"The Power of the Dog" by Rudyard Kipling is a good poem about grieving the loss of a pet. Alternatively, "My Dog" by Robert William Service is also another good option.
Rudyard Kipling is well-known for his animal-related works of literature such as the "Just-So Stories" and "Jungle Book." "The Power of the Dog" speaks of the strong bond between a dog and its master while stating this strong bond can result in much grief when severed through the pet's death. With lines such as "There is sorrow enough in the natural way," Kipling asks why people choose to have pets when they will inevitably encounter grief when the pet dies, likening it to "giving our hearts to a dog to tear."
"My Dog" by Robert William Service also grieves the loss of a pet while reminiscing and cherishing the relationship they shared. British-Canadian poet Robert William Service wrote many dog-related poems celebrating his relationship with his dog, such as "My Dog My Boss." In "My Dog," the speaker recounts how the dog and his master first met, noting that the dog "shared my solitude." The poem ultimately ends on a positive tone as the speaker, in the midst of his grief, notes his gratitude that he has at least "given / One dog a happy life."