I am curious as to why people are thinking it is spleen. The spleen is a viscus, its parenchyma is spongy and trabecular and there is no "muscle" like what is on that piece of meat.
In regards to the OP, I am not sure of the answer. The caul, from my best guess looks to be omenta. In the human the greater omentum attaches the to the greater curvature of the stomach and the Spleen (as it forms from the dorsal mesogastrium) and in adults, attaches to the anteroinferior aspect of the traverscolon (though I don't know if such an event occurs in bovines). As that piece of meat looks like muscle....I would say it is some part of the abdominal wall or a pre-vertebral muscle. Although that is on the basis that it is greater omentum...which is just a guess
Edit: Wow...probably should have zoomed in...guess it is spleen after all. From the thumbnails it looked like Skeletal muscle...my bad
