Hi Anne,
I'm wondering if this would be an example of a lower burner Excess state. Like a Spleen Qi sinking? It would naturally worsen over the winter, and commonly the condition has a Floating pulse like that, but starts as a thin deep Wiry Liver pulse (such as in years past). The current Floating pulse suggests a propensity to invasion of the periphery by pathogens due to Wei Qi deficiency. Wei Qi deficiency is a common feature of Spleen Qi sinking.
That's one example, anyway, of how a dog prone to deficiency somehow would convert to an excess presentation. The immune stimulating effects of the formula might hopefully rally cells like Natural Killer cells to deal with any 'dirty margins' left over from the surgery.
If you try the treatment for this, which is Bu Zhong Yi Qi Tang, let us know how it goes. You could also add in a Blood mover for the lower burner, like Shao Fu Zhu Yu Tang. If she's overall chilly, then it's probably not a bad thing to try. If the dog is hot instead, consider Ge Xia Zhu Yu Tang.
Hopefully this helps you out!
Steve