Horseshoe gate latch. Simple and very effective!
Tips for Creating Beef Cattle Handling Facilities
Benefits of one man tub designed by http://www.onemancorrals.com/ safety for cattle as well as for caretakers or cattleman
A "Kissing Gate" at Hadrian's Wall - FineWoodworking
kissing gate - YouTube
Adjustable Gate Latch (Gravity Latch Style) - YouTube
2-Way Gate Locking Latch from RAMM - YouTube
How to install the gate shut spring gate closer on a ranch gate - YouTube