Plasma concentrations of bovine pregnancy-associated glycoprotein (bPAG) do not differ during the first 119 days between ongoing pregnancies derived by transfer of in vivo and in vitro produced embryos.
ABSTRACT Calves derived from IVP embryos may suffer from the large offspring syndrome that has been related to effects of in vitro culture on the intrinsic quality of the embryo. Limited information is available on the role of the placenta in such cases. In this study, bovine pregnancy-associated glycoprotein (bPAG) was used as a marker to test whether placental function is influenced by the route of embryo production. Therefore, from day 7 until day 119 of ongoing gestations, resulting from transfer of MOET (n = 53), IVP-co-culture (n = 21) and IVP-SOF (n = 38) embryos, bPAG levels were compared in peripheral plasma of recipients. Plasma progesterone levels were compared as well. From day 25 of gestation onwards, bPAG could be detected in all recipients and the levels were significantly influenced by the day of gestation. Although IVP calves were significantly heavier than the in vivo produced calves, this difference was not reflected in the bPAG profiles of the embryo production groups. Yet, the mean bPAG level of the three last sampling moments (days 105-119) tended to be positively related to the birth weight of the calves, irrespective of the embryo production technique. Progesterone concentrations were not influenced by route of embryo production, but were significantly affected by parity of the recipient and day of gestation.
Article: Dietary protein during gestation affects circulating indicators of placental function and fetal development in heifers.[show abstract] [hide abstract]
ABSTRACT: The influences of nutritional protein during the first and second trimesters of pregnancy on placental hormones and fetal growth were determined in composite beef heifers. At artificial insemination, heifers were stratified by weight within each composite genotype into 4 treatment groups: High High (HH=1.4kg crude protein (CP)/day for first and second trimesters of gestation; n=16), High Low (HL=1.4kg CP/day for first trimester and 0.4kg CP/day for second trimester; n=19), Low High (LH=0.4kg CP/day for first trimester and 1.4kg CP/day for second trimester; n=17) or Low Low (LL=0.4kg CP/day for first and second trimesters; n=19). Maternal plasma bovine pregnancy associated glycoprotein (bPAG) and progesterone (P4) were determined at gestation day (gd) 28, 82, 179 and 271 (mean gestation length 286 days) in addition to P4 at term. Estrone sulphate (ES) and bovine placental lactogen (bPL) concentrations were measured at gd 124, 179, 236 and 271 and at term in addition to ES at gd 82. Low dietary protein increased placental function as indicated by increased bPAG (P<0.001) and ES (P=0.02) concentrations in first trimester and increased bPL concentrations (P=0.01) in the second trimester of gestation. In the third trimester, when dietary treatment had ceased, placental function was no longer associated with previous dietary treatments. Dam genotype affected placental function as measured by bPL (P<0.001) and ES concentrations (P=0.02). Calf gender, heifer age and maternal insulin-like growth factor (IGF)-I, -II and leptin did not affect hormonal indicators or circulating markers of placental function. Enhanced placental function during the third trimester, as measured by ES, was associated with increased calf birth weight (P=0.003).Placenta 03/2009; 30(4):348-54. · 3.69 Impact Factor
Article: Milk production correlates negatively with plasma levels of pregnancy-associated glycoprotein (PAG) during the early fetal period in high producing dairy cows with live fetuses.[show abstract] [hide abstract]
ABSTRACT: This study was designed to establish possible factors affecting plasma pregnancy-associated glycoprotein (PAG) concentrations during early pregnancy in high producing dairy cows with live fetuses. Blood samples were obtained on days 35, 42, 49, 56 and 63 of gestation from 80 lactating cows in two herds carrying live fetuses. Radioimmunoassay systems were used to determine PAG (RIA-497 and RIA-706) and progesterone concentrations. We evaluated the effects on PAG concentrations of herd, lactation number, sire of fetus, day of gestation, fetus number, plasma progesterone and milk production at each time point established, along with possible paired interactions. Mean milk production per cow approached 41kg during the study period. PAG concentrations were not affected by herd, lactation number or plasma progesterone concentration. Significant positive effects on PAG concentrations were shown by the gestation day, and the interaction between day of gestation and twin pregnancy. Significant differences between bulls and a significant negative correlation between milk production and PAG values on day 63 of pregnancy were also detected. Proportions of blood samples showing undetectable PAG levels and false negative diagnoses throughout the study period were significantly higher (P<0.001) using the RIA-497 system (2.5% and 5.3%, respectively) compared to RIA-706 (0% and 0.8%, respectively). Our findings suggest that PAG concentrations during the early fetal period are related to the day of gestation, milk production, number of fetuses and sire of fetus in high producing dairy cows. Under our working conditions, the RIA-706 method was better at detecting plasma PAG molecules than the RIA-497 system.Domestic Animal Endocrinology 02/2007; 32(1):29-42. · 2.06 Impact Factor