Anoestrus Due to Parovarian Cyst in Holstein-Friesian Crossbred Cow: Case Report

Parovarian cysts arise from remnants of the mesonephric tubules and ducts. The cysts derived from the cranial mesonephric tubules are called "epoophoron", while those from the caudal tubules are referred to as "paroophoron". Parovarian cysts are filled with a clear fluid, and are usually round or oval in shape, occur as a single cystic structure, and range from 1-5 cm in diameter. They have been found in both left and right side of the ovaries. It occurs in all animals, and has been reported in both monogastric and ruminant livestock at low frequency. The parovarian cysts in animals are usually benign, but malignancy has been observed in very low frequency in large size tumors. They are of little clinical significance, unless they interfere with ovulation or oocyte transport Large parovarian cysts cause infertility because of stenosis of oviductal lumen due to compression. Parovarian cysts have mostly been reported in abattoir animals. The present study reports parovarian cyst in a lactating primiparous Holstein-Friesian crossbred cow presented at Madras Veterinary College Teaching Hospital, with the history of post-partum anoestrus. Per rectal manual palpation followed by ultrasonography revealed the existence of a large (Diameter-16 cm) parovarian cyst adjacent to the right ovary. The owner was advised to cull the animal, as cost involvement and post-surgical management were not in favour of surgery in large animals. The study reaffirmed that large size parovarian cysts could be a cause for anoestrus/ impaired fertility in cows.