Very little information is published on puppy coats but lots of myths, long established breeders and show people have lots to contribute from years of experience and should never be overlooked as a reliable source of information. The information in this article is based on fact and science and will provide a solid foundation to your knowledge in this area
Puppies are born with the amount of follicles they will have throughout their lives this number will never change, their coat density and texture are predetermined by DNA and will not alter unless changes to the dogs health or mental wellbeing occur. Neutering and endocrine disorders for example hypothyroid are the main triggers to coat changes along with stress which takes its toll on nearly every system in a dogs body including the delicate cycle of the coat.
An adult dogs follicle on average holds around 17 hairs and is a mixture of primary and secondary hair, when a puppy is born the Primary hairs are absent so the follicle holds around 7 secondary hairs which are soft and fine. The follicle itself is shallow so cannot yet support a primary hair, in time depending on the coat type the follicle will develop deeper into the skin and be able to support primary hairs. This process is dependant on coat type with wool coats and fur bearing dogs maturing earlier than wire coats that require more time due to wire hair needing the deepest follicle for a longer growing phase to provide a coarse texture.
The transition from puppy to adult coat on average happens from 6-12 months and with new hair growing along side puppy hair this change can be challenging for an owner, more regular grooming is recommended at this time to prevent matting and disruption to the cycle.
When the transition is happening the follicle is undergoing changes and is on a delicate cycle and it is recommended the coat not be cut until after this period, as any interference can harm the coat, and the process of grooming needs to be imbedded into the dogs routine to minimise stress.
Hope this helps understanding!