Have You Ever Seen An Ox Eat Grass?

Here is an odd Midrash that I would like someone to explain to me.

The Midrash Rabbah on Ruth Chapter 7 sif 11 states:

"There is nothing as vulgar, abhorrent, and outlandish as the sight of an ox eating grass".

My question is... why?

Is this telling us that an ox eating grass is more vulgar than maggots devouring a carcass?
Or vultures eating a dead ox?

If there is a deeper meaning to this Midrash it escapes me (as most would).

Any ideas?

(I ask this knowing full well almost no one, and perhaps mamash no one comes to my blog. But maybe someday someone buki in Maharal will stumble here and be able to answer my question. :) )