garseer - Do you have any bossy cows that he's with? Ones that have a tendency to push or head butt others out of their way?
I had a cow this summer that looked like she was trying to shoplift a soccer ball. It was on her side in the mid-lower rib area. Cow acted normal, ate normal, and was able to jump a gate when trying to pen her. Had the vet look at her and determined it was an edema, or blood and fluid buildup. Vet poked with a needle a drew some blood and fluid out. No puss so it was not an abscess or infection. There was no break in the skin or drainage. He advised not to lance it if there was no infection and Antibiotics weren't needed at the time. Most likely she got jammed by a branch in the wooded area of the pasture or got a headbutt just right.
Kept an eye on her and in 3-4 weeks it was completely gone.
