Under Dosing Heptavac P

[Puddinghill]

I made a mistake with the calibration of my injector and gave my in lamb ewes 1.5ml approximately of Heptavac P instead of the required 2ml.

I can’t really afford another bottle but would I be best advised to do them again?

 

[ringi]

Assuming the vaccine had been correctly transported and stored, it is unlikely to make much difference to most of the ewes. The doses of vaccination are calculated so they will practically always work for practically all the ewes, yet most ewes would be OK with lower doses. We just can't predict when a lower dose is not OK.

 

[BAF]

I wouldnt worry too much. If you're really worried you could always dose them again when you do the lambs or buy a bottle of bravoxin which does most of the same clostridials at a fraction of the cost.

 

[Pistonbroke]

I made a mistake with the calibration of my injector and gave my in lamb ewes 1.5ml approximately of Heptavac P instead of the required 2ml.

I can’t really afford another bottle but would I be best advised to do them again?

Any other medicine is dosed according to weight so it's pretty flexible. Plenty of people give half a dose in the first place

 

[Puddinghill]

Thank you for your replies. Very helpful and reassuring.

 

[andybk]

we did same thing years ago , rang company they said dont worry made with large margin for error , they prob double the amount needed for immune response from what we could gleen , how lucky are you feeling lol make sure you do second vax properly as if you do get issues over the next few weeks that could be used as primer dose , i often do footvax at half dose to prevent the large reaction that comes up , works exactly the same

 

[Puddinghill]

Good advice thank you. I’m going to invest in a new injector before I do anything!

 

[Puddinghill]

Out of interest this is my vet’s opinion

The truth is that we cannot say for certain as the drugs company has never done any testing on giving a lower dose of vaccine and protective responses. It seems likely that it will give some protection but whether it will fail in some animals or not I cannot say. I guess your options are cross your fingers and hope it works or repeat with a 2ml dose!

It’s noteworthy that the drug company has never tested a lower dose. I wonder why not…..?

 

[Paddington]

Can't think of any of the vaccinations I've had over the years where my weight has been a factor. Must be a huge range of weights covered by the covid vaccine, do they use a 2ml dose ?.

 

[neilo]

Out of interest this is my vet’s opinion

The truth is that we cannot say for certain as the drugs company has never done any testing on giving a lower dose of vaccine and protective responses. It seems likely that it will give some protection but whether it will fail in some animals or not I cannot say. I guess your options are cross your fingers and hope it works or repeat with a 2ml dose!

It’s noteworthy that the drug company has never tested a lower dose. I wonder why not…..?

The drug companies are unlikely to publish any trial work, even if they had it, that showed you could get away with buying less.

Because of the way vaccines work, I very much doubt that you would get less protection from giving a lower dose. It likely either initiates an immune response, and the consequent antibody production, or it doesn't, in which case the animal will be protected fully, or not.
Of course, without testing antibody levels, it would be impossible to tell whether any animal has protection from a vaccine or not, even at the full dose.

 

[Nithsdale]

Heptavac is brilliant stuff.
I mean, folks leave it at their arse in the sheep pens for a year, pick the bottle back up and use the rest of it and it works perfect

















Giving 25% less vaccine per ewe won't have any detrimental effect on the ewes immunity stimulation. Don't worry about it.

 

[ringi]

It’s noteworthy that the drug company has never tested a lower dose. I wonder why not…..?

The tests needs to ramdomly choose sheep from many different very large flock to have different doses, then expose them to infection risks while measuring the outcome. This is very costly to do.

To speed up (and reduce costs) the sheep will often be exposed to a much higher infection risk then they are in real life. Hence the "minimal required protection level" is not measured, but it is proven that antibodies from the vaccine predict if a sheep is protected.

There is also no way to measure how much a vacine degrades when stored in uncontrolled farm fidges that don't have temperature monitoring/recording, likewise with unmonitored transport. (Human vaccine are often transported in insulated boxes that have continues GPS and remote temperature monitoring. And stored in fridges/freezers with continues temperature monitoring/recording.)

 

[Troward]

we did same thing years ago , rang company they said dont worry made with large margin for error , they prob double the amount needed for immune response from what we could gleen , how lucky are you feeling lol make sure you do second vax properly as if you do get issues over the next few weeks that could be used as primer dose , i often do footvax at half dose to prevent the large reaction that comes up , works exactly the same

Sorry to pull it slightly off topic, but does this reduce the reaction a lot? Had some pretty nasty looking injection points this year from Footvax....and half the flock seems to go lame for 2 weeks after

 

[andybk]

Sorry to pull it slightly off topic, but does this reduce the reaction a lot? Had some pretty nasty looking injection points this year from Footvax....and half the flock seems to go lame for 2 weeks after

yes a lot , i carefull use half ml (once)and rub in well (it was only ever one dose or 1ml early on so i dont know where the double dose came from ) , its the oil adjuvate that causes the lump so less of that + less reaction , we dont have a foot problem but my customers might so its done as a precautionary , certainly reduces scald through summer months .

 

[Troward]

That's great, thank you. Annoyingly I've already bought all my Footvax for this year as it was such a pig to get last year, so I may have 2 x too much

We're not a nice farm for sheeps feet, and have a lot of issues regardless of their breeding, but Footvax keeps a bit of lid on it thankfully.

 

[muleman]

Covexin used to be a 2ml dose , now it's 1ml for some reason, nearly caught me out.

That's great, thank you. Annoyingly I've already bought all my Footvax for this year as it was such a pig to get last year, so I may have 2 x too much

We're not a nice farm for sheeps feet, and have a lot of issues regardless of their breeding, but Footvax keeps a bit of lid on it thankfully.