usually use a shutter speed of at least 1/800 for capturing my dog in motion ( always usually outside , with lots of light)
for dogs in general i probably wouldnt go lower than 1/50, it depends how dark/light it is and what shes actually doing. if she is still or sleeping and the light is bad then i will go down to a slower shutter speed.
Apperture i usually always go for the biggest I can (smaller number) because i like shallow depth of field. (and lets in more light!)