The best place to treat a calf intravenously is in the jugular vein of the neck (either side) because the jugular vein is fairy large.
It is very difficult and impractical to use other locations because the veins in other locations are small and difficult to find.
If you are unable to use the jugular veins, you can give fluids under the skin (subcutaneously) in the neck area in front of the shoulder. It takes longer for the fluids to be absorbed than by the IV route, but it's the only route available to you.
You can also give oral electrolytes once you learn to use an esophageal feeder. You have to be very careful with the feeder. If it's not done correctly, fluids can be put into the lungs instead of the stomach.
The tail vein is suitable for small-volume injections (1 cc or less) but not suitable for IV fluid administration.
The accumulation of fluid around the jugular veins makes it almost impossible to do any more successful jugular venipunctures.
You will have to go the sub Q route.
You may read or be told to use the intraperitoneal route. Don't do it. It's likely to cause a raging peritonitis.