A few weeks ago I mentioned a few sick pacas. All turned out to have high worm counts and the worms have been dealt to. One was a lactating female so her milk was in short supply and her cria Twilight Sparkle started to lose weight. We've been topping her up for a week or so now.
If you are doing it for the first time (as we were!) the key is to tip the head right back and hold the bottle up almost straight. The first few goes it helps to lightly massage the side of the mouth to release the pressure every few seconds otherwise everything comes to a grinding halt. They apparently usually get it pretty quick although this one has taken a while...She is now having 300ml twice a day and gaining weight nicely. She still feeds off mum too. One of the better alpaca rearing jobs :)