Not to draw attention to one of the earlier comments, but this doesn't actually say much about discrimination per say. More than 50% of DO students are in AOA positions. This means that only 3000 or so DOs are applying to ACGME as compared to nearly 20,0000 USMD graduates. Many PDs seldom accept DO applicants purely on the basis that they may get 1 or 2 a year and accept one as opposed to 7 MDs.
But it really depends a lot on the field. Lots of fields are very DO friendly, others like mid & top tier IM and surgery are not.