Hello everyone I am now the proud owner of a precious little rough collie named Albus. He is Mdr1 and my vet gave me sentinel for heartworm prevention, but after doing my own research I am reluctant to give it to him because of the mixed information regarding the Milbemycin oxime. I normally trust my vet but this time walking in with Albus it was like walking in with a unicorn as every tech and vet came out to take a peek and a pet, as they said it had been years since they seen a rough collie. Some of the younger vets had never even treated one. I just really want to do whats best for him and any advice would be greatly appreciated. Also they gave me bravecto for flea and tick prevention. Thank you from both my family and Albus!