The subject does the question quite nicely, I think.
It’s a little ridiculous, yes, but the thought sprang to mind when one of my neighbor’s bitches was in heat. This was a Jack Russel terrier runt, perhaps six pounds of 3yo dog. The males of my neighbor’s five dogs were both Scottish Woflhounds, magnificent horselike things weighing at least 110 pounds. They knew something was up <ahem> but couldn’t figure out for the life of them where the female was. I guess the appropriate smell signals are the same for all dogs, but the boys thought of her as their wonderful little rodent playmate.
Now, ignoring certain problems with the mating (let’s suppose artificial insemination), will there be a problem with the pregnancy and whelping? Do little dogs have short periods of gestation and the pups will appear only part-formed?