Ask the Vet

AI Not Always a Slam Dunk

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READER: We bought a pregnant Jersey cow to use for butter and cheese-making. She just calved, and now we need to get her rebred. We don't need a bull for just one cow, so we want to artificially breed her. Can you give us some advice?

Dr. McMillan: Artificial insemination (AI) can be a good option in cases like yours, but there are obstacles. You need a chute or stanchion to restrain her while she is being AIed. Also, cows must be in heat to be bred. They need to be in good body condition and on a good plan of nutrition to cycle every 18 to 24 days. Catching a single cow in heat can be difficult since cows in heat demonstrate certain behaviors with other cows, especially riding or standing while being ridden.

Unless you are skilled at AI yourself and have the necessary tools, you will need someone experienced in the practice to breed this cow. Of course, you must select the bull you want to use and have that semen available for the AI technician. If you're working with an AI company, its representative can help with this process.

In cases like yours, estrus synchronization and timed AI will usually be necessary. There are many programs that use hormones to manipulate the estrus cycle and allow us to breed a cow at a set time. This eliminates the need for heat-checking and gives a specific time for your AI technician to be there for breeding.

Under the best conditions, AI will have an average success rate of 60 to 70%. A lot of factors can decrease that rate, including the summer heat.

If this cow does not get pregnant, she should cycle again between 18 and 21 days. In that case, you would need to catch her in heat and get the AI technician back on short notice.

Cows can be pregnancy-checked by your veterinarian or with a blood test around 30 days at the earliest. If they are open (not pregnant), you can try to resynchronize her, but this is expensive and time-consuming.

All of this is to say that in most cases, a bull may need to be in the picture at some point. If you know someone with a Jersey bull, you could send her to the bull to be bred. You could also AI her and then send her to the bull.

Low-birthweight, easy-calving beef bulls are also an option, but in these cases, you may have a dairy cow being treated like a beef cow, and this can lead to its own set of problems, especially if she is a heavy milker.

Borrowing a bull is another alternative, but this can bring issues, as well. Dairy bulls can be much more aggressive than beef breeds.

I don't want to rain on your parade, but AI is not a simple slam dunk. Backyard cows are popular today, and some owners don't understand all that is involved in keeping one. Breeding these cows can be difficult for the average owner. Just understand and plan for the obstacles. Good luck.


-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

-- Write Dr. Ken McMillan at Ask The Vet, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email


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