Adding the cottage cheese / flax oil mix to your Dane's diet should definitley help. As diet is soooo important, you may want to check closely into the manufacturer of his(?) food. Many very popular brands add in slaughterhouse rejects (sick or diseased animals) and poor quality grains to their feed.
Much information can be found about healing your Dane with flax oil and other optionsHERE.
That site also has information on the benefits of a raw diet. A raw diet may sound unappealing, but it is something you may want to check further into.