Hi Dmitry, I've often admired your work, but for me this set has a few issues, I'm not trying to be contentious - just offering a different perspective.
Firstly, as a dog lover and owner, I'm upset that this dog has 'clipped' ears - the practice of cutting a dogs ears to shape is utterly barbaric, totally unnecessary and it's the very first thing I've noticed - it's not permitted in the UK and my immediate feeling is that 1. this is an image taken outside of the UK, and 2. anyone that owns an animal that has this type of cosmetic alteration (there is no valid argument for this type of procedure) that I find myself questioning the owners ethics (and I appreciate this dog might be a rescue and therefore not something it's present owner has inflicted)
Secondly, the 'leaping' pose makes me feel a bit concerned too - I wholly accept that I'm a complete 'softie' when it comes to any animal, but a 'dog handler' who is encouraging this type of behaviour is not only endangering the dog physically (i.e. ruptured ligaments or damaged back) she is also encouraging a behaviour that could endanger this dogs life - jumping up and grabbing is usually (in the UK) something we discourage. It
could be classed as 'aggressive behaviour' if a dog consitently jumps up to grab something from a person who is scared of dogs, or a small child who doesn't understand the dogs behaviour is playful could be scared out of their wits - and their parents decide to take very drastic action which might result in the dog being destroyed
I wholly understand that you may have been just doing what your client requested, but for the reasons I've given above, I really don't like them.
However, the dog looks happy, confident and very well cared for which is great, and just on a photographic perspective I really like your fourth image - the connection you have with the handler is great, I could only improve it if the dog looked directly at you.
As previously stated, I'm not trying to be contentious, just offering a different perspective.