Mineral Metabolism Studies in Dairy Cattle

A study was made of the metabolism of managanese in 12 cows at 3 intervals each during the first 5 months of lactation. Lactating cows retained 154.4 ± 9.8 mg manganese daily; about the same quantity of managanese was used regardless of the quantity of the element ingested. The amount of manganese excreted in the feces was found to be directly proportional to the amount of manganese ingested in the range of 622.4 to 1325.6 mg daily; the correlation coefficient for this relationship was 0.958 ± 0.014. An equation is presented which allows the quantity of manganese excreted daily (and, conversely, the amount retained) to be calculated when the daily intake is known for cows receiving diets similar to those used in this investigation. The supplementation of the ration with calcium and various trace elements did not appear to influence significantly the amount of the ingested managanese retained. Manganese added to the ration as MnSO4 was utilized equally as well as that provided by the feed materials.