Placental transfer of fluoride in Holstein cows
Shupe, J.L.; Bagley, C.V.; Karram, M.H.; Callan, R.J.
Veterinary and Human Toxicology 34(1): 1-4
1992
ISSN/ISBN: 0145-6296 PMID: 1621353 Document Number: 399038
Groups of 10 Holstein cows were given NaF by mouth at 0.0, 0.51, 1.31 or 2.66 g/d (equivalent 10, 25, 50 or 100 micro g/g of feed) starting 5-7 days before the expected calving date. Fluorine levels were measured in heparinized maternal blood plasma before and immediately after calving, and in calf plasma and placental cotyledon immediately after calving. The number of fluoride treatment days which ranged from 4-14 days (mean 6.4+or-3.6 d) before calving did not affect fluorine levels in any tissue examined. Fluorine levels in maternal plasma and cotyledon increased with increasing NaF dose levels. Calf plasma fluorine levels at birth did not increase significantly in relation to maternal dose levels. It is concluded that, in cows, a partial placental barrier to fluoride limits concentrations in fetal circulation and tissues.