A method and apparatus for feeding livestock is presented. The method includes providing a mobile feed preparation apparatus that includes a feed container containing a base feed, a conveying assembly that receives the base feed from the feed container, a feed additive assembly comprising a reservoir containing a feed additive, where the feed additive assembly is in flowable communication with the conveying assembly, a weight sensitive platform having a weigh cell, where the reservoir is mounted on said platform, and a controller in communication with the conveying assembly and the weigh cell. The method further includes weighing the reservoir to determine a first weight, dispensing from the mobile feed preparation apparatus a feed ration, and weighing the reservoir to determine a second weight. Additionally, the method includes calculating a distributed amount of the feed additive using the first weight and the second weight.