The 20 gauge 1/2" is useful in case you ever decide to inject in future is all. You can pull off a bottle of Tylan with anything 20 or larger, meaning numbers 20 or lower. Needles go smaller the higher the gauge.
Those are slips, yes. The others will be obvious that they need to screw on, thus the lock term.
I looked it up, it's 1/4 ml per pound three times per day. You can either just be very careful and draw that much up, or what I would do is draw out 3/8 ml and then draw up a little water to make it more in the syringe and give a third of THAT 3x a day.
Yes behind the trachea and make sure it dosent get down it or itll get in there lungs.....correct? That's how I've always done it but its theres a better way
Well, I generally just dribble it on their tongue and let them swallow. But if you're comfortable truly dosing them in the esophagus, that works.
You'll probably have to ask an associate for help to get what you want, so if you explain you're wanting to both draw off the bottle and dose orally, they *should* know what you mean. Always a crapshoot.