Why did we start using antibiotics in animal feed?

In 1950, farmers praised the news that small amounts of antibiotics would help their livestock put on more weight, faster. Ironically, that same year, different scientists published some early evidence of antibacterial resistance. At Scientific American's new food blog, Maureen Ogle writes about the history of antibiotic use in agriculture. Her story provides some great context to recent headlines, helping us better understand why our society originally made the decisions that led to our current struggle against antibiotic resistance.