Early pregnancy diagnosis in goats by determination of pregnancy-associated glycoprotein concentrations in plasma samples.

Abstract Different RIA systems available for measuring the concentrations of pregnancy-associated glycoproteins (PAGs) in dairy goats were compared in order to evaluate their accuracy in early pregnancy diagnosis. Plasma concentrations of PAGs were determined by 3 heterologous RIA systems with a bovine PAG standard and tracer in combination with antisera anti-ovine PAG (RIA 1), anti-caprine PAG 55+62 (RIA 2), anti-caprine PAG 55+59 (RIA 3), and by 2 homologous RIA systems that employed caprine PAG 55+62 and caprine PAG 55+59 and their specific antisera (RIAs 4 and 5, respectively). In all of the RIAs, the mean concentrations of PAGs were significantly higher (P 99% for RIAs 2, 3, 4 and 5. The RIAs for PAGs depend on proteins from the placenta being present in maternal plasma and require only a single sample of blood, to distinguish pregnant goats from those that fail to return to estrus for other reasons. The homologous and semiheterologous assays are highly accurate as early as Day 21 of pregnancy.