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Heartworm Prevention in Australian Shepherds – My Experience

We do not have any relevant pictures of this topic, so random photos will be scattered throughout this post instead. 

I know this can be a rather contentious subject and I want to preface this post by stating that this is my personal experience and I am not a licensed vet.

When we rescued Trooper from the kennel I worked at, we decided to follow our vet’s recommendation for endo and ecto parasite prevention – Advantix for fleas and ticks and Heartgard for heartworms and other internal parasites. I was led to believe I had to purchase both through the vet. We did this until I moved to Massachusetts and asked my mom to mail (put on an airplane) Trooper to me.

Trooper in May of 2010, hike in Western Massachusetts

At the time Trooper came to join me in Western Massachusetts, the internet had blossomed into a reliable and user-friendly technology. I discovered with glee that I could order my flea/tick medicine online for a discount. Heartworm preventatives, on the other hand, still required a prescription from a vet. (Many online stores now offer Heartgard but you still need a prescription from your vet.)

After some settling in, I took Trooper to the vet for his annual check-up and to get another year’s worth of Heartgard. While he was there, the vet suggested we test him for lime disease. To my great surprise, he came up positive. The vet proceeded to describe our treatment options. Since that was back in 2009, I’m no longer certain what they were. But I do remember something having to do with pills for a long treatment window or waiting and re-testing.

I had just graduated from college with a tremendous amount of debt and had a tough time convincing myself to buy the expensive medicines. I also highly doubted the diagnosis given Trooper’s velcro dog habits and general inside lifestyle. I decide to re-test.

He tested negative.

And later negative again.

This was a positive experience for me. I learned to have patience and that the first test result is not always accurate. I also started to distrust the protocols and medications being ‘strongly recommended’ by vets.

I adored the vet we used growing up. When Trooper was a puppy, we lived a half mile from his office. We did his daily walk to the vet’s office, greeted the staff and resident cats, and practiced stepping on the scale and sitting.

I respect their training and knowledge and in most cases, their genuine desire to help our animals.

But having experienced the doubt associated with a vet’s diagnosis and being displeased with all the medications being required, I wanted to start thinking and researching for myself.

That desire was kind of short lived. I bought the next round of heartworm preventative and went on with life.

Summer of 2010 in Manchester, CT. I don’t remember Trooper ever (willingly) playing frisbee. He must be acting.

In summer of 2010, Trooper and I moved in with Brian down in Connecticut. By that time, we had run out of heartworm preventatives. And after relocating, we did not bother switching vets. I continued to prevent fleas and ticks, but from 2010 to 2012, Trooper was not given Heartgard.

According to my Amazon purchase history, I made the next change in 2012. We had just adopted Sydney – who came to us overweight, out of control, covered in years’ of messy, matted undercoated and a tick or two. We cleaned her up and got her started on flea/tick medicine.

So, with this new – and likely unhealthy – ward in my care, what should I do about hearworm prevention? Two dogs meant twice the cost – around $200 a year. I decided to not approach it with the flippant attitude I had had two years earlier. This time I did some research.

I read about the life cycle of the heartworm and I discovered that, given the life cycle of the worm and the conditions essential for its survival, some owners determine they live in a low risk area. They make the informed decision to not use preventatives.

One author wrote –

“With the advice of two local vets, I decided to protect my own dogs (both of whom have health challenges) against the toxicity of heartworm “preventatives” rather than protect against an unlikely infection. I use non-toxic alternatives like mosquito control, an excellent diet and no drugs unless they’re absolutely unavoidable. I increase safety by testing blood twice yearly. I haven’t used “preventatives” for five or six years and my dogs remain heartworm free. This is my personal decision.

I found these kind of statements inspiring but I was not totally convinced. Instead, I discovered an alternative to the expensive (and prescription mandatory) Heartgard. It is called Ivermectin Sheep Drench and I was able to find it on Amazon.

Beautiful pine cones we found in Morenci, Arizona.

NOTE: The active ingredient of both Heartgard and Sheep Drench is Ivermectin. Ivermectin is an effective means to kill heartworms but has been known to be toxic to some dog breeds. With any medication – conventional or alternative – please understand the possible side effects associated with its use.

“A genetic sensitivity to ivermectin can be seen in several breeds, but is more commonly seen in the following breeds:

  • Collie
  • Old English sheepdog
  • Shetland sheepdog (Sheltie)
  • Australian shepherd
  • German shepherd
  • Longhaired whippet
  • Silken windhound
  • Border collie
  • Dogs of mixed breeds that include herding breeds

This genetic sensitivity is due to a mutation in what is called the MDR1 gene.” (Read more here)

Considering that Trooper had been on Heartgard, I took a chance and gave him (and Sydney) the sheep drench. I watched them closely for signs of toxicity (lethargy, drooling, vomiting, etc.). All was fine.

Trooper making himself comfortable in my old ’88 Ford Escort wagon. This was pre-Sydney so he got the whole back seat to himself. (~2009)

Fast forward about sixth months. I was feeding the dogs a RMB diet, and I believed in the ideas behind mimicking dog ancestors. When Sydney later got a dog bite would, I would shave the hair away from the wound, disinfect it and then allow her to take over keeping it clean while it healed.

I don’t know what caused it, but something gave me a wake-up call. Why was I following an ancestral approach to dog food but poisoning my dogs each month? Each time I dripped that little bit of Sheep Drench on the piece of bread, I was feeding poison to my dogs.

I started in again on my research into heartworms. Long story short, I stopped ‘treating’ them. That was around late 2012.

We spent two more years in Connecticut, most of which was busy and stressful, spent preparing to sell the house and move across the country. After moving to New Mexico, we went into a sort of fugue state for 2.5 years, building our house and running our new business. We rejoined the world earlier this year and started adventuring again.

Prior to flying to Connecticut, Trooper lived with two cats. In this photo, we have Chance, his best bud. Ever since moving across the country, however, Trooper has decided cats are his arch nemesis.


Present Day…

In preparation for an upcoming adventure (which we will talk about in ~60 days), I took the dogs to the vet. The dogs were tested for heartworm and both were negative. Trooper had gone without preventatives from 2010 to 2017, except for about 6 months of Sheep Drench in 2012. Sydney, with an unknown background pre-2012, had had the same sixth months as Trooper and then had gone without ever since.

I also took them off flea/tick medicine when we left Connecticut for the desert and they have not had problems with either.

They both tested negative to heartworm and both were shown to be without ectoparasites.

The tagline on Heartgard’s website is “Dogs can’t hide from heartworm disease.” Well, both of mine did.

My current feeling on the matter is that, based on where we live, my dogs do not need heartworm preventatives or flea/tick medicine. Should we discover fleas or ticks some day, we will respond accordingly. As other authors have recommended, we may also introduce a once or twice annual heartworm test.

I’m linking below articles that I read in my research campaign to better understand how to keep my dogs healthy and happy. I strongly recommend reading these three articles and using the map to determine a protocol for your dog. I feel good about my decision but understand that disregarding a vet’s recommendation may not be for everybody.

Why Monthly Heartworm Protection Might Not Be Necessary
Heartworm Medication Part 1: Truths, Omissions and Profits
Heartworm Medication Part 2: Options to Fear-Based Recommendations

Trooper has moved a lot. In January of 2012, he moved with me across the country to California. The car was so full that he was sitting at the height of the window. At bathroom breaks, we would have to hoist him up and squeeze him into between the top layer and the roof. He did not seem to mind.