I always feel compelled to weigh in on these multi-dose syringe threads...
Processing feeder calves that will be going to slaughter within a few months...OK. In the cow herd, NOT - unless you're planning to change needles between each animal.
Yeah, I know, it's a PITA, and it's so expensive(what, $.20/animal?).
But, if you are in an Anaplasmosis endemic area, or have Anaplasmosis in the herd, every time you stick a needle in a carrier animal, there's a 60% chance that you're gonna transmit that agent to the next cow you stick with that same needle.
I haven't seen any documented 'numbers' for ease of transmission of Bovine Leukosis Virus - which is pretty widespread in some areas of the country - but from my own experience, using the same needle over and over - I ended up with a 90% infection rate in my herd; when I finally broke down and did a whole-herd test about 6 years ago, because we were losing 1-2 cows/year to lymphosarcoma.
Have not re-used a needle on anything except steers and older cows that I know are infected since then, and each cow gets a new OB sleeve when palpating or breeding - and I may still not have made much headway in cleaning up that mess.
Do what you want, but I don't recommend multi-dose syringes for use in breeding stock, unless you're prepared to switch to a fresh, new, sterile needle for each animal.