Nitrate Toxicity in Dairy Heifers. I. Effects on Reproduction, Growth, Lactation, and Vitamin A Nutrition

Abstract

Forty-five dairy heifers were fed nitrate at levels of 0, 440, and 660 mg/kg body weight daily beginning three estrous cycles before breeding, or at 40, 150, or 240 days of pregnancy, continuing until they were killed at 30 days after parturition. Conception rate was lower in heifers fed 660 mg nitrate. One abortion occurred in those fed the lower level of nitrate and two abortions and two deaths occurred in those fed the higher level. Growth, length of estrous cycles, length of gestation, birth weight and performance of calves, vitamin A and carotene nutrition, and milk production were similar in all groups. Nitrate feeding increased the nitrate content of milk and meat, but the contamination was so small that it did not appear to constitute a hazard to human health. © 1964, American Dairy Science Association. All rights reserved.