Vitamin D Studies in Cattle

Abstract

For the past 12 years the calcium and phosphorus requirements of dairy cattle have been under investigation at this Station. During this period several long-time mineral feeding trials and many balance experiments have been carried out (1-4). In order to complete certain phases of this investigation, it became necessary to study the vitamin D requirement of dairy cattle and also the antirachitic value of common dairy feeds. These factors are essential for the proper utilization of calcium and phosphorus.