DEAR READERS: Monsanto's Roundup herbicide, which contains the active ingredient glyphosate, recently designated a possible carcinogen, is absorbed by genetically modified crops that have been engineered to be resistant to the weed killer. Most corn, soy, sugar beet, cotton and canola produced in the United States are genetically modified, as is much imported rice. My concerns about this herbicide getting into the food chain for both humans and animals have been recently confirmed.

Research scientist Dr. Anthony Samsel of Deerfield, New Hampshire, has shared some of his findings prior to his scientific report being published. Using High Performance Liquid Chromatography (HPLC), the Environmental Protection Agency-accepted method of analysis, he found levels of glyphosate ranging from 0.022 to 0.30 milligrams per kilogram in cat and dog foods. Brands evaluated include Purina, Friskies, Iams, 9 Lives, Kibbles 'n Bits and Rachael Ray.

According to Dr. Samsel, the pet food industry "adds NaNO2 (sodium nitrite) to some pet foods as a preservative. This is very common, and, in the presence of glyphosate, is deadly. Glyphosate reacts continuously over time with NO2 and produces N-Nitrosoglyphosate, which is a nasty carcinogen, along with phosphonic acids AMPA and MAMPA. Another scary scenario is nitrite (NO2) formation from nitric oxide (NO), which reacts with glyphosate, resulting in N-Nitrosoglyphosate. This is another reason why this stuff needs to be immediately pulled from the market."

The peer-reviewed research article by Drs. Samsel and Seneff, "Glyphosate, Pathways to Modern Diseases IV: Cancer and Related Pathologies," which includes these findings, will be published this month in a special issue of The Journal of Biological Physics and Chemistry. Samsel launched a GoFundMe site with the GMO Free News to help raise money for research: gofundme.com/xrp4h9g.

As per my review of GMOs in pet foods posted on my website, DrFoxVet.net, several health conditions, including inflammatory bowel disease, allergies and skin and organ problems, may arise as a consequence of GMOs being included in the animals' food.

DEAR DR. FOX: My friend has multiple cats and, therefore, lots of cat toys. We were at her house, and my daughter picked up a wand with a long cord and a squeaky mouse on the end. I guess it is a common cat toy, but not having cats, we've never seen one before. She started playing with it, and our 7-year-old Yorkie, Cooper, went crazy! We bought one for our house immediately, and he plays with it several times a day. We chide ourselves for not realizing sooner that we were going against his natural instincts in trying to get him to play with us in "normal" ways. We'd always had Labradors before our Yorkie, so we bought him tiny tennis balls and tried to get him to fetch. No deal. He'd chase it, but never bring it back.

Once we introduced the cat toy, we quickly realized that his instinct is to chase rodents, and a toy that promotes that is going to be the trick. We run around the house trailing this "rat" on a string, and he chases us with passion bordering on obsession. It is some serious exercise for us all. We fling the squeaky toy under the furniture so he can burrow for it, and eventually we let him pounce on the rat and chew it for a minute or two so he feels successful.

This toy has been so much fun for us and our little dog; we can't believe we didn't discover it sooner. We've always wanted to engage with him on a physical level but didn't know how. Cooper is a great lap dog, but we all wanted to play with him. My daughter says he looks happier and healthier ever since we got his toy.

I hope this inspires other terrier owners to explore different types of toys; we wasted seven years by skipping the cat aisle at the pet store. -- R.C., Washington, D.C.

DEAR R.C.: Thanks for reminding all dog caregivers that different dogs need different toys, and as a result, so many poor dogs are bored and lack playful stimulation for their minds and bodies. Be sure the toys are nontoxic and not likely to break and be swallowed, causing internal injury. Yorkies are little hunters indeed, and a mouselike squeaky toy could be a trigger for great fun for them.

