Colostrum, the first milk produced by a cow after calving, has been widely celebrated as having health benefits for humans.
Now Colostrum UK, which has a production plant in Bethesda, has started producing it for customers including Olympic athletes and Welsh professional rugby players.
Director John Rolfs described it as "real Welsh gold".
The yellow product is much denser than regular milk and has been sourced from local farms.
The company is also working with Welsh universities to prove the product can boost the immune system and improve a number of digestive conditions.
Mr Rolfs started using it himself after undergoing major surgery five years ago but had to import it from New Zealand.
"It seems strange to me that we have cows standing in the fields here and no-one is collecting it," he told BBC Radio Wales' Country Focus.
"People have been unaware of its qualities."
He said the company now has a "sizeable demand" but is trying to get more local farms on board.
"We need another 3,000 cows signed up to get through the immediate demand," he said.
"We are in the right place, among the right community, at the right time. This is the real Welsh gold; this is the secret."
Calf milk is being trialled as a diet supplement by a Pembrokeshire company.