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Cystic Ovarian Disease

IRM-25

Dairy Integrated Reproductive Management
Dr. D. A. Coleman West Virginia University

As early as 1831, abnormally large ovarian follicles that failed to ovulate (release an egg) were reported to result in altered cyclic activity, abnormal sexual behavior and reduced fertility. This condition, termed cystic ovarian disease, occurs in 5 to 10% of dairy cowsnationally. In a study of 2532 health records in West Virginia, 7% of the cows had cystic ovaries. Cows that experienced cystic ovaries had calving intervals nearly 2 months longer than herdmates without cysts. Each day a dairy cow remains open past day 85 postpartum represents an estimated loss of $2.50 to $3.00. Thus, approximately $180.00 of potential income is lost per year for each cow that developsan ovarian cyst—over $1200 per year for a 100-Cow herd. Occurrence in one West Virginia herd is 28%. This herd loses an estimated $5000 each year because of cystic ovarian disease. Because of financial consequences associated with ovarian cysts in dairy cows, scientists have studied the disease for over 100 years. Future research may determine why some follicles develop into cysts, factors ortraits that make a cow more likely to develop cystic follicles and methods for treatment of cystic cows to minimize extra days open. The following is a brief summary of current knowledge concerning cystic ovarian disease in dairy cattle. Ovarian cysts are characterized by rectal palpation as structures greater than 2.5 cm (approximately 1 inch) in diameter remaining on an ovary for more than 10 days.Major categories of cysts include follicular cysts, Iuteinized follicular cysts and cystic corpora lutea. Follicular cysts result from failure of ovulation and Iuteinization. (Luteinization is the structural and biochemical changes that occur in cells and tissues of a follicle when it releases the egg. Follicular cells that once produced estrogen change into luteal cells of the new corpus Iuteum(CL, also called a yellow body) that secrete progesterone. Follicular cysts are blister-like structures, flaccid to the touch.

Luteinized cysts apparently fail to ovulate, but some Iuteinization occurs. Because of the varying degree of Iuteinization, Iuteinized cysts are firmer to the touch than follicular cysts though not as solid as CL. Cystic CL are CL with a fluid filled center. Several earlyresearchers did not find cystic CL in pregnant cows and reasoned that cystic CL could not support pregnancy. However, researchers at Cornell University report that a CL needs to produce only approximately 100 µg of progesterone to support pregnancy. Therefore, a cystic CL could maintain pregnancy. In the absence of pregnancy, cystic CL regress and are considered nonpathological.

Symptoms
Anabnormal pattern of estrous behavior is the most noticeable sign of cystic ovarian disease. A cow with an ovarian cyst might exhibit “constant” estrus (nymphomania), no estrus (anestrus) or an erratic combination of estrus and anestrus. Ratios of estrus to anestrus vary among studies from 74%:26% to 17%:83%. Detection of cysts in the early postpartum period might account for the reported predominance ofanestrous behavior. Sexual activity does not normally accompany follicular maturation during this time. A predominance of nymphomania was reported in many early studies when more bulls were present on farms. A greater proportion of cows with cystic ovaries will be classified as nymphomanic where good estrous detection practices are used. Other general symptoms of cystic ovarian disease include:1) lack of muscle tone in the vulva, vagina, cervix and uterus; 2) passive prolapse of the vagina and/or excessive discharge of mucus; 3) relaxation of sacroiliac and sacrosciatic ligaments of the pelvis (resulting in the “sterility hump” appearance

of the tail head); 4) changes in general metabolism; 5) erratic changes in milk production; 6) rough dry hair coat; 7) nervous tension; 8)...
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