DEAR DR. FOX: We have three dogs and one cat. The dogs sleep as long as we do, but the cat used to wake up at about 6 a.m., walk on my body and lay on my chest, purring. If I closed the bedroom door, he scratched the door and meowed until I let him in. We had an old kennel from the dogs, and I recently put the cat's tepee-type bed in it with an old blanket he likes, along with some food and water. I put him in there, and he sleeps all night. He likes it so much he goes in his "house" way before we go to bed. We now have a happy cat and happy owners. -- T.T., Silver Spring, Maryland

DEAR T.T.: Thanks for sharing your solution! This may not work for all cats, but many readers with early-rising cats may find your solution an effective remedy. Be sure to play with your cat before bed.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)

DEAR DR. FOX: My almost-12-year-old Labrador retriever has recently exhibited signs of severe anxiety.

He's panting and pacing a lot, and recently started waking in the middle of the night to pant and pace. He's been increasingly barking at passersby and seems more anxious than usual at being left home alone -- with the run of the house -- during the day, although he's not damaging anything. While he's always been a little anxious at thunderstorms, that anxious behavior is now happening with greater frequency, more severity and absent thunderstorms.

He seems in otherwise decent shape. He has some fatty tumors, which the vet has said are not particularly problematic; he eats well, drinks well and eliminates with no problems. He has slowed down, sleeps a little more and can no longer jump into the car, although he manages stairs with no trouble.

What do you think is the problem, and is there something we can do to relieve his anxiety? -- A.F., Rockville, Maryland

DEAR A.F.: Many animals, including the human species, show signs of anxiety associated with age-related impairment of sight, hearing and cognition, and chronic debilitating conditions, such as painful arthritis. The latter can be ameliorated with various supplements, which you should discuss with your veterinarian. Add to his regular diet small portions of high-quality protein, such as egg, turkey and cottage cheese -- especially if he is losing weight or muscle mass, a condition called sarcopenia, common in the elderly. Give him a tablespoon or two of coconut oil daily, which has been shown to help improve brain function in old dogs. Above all, keep him off slippery floor surfaces and provide him with a soft bed and nonslip carpet so he does not tear ligaments and damage joints sliding all over. Also discuss with your veterinarian giving your dog a light dose of Valium in the morning and melatonin in the evening.

DEAR DR. FOX: Thank you! We are doing a few of these things anyway, particularly the anti-skid mats, although he's smart enough to bounce around on the carpet and calm down a bit on the tile. My vet has recommended carprofen twice a day. We've tried this for five days, and it's like he's a new dog. However, I have read a lot of the information on the Senior Dogs Project website about Rimadyl, and now I'm concerned that this treatment may cause more problems than it's worth. -- A.F.

DEAR A.F.: Carprofen, marketed as Rimadyl, can give short-term relief for dogs with arthritis. In my opinion, it should only be used for up to three days because of the risk of harmful side effects, notably nausea, gastrointestinal inflammation and bleeding, and liver and kidney damage. This is the problem with this class of non-steroidal anti-inflammatory drugs.

Excellent results have been seen in arthritic dogs given supplements such as fish oil, ginger and turmeric, and in preparations like Cosequin, which contains glucosamine, chondroitin and methylsulfonylmethane. Discuss these safer alternatives with your veterinarian.

PET FOOD TROUBLES

Thanks to Susan Thixton at Truth About Pet Food for these postings on her website:

-- A nationwide class-action lawsuit has been filed against Nestle Purina Fancy Feast pet food alleging, "the pet food manufacturer knowingly supports a system of slave labor and human trafficking (on fishing boats) to produce its Fancy Feast cat food, while hiding its involvement with human rights violations from the public." (See: truthaboutpetfood.com/pet-food-consumers-sue-fancy-feast-for-using-slave-labor-ingredients/.)

-- Orijen/Champion Pet Food confirms counterfeit Orijen cat and dog food is being sold in China. (See: truthaboutpetfood.com/counterfeit-orijen-pet-food-found-in-china/.)

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)

DEAR DR. FOX: Nine days after my 1 1/2-year-old healthy cavalier King Charles spaniel was given a single dose of the oral flea and tick preventative Bravecto, he became ill, exhibiting many of the side effects published by the manufacturer. These included diarrhea, loss of appetite and lethargy. He also developed problems with his kidneys, ultimately resulting in euthanasia. A necropsy was performed, and initial testing indicates a possible cancer, but there is no explanation for the sudden transformation from healthy to deceased.

