected by the total birth weight (P < 0.05). In ewes pregnant with multiples, the ovPAG concentrations were higher (P < 0.01) than in ewes pregnant with singles at T25, T35 and T45, respectively. Because ovPAG concentrations were affected by the farm, it was impossible to predict the number of lambs by the ovPAG level. In conclusion, ovPAG concentrations were not affected by the sex of the lamb. However, ovPAG concentrations were related to the total birth weight. Within the farm, increased ovPAG concentrations may indicate pregnancy of multiples

    A new test for early pregnancy diagnosis in sheep: determination of ovine pregnancy associated glycoprotein (OVPAG) concentration by means of a homologous radioimmunoassay

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    Early pregnancy diagnosis is a useful tool in the management of sheep breeding. In this study different methods for pregnancy diagnosis in sheep, including the assessment of ovine Pregnancy-Associated Glycoproteins (ovPAGs), are briefly discussed. Subsequently, in a field trial the use of transrectal ultrasound is compared with the assessment of the concentration of ovPAGs for early pregnancy diagnosis. At the start of the breeding season in 2002, 192 Texel ewes at 4 different farms were synchronized and afterwards mated or artificially inseminated (AI). At the moment of synchronization (D-14) and at 25 (D25), 35 (D35) and 45 (D45) days after mating/AI, transrectal ultrasound was performed and blood was collected by jugular vein puncture. The ovPAG concentration in the plasma of the ewes was measured by means of a homologous radioimmunoassay (RIA). The specificity of transrectal ultrasound was 85%, and the sensitivity was 92% at D25, 94% at D35 and 95% at D45. The specificity of the homologous RIA was 100%, and the sensitivity was 99% at D25, and 100% at D35 and D45. Higher ovPAG concentrations were detected at D35 and D45 than at D25 (P<0.01). An interesting finding was that within the same breed (Texel), ovPAG concentrations were significantly affected by the farm (P<0.01). In conclusion, determination of ovPAG concentration by means of homologous RIA can be used for early pregnancy diagnosis in sheep and is more reliable than transrectal ultrasound at 25, 35 or 45 days of gestation

    Effect of number of lambs, their sex and birth weight on ovine pregnancy-associated glycoprotein (ovPAG) concentrations

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    Early pregnancy detection and prediction of the number of lambs would be profitable for sheep breeders, as this enables nourishment of pregnant ewes to their individual needs. Nonpregnant ewes can be separated and sold before winter. Prediction of sex is interesting for the curiosity of impatient breeders. Early pregnancy detection (before 45 days after mating) by means of ovine pregnancy-associated glycoproteins (ovPAGs) has proved to be a more reliable test than the commonly used transrectal ultrasound. The concentration of ovPAG has been claimed to be related to the number of lambs, their sex and birth weight, but contradictory results were obtained in different small-scale studies. In this study the correlation between number of lambs, their sex and birth weight and the ovPAG concentration in the serum of the ewes was examined. In a field trial, 160 and 70 ewes of the Texel and Suffolk breed, respectively, housed on 6 different farms, were synchronized by means of intravaginal sponges impregnated with 40mg cronolone (Chronogest®, Intervet, Boxmeer, The Netherlands).At the moment of synchronisation (T0) and at 25 (T25), 35 (T35) and 45 (T45) days after mating or artificial insemination, blood samples were taken by jugular vein puncture. A heterologous radioimmunoassay (RIA) was used to determine the ovPAG concentration. In the heterologous RIA boPAG molecules were used as tracer, and ovPAG molecules as standard, while rabbit antibodies against ovPAG were used as antiserum.At parturition, number, sex and birth weight of the lambs were registered and their effect on ovPAG concentrations was statistically evaluated. No significant difference in ovPAG concentration was found between ewes pregnant of a single male or female lamb (P=0.29). ovPAG concentrations were affected by the total birth weight (P<0.05). In ewes pregnant with multiples, the ovPAG concentrations were higher (P<0.01) than in ewes pregnant with singles at T25, T35 and T45, respectively. Because ovPAG concentrations were affected by the farm, it was impossible to predict the number of lambs by the ovPAG level. In conclusion, ovPAG concentrations were not affected by the sex of the lamb. However, ovPAG concentrations were related to the total birth weight. Within the farm, increased ovPAG concentrations may indicate pregnancy of multiples
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