I enjoyed Gunda. I found it audacious — pointing cameras at farm animals and, with some skillful editing, letting the visuals tell the story.
(Or, more accurately, giving the audience plenty to work with in the construction of a story in their own minds. We humans apply a narrative structure to ambiguous events in order to make a coherent and causal sense of events.)
Further, Gunda was full of startling and beautiful images. The choice to play some of the scenes for excruciating lengths of time turned out to be an interesting and effective method for inviting the audience to contemplate the lives of the farm animals.
Cow is not audacious, interesting, effective, beautiful, or startling (well, it was startling and brutal at the end). It is simply the result of a second-hand idea captured in mundane, and annoyingly shaky and relentlessly close-up, images.