missing a TTL

[apple]

when I started my named, I kept getting the following mesg

Jan  9 00:27:47  named[4232]: Zone "mydomain.com" (file mydomain.com): No
default TTL set using SOA minimum instead

but, I followed the book and used all the field, what am I missing?
thanks

@       IN      SOA     ns.mydomain.com. hostmaster.mydomain.com. (
                                                 1
                                            10800
                                             3600
                                            604800
                                            86400)

thanks!

apple