Beware of dramatic birth rate decrease
Beware of dramatic birth rate decrease
MOVING to a 15-month calving interval would have a dramatic effect on the number of calves born a year.
Combined with a reduction in productive suckler cow numbers through Agenda 2000, it could reduce UK self-sufficiency in beef from 75% to 60%, says SAC researcher Basil Lowman.
"The UK dairy industry is already moving towards extended lactations. Sometimes this is a management decision, but is often due to the difficulty of getting todays high yielding cows in-calf."
A 100-cow dairy herd with a 90% pregnancy rate, 6% mortality and 365-day calving interval produces 84 calves a year, said Dr Lowman.
For a 15-month calving interval, he assumed that milk yield increased by 5% a day of herd life compared with a 12-month calving interval, meaning cow numbers could be reduced to 95. "Assuming the same pregnancy and mortality rates, only 80% of the herd would calve each year resulting in 65 calves a year."
Suckler calf production was also expected to fall dramatically. "Agenda 2000 rules could mean that in two to three years, the UK will produce 25% fewer suckler calves than at present.
"Excluding heifer replacement figures for suckler and dairy herds, extended calving intervals and Agenda 2000 would reduce the annual clean cattle kill from 2.25m to 1.8m. That represents just 60% of UK consumption, compared with 75% self-sufficiency now."