It is important to follow BQA principles and label directions when giving injections.
Subcutaneous injections (i.e., under the skin) should be given in either the neck or elbow pocket. All intramuscular injections should be given in the neck regardless of the animal or the type of injection; this includes estrus synchronization products sometimes used in replacement heifers and cows.
Whenever the label allows for either intramuscular or subcutaneous injections, the subcutaneous route should be used.
Additionally, make sure to leave at least 4 inches between each injection and do not place one injection under another one.