I lived for 35 years on a rural mountain 40 acre parcel. A guy rented a pasture about 5 miles away and put about forty head of cattle on the property, his herd was a shabby group that appeared to be sale barn cast offs, about a third appeared to be sick. About a year before I had looked at the pasture to buy it, the fencing I could easily date to the 1880's.
I came out one morning drinking coffee and stepped off the porch and looked down and noticed I was standing in a large cowflop, I looked back towards my shop building and saw a 2500lb. bull with his hove's on the hood of my car licking rain water off the roof, I saw a cow eating and swallowing a large piece of garden hose, another cow had stepped on a short piece of 2x4 with a nail and was frantically trying to kick it off. Out of concern for the safety of the animals, I drove all 40 head into a 2 acre fenced pasture and then tried to find the owner, the animals all had brands but they were unreadable and had more in common with an injury I wondered if they were branding or barbecuing. I finally got the owners name and called him and he was clearly annoyed and said he was too busy to come and get them and I should stop bothering him and stated that I should build a fence, I told him he should repair his 100 year old fences, he then hung up. The rule with confining loose livestock is you have to feed and water them, you can then charge the owner reasonable costs, my problem was I didn't have the 30 gallons of water per animal it would take so I just turned them out. Welcome to Open Range Law.
Over the years I caught and returned a number horses,dogs. but the guy with the cattle just wanted to take advantage and get free feed. The area where my place was at one time was a large cattle ranch, but the owners quit because the forage was toxic, When I first got there I was raising calves and they were always sick, I got a plant identification book and discovered the reason why, the area had every toxic plant known to Colorado, Lupine, Loco weed, larkspur, pine needles and on and on, in the creeks there were plants with names like Deadly Nightshade. However there would not be a good reason to start shooting.