Sick Like a Dog

Do dogs tend to get sick a lot? Or do they get very very sick when they are ill? Basically the question is: what is the origin and meaning of this phrase?

http://www.word-detective.com/061202.html#sickasadog

It means you have to eat it afterwards.

Just realised that isn’t going to work across the pond.

Goliath taught me many things. The bark of a miniature dachshund can be surprisingly deep and loud. The breed can jump quite high despite their small legs. The ‘weiner dog’ will not back down from a fight even with a doberman three times its size. Finally, they have an astounding resistance to toxins of all kinds.
My mother had sent in the appropriate number of labels plus shipping and handling. The Lenders bagel company sent back two bagel necklaces. These were actual minibagels, covered with some clear sealant and painted to resemble a child’s face. The bagel was mounted on a shoelace and was invested with a bizarre appeal. I thanked my mother and wore it proudly.

Until the day I thought that it was safely out of reach. I had gravely underestimated both Goliath's desire to eat a year-old, varnished bagel and his ability to reach it. When I returned from school that day, the living room fireplace was in shambles. The many obstacles that I had thought to protect my prize were scattered. Of my doughy pendant, only the shoelace remained.

 Goliath had, naturally, been sick as a dog. Since that day I have been sure of how the phrase originated.