someone is wrong on the internet

Just a safety thing, for both people and cattle. Horns are there to damage, and cattle know how to use them against other cattle and people. Further, if there are cattle that have horns mixed in with cattle that don't, they're more likely to bully and maim the other cattle. Therefore, no horns = safer and happier cows (not in every case, but lots).

thank you :)

thats just like saying color not colour. Some countries spell it that way...