Hayfield gate down

When I started to cut my hay on Monday I moved the cattle from the neighbor's field to my middle pasture. This was done using the corner gate.  Once that was done I started cutting hay.  When I drove by the other gate to the neighbor's field I saw that gate was down.

The cattle once again messed with a gate.  The top lag bolt faces down to hold the gate in place. But the cattle somehow worked the gate to loosen the lag bolt and for the bolt to turn slightly sideways.  Down went the gate.  At least this time the gate was partially down and the cattle couldn't walk over the gate to get into the hayfield.

Today I fixed the gate.  Yesterday I had bought a new slightly larger lag bolt.  It is more snug in the railroad tie fence post.  Hopefully this lag bolt lasts longer than when I last rebuilt the fence and gate back in June 2019.