A U.S. zoologist says contraceptives work well to reduce deer populations, but they are costly to administer and will have no impact on the rate of Lyme disease in New Brunswick.

Dr. Allen Rutberg of Tufts University said he's overseeing six long-term research projects involving deer and the contraceptive vaccine PZP in communities across the U.S.

"There's not much evidence to show that modest reductions in deer populations will do anything for Lyme disease," said Rutberg, director of the Center for Animals and Public Policy at Tufts' veterinary school. 

"That's worth keeping in mind."

The City of Saint John is looking for ways to control a growing deer population in the Millidgeville area.

Coun. John MacKenzie cited Lyme disease as the biggest concern in his motion to get the initiative rolling. 

He said he's also hearing from residents about deer that dart in front of cars or destroy gardens.

MacKenzie cited contraceptive vaccine as a possible solution to the deer numbers.

allen rutberg

Dr. Allen Rutberg of Tufts University has been studying the use of contraceptive vaccines on urban deer for two decades. (Tufts University)

Rutberg said the vaccine will be effective against the problem of deer in the garden or on the road but not against Lyme disease.

"It's a complicated disease with a complicated life cycle,"  he said. "Deer are part of the life cycle but they are not determining the rate of Lyme disease."

The other factor for consideration is cost.

PZP is administered in the U.S. either by capturing does and injecting the vaccine by hand or by shooting the vaccine into the doe from a distance using a dart gun.

Hunters would need to know

Health Canada rules, however, require any vaccinated food animal be tagged at the same time, so that if it's killed later in hunting season, the hunter can check to ensure the meat is edible.

That rules out the less expensive option of darting the animal.

"Most of the cost is actually labour cost," Rutberg said. "If you have to capture a deer, it's a lot more expensive because it may take eight or 10 person-hours per deer to catch a deer."

The vaccine itself costs $250 US for the hand-injected form, which will last multiple years.

Rutberg said the most dramatic success for PZP was seen in the community of Fripp Island, S.C., where the deer population was reduced over time by 50 per cent.