Some unusual cases that stand out over the years include the dog that slurped up water in a hot tub and ingested two plastic ducks that had to be surgically removed. There was the dog that ate a vest studded with metal, and then the operations to extract tennis ball pieces and rocks out of more than one dog.
Perhaps more challenging was treating the dog that ate a marijuana brownie. Chocolate can be toxic for a dog, and pot can cause other complications.
Most of Dr. Wengren's days are more routine at his one-man shop, Windy Hill Veterinary Practice at 884 Portola Road, where he rents space from veterinarians Bill Klein and Bill St. Lawrence. However, Dr. Wengren has noticed some changes in the business over time such as an "obesity epidemic."
"People are feeding their animals too much. They are killing their dogs with love and giving them treats," he says.
He has observed an uptick in diabetes problems, too, "because fat cats are more prone to developing diabetes."
He explains how it can be tough to regulate the right amount of insulin, so he sometimes confers with a specialist on diabetes cases. He notes there are a lot more specialty practices in veterinary medicine these days — internal medicine, ophthalmology, and surgical specialists.
"I will refer clients to them if they offer the best care. ... When I first started out, I would do a few more different things than I do now," he admits.
Dr. Wengren grew up surrounded by dogs, cats, chickens, cows, rabbits and hamsters in Chelsea, Michigan, home to one of the oldest veterinary hospitals in the U.S.
Fresh out of Michigan State University's vet school, he drove down the coast from Oregon to California in 1981, "looking in the telephone book for veterinary offices." He walked in unannounced to Carlo Besio's clinic at 808 Portola Road and was hired on the spot. Dr. Wengren stayed there until 1995, when he moved a few doors down to his current office.
He comes across as low key, dressed in jeans, a plaid flannel shirt, comfortable shoes, a beard and glasses. Occasionally he brings his mixed breed shelter dog to work, or leaves him at home in Woodside with two cat companions.
In the Portola Valley-Woodside area "in general, people take better care of their pets," Dr. Wengren says. "Most of the animals are family members and people have a lot more interaction with their animals than years ago when I was growing up."
He gives the example of his elderly customers with elderly pets. "There are a few 18-year-old cats living in the Sequoias because people tend to keep them indoors, and their cats live a long time."
One downside to more interaction between people and dogs can be more sports injuries. He recommends pet insurance "for certain people with certain kinds of dogs," he says. "Labradors and goldens have problems with their knees because they're active dogs."
According to Dr. Wengren, knee surgery is the most common insurance claim, and replacements can run about $5,000.
In the Portola Valley-Woodside area, he sees a lot of larger breeds, but has also noticed more mixes: Labradoodles, goldendoodles (Labrador and golden retrievers that are crossed with poodles), and puggles, a pug-beagle cross. Small dogs such as Chihuahuas and schnauzers are popular, too. He estimates half his customers own purebreds, and the other half own mixes rescued from shelters.
One worrisome observation he has made is that golden retrievers "are getting cancers at an early age, 8 or 9 years old, in the spleen or around the heart."
He postulates it could be caused by exposure to pollutants in the air and/or on the ground.
He suggests a somewhat new vaccination to guard dogs against leptospirosis, a disease spread through contaminated water that can cause kidney problems.
In his business he has seen a shift toward more emphasis on preventive care. Every year he mails out postcards to remind clients to bring in their animals for wellness checks. He says shots are now given less often than they used to be because most vaccinations last longer than a year.
But he still encourages his clients to come in for an annual appointment. "People are always glad to hear their animals are doing well, and find out what to look out for as they get older."
Margie Mackenzie has been taking her dogs and cats to Dr. Wengren ever since she moved to Portola Valley 18 years ago. When two of her cats were hit by cars, she remembers his thoughtfulness in calling the following days to monitor their recoveries.
When her Westie suffered renal failure and then her Scottie had advanced lymphoma, Dr. Wengren put them both down.
"We (her family of four) were all there," she says. "It was a very gentle passing."
"End of life issues" as he calls them, are all part of his practice. He's willing to make house calls if an older client can't manage to load an animal in the car, or wants to do "everything at home."
"Many clients have a hard time figuring out when is a good time" to turn to euthanasia, he says. "It's a blessing in this business that we can assist them."
Over the years Dr. Wengren has noted a slight increase in heartworm cases in the Los Trancos and Mountain Home Road neighborhoods, and other places where mosquitoes have access to water year-round.
Foxtails are a common problem everywhere, depending on the season. He urges clients to check dogs' noses, ears, and paws after hikes.
Other potential hazards found locally are poisonous plants such oleander, lilies and some wild mushrooms. He warns that eating drugs and foods meant for humans can be harmful, too. Tylenol can kill cats, and dogs can develop toxic reactions from consuming macadamia nuts, raisins, grapes, onions and garlic.
Feeding pets table scraps in small portions is OK with him as long as it is a little meat or vegetables, but not bacon grease, as that could lead to his first lament: obesity.