"I use homeopathy, Chinese herbs and acupuncture," said the 50-year-old veterinarian, who practices at "South Paws" in Fairfax, Virginia just outside the US capital Washington.
"It's the same type of needle as for people. The basic acupuncture channels are the same. Acupuncture pathways mirror the nervous system and stimulate it the same way."
Kocen had just riddled with needles a 13-year-old cat, Alexa, whose mysterious symptoms, constantly staggering and nodding her head, have improved in the four weeks since the sessions began, owner Joan Ferguson said.
"I had her do two MRIs (radiological body scans), a spinal tap and some blood work. (It cost) a lot of money. The neurologist just didn't know what to suggest," she said.
Desperate, Ferguson turned to an acupuncturist and Alexa has not battered an eyelid at the treatment, rather finding relief in the forest of needles lined down her spine.
More and more vets are turning to this alternative therapy in the United States where the market for pet products, never lacking in imagination, is constantly growing.
Out of 86,000 veterinaries worldwide, between 900 and 2,000 practice acupuncture, according to professional groups, whose numbers are also rising.
"More and more pet owners are looking at holistic modality. It's growing. Three hundred veterinarians each year take a post-doctoral course in acupuncture. It's been like this since 2002," said International Veterinary Acupuncture Society executive director Vikki Weber.
Weber, whose group counts 900 members in the United States, said acupuncture has been recognized as a valid treatment by the American Veterinary Medical Association (AMVA).
The number of acupuncturists is "certainly on the rise" and there is "some anecdotal evidence to support the efficacy" of alternative veterinary medicine, including acupuncture, recognized Michael San Filippo, spokesman for the association, which focuses on conventional medicine.
Kocen, who has been a veterinarian since 1986 and practiced acupuncture since 1995, said that "80 percent of the cases show improvement."
He now has some 1,500 clients, with between eight and 15 appointments per day shared between himself and his assistant. Each consultation costs 95 dollars.
Acupuncture is "more accepted", Kocen said as he leaned over one of his regular customers, Lexus, an 11-year-old Saint Bernard dog, who has suffered weekly epileptic fits since the age of two.
Owner Sally Rabb has brought Lexus in for a monthly acupuncture session for the past four years. He also receives five doses of anti-epileptic medication per day.
"We can see a change in him after he had his treatment," Rabb said. "He can't get out of the car fast enough, he likes to come here."
As with a clinic for humans, the vet goes from room to room to place or check the needles during the 20-minute sessions.
"It was an opportunity to expand what I do and it kept me busy," said Kocen, before turning to Trixy, a handicapped dog rescued by Washington Post photographer Carol Guzy after deadly Hurricane Katrina devastated New Orleans in Louisiana.