Hi
Basically until the poos have normalised.
There is no given or recommended time span because it all depends on whether or how much an antibiotic is impacting on the gut microbiome. This can range over the whole spectrum from not at all to totally wiping it out.
You always have to play this one by ear as you go along depending on whether your piggy has a reaction or not; and if they have a reaction, then how strong it is. Different antibiotics can generally impact with different frequency, and the individual response to each can also range over the whole spectrum - while some antibiotics tend to cause less adverse reactions, any antibiotic has the potential to cause an individual negative reaction.