Changes in milk and plasma progesterone and pregnancy-associated glycoprotein and their relationships with the foetal number during early pregnancy in Jakhrana goats

This study was designed to investigate milk and circulating profiles of progesterone (P4) and pregnancy-associated glycoprotein (PAG) during early pregnancy and to determine their associations with the foetal numbers in Jakhrana goats. For this, milk (whole and defatted milk) and blood samplings from10 pregnant and 3 non-pregnant Jakhrana goats were continued from the day 7 until day 51 post-mating. The PAG profile in both milk and plasma increased gradually from day 26 to 51 of gestation. Whereas, circulating P4 remains unchanged during early pregnancy in pregnant goats. The P4 and PAG concentrations in blood plasma, whole milk and defatted milk were 1.30, 1.24 and 2.04, 1.98, 1.99 and 1.88 folds higher in twin foetus than the single foetus bearing does, respectively. The P4 and PAG in plasma and milk samples were positively correlated with the foetal number. However, the results of stepwise-multivariate linear regression analyses indicated milk and circulating P4 as better predictors of foetal numbers than plasma PAG. The defatting of milk samples resulted in about 2-folds decline in the P4 concentration, however, the PAG level remains unaffected. In conclusion, milk and plasma profiles of P4 and PAG were affected by the foetal number and P4 is a reliable predictor of foetal number during early pregnancy in Jakhrana goats.