They didn't have cow catchers because most, if not all, rail tracks are fenced off so cattle can't wander into the path of a train. The posts are buffers for shunting other stationary trains and to prevent the trains crashing into platforms at termini where the track is a dead end.
Yeah, the comment was kind of in jest; actually, I've always been more intrigued that North American steam locomotives had cow-catchers at all.
Somebody here like OkieJohn or JohnnyReb might know; I always thought of cow-catchers as, really, ornamental objects with no practical use. I really doubt they could perform the function which many people seem to think was their function, scooping up cows and setting them to the side of the rails.
Even the utterly massive Union Pacific 4-8-4s and 4-8-8-4s, built during the 1930s and 1940s, had cow-catchers, and these things are so big any cow on the rails would be long gone before the train showed up.
Someone could correct me, of course, but I always suspected cow-catchers had the same function as hood ornaments on automobiles.