Free Access
Reprod. Nutr. Dev.
Volume 43, Number 6, November-December 2003
Page(s) 577 - 586
Reprod. Nutr. Dev. 43 (2003) 577-586
DOI: 10.1051/rnd:2004005

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

Aly Karena, Jean-François Beckersb, Jose Sulonb, Bouchra EL Amirib, Krisztián Szabadosc, Sanaa Ismaila, Jenö Reiczigeld and Ottó Szencia

a  Clinic for Large Animals, Faculty of Veterinary Science, 2225 Üllö-Dóra Major, Hungary
b  Department of Physiology of Reproduction, Faculty of Veterinary Medicine, Bd de Colonster no 20, B41, 4000 Sart Tilman, Belgium
c  Awassi Corporation, Bakonszeg, Hungary
d  Department of Biomathematics and Informatics, Faculty of Veterinary Science, Budapest, Hungary

Received 9 July 2003; accepted 7 October 2003

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  $\times$ 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 Blood samples were withdrawn after each transrectal ultrasonographic examination in both experiments.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 $\geq$1 ng $\cdot$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.

Key words: transrectal ultrasonography / ovPAG / pregnancy diagnosis / sheep

Corresponding author: Aly Karen

© INRA, EDP Sciences 2003