Piperazine Citrate Dosage

for Piperazine, I found piperahelm 450 pro which is Piperazine Citrate powder 450 mg/g and the dosage for cattle is .7gr/kg one time and .2gr/kg. how do I translate that to 3g/D with teaspoons? or do I need to use a scale? for 160 lbs 0r 72kg, I think the container has 100gr. of powder so I'm assuming its about 33 doses. I haven't measured it yet in cups, but seems like about 3/4 cups. I'm assuming 3g is about a teaspoon. would that be correct?