
Hi Steven!
I would also agree your first logical port of call would be your dog's Breeder for good advice specific to your breed, is this possible? ( your dog may be a rescue? or gone through several owners before you and not come from a breeder?)
If you cant check back with your dogs breeder, for whatever reason then rest assured there's quite a few Mal owners here and Im sure Mel or the others will be along soon.
Just so you get near the mark info it'd be useful to tell us:
-How old is your dog?
-and is the dog a pet or do you intend to start 'conditioning' for Rig racing/work etc?
I myself have a Siberian, in my younger,
fitter!
days I worked out in Canada and Val Thorens France with teams of Sibes, Im not entirely sure about Purina foods....but thats a personal opinion of course.
Do your reaserch as its up to you but foods with the highest % meat are best, Mine has Nature diet and a dry food called Wafcol salmon and potatoe, and raw foods as treats veg,sardines,chicken wings,liver being his favourites!
Best wishes
:D