Responses in Pregnant Ewes Fed Forages Containing Various Levels of Nitrate

In 1961-62, 25 pregnant ewes, divided into groups of five, were individually fed pelleted alfalfa-timothy hay -t-1.5% nitrate, or corn, oats, pigweed (Amaran-th~s retroflexus) or lambsquarters (Chenopodium album) forages containing 0.4 to 1.5% nitrate. Hemoglobin, methemoglobin, body weight and plasma vitamin A were not significantly affected by nitrate level. Liver vitamin A levels reflected carotene intake. No pathological changes could be attributed to nitrate. In 1962-63, 40 pregnant ewes divided among six groups were individually fed alfalfa-timothy hay with and without 3.4% added nitrate, or corn, oats, pigweed or lambsquarters containing 0.4, 2.6, 2.6, and 2.4% nitrate, respectively. The hay + 3.4% nitrate ration was unpalatable. Methemoglobinemia increased as feed consumption increased. Ewes fed oats, pigweed and lambsquarters developed higher hemoglobin and methemoglobin levels and higher blood volumes than ewes fed corn or hay. Two abortions associated with toxoplasmosis occurred in ewes fed hay. Three ewes fed hay + 3.4% nitrate