without ssh prompt

[Jacky Kim]

When I ssh-keygen a passwordless key pair for root and give the public key 
to openssh server(sshsrv), then it is ok to 
	# ssh root at sshsrv

But when I generate a password key pair for root and give the public key 
to openssh server(sshsrv), then I fail to 
	# echo "rootpasswd" | ssh root at sshsrv
and get the follow message:
	Pseudo-terminal will not be allocated because stdin is not a terminal.
	Enter passphrase for key '/root/.ssh/id_rsa':

How can I login into ssh server automaticly, without getting the prompt?	

Best Regard

Jacky Kim
.