CYSTIC ovaries tend to be most prevalent in high yielders during the winter, when cows are housed and many are due for service.
Incidence tends to be high on some farms, often with the same high yielders becoming cystic each year, says vet Clive Norrell, Malthouse Surgery, Shewsbury.
Cysts are found when the egg formed on the cows ovary is not released. She is stuck at that stage in her heat cycle, releasing hormones and showing oestrus frequently.
"Cows with cysts are best treated promptly even when due for culling," says Mr Norrell.
"Treatment usually with a progesterone releasing device, such as a PRID, works better when cows are not left cystic for too long." And although cystic cows help identify bulling cows they also lose weight which could affect their fertility.
CATTLE: WATCH FOR
• Cystic ovaries.
• Toxic mastitis.
• Poor performance and infertility.