IDIOMS

dog my cats

(idiomatic) used as a mild oath, or as an expression of astonishment

Example:   "Why, dog my cats, they must a ben a house-full o' niggers in there every night for four weeks to a done all that work, Sister Phelps." — Mark Twain, — Adventures of Huckleberry Finn", 1884
  I began to feel sorry for Hubby, dog my cats if I didn't." — O. Henry, "The Four Million," 1906
  And standing on one leg beside the bath, like Slingsby, had whispered: "Ho, ho, ho! Dog my cats!" mysteriously, to bring luck. — John Galsworthy, The Forsyte Saga, "Awakening", 1920
  Buffalo Bill Cody: Dog my cats " - to Annie Oakley, "Annie Oakley"', 1935
  Salesman: Well, dog my cats!" — Preston Sturgis, "Christmas in July", 1940
  Ty Ty: "Well, dog my cats!" - to himself, "God's Little Acre"', 1958
  Joe Ross: Funny old world.
  Susan Ricci: Funny old world? Dog my cats!
  Joe Ross: Dog my cats indeed." — David Mamet, "The Spanish Prisoner", 1997
  Marshall Ericsen: "Well dog my cats..." - to Robin Sherbatsky, "How I Met Your Mother"' 2010