Maryn McKenna summarizes a recent study about the dangers of antiobiotic resistance in farm animals:

Chickens, chicken meat and humans in the Netherlands are carrying identical, highly drug-resistant E. coli resistance that is apparently moving from poultry raised with antibiotics, to humans, via food. ... The first observation that giving antibiotics to animals spreads antibiotic-resistant bacteria to humans was made in 1976, and there has been a steady accumulation of evidence since. Nevertheless, the argument keeps being made that the connection is not water-tight , and that antibiotic use outside agriculture in human medicine, perhaps can be blamed for the vast rise in antibiotic resistance.

Denmark quit giving antibiotics to their pigs, poultry and other livestock. Scientific American argues their example "has shown that it is possible to protect human health without hurting farmers":

Although the transition unfolded smoothly in the poultry industry, the average weight of pigs fell in the first year. But after Danish farmers started leaving sows and piglets together a few weeks longer to bolster the littermates’ immune systems naturally, the animals’ weights jumped back up, and the number of pigs per litter increased as well. The lesson is that improving animal husbandrymaking sure that pens, stalls and cages are properly cleaned and giving animals more room or time to matureoffsets the initial negative impact of limiting antibiotic use. Today Danish industry reports that productivity is higher than before.