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Heartgard or Sentinel / frequency


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Gil is my first dog I have owned since I came to the US. Heart worms were not a problem in the UK and so I have no experience as to what to give him and how often.


My vet said as long as he starts something before he is 6 months and not to worry. Well he is my Baby LOL (Gil not the vet) and I do worry.


I read up on these heart wormers and the fact they say safe for "collies" made me suspicious! Apparently there is something toxic, that collies are more susceptible to than other breeds, which can cause liver failure.


So my question is what are you using on your collies and do you treat all year or just mosquito season ? Anyone had any problems..I know I have to protect him against this..I just want to take the safest option.


Thanks in Advance.

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I am overprotected of my dog too. First vet told me not to start Heartworm until she finished her last set of shots.


When I took her to my new Vet, he was furious. He told me to start immediately when she was around 4 months old. We used Sentinel but I found some fleas so we switched to Interceptor + Advantage once a month. She is doing fine.


There was a discussion about which one to use a while back. Let me see if I can find it...


Thread 1

thread 2

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We have been very satisfied with Interceptor and Frontline monthly for Fergie, for 8 years now.


Yup, got to do the stuff every month. It might stay below freezing for a week at a time. But we might also get 60 degrees or more for a week at a time. There was a mosquito between the back door and the screen door yesterday.

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Things to know about heartworm disease:


1) It is a mosquito-borne disease that is present in every state in the union except AK. (This is me smiling reeeeally wide at that, since given our mosquito population up here it would be devastating to the wildlife.) The reason for this is that the worm larvae have an obligate life stage which takes place in the mosquito's mouth parts - this is an essential part of their maturation, during which they go through (if I recall aright) two larval instars, from L3 to L5. They are not infective - are incapable of setting up an infestation - until they pass through those larval instars. The maturation process requires that the ambient temperature be at least 70 degrees F, 24 hours a day, for 2 weeks in a row. We don't HAVE any 14 consecutive days where the temp is above 70, 24 hours a day. Even if we had a freak year, it would require a lot of things to go wrong all at once to establish the population, and it would have to KEEP going wrong year after year to set up here. Most everyplace else DOES have the appropriate conditions, however.


2) It takes six months from the first exposure (in other words, from the day a susceptible dog is bitten by a heartworm-positive mosquito) until there are adult heartworms living in the heart. This is why INU's first vet and River's vet said it was okay to start after the shots were done or before 6 months, respectively - shots should be finished at 16 weeks, and even if a pup was bitten the day they were born, they would not have adult heartworms in the heart by 4 months. However, there is no reason why you can't start them on preventatives earlier than that, as most are safe in younger pups. I certainly would not wait longer than 5 months, myself, just in case, but we must all bear in mind that I am a gigantic medical chicken.


3) Preventatives should be given on schedule as long as the dog is in a heartworm-positive area and there is a mosquito alive in the vicintity. If you lived in, say, North Dakota, all the mosquitos would be dead in winter so there would be no need to treat in winter months, SO LONG AS your treatment protected the dog until AFTER the last mosquito was dead.


4) The product that collies are more susceptible to than most dogs is Ivermectin, which is a neurotoxin, not a liver toxin. However, any dog can have any reaction to any drug, and never say never and always avoid always in medicine. So it's possible a given dog MIGHT have liver disease from Ivermectin, but that isn't the classic toxicity we see. Also, the most vulnerable collies are the rough-coat "lassie" collies, not BCs. However, there are other treatments besides Ivermectin so it's easily avoided.


5) If you somehow progress to the point where there ARE adult worms living in the heart, treatment is tricky, expensive and toxic, and may not save the dog. It's just better not to go there, so if in doubt, use the preventatives.


6) Heartworm disease is starting to be seen in cats as well, so if you live in a heavy infestation area (all coastal areas except AK, the Mississippi and Ohio river vallies, HI, anyplace warm and humid - less common in the Rocky Mountain states and the desert states) you might just ask your vet what incedence they're seeing in cats. It's still pretty uncommon from what I read.


Hope that helps clarify.

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Hi again,


INU thanks for digging up the old links for me, much appreciated.


AK thanks so much for taking the time to explain again.


My vet recommended only giving the during mosquito season here in madison WI and said I had no need to give him protection until March and then after his first year a blood test each year. It seemed a little bit daft to me, if these products are safe why take the risk and have to have his blood taken every year.


So thanks I will definately start him on something next week and give it 12 months a year(not heart gard) but undecided on the others I need to go back through the other thread and go with the majority.

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If you CAN refrain from giving preventative during winter (lucky you - it's all year for us in Hawaii) and you are SURE there are no mosquitos left, then I would do that. It is a drug. And anytime you don't HAVE to give some sort of foriegn thing to your dog - that's good!


Yes they are "safe." But still - if you don't have to give it, don't.


The blood test is done in Hawaii even though my dog is on Interceptor all year. I like to know that it's working anyway. Plus, the sooner you catch it, I think the better your chances.


Interceptor is good as it also helps with certain worms as well. We've done good with Interceptor and Frontline. Some folks use other heartworm treatment that helps with fleas. However, Frontline does fleas AND ticks - and we really nead the tick treatment here. So, why double dose on the fleas if you are going with Frontline. Something to think about.



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