Pregnancy-associated glycoprotein concentrations during early gestation in pregnant Awassi sheep

Abstract

This study was aimed at determining the serum pregnancy-associated glycoprotein (PAG) profile of pregnant Awassi sheep during early gestation. A total of 122 Awassi ewes were used, which were in days 28-56 (28, 30, 32, 36, 42, 49, and 56) of gestation. Blood samples were taken via jugular venepuncture. Out of these animals, 104 ewes that had delivered (singleton lambs, n = 60; twin lambs, n = 44), according to lambing records, were selected for the assessment of serum PAG levels. The serum PAG level was measured using a commercial enzyme-linked immunosorbent assay (ELISA) kit (IDEXX Bovine Pregnancy Test). Whereas serum PAG levels (mean ± standard error) on days 28, 30, 32, 36 and 42 of gestation were found to be similar (0.237 ± 0.031, 0.402 ± 0.067, 0.329 ± 0.036, 0.397 ± 0.075, and 0.409 ± 0.060, respectively), the levels measured on days 49 and 56 of gestation were significantly higher (0.712 ± 0.088 and 0.798 ± 0.115, respectively) (p < 0.05). The serum PAG levels of the twin-pregnant ewes on days 28, 30 and 42 of gestation were higher than those of the singlepregnant ewes (twin-pregnant ewes: 0.314, 0.648 and 0.594, respectively; single-pregnant ewes: 0.186, 0.258 and 0.308, respectively; p < 0.05). With a cut-off sample minus negative (S–N) value set at > 0.300, the sensitivity of serum PAG level-based pregnancy diagnosis was 51.95% between days 28 and 42 of gestation and 92.69% between days 49 and 56 of gestation. On the other hand, with a cut-off S–N value set at > 0.100, the sensitivity of the PAG ELISA test was 94.81% between days 28 and 42 of gestation and 100% between days 49 and 56 of gestation. In conclusion, the serum PAG levels of the pregnant Awassi sheep remained similar between days 28 and 42 of gestation, but progressively increased thereafter. The serum PAG levels of the twin-pregnant Awassi ewes were significantly higher than those of the single-pregnant sheep on days 28, 30 and 42 of gestation, but they were not different on days 32, 36, 49 and 56 of gestation.