It’s a dilemma. We have an animal on pasture that requires antimicrobial treatment for a condition such as foot rot or pneumonia. If the pasture is remote or has no handling facilities nearby, your treatment choices are limited.
You may rope and restrain the animal to administer an injectable, long-acting antibiotic or you can try to move the animal to the nearest handling facility. The latter option may not be possible if the animal is severely lame or sick or if a handling facility is not close or available.
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The third option is to use a remote delivery device to administer the drug. This can take the form of a dart gun, a crossbow designed for administering injections or a pole syringe.
These remote delivery devices have advantages. We have an animal welfare issue in that an animal requires treatment and this may be the only way to easily provide it. Remote delivery devices make it possible to treat an animal without moving it to a treatment facility.
Some beef cattle producers are good at roping and restraining animals, but many are not accomplished ropers and that may not be a viable option.
It’s clear that producers recognize these advantages as well. Jayce Fossen and Dr. Cheryl Waldner and colleagues from the Western College of Veterinary Medicine recently published a paper describing antimicrobial use in Canadian cow-calf herds.
In that study, 62 percent of beef cow-calf producers reported the use of a remote delivery device for the administration of at least one antimicrobial treatment. As expected, this was more common in Western Canada where 75 percent of producers reported using these devices compared to 35 percent of producers in Eastern Canada.
Dart guns were the most popular remote delivery device, with 41 percent of producers reporting using them at least once. Twelve percent of producers reported using crossbows and 11 percent of producers reported using pole syringes.
However, these remote delivery devices have major disadvantages. These devices mostly require a relatively small volume of drug to be used to deliver all the antibiotic in one shot. This means producers may have to use antimicrobials such as the macrolides or ceftiofurs, which have a smaller volume of delivery, instead of drugs like penicillin or tetracycline.
In some situations, this means we end up using an antibiotic that would not normally be our first choice for the condition. These “lower volume” antibiotics are drugs of higher importance for human medicine or antibiotics that we may want to reserve for more serious conditions in our own cattle.
Second, when we use these remote delivery devices, we are not administering the antibiotics in the way they were designed to be administered and this may affect the way the antibiotics work and the length of the withdrawal period. Many of these antimicrobials are designed to be administered subcutaneously and remote delivery devices give an intramuscular injection.
Furthermore, these remote delivery devices may cause more severe tissue damage because of the force of the injection, as well as the administration of these drugs in the muscle, rather than the subcutaneous tissue.
This can affect the carcass of that animal and in most cases those injections are being given in the hip area rather than the neck area.
The industry has focused on moving all injections into the neck area for years to avoid damaging the prime muscle cuts. Using remote delivery devices makes it almost impossible to follow the guidelines for beef quality assurance.
In addition, there is more danger of needles being broken off and remaining in the tissue when using devices such as dart guns.
The good news is that a tiny percentage of overall treatments are probably administered using remote delivery devices. The recently published study showed that in most herds using dart guns, less than 10 percent of total treatments were administered using these devices. We also know from this study that antimicrobial use is relatively limited overall in cow-calf herds.
However, as an industry, we should be cognizant of the significant disadvantages of these remote delivery devices and they should only be used as a last and infrequent option.
If we have handling facilities available, or any other method of restraining and treating these animals, we should select those options first. Remote delivery devices should be used only as a last resort for a small minority of treatments in situations where animal welfare is a concern and there are no other options.
Consult with your veterinarian to ensure you are using the appropriate antimicrobial for the condition you are treating.
John Campbell is a professor in the department of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.
