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 little studied. Their study in these species is very important in the evaluation of prediction of early pregnancy. Even though numerous research has been 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 the dynamics of PAG in goats and ewes in the first part of pregnancy(1-35 days after mating) and the determination of correlations with the reproductive status of females and to earlier 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. The 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 minutes and stored at -20oC till the RIA determination. The 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 – The Faculty of Veterinary Medicine, Liege, Belgium. The RIA dosing was realized after the application of the method with the 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. Non-pregnancy involves the attachment of the antigen marked by non-specific antibodies. The preliminary results have demonstrated that the sheep PAG were had values ranging between 4.197-15.985 ng/ml and 0.01-3.39 ng/ml in nonpregnant ewes. In the pregnant goats, the PAG concentrations ranged between 16.75±3.44-27.17±2.95 ng/ml, while in the nonpregnant goats, the 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.