what steroid is used in pig feeds?

Answer 1

Most feeds for broiler and pig production in some countries contain antimicrobial growth promoters. These compounds can also be administered to calves, yearlings, and finishing cattle either in milk replacer or in supplementary concentrates. Antibiotic compounds, in general, increase growth rate by 2-10% and feed conversion efficiency by 3-9%. Their effects are greater in young animals, and production responses are reduced when production conditions are optimized (good housing, optimal health, and hygiene). They have minimal effects on carcass composition other than that due to better growth rate.
FROM http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/192005.htm&hide=1

Sub-therapeutic levels of antimicrobial feed additives have been used in swine feeds since the 1950's for improved growth rate and feed efficiency and to maintain pig performance
FROMhttp://www.ext.vt.edu/news/periodicals/livestock/aps-04_02/aps-311.html

Steroids are never added (boars for slaughter are neutered when still young). All additives are withdrawn prior to slaughter (how long befor slaughter depends on what type of additave)

Answer 2

Wouldn't really call it 'steroid' if used on an animal, but I would venture to guess it's growth hormones.
If you're worried about the pork you're eating, you might want to quit eating pork, seeing as pigs and humans are really similiar (similiar enough to allow some kinds of organ transplants) , so what affects them is likely to affect us too.

Answer 3

to grow pigs bigger and stronger, so they are worth more because they are heavier.