| Abstrakt: |
Seventeen gravid cross-bred heifers, maintained on corn, CSM and CS hull rations were dosed with 35S-sulfate and sacrificed at 90, 180 and 270 days gestation, following 1 to 7 day blood-balance studies. Cows consuming 6.3 gm. S/day excreted 73% total sulfur, and retained 9.2% of a single oral radiosulfur dose. Excretion patterns were not affected significantly either by stage of gestation or route of 35S administration, and 7 day excretions averaged 78% and 13% dose in urine and feces, respectively. Radiosulfur readily traversed the placenta of the cow at all trimesters, and fetal tissue distribution patterns for S and 35S paralleled those of the dam, being higher in organs and metabolically active bone areas of the dam than fetus. At 90 days gestation 76% total S and 83% of the retained 35S dose in the products of conception were in the placenta, and at 270 days 70% of the total S and 82.5% of that 35S absorbed and transferred to the conception products was in the fetus after 168 hours. |
