No need to worry, we (the pilots) know when and what livestock we carry onboard the aircraft.
I can't speak for BA as I don't work for them. But when I know that we carry livestock I make an effort to go downstairs and have a look at the animals before they are loaded. I make sure that they have got water and if necessary will top the water up from my own bottle.
May I make one suggestion? Please make sure that you attach a bottle of water to the dog kennel. So that the handlers can top up the dogs water after they loaded him into the hold.