There is a growing concern in agriculture about the inclusion of antibiotics into animal feeds. This is increasing herd resistance. Unfortunately with a reduction of feed antibiotics comes lowered productivity and increased disease, which often results in more antibiotics. In the past, as price of antibiotics decreased, feed antibiotic inclusion increased. Today, there is the concern of whether antibiotics in animal feed increase human antibiotic resistance. Studies have shown that animals given sub-therapeutic levels of antibiotics in their feed did not show a significant increase in antibiotic resistance over an extended period of time (although the research is debatable). Since antibiotics are effective in improving growth and efficiency of feed utilization, the benefits of its use is far greater than the risk of antibiotic resistance. In 1986, Sweden banned the use of feed antibiotics, and that resulted in a two-fold increase in piglet diarrhea, and similar attempts since then has showed a decline in nursery pig health, consequently increasing the need for therapeutic antibiotic administration. The result of omitting antibiotics in finisher feed is a reduction in feed efficiency and average daily gain. Alternatives to antibiotics can only really be found once the microbial ecology and microbiology of the digestive tract is determined. Some alternatives already in use include probiotics, prebiotics, organic acids and enzymes. Probiotics are essentially microbes added to animal feed that prevent pathogens from affecting the animal. Prebiotics exist to promote the growth of already established good (“non-pathogenic”) bacteria that live in the gut. Organic acids can influence the microbes of the gut by changing the physical conditions, making it less optimal for growth of bad (“pathogenic”) species. Enzymes can work for and against (respectively) non-pathogenic and pathogenic species in the gastrointestinal tract.