>>replace horse_name with left(horse_name, at("(", horse_name)-1))
>
>This gives me a error message "command contains unrecognized phrase/keyword"
>
>Do you think that the strtran function can be used with wildcards?

Doh! One too many parentheses at the end! Sorry...
should be

replace horse_name with left(horse_name, at("(", horse_name)-1)

Strtran doesn't work with wild cards.