A bovine head seems like a necessity for a minotaur for me. But then again I'm more inclined to see minotaurs as savage creatures as opposed to humans with horns.
As a casual liker of anthromophic characters in fiction.
There is a sliding scale of how much they should look like the thing they are based on. And it depends entirely on what you're doing with your setting.
Sometimes just horns and a cow tail will work, but other times you'll want them to look more 'authentic' I guess. Depending on how much fantasy is in the setting.
You should just do what fits your setting than what 'makes sense' and if you do it well enough the audience will accept it as normal.
I'm personally creating a dragon race with a few dragon like features and dragon tail, but are otherwise human. They do dragon like things and have dragon-like personalities, and that seems enough for me. What's more important is the lore behind them and their culture in my opinion.