Enzyme link immuno assay for early detection of pregnancy associated glycoprotein’s in African dwarf goat

A pregnancy test based on detection of the goat pregnancy associated glycoprotein (caPAG) by the ELISA method was designed and carried out on serum from slaughtered goats. The objective of the study was to describe the ability of this test to detect pregnancy associated glycoprotein and also their ability to discriminate between pregnant and non-pregnant
females of African dwarf goats. The test was evaluated and compared to a post-mortem clinical pregnancy examination.
In order to perform the test, rabbits were immunized with caPAG initially purified from cotyledons collected from pregnant goat. The antibodies obtained were biotinylated, titrated, and used in a “Sandwich” ELISA to detect caPAG in goats sera.
Blood samples as well as informations related to each animal (pregnancy status, gestational stage, presence of corpus luteum or milk) were collected on 506 slaughtered goats, and the sera obtained were tested for the presence of caPAG.
The ELISA test results obtained from the 506 goats were different from those of the clinical examination, with 226 (44.7 %) seropositives against 221 (43.7 %) gestation with clinical diagnostic. The serological test results showed a few number of false positives 34 (6.7 %) and false negatives 39 (7.7 %). Indeed, nearly all the false negatives were female of less than 28 days of
gestation. The entire false positive female had corpus luteum but 7 of them (18%) had also milk in the mammary gland. The sensitivity and the specificity of the test are respectively 84.6 and 86.3 %. The accuracy of the test is 87.8 %.
These results showed that the sensitivity and specificity of the test depends on the stage of gestation. PAG “sandwich” ELISA could then be suitable for pregnancy diagnosis in African dwarf goat as early as from day 28 after insemination.