Preliminary results obtained by RIA determination of the proteins associated to pregnancy (PAG) in goat and sheep.

In goat and sheep the glycoproteins associated to pregnancy (PAG) are not well studied. Their study in these species is very important in the evaluation of prediction of early pregnancy. Even though numerous research was done in order to investigate the physiological functions of placental proteins; the exact
biofunction of the glycoproteins associated to pregnancy is still unknown.
The objective of research was the study of dynamics of PAG in goats and ewes in the first stage of pregnancy (1–35 days after mating) and the determination of correlations with the reproductive status of females and to earlier stages of the pregnancy.
The experiment was realized on 49 Saanen x Carpatina goats and 72 Merinos of Palas sheep from the biostation of the Research and Development Institute for Goat and Sheep, Palas Constanta. The females in normal reproduction season were monitored for the detection of estrus and mated naturally. Blood was collected by puncture of the jugular vein on days 0, 7, 14, 25 and 35 after mating (day 0). The serum was obtained after centrifuging at 1500 x g for 15 min and stored at −20 ◦C till RIA determination.
RIA of the plasma with the purpose of detecting the concentration of proteins specific to pregnancy was realized in two experimental series in February and December 2008, at the Laboratory for Reproduction Physiology, Faculty of Veterinary Medicine, Liege, Belgium.
RIA dosing was realized after application of the method with preincubation of the serums to test with specific serum (Atg◦) and then with the marked antigen (Atg∗), considering the high sensitivity of this method to detect the smallest values of PAG from day 0 to day 35 after mating. The diagnosis of the pregnancy state was based on the principle of PAG antibodies binding to the
specific antigen, establishing through RIA the quantity of free antigen. Nonpregnancy involves the attachment of the antigen marked by non-specific antibodies.
The preliminary results demonstrated that the sheep PAG had values ranging between 4.197–15.985 ng/ml and 0.01–3.39 ng/ml in nonpregnant ewes. In pregnant goats PAG concentrations ranged between 16.75±3.44 − 27.17±2.95 ng/ml, while in nonpregnant goats, PAG values were 1.38±0.35 − 2.03±0.51 6 ng/ml.
The purpose of the experiments was to find one accurate method for early pregnancy diagnosis in goat and sheep. The conclusion was that ovine pregnancy can be reliably diagnosed on day 25 after AI and goat pregnancy on day 30, by using a heterologous radioimmunoassay of PAG.