Mr Walker started with the business in Waipukurau in 1983 as a veterinarian, after moving to Central Hawke's Bay from the Bay of Plenty, and continued full-time in clinical practice until 2002, when he took over the managing director role from Bert Middleberg.
In the 14 years since, he has overseen the expansion of the business beyond Hawke's Bay to one that now operates in Waipukurau, Hastings, Dannevirke, Napier and Masterton, employing 80 vets and support staff.
"We have got a culture that seems to work both for the people in the company and the clients who receive the services provided," he said this week while at home enjoying his first days of retirement. He formally left the position on March 31.
The success of the business he puts down to always striving to employ top staff and the advocacy role these staff play for the farmers and clients in the community.
Traditionally the practice centred on sheep and beef farming, he said, but changes in the agricultural landscape had seen services extend to deer and dairy, and the growing companion animal market, including horses.
"Our main focus has always been to achieve continuous improvement of our services and ensuring they are relevant for both farm and companion animal owners."
This had included such initiatives as weekly facial eczema monitoring on a number of Central Hawke's Bay farms to provide up-to-date localised data, and strong principles around the animal health products offered.
"We have to be convinced of their quality before we make them available."
In his role, Mr Walker was responsible for everything from the veterinary services to the retail shop, paying bills and wages, administration systems, employment and organising contracts.
This was a sole-charge position until Brendan James was taken on as business manager, and taking over the reins from Mr Walker is veterinarian Richard Hilson.
Aaron Scoble has replaced Mr Bettelheim as retail manager. Looking ahead, Mr Walker said he had no firm plans on what he would be doing next apart from overseeing he and wife Helen's 1200ha sheep, beef and deer farm near Waipukurau.
He would also be continuing with his directorship duties with different companies including Central Hawke's Bay electricity lines business, Centralines.