Ask the Vet

Anaplasmosis Management Takes a Team Approach

A cow herd may show no signs of anaplasmosis, but that doesn't mean they aren't carriers.(PF photo by Joel Reichenberger)


We have a cow that checked PCR positive for anaplasmosis. We treated her with antibiotics, and she appears to be fully recovered. After she weans her calf, should we sell her? We don't know if she's likely to contract anaplasmosis again or if she poses a threat to her herd mates.


This cow is almost certainly a carrier, and she will not likely ever show signs of the disease. But, as a carrier, she is a definite risk to other cattle.

I am not sure whether anaplasmosis is considered endemic in your area. If it is, you need a plan possibly with ongoing treatment. That is a decision to make with your herd veterinarian. I also do not know how many cows you own or if you are "fence to fence" with other herds. This, too, can affect how you handle anaplasmosis. You can probably tell what I'm saying is there is no across-the-board best answer for how to handle this.

I do advise checking your entire herd to determine its status. That is Step 1. Other standard recommendations that will not change include the use of a clean needle with each injection, as well as the cleaning of all surgical instruments (tattoo pliers, castration tools, dehorners) between each use. Anaplasmosis is a blood-borne disease, which is why it's so important to take these steps when working cattle to avoid spreading it within your herd.

This is also why tick and biting fly control is important. Both of these pests can be significant sources of anaplasmosis transmission, but because ticks are a biological vector, they are an especially common mode of transmission. So, make sure your management is on target for these pests to avoid additional problems.

Lastly, be very cautious when introducing new cattle to the herd. While your cows may be carriers and show little ill effect from the condition, they could infect a new herd member, causing serious illness that could lead to the loss of that animal.