by: Lee Jones, DVM, MS
University of Georgia College of Veterinary Medicine
Even in this technological age, it's the simple things we do that are usually the most effective. You can buy a fancy, expensive pickup with all the gadgets but if you don 't maintain it right, it won't last. You can buy the best genetics, but if you don't manage them right they won't perform as expected. It's the same with our common management procedures. If we ignore the fundamentals, we will not achieve our purpose.
Using the right needles and using them properly follows the same rules. Any good herd health program can be undone with poor technique. If I've heard it once, I've heard it a hundred times: "aw Doc, you really want me to change needles? I don't have time to do that. That might be alright for you folks that got nothing else to do! But I got too many cattle to go through."
I've spent time on too many feedyards to know that good technique can be followed at the speed of normal processing, and good technique improves effectiveness of our procedures and products.
When it comes to thinking about needles, the first decision is what size needle to use? Considerations for size selection include: 1) the kind and size of cattle I am vaccinating or treating, 2) the volume of product I am administering, 3) whether the product is labeled to go in the muscle (IM) or subcutaneous (SQ, under the skin) and 4) the thickness of the product I am injecting. When deciding what vaccine or other products to use, also think about how you are going to administer it and if you have the correct tools and equipment to get the job done right.
Just like shotguns, smaller needles have a higher number. In other words, an 18 gauge needle is smaller than a 16 gauge. Short needles (less than 1 inch) are preferred to give SQ injections, whereas 1.5 inch needles are recommended for 1M injections such as synchronization products. Trying to give a SQ with a long needle (an inch or greater) is likely going to damage the muscle under the SQ space. Even with the best restraint, some animals react to the pain of injections and we have no control of where that needle goes when they are moving.
Longer needles also have a tendency to bend easier than short ones even with the larger gauges when they get dull or the animals move. When vaccinating young calves, we can get by with a smaller needle. Young calves have thinner skin, and the smaller size (larger gauge number) needles cause much less pain and damage than larger needles. While pain might seem like a small consideration, if you keep replacements it is wise to think about making every trip through your chute as low stress as possible. Some pain is necessary, but unnecessary pain can be harmful and condition the heifer to avoid the chute. We educate animals every time we work with them, so it's important to make sure they get the right message.
Change needles. Yes, this is important. Needles get dull, damaged and contaminated. None of these things are helpful when giving an injection and definitely are obstacles to a successful vaccination or treatment program. Animals experience more pain from a dull needle. The reason they experience more pain is that dull needles actually cause more tissue damage and bruising than a sharp needle. Tissue damage and bruising increase the inflammatory response at the injection site and also increase the chances of forming an abscess. None of these are helpful to getting the desired immune response from our vaccine.
So not only are we causing more pain and damage, we aren't accomplishing our goal with the procedure and we just as well as left her in the pasture. The common rule of thumb if you are vaccinating large groups is to use one needle not more than 10 times or change every time you refill the syringe.
That is if you are absolutely certain you don't have any endemic disease in the herd like BVD or anaplasmosis. Both of these have been shown to spread through needles contaminated with blood to the animal(s) next in line. One of my clients vaccinated 125 cows about 30 days before calving and spread anaplasmosis through his herd. Before the damage was over, he had lost 10 cows and aborted almost 20 other cows. So if there is concern you might have anaplasmosis or something else, then changing needles after every animal is the best bet. May be a little more time consuming but definitely less risk. Plus, one cow will pay for a bunch of needles!
Needles can get dirty. Even cattle that look clean have small amounts of dirt and dandruff that can get on the needle. This increases the chances of an injection site abscess and likely neutralizes the vaccine. While some recommend wiping the needles with disinfectants or alcohol, it is better to just replace the needle. Using a disinfectant with a modified live vaccine can neutralize the vaccine and make it ineffective. Using alcohol can increase the sting in the vaccine, and some disinfectants are reactive to tissue.
Bent needles are weakened and should be replaced, not straightened. A straightened needle might break off in the animal. Legally, this animal should never be sold unless the needle is recovered. The animal is considered "adulterated" and the meat isn't actually safe for human consumption unless the needle is located and removed. Occasionally, broken needles do make it through the processing plant and can lead to metal shreds in ground beef or a needle in someone's steak. There are detectable needles that can be used if there is a high risk of broken needles, but the best approach is prevention and always use sharp, straight needles.
Always use a new needle when refilling a syringe or inserting into the vaccine container. You don't want to contaminate the whole bottle.
Simple attention to detail and taking time to do things right is essential. That advice may not be exciting, but it is still worth remembering.
For best results, please follow all product label instructions and administer cattle injections according to Beef Quality Assurance guidelines. For more information see www.bqa.org.
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