brookcove
Posted : 2/17/2008 9:40:12 AM
That's weird because I've never heard of anyone using feeds with antibiotics in them to prevent sickness.
Seriously, feedlot animals are routinely fed prophylactic coccidiostats, and usually other antibiotics for a more complicated reason.
When you feed a mostly corn-based (or other concentrate-based) diet, you change the rumen Ph enough to facilitate the growth of bacteria, with e. coli and salmonella being the most common problems. Ruminants don't usually suffer from these issues once they are eating forage (young animals with undeveloped rumens are just as susceptible as us, or more so actually). But when you change things so that they are getting the bulk, or all of their energy from non-forage sources, it leaves them open to overgrowth and infection again.
Being slightly ill all the time reduces gains, so the antibiotics are added as "gain enhancers." It works - the cattle in particular respond very well to this treatment - it makes a difference between months to slaughter time, since they can be put on very concentrated feed. Once, cattle were slaughtered at about two to two and a half years old. Now, they are pushing ten months with various systems and combinations of hormones and antibiotics.
This is not just a guess - it's an concern which I have seen addressed many time in industry papers. I have several friends who are cattle farmers - they are a little outside the feedlot industry, but it concerns them too because they have to purchase crazy expensive weird antibiotics for normal disease like shipping fever or joint ill because cattle are so overexposed. The drugs I can use, you would recognise easily - penicillin, oxytetracycline, cephalexin. Cattle people can't use those anymore.
It's a catch-22 for them though. Americans expect 99 cent cheeseburgers and ground round at $2.50 a pound. You can't do that by pasture feeding 1,000,000,000 cattle - because Americans also want to live on all that pasture (and don't want the cattle anywhere nearby).