IM or Subcutaneous does it matter?

[ladycrofter]

I'm sure it does but was just reading the data sheet for Vitasel: IM or subcutaneous for lambs BUT subcutaneous only for ewes.
Can someone please explain?

 

[yellowbelly]

Google says,

Showing results for which is absorbed quicker, subcutaneous or intramuscular injection
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Intramuscular injections are absorbed faster than subcutaneous injections. This is because muscle tissue has a greater blood supply than the tissue just under the skin. Muscle tissue can also hold a larger volume of medication than subcutaneous tissue.

Maybe it needs to be utilised slower in bigger animals so it stays in their system longer??