There is this, from October 2013: 100,000 Cattle feared dead after early South Dakota snowstorm
I guess the key with the Wholly Mammoths is that they stayed frozen. And not just for the winter.
These incidences, which there appear to be many, would rot the following season. The WM did not. It stayed frozen for thousands of years.
The article I saw in a newspaper (BI; before internet) had a picture of a frozen cow, still standing in the the barnyard.