When selecting needles for injections to beef cattle, size is important. Select a needle 1/4-inch to 3/4-inch long for subcutaneous injections. Using a longer needle can penetrate the muscle. Give intramuscular injections with needles that are 1-inch to 11/2-inches long. Medication given intramuscularly needs to be injected deep enough to prevent the medication from seeping out of the muscle. A needle that is less than 1 inch long won't place the medication deep enough.

Needle diameter is also important. Use an 18-gauge needle for most injections. Remember that as needle gauge increases, the diameter decreases. Use a small diameter needle to lessen the possibility of tissue damage.