Our center of attention in a painting, (in this case, those two Hereford steers) should have "more", and everything else, "less". Since our eyes are attracted to contrast, our focal point should have the greatest area of contrast. We should probably think about having the richest color, the most defined edges, the most detail, etc. in our focal point.
Some things that those Herefords have in this painting are:
More: value contrast
More: sharply defined edges
Contrast this with, say, the tree edges, the tire tracks, the distant hill... all of these have LESS, and thus our eye takes them all in, but always returns to the center of attention.
Use the principle of "more and less" to aim your viewers eyes where you want them to go!