I haven't seen this number reported on CNN or on the AP wires, but I've been reading a newsgroup listing of horse owners. One regular on the list evacuated her horses to "the fairgrounds" (in San Diego? I've lost track of where exactly she is, but can go check again.)
She's reported that the last inventory of horses on that property was 2530.
Not including dogs, cats, etc.
CNN keeps reported "Thousands of animals on Del Mar racetrack", but then they keep going back to all the dogs in crates. More than a thousand horses is just an insane number.
One million people, twenty five hundred horses, thousands of dogs and cats. Can barely get my head around it.