Until the death of my dog, there was no central platform available for people to discuss possible side effects and problems associated with use of Bravecto. Most owners and veterinarians are unaware that all side effects need to be reported to the drug manufacturer, Merck, and to the Food and Drug Administration. For these reasons, I started a new group on Facebook called, "Does Bravecto Kill Dogs?"

In less than three weeks, almost 1,800 people have joined the group. Seven individuals reported that their dogs died within a short period of taking this medication. We found seven additional reports of deaths on other websites, which have been copied to this Facebook group. Additionally, in this short period of time, over 25 reports of horrible side effects have been posted. Common side effects reported include diarrhea, vomiting, lethargy, failure to eat and seizures. While most of these were reported as side effects in the product brochure, the symptoms are not short-lived. Numerous dogs have required treatment by veterinarians or have been hospitalized. Most of the dogs who died experienced these symptoms subsequent to taking the medicine. Reports of kidney and liver failure have been reported, along with three individuals who are concerned cancer may have developed from this medicine. We are trying to bring awareness to this medicine so that all side effects can be documented and reported. Please visit our Facebook group -- "Does Bravecto Kill Dogs?" -- to report any side effects your dog has experienced subsequent to taking Bravecto. Owners should contact Merck with any adverse side effects and report them to the FDA using the FDA Event Adverse Reporting Form. -- S.W., Andover, Massachusetts

DEAR S.W.: Thank you for your information and vigilance on this product. Readers of my column should know that I do not advocate the routine use of most of the widely marketed anti-flea and -tick products, both oral and topical, from the big pharmaceutical companies. For safer, integrated control and prevention of these external parasites, visit DrFoxVet.net and see the article "Preventing Fleas."

DEAR DR. FOX: I was disappointed to see yet another attack on homeless cats in your column. It is particularly unseemly that someone who could and should be an animal advocate would embrace the dark side. Your thinking is a classic case of blaming the victim. Many cats already carry the burden of misguided guardians who believe they should be allowed outside, silly old superstitions, nonsense myths and tired stereotypes that, even in the 21st century, often surround them.

The letter writer used violent words like "terminate" and "eliminate," displaying a disturbing level of ignorance and total lack of empathy and compassion. My husband and I managed a feral colony for decades on our 20 wooded acres. They were a wonderful group who helped keep natural balance. Since the last old cat passed away, we have been overrun with field mice and chipmunks.

We live in the heart of prime Midwestern farmland, where cats are very welcome on farms because they keep down all rodents, as well as the myriad birds who can wreak havoc in planted fields. I can assure you that nuisance birds and chipmunks are not beloved everywhere. They are merely tolerated as part of the ecosystem. Cats deserve to live every bit as much as any of these critters -- maybe more so. -- S.A., Springfield, Illinois

DEAR S.A.: Thanks for your heartfelt and informative letter (which I shortened for publication). Yes, it is a controversial issue.

Establishing a colony of cats in your woods would lead to rodent population decline, and their resurgence after the last of your colony cats died was probably because the area's indigenous rodent-controlling predators, such as red and grey foxes, owls, hawks and even snakes, had been displaced competing with the cats for the same prey.

I am as opposed to the deliberate release and "dumping" of cats deemed unadoptable by humane societies and animal shelters back where they were caught as I am against mass killing of such cats. Instead, I encourage setting up humanely operated enclosed sanctuaries to protect them, other free-roaming cats, wildlife and public health. It will take another generation or more before a consensus is reached in all communities as to how best address the free-roaming and feral cat issue.

DEAR READERS: I am now closing further discussion on this issue in my column and refer all concerned to my report posted on my website, "Releasing cats to live outdoors: humane, environmental and One Health concerns." I trust that this will help convince local humane societies, notably the Washington Humane Society in our nation's capital, to phase out releasing cats outdoors after neutering to fend for themselves.

(Send all mail to animaldocfox@gmail.com or to Dr. Michael Fox in care of Universal Uclick, 1130 Walnut St., Kansas City, MO 64106. The volume of mail received prohibits personal replies, but questions and comments of general interest will be discussed in future columns.

Visit Dr. Fox's website at DrFoxVet.net.)