I use Clean Start shampoo on Shelby & Seymour. Because they have full coats, they can get kind of stinky on the backside ( Especially Shelbs because she squats more to pee). It really cleans their hair well. It is made for dogs and is in the Chris Christensen line. There is a website for their products. I also use the conditioners from them also.
BUT...... ok..... here's my secret. I buy the Detangling solution by Biolage and use in in there long body hair. Take note.... not using it near face and eyes. IT MAKES COMB-OUTS a Piece of CAKE!!!!