Increasing calving interval by 71 days equates to a cost of £173 a cow or £2.40 a day, said William Johnston, College of Agriculture Food and Rural Enterprise (CAFRE).


Speaking at the recent Beef Expo Northern Ireland, Dungannon, Mr Johnston explained a study of 123 suckler herds had identified a marked difference in calving index between herds.

“The top 25% of herds had a calving index of 367 days compared to 439 days for the bottom 25%.

“This means each calf is born 71 days later – at loss of 1 kg of liveweight gain a day worth £1.50/kg, this results in a loss of £107 a calf in live weight gain alone.”

And along with these obvious costs, there are also less easily identifiable costs in the form of prolonged calving/service period and mixed age batches of calves.

“In terms of herd output, for a 30 cow herd, a calving index of 365 days will produce 150 calves in five years compared to just 125 calved in the same period with an index of 440 days.

“In fact, with an index of 440 days it will take six years to produce 150 calves.”