Unintended consequences
The use of antibiotics in the meat industry helped the animals to put on weight faster. The conditions for the animals are stressful and unhealthy when they are crowded into cages for their entire lives. Another consequence is mono culture of beef, pork and chicken makes the food industry more vulnerable to a few diseases that have to be prevented by more medication. It was a monoculture of potatoes that made the crops in Ireland that led to a major famine and a large immigration wave to the US.