Penicillin is an old commonly used drug. I use it commonly for treating what I consider crud infections, opening abscesses, after assisting a difficult birth, repairing a prolapsed uterus. Also use it in conjunction with Nuflor or oxytetracycline 200 to treat mastitis and prevent gangrene. Another major use is to prevent tetanus when banding. For those ideologues out there that don’t understand use of antibiotics to prevent disease this is a classic. The inclusion of penicillin with CDT is the most effective method of preventing tetanus. Antitoxin is ineffective due to short half life and chances of death resulting from anaphylactic shock are greater than developing tetanus. Penicillin also helps with other bacterial infections in the banding process. When I was younger I didn’t know what an ideologue was.
The problem comes when animals are to be slaughtered for human consumption. Penicillin is almost never used at labeled levels. I recommend 1cc per 10# bdy wt. subq daily. This is an over dose and and a different route of injection that requires a slaughter withdrawal of 50 days. I see no need to ever use long acting penicillin because the object is to increase dosage to develop effective blood levels and this is impossible with a slow release product.