Effects of Molybdenum and Sulfate Sulfur on Metabolism of Copper in Dairy Cattle

Abstract

Experiments were performed using first-calf Holstein heifers to study the occurrence of molybdenum toxicity. Levels from 5 to 50 ppm molybdenum were added to a diet low in copper and to which no sulfate or 0.3% sulfate sulfur was added. Heifers which received diets containing from 5 to 50 ppm molybdenum and no added sulfate sulfur did not develop any symptoms of molybdenum toxicity such as alopecia, achromatrichia (loss of hair color), diarrhea, emaciation, or anemia, but copper in the liver and blood serum was lowered. Identical results were observed in heifers receiving a diet containing from 5 to 20 ppm molybdenum and 0.3% sulfate sulfur. Heifers receiving 50 ppm molybdenum and 0.3% sulfate sulfur developed alopecia and achromatrichia; however, no further symptoms of molybdenum toxicity were observed when two heifers were continued on this diet 625 days. When lactating heifers were subjected to the stress of being housed in a pole barn and fed in an open lot during winter months, there was no increase in susceptibility to molybdenum toxicity observed. Four heifers which received a diet containing either 100 or 200 ppm molybdenum with 0.3% sulfate sulfur became emaciated, developed alopecia, achromatrichia, and lost nervous control of their hind quarters within three weeks; however, no changes were observed in liver copper or blood serum copper levels. Copper added to the diet of heifers which developed achromatrichia and alopecia completely corrected these conditions. © 1964, American Dairy Science Association. All rights reserved.