How will neutering affect my adorable, but reckless male 1 yr old?

George has just turned one and is adorable, super friendly to humans and dogs alike but naughty as anything. Granted this is probably our fault as we did not stick with his puppy training very well at all. He is so sweet and sometimes listena quite well but when the attraction is too great he will run off and not come back to our calls.
Today he was delighted to meet a herd of cows while we were walking in farmlands and began trying to play with them. I’m so grateful they did not kick him any harder than they did (he got one kick) but we spent half an hour trying to chase him while he sped round their feet barking at them.
He is not neutered as my husband feels this is unfair on George and will change his character… I’m hoping it WILL change his character… just enough for his safety and our sanity!
How is neutering likely to change him? Will it make him less likely to challenge a hers of gigantic cows? Or will it make him dull and joyless? Or neither of these but something else! Please help! Is it too late to do further training?