I even did a web search on the issue and did not find anything about it. All I have heard is that the boosters can be rough on a dog.  My dog seems very healthy and active. However, I feel like a a worry wart at the same time. 
  I am also not going to let her play outside for a while..... To protect her from all the yucky stuff pupps are so susiptable to... I have let her play on the grass a few times, but the vet did not reccomend it. 
   She is a stalky little yorkie, but, it really is mostly her hair. I am teaching her to like to be brushed right now, and get her use to it.