An ordinary part of your veterinarian's herd health visit is treating cystic ovaries. However, on his next visit, he may have an out-of-the-ordinary treatment plan for cystic cows. Researchers now suggest using the OvSynch protocol to treat cows with
cystic ovaries.

Three years ago, veterinarian Richard Martineau changed the way he treated cystic ovaries. Instead of using the traditional treatment of prostaglandin for luteal cysts and gonadotropin-releasing hormone (GnRH) for follicular cysts, Martineau now enrolls all cystic cows in the OvSynch protocol.

Martineau, who practices in Coaticook, Quebec, has had great success with the treatment. In 38 herds, he has seen a 44 percent pregnancy rate on 104 cystic cows. That compares with his clients' average pregnancy rate of 40 percent on approximately 2,200 cows.
The idea of using OvSynch for cystic cows originates with the researcher, Milo Wiltbank, reproductive physiologist at the University of Wisconsin, who designed the program. OvSynch calls for a shot of GnRH followed seven days later with a shot of prosta-glandin. Then, 24 hours later, a second shot of GnRH is given, followed with a timed insemination eight to 16 hours after the final injection. Although not determined with hard-core research, on-farm trials and the success of the OvSynch protocol suggest that it may be the right treatment for cystic ovaries. That's because, unlike traditional treatments, OvSynch results in ovulation for cows with both luteal and follicular cysts.

Encompasses all cysts
The traditional treatment for ovarian cysts depends on what type of cyst a cow has, says Wiltbank. For luteal cysts, you treat the cow with prostaglandin to regress the cyst and allow a new follicle to grow and cycle. For follicular cysts, you treat the cow with GnRH, causing the cells of the cyst to become like that of a luteal cyst. Then, the cyst regresses or you treat the cow with prostaglandin - causing the regression.

The traditional approach to cystic ovaries works if the type of cyst has been identified. However, a 1992 study, reported in the Journal of the American Veterinary Medical Association, showed that a typical veterinarian, when using rectal palpation, accurately identified the type of cyst 51.1 percent of the time. When using ultrasound, veterinarians correctly identified cysts 85.1 percent of the time. The study used progesterone levels to determine actual cyst type. If progesterone levels rose above 0.5 nanograms per milliliter, it was determined to be a luteal cyst. If the progesterone level was below 0.5 nanograms per milliliter, the cyst was follicular. (See the related story, "Differences in cyst type," to learn about the hormonal and physical characteristics of cysts.)

"Just on palpation, you can't accurately identify the type of cysts," says BobYoungquist, veterinarian and professor of veterinary medicine at the University of Missouri and one of the authors on the study. For definite results, you need to check progesterone levels or use ultrasound he says.

However, collecting milk or blood samples for progesterone and using ultrasound equipment is impractical for most dairy producers at herd-health checks. That's where OvSynch comes in. The best treatment method will be the one that's effective for any type of cyst, says Wiltbank. The chart, "How OvSynch helps all cyst types," shows how the therapy results in ovulation for different types of cysts.

While further research is needed to test the OvSynch treatment in a controlled study, results from the field show it may be successful for treating cows with cystic ovaries.