Kim Haywood, director of the National Beef Association (NBA) said she was worried about the number of good cows being sold for slaughter, when there could be a drop in slaughter rates in the coming year.
Haywood said: "Now is not the time to reduce cow numbers or try to get by with a smaller herd. The amazingly high prices being paid for well-fleshed cows should encourage breeders to clear out poor performers, but no-one should be cashing these in without immediately buying in replacements."
According to NBA statistics, feed costs are set to fall, with dry barley at £105 a tonne compared to a price last season of £180 a tonne, so large herd numbers will not be the financial burden they once were.
"It is sensible to improve future herd performance by getting rid of sub-fertile animals and bad doers, but it would be a mistake to be tempted into herd reduction just because an uncommonly high number of heavy culls are being sold for more than £1,000," said Haywood.
"Fortune is about to smile on the suckled calf breeder and they should do their best to avoid being caught in the trap of not replacing culled animals after they have pocketed the cheque."