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Jul 7, 2008
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I have always had issues with my 150 pound mini receiving the same amount of vaccine as my 2000 pound draft horse but a friend of mine just told me they have "improved" the Rabies vaccine and her two minis had a violent reaction to it. Does anyone know if there has ever been a study done on the amount of vaccine needed to "protect" a horse? Does anyone one else find it ridiculous that our minis get the same amount as their larger counterparts? What can we do?
I feel the same as you. It is also the same way from 95 lb. Rhodesian Ridgeback get the same size vaccine as my 3 lb. Chihuahua!! I dont like it either!!
Because it was reported to me by a friend w/ minis that an animal professional was advising people in an internet chat room that a HALF dose of standard vaccination was OK for minis(this was some years ago)--my vet and I did a test. We boostered one of my miniatures with a half dose of a multidose vaccine(E,W,V, tetanus, rhino, flu--the one I have routinely given for many years), waited the required time(usually a couple of weeks for 'good' immune levels to build/rebuild), then he took blood and had it tested for titers. The horse did NOT have adequate levels of immunity.

That was enough to convince me to always give full doses. As was pointed out--my 4 lb. Chihuahua gets exactly the same dose as my 115 lb. Ridgeback, and has never suffered any ill effects...there can ALWAYS be the rare exception, but overall, it seems to me proper practice to use full doses. If they were fomulated for use by WEIGHT,as are antibiotics, etc., it would be different, but, most are not!

(Of COURSE, the most important thing is to read the official instructions for use!)

JMO, and experience,

I am assuming the vaccine used was the new one that is not improved but rather the first rabies vaccine developed specifically for horses. Here is a link the a write-up about it: There is always a danger to any horse of a reaction when you vaccinate them. Size might have had nothing at all to do with the bad reactions. From the information in that link it is safe for foals as young as 4 months and is low dose. How much do 4 month old big horse foals weigh? I wouldn't think it would be much more than a miniature.
There was an article in TheHorse back a couple years ago, not speaking to the amount of the

dosage, but about the frequency of innoculations. It suggested having blood work done and

testing the titers for the level of immunity still in the blood before blanketly innoculating by calendar date.

I did post a link, which I've since misplaced, back a few weeks ago on a similar topic, that was from? ArabWorld Magazine, maybe? that was discusing a similar topic.......

Another article, in TheHorse, spoke to not giving foals shots their innoculations immediately as it would just be overkill, if the mare had been given her boosters, in the time frame of 30 days prior to foaling.

Maybe we should questions how often we give them their shots rather than the amount

they are dosed with when we do....?
Yes, Equusize, the "best" way is to check the titers to see what the animal needs to be inoculated for, but realistically the majority of animal owners are not going to go through the time and expense of it. Personally (and I have a needle phobia) I'd rather just get an injection than have blood pulled and THEN get an injection
But truthfully, I'd rather just administer the $10 4-way injection and be done with it.

Most foals are not vaccinated until they are four months old, even if their dam did not receive the vaccinations within that last 30 day window (for those of you newer to horses, if you have a mare in foal she should be vaccinated for everything 30 days before her due date to properly pass antibodies to her foal). My friend has a foal with low immunities and he has to wait until he's four months old to start being vaccinated.

My vet said that ALL horses get the same amount of vaccine and the same is true of dogs... any less of the dose and it can be ineffective. If you're going to do it, you might as well do it so you get the most effectiveness out of it! So yep, whether a 100 pound mini weanling or a 2,500 lb draft horse, they need the same amount of exposure to the vaccine!

I wonder if there is any study's going on to make a vaccine that the dosage goes by weight. Almost all injectables go by weight. That is very strange that every vaccine is the same dose size!! Like it was pointed out a 2500# draft gets the same as a 200# Mini.?!?!?! Makes no sense
Personally I don't want to have to start guessing at the weight of each of my horses so that I can vaccinate them with the appropriate dose, and I'm not going to haul them all to the stock yards to weigh them every spring before I vaccinate. I like knowing that each horse gets 1cc of vaccine no matter if he weighs 150, 300 or 1200 lbs. It's just easier that way.
Remember your kids get the same dose of flu vaccine as an adult and a 50 child gets the same as a 250 lb man.

For vaccines you must give a certian amount of antigen to illicite an immune response, doesn't matter how much the animal or person weighs.
There you go! I believe stormy has put it 'in a nutshell' to the 'why' every size should get the same dose! Well-stated, stormy!

Not to crack the "nut shell" but children usually get the flu shot split into 2 doses spread out, they make a special vaccine for children.
Of course I will give the recommended dose until studies have been done, but I guess my main question was if anyone had known of any tests that had been done on this subject matter. It's very cool that, I believe it was Margo, tried out giving a smaller dose. I think there should be studies done on the efficacy of these vaccines and their dose amount. JMO.....

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