Ask the Vet

Dr. Ken McMillan, Contributing Columnist

READER QUESTION:

We have a heifer that is cycling all the time. What could cause this, and what do I need to do?

DR. MCMILLAN'S ANSWER:

Any reproductive issue during breeding season needs to be dealt with immediately. Time is critical. The most likely problem in this case is follicular cystic ovary disease. This occurs when there is a disruption of the normal hormonal pattern to the estrus cycle. These cattle develop one or more large cystic follicles on the ovary or ovaries. They display shortened heat cycles and excessive heat behavior because of low levels of the luteinizing hormone and persistently high estrogen.

Have your veterinarian check her. A rectal examination can confirm whether these cystic structures are the problem.

Treatment for the condition involves giving a GnRH (gonadotropin-releasing hormone) product to jump-start the heat cycle. That would be followed by a prostaglandin injection about 10 days later. Treatment is not always successful, and retreatment may be called for.

Follicular cysts are more common in mature cows than heifers. There can be a genetic component, especially if it's a Holstein. But the exact cause or factors involved in this condition are poorly understood.

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Editor's Note: Please contact your veterinarian with questions about the health of your herd or other animals. 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. Email Dr. Ken McMillan at vet@dtn.com.

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