[Backinwellies]

Has anyone got a definitive guide to what size needle to use for what injection and on which stock ...... I find this information very hard to locate

[devonlady]

You could ask you vet. ?

[Bionic]

You could ask you vet. ?

Even this isn't reliable. The vets seem to use different needle sizes themselves but it is always something I struggle with too so it will be interesting to see the other replies.

[Womble]

Yes, I struggle a bit with this too. I think I've got it sorted out now, but not well enough to tell anybody else  . I'm sure someone knowledgeable will be along in a minute though! 

Even this isn't reliable. The vets seem to use different needle sizes themselves

Indeed! After much confusion having been given the wrong size twice by our vet, I bought a stock of needles and syringes from a first aid shop on Ebay. This means I now have a selection to choose from, and they were actually cheaper than I can get them through my sister, who is also a vet!

[Rosemary]

This is the best I could find and my vet was fine with it.

http://www.accidentalsmallholder.net/livestock/general/injecting-livestock/

[Fleecewife]

The thing to bear in mind is that the smaller the bore of the needle, the faster the liquid will be injected into the tissue. Green needles are fine and white are wider bore; there's also pink and yellow, which I rarely use.  Each has a gauge size printed on it.

For lambs and subcutaneous injections, I use a green needle, short length as our lambs are primitives so don't have layers of fat under the surface. I take care not to inject too rapidly through a green needle to avoid damage to the underlying tissues.
For larger animals, with a thin liquid, I would use a green needle still, but a longer one, at least for intramuscular injections.
For a thick liquid, usually the oil based ones, I use a long white needle and again don't inject too quickly as these can be quite painful when you're on the receiving end.
Nippy injections of thin liquid are best given fairly quickly or your patient will disappear over the horizon, so a white needle is best for them.

[Me]

In general I find an 18g-20g needle good for sheep, 16g  cattle. White 16g is a bit brutal for sheep though I use one when I can't find smaller

[Foobar]

Can't comment on other animals but for sheep:
21g 5/8ths for lambs first vaccination (ie <10kg)
20g for lambs 10-20kg
19g for older lambs 20-40kg
19g 1" for intra peritoneal glucose injections in new-born lambs
18g for adult sheep
16g 1" for calcium injections in adult sheep (just because of the volume you have to get into them)


Length of needle will depend on application - i.e 1" for IM, shorter for SQ; but also if you use sterimatic system then length will depend on the sleeve you have (usually 1" for everything).  I use 1" for everything really apart from 21g.