Lion, which has brands including Dairy Farmers, Moove and Dare, held a centenary celebration to show its appreciation to 16 farming families who have supplied milk to the Dairy Farmers brand for 100 years or more.

Two of those families are from the Highlands: The Hayes from Avoca and the McEvillys from Robertson.

Five generations of Hayes have worked the same 240 acres, progressing from a three-cow hand-milking dairy to a 32-aside herringbone dairy to cater for 300 cows. Colin's father started the diary, and now his grandson Jack works with the cattle.

"I think it is important to keep the dairy going," Jack said.

Evan Hayes said it was a pity that there were only about 14 diaries left in the Highlands, which used to have a very strong dairy industry.

"The Highlands is great for dairy because you don't have to reply on irrigation, and we're so close to Sydney," he said.

Just down the road at Belmore Falls, Bryant McEvilly's family has been supplying Dairy Farmers for 130 years.

"I love the cows and never wanted to do anything else. We have 200 head at the moment and plan to expand," said Mr McEvilly, who is the fourth generation of his family to work the property and hopes his children will continue the tradition.

Lion Dairy and Drinks Managing Director Peter West said it was "incredible to think that some of the farming families with us today were there at the very beginning.

"While so much has changed over the last century, success in the dairy business is still about hard work, a commitment to quality, building relationships and thinking long-term.

"These 16 farming families have these qualities in spades and we're very proud that they have chosen to partner with Lion and supply the Dairy Farmers brand for 100 years or more," he said.

To coincide with the 100 year celebration a new television advertisement will screen from this Sunday, asking consumers to think about why milk matters.

For families such as the Hayes and McEvillys, milk is not only their livelihood, but is also a link back to early last century when the Highlands was one of the most productive dairy regions in Australia.