PURDUE UNIVERSfTY COOPERATIVE EXTENSION SERVICE WE5t1LAFAYETTE INDIANA 47907
Ovarian Cysts in Dairy Cattle
R. D. Allrich, Department of Animal Sciences Purdue University, West Lafayette, Indiana
Ovarian cysts reduce reproductive efficiency on almost every dairy farm in the United States. It has been estimated that the incidence of ovarian cysts ranges from 5 to 20 percent in most herds. A recent Wisconsin field study of dairy herds reported that the incidence of ovarian cysts ranged from a low of 16.2 to a high of 47.4 percent. Mature cows have a higher incidence (39 percent) of ovarian cysts than do first-calf heifers (11 percent). Breeding age heifers have a lower incidence of ovarian cysts (3-6 percent). It is interesting to note that beef cows have a relatively low incidence of cystic ovarian disease. Because ovarian cysts reduce reproductive efficiency, they are a source of severe economic loss in most dairy herds.
Description
Ovarian cysts (Figure 1) are follicular structures having a diameter of at least 2.5 centimeters (about 1 inch) that are present for 10 or more days on the ovaries in the absence of a functional corpus luteum (CL). The only practical method to detect cystic ovarian disease is by rectal palpation of the cow’s reproductive tract. This fact emphasizes the importance of regularly scheduled herd health examinations of postpartum cows by a veterinarian skilled in rectal palpation. Ovarian cysts can be classified as either follicular cysts or luteinized follicular cysts. Table 1 lists the characteristics of follicular and luteinized follicular cysts. Cystic corpora lutea (CL with a fluid-filled cavity) should not be confused with ovarian cysts because the former are not pathological and function normally both during the estrous cycle and pregnancy.
General Symptoms
Cows with ovarian cysts have an abnormal pattern of estrous behavior (see Table 1), and, in
many cases, the absence of estrus (anestrus) is a common symptom of a cow with cystic ovarian disease. The physical appearance of cows with ovarian cysts is usually not different from that of other cows. However, the following are general symptoms that cows with ovarian cysts may have: 1) thick, cresty neck, 2) little or no muscle tone in the vulva, vagina and uterus, 3) relaxation of the sacroiliac and sacrosciatic ligaments, resulting in the appearance of an elevated tailhead and 4) abrupt changes in milk production. It should be noted that these general symptoms are useful only in a preliminary diagnosis of cystic ovarian disease and that rectal palpation is required for a definitive diagnosis.

Figure 1. Ovary containing three follicular cysts (blister-like structures).
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