Anne,
I am so sorry for your loss. Cowboy sounds like a great dog and I hope you have peace in your heart as he is at peace now. Here is a nice reading I found when searching for a pet sympathy card for a friend a while back:
Our inability to completely protect and keep from harm those we love is a painful but inherent part of the human condition.
Let solace be taken, however, in knowing that we gave the best we had to our little friends, and that they knew, without an inkling of doubt, that they were deeply loved.
For, beyond all else, that is the greatest gift we give to them, and in turn, the greatest gift they give to us
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