Question labels/axis size

[RanganathanSri]

Hi,
I'm new to R. Thanks for making a great package for analysing likert data. I have made this plot using the following code. What I am having trouble with is changing the font size of the labels so that they are more readable. I can't get them to become larger using any of the ggplot code.
Thanks :-)

plot(Q21Likert,
type="bar") +
theme_bw()+
scale_x_discrete(
labels = c("Q21CowNever" = "Never", "Q21CowResistantLM" = "C&S indicates resistance to low and medium rated antimicrobials", "Q21CowIndependentApproval"= "With approval from an independent office","Q21CowAlwaysLabelled" = "Always - ceftiofur is labelled to treat pneumonia in cattle", "Q21CowAlwaysNilWHP"="Always - ceftiofur carries a nil milk with-holding period "))