Christmas is long gone, but sales of a fund-raising CD called "A Very Silent Night" -- audible only to dogs -- are still going strong.

Produced to raise funds for the New Zealand Society for the Prevention of Cruelty of Animals (SPCA), the song, the organization says, is recorded at a frequency only dogs can hear.

Nevertheless, it was so popular among New Zealand dog owners it hit No. 1 there at Christmas, raising $17,000 so far and prompting the SPCA to consider marketing it in Australia and the United States.

Bob Kerridge, chief executive of animal welfare group, says the CD has been receiving mixed responses from listeners.

"The most violent one was a dog that physically attacked the radio when it was played and went quite berserk and totally destroyed it," he told Reuters News Service.

I haven't tested it on my own dog yet. Maybe tonight I'll see how he reacts. Meanwhile, if you want to "listen" to the music video version, click below (at your own risk, if the dog is in the room). We can compare results -- and perhaps even figure out if this is real or a gimmick -- in this entry's comments zone (see button below).