Cystic Ovaries are an ever present bane to fertility in the dairy industry with fertility being arguably the most important problem and cost. Cysts historically haven’t been associated with beef animals but are certainly something we are seeing more frequently - regularly on barren cows that don’t conceive. They are essentially normal structures that aren’t removed at the normal point of the cycle, swelling and growing large and blocking both ovaries, stopping the cow from ovulating, thus not allowing any chance of conception. Some of them will clear with removal of the problem causing the cysts, but most will require vet input to diagnose them and remove with the administration of hormones.
Follicular cysts (Thin walled cyst)
Follicular Cysts are over 2.5cm wide with a thin wall (under 4mm), so they are follicles that have failed to ovulate and require administration of GnRH (Ovarelin) to make them dissipate.
Luteal cysts (Thick walled cyst)
Luteal cysts are over 2.5cm wide as well, but are thick walled (>6mm thick, often much thicker) but may be treated just as big CLs with prostaglandins (Estrumate).
With cysts there are a few things we can influence to really reduce their risk of forming: overfeeding in dry period (leads to excess body condition score pre-calving and most importantly reduces intakes post calving), subclinical and clinical ketosis, low body condition score post calving, lameness and low selenium levels. These highlight the importance of nutrition on the standard ovarian cycle.
Of those that we can influence, there are many more we can’t and have to accept: age, previous abnormal calving, previous cysts, high milk yield associated with negative energy balance, herd size, location and calving season, genetic predisposition to cysts although heritability is low (0- 13%) and more cysts are seen with cows calving indoors compared to out at pasture.
If cysts are something that has cropped up at your routine visits or your latest PD session, please do not hesitate to contact one of our team.