3-6months i believe, meaning the process starts around 3mo and is complete by 6. unless he's a longhair - they lose their puppy coat around the same time, but it takes alot longer to come into full coat.
Don't know if this is relevant in your case, but I bought some flea and tick shampoo and only used it once because my puppy was noticeably more itchy afterward! The can be allergic to the darndest things...and for that matter, I don't really know it WAS an allergic reaction. But as soon as I stopped using that shampoo the itching went away, so....My pup is 11 weeks and has had the black stripe along the spine for about a week or so. However, he seems so itchy and chewing at his back and tail. His tail has one spot of the slick black coat. Looks funny. Do puppies get itchy when they start to lose their puppy coat? He also has a bit of dandruff but really itchy in the back end. No fleas and he is on fle meds. Thanks!