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!!!
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.''