Beef on Dairy Summit: Injection site lesions leave lasting mark on calves
Why improper injection techniques can damage muscle and reduce treatment effectiveness
16 April 2026
4 minute read
By: Dr. Spencer Wolter, a beef veterinarian with Minton Veterinary Service a partner of Four Star Veterinary Service, was recently interviewed by The Cattle Site’s Sarah Mikesell in Celina, Ohio, at the Beef on Dairy Cattle Producer Summit put on by Four Star Veterinary Service.
You spoke today about injection site lesions – share a few highlights.
Anytime we give antibiotics or vaccines, because they're imperative for the calf’s health, we often forget that it's still a foreign material in the calf’s system. It's not something that's meant to be in the calf’s body. It was impressive to hear as soon as I got off stage how shocking those lesions were to see. Thankfully, all your readers will not see them – they were pretty vivid, showing the negative impact injections can have.
Even if the antibiotics or vaccines are given at the appropriate location and dose, you can still have a reaction to it. That can snowball into a bunch of different problems.
If we do it wrong, it's even worse. I just want to make sure producers are aware of the repercussions of giving an antibiotic or vaccine in the wrong place.
When you spoke about lesions, I thought they left a small mark, but these were not like that. These lesions showed significant damage to muscle tissue.
Absolutely. We did this study on a 400-pound calf. The calves that go to the packer to supply beef for the US and the world are closer to 1,500-pound animals. That would mean even more volume and even a bigger lesion.
Packers have published papers with baseball to softball-size lesions. These lesions are caused by antibiotic which is a fluid, but it's not what the calf is used to. So, there's going to be a reaction. Making sure producers are as educated as possible can help minimize these reactions.
Some of the injection sites were off label, right?
Yes, absolutely. If I have sick calf, as a producer there's an emotional involvement. You want to get an antibiotic or sometimes multiple antibiotics in that calf as quickly as possible.
Needle length is what dictates where we're placing it. Is it going right under the skin, or is it going in the muscle? When we're in a frenzy because we want to help that calf, we might grab the wrong tool. And there can be repercussions to that action.
Today, we are trying to spread awareness. Producers aren't trying to do the wrong thing by the calf. They don't want to see these lesions, but they don't know what they don't know. We're just trying to pull back the curtain to ensure dedication to reading the label and administering the vaccine or antibiotic appropriately.
It pays off in the end to take the time to do it right.
Yes, exactly. One of my points was having a good relationship with your veterinarian, because there are injectables that are essentially like aspirin to reduce pain, suffering and inflammation. Then a calf might need an antibiotic or vaccine – that ends up being a lot of pokes, right? We only really give injections in a very tiny triangle on the neck.
We should consider if oral fluids or oral pain medication could work rather than an injection. Essentially, how do we spread out the route of administration being used?
What does the damage mean for the animal and the producer?
To bring that into focus - anytime there's a reaction, like what you saw in some of the pictures in my presentation. It’s just like when we scrape our knee, a scab and a scar are going to form. With a scar, there are no blood vessels through that as a generalization.
If we have given a lot of injections, and later on we need to give an antibiotic or a vaccine, the calf’s body might not recognize it because they're administered into an area of scar tissue. There are no blood vessels there, so there's no way for the calf’s body to recognize it. It's just going to abscess unfortunately, which isn't great for the calf and the calf's not getting the benefit of the vaccine or antibiotic.
How can producers minimize the damage they may have unintentionally caused?
It’s important to have a great working relationship with your veterinarian. If you are a family operation and have a lot of employees, make sure everyone's trained and educated on the amount per location and where in the body it's supposed to be given.
Then, if you give one antibiotic today, give it time to work. Don't just jump on board and start throwing everything at the calf. Producer are doing it out of genuine care and compassion for the calf but just make sure that you know everything about the antibiotic.
What's the one thing producers should remember from your talk?
Yes, any injection you give is going to leave some sort of mark, and it potentially could be there for months. It's going to leave a lasting mark if it's given incorrectly.
