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

Abstract

-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 × 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 Blood samples were withdrawn after each transrectal ultrasonographic examination in both experiments.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 ≥ 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.transrectal ultrasonography / ovPAG / pregnancy diagnosis / sheep Reprod. Nutr. Dev. 43 (2003) 577-586 577

Establishment of an ELISA for Measuring Bovine Pregnancy‐Associated Glycoprotein in Serum or Milk and Its Application for Early Pregnancy Detection

“…Various PAGs differ in molecular weight, amino acid sequence (Xie et al 1991) and degree of glycosylation (Klisch et al 2005). Detection of PAG by way of RIA (Sasser et al 1986;Zoli et al 1991) or ELISA (Friedrich and Holtz 2004;Friedrich et al 2005;Green and Roberts 2006;Ga´bor et al 2007) in maternal serum has been shown to be a useful means of early pregnancy detection in cows (Sasser et al 1986), goats (Gonzalez et al 1999) and sheep (Karen et al 2003;Ledezma-Torres et al 2006). In cows, it was found to be reliable from day 30 after insemination onwards (Szenci et al 1998).…”

Identifikasi Pregnancy-Associated Glycoprotein (PAG) pada Kotiledon Kambing Jawarandu

“…Other PAG which isolated from goat cotyledons have 3 molecular weight at 55, 59, and 62 kDa (Sousa et al, 2006). Likewise, it were smaller than sheep which had molecular weight ranged between 55-59 kDa or 58-61 kDa (Karen et al, 2003; El Amiri et al, 2004) extacted at different gestation. Perenyi et al (2002) Sumadiasa and Yuliani (2008) that protein with 43 kDa of molecular weight ever been found in goat embryo through in vitro fertilization.…”

“…Pregnancy-Associated Glycoprotein is a molecule produced by tropoblastic cells (Perenyi et al, 2002), part of the aspartic protein synthesized by the superficial epithelial layer (mono and binucleic) of placental cells (Karen et al, 2003;Sousa et al 2006). Karen et al (2003) stated that glycoprotein is a good marker of successful conception.…”

“…Garbayo et al (1998) showed the molecular weight of PAG in cattle and goat at 67 kDa and 55 kDa of 48-69 day of gestation. Karen et al (2003) Some research showed that PAG have a various range of molecular weight among breeds and species. It is necessary to identify the molecular weight of PAG in Jawarandu goat to enlarge the data record.…”

Characterization of Pregnancy-Associated Glycoprotein as a Biomarker of Pregnancy in Etawa Crossbred Goat.

“…Diagnosis of early pregnancy in goat can be done in two ways: through detection of specific substances in the peripheral circulation such as Pregnancy-Associated Glycoprotein (PAG) or non-specific substances in the blood, urine or milk such as progesterone and estrone sulfate (Hafez, 2000). PAGs are pregnancy indicators that are produced by mononucleate and binucleate trophoblastic cells (Perenyi et al, 2002;Karen et al, 2003;Sousa et al, 2006). Garbayo et al (1998) purified three PAGs from goat placenta which differed in amino acid sequences and molecular weight (55 kDa, 59 kDa, and 62 kDa) and each of them had several isoforms with different isoelectric points.…”