Posted: 10/12/2017

How long is too short?

Points to consider when selecting cannula length for remote drug delivery.

  • Are you sedating or medicating?
  • What type of injectable liquid is intended to be delivered?
  • Why are you delivering said injectable liquid?
  • Will the desired injection be Subcutaneous (SQ) or Intramuscular (IM)?
  • What species, size and gender is the animal?
  • What time of year are you attempting to deliver the injectable liquid?

Species of discussion: Male whitetail deer (WTD)

Subcutaneous injections can be facilitated with a ½” cannula equipped with a gelatin collar. As the animal ages and seasonal factors are accounted for, such as increased fat deposits, hide thickness and hair density, a ¾” tri-port cannula may be warranted. With any subcutaneous injection, shot placement should fall within the O-Zone™ area. (This is the neck region forward of the front shoulder.)

Capture work, whether in the field or in a controlled environment, requires a bit more thought. With a majority of US whitetail operations moving away from traditional drug combinations and administering injectables such as “BAM” and “MK” it is crucial to alter the cannula length and cannula type based on time of year and the animal’s body score.

For the average male WTD six months and older, a ¾” end-port discharge cannula is sufficient to deliver intramuscular injectables. However, in the fall and winter many factors will influence the outcome of successful sedation. Hair density and body condition, including hormonal changes during breeding season, will often dictate the use of a longer cannula and increased drug volume. Understanding and adapting to these changes is key to successful encounters.

An adult male WTD chemically immobilized in September may require X amount of drug volume supported by a ¾” cannula. This same animal in the fall will most likely have increased its body mass by 20-30% and is influenced by hormonal changes due to breeding season activity. It is not uncommon for these animals to require an increased amount of immobilizing agent and a longer cannula to achieve ideal sedation.

If not delivered intramuscularly, lipophilic drugs have an affinity for fatty tissue causing delayed or secondary sedation (sedation post reversal). It is for this reason we discourage the use of ¾” tri-port cannula when delivering BAM during and throughout the pre- and post-breeding season to adult WTD. By exercising the principals of extended cannula length & end-port discharge, successful procedures can be accomplished when using lipophilic drugs such as butorphanol.

Note: All decisions pertaining to animal health must be consulted with your herd Veterinarian prior to execution.