Prepare a basic slip knot with your rope. Wrap one rope end over itself, then pull the end through the hole created. Don't pull it tight yet; instead, keep some slack.
Get the calf on the ground so that it is lying on its side. Sweep the legs from under the calf, and use your body weight to push it down.
Keep your knee on the calf so it stays down, then grab the front leg.
Loop the slip knot over the front leg and pull it tight so it secures the leg.
Grab the two back legs and pull them toward the tied front leg.
Loop the rope around the three legs several times. The legs should be pulled together as closely as possible with the rope wrapping around the ankles.
Pull the remaining end of the rope through the center hole created. Pull the rope to tighten the knot and prevent the calf from wiggling free.