The Accidental Smallholder Forum
Livestock => Sheep => Topic started by: princesslayer on March 02, 2015, 10:06:52 pm
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This is aimed at Welshcob - I know we've gone on about this a bit recently.
I went on a lambing talk recently, and there was lot's of talk about how it's fine to re-seal a heptavac bottle and put it in the fridge for four weeks time. You recently said the quote below and I was wondering if you would be willing to expand a bit, so I can make up my own mind about this issue.
The thing I don't understand is (having never seen a bottle of heptavac):
How is it sealed? Once opened, can it be re-sealed properly?
I'm assuming it contains a proteins from the bacteria clostridium/pasteurellosis which stimulate an immune response, thereby protecting the ewe?
What gets into/out of the bottle when it's opened to cause the proteins to start to degrade?
Why don't they degrade in the bottle prior to opening?
Hope you don't mind the questions - they keep bugging me!!!
:thinking:
Quote ''I am a farm vet looking at lots of dead lambs every year, mostly of clostridial disease and pasteurellosis, and would never ever risk vaccinating them ineffectually with a vaccine that has been opened for weeks. It really does go off, the drug companies don't test it because there is no point in doing so - purified proteins do not last and they are not going to spend money to show something they already know (this comes from someone - me - who's done a PhD on protein purification).
Some bacterial proteins might last a few more days than others but all slowly degrade sooner or later and if you inject with a bottle open for more than 12 hours or so you are just wasting time as it is fresh water by then.''
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hmm ..... also intrigued my vet advised that it would be ok to do the first heptavac p injection, put the bottle straight back in the fridge and use it for the 2nd one didn't say anything about sealing the bottle
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When I first used Heptavac I read the info on the bottle and didn't question that after ten hours the product wouldn't be any good. Then other people said " I keep mine in the fridge and use it up" and "my vet says it will be fine to keep in the fridge and use up". So, I contacted the manufacturers and asked them. Their reply was they have no data on the vaccine after being opened for over 10 hours.
I read the quote by Welshcob also.
I have no reason to doubt either the Heptavac info or Welshcob.
If people are vaccinating water after 10 hours and more are they have problems in their flocks?
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The thing I don't understand is (having never seen a bottle of heptavac):
How is it sealed? Once opened, can it be re-sealed properly?
It comes in a rigid bottle with a rubber membrane seal. To draw off a dose, you stick the needle through the seal and then suck it up into the syringe.
So thinking practically, the possible causes of contamination are:
- bacteria on the needle (which came straight out of a sterile package)
- contamination on the surface of the rubber (which you can swab first with a surgical wipe)
- leakage into the bottle after you've taken the dose (the rubber will re-seal fairly well, and then you can also cover the lid again with tape or similar)
- Leakage into the bottle from the air, as it 'breathes in' to equalise pressure after you've taken your dose (unavoidable)
I'm not qualified to quantify the risk above though. Presumably most of the time it works out ok, but sometimes it's an issue. The problem is, you don't know which is which!