26 February 1999

FERTILITY FIRST TO CUT CULLING

FOCUSING on fertility for a cows first three lactations could reduce forced culling, leading to cost savings of 0.7p/litre.

So Duncan Forbes of Kingshay Farming Trust, running an MDC-funded longevity project with NMRs support, told the conference.

Interim study results from 30,000 culls reveal that on average cows leave the herd after just 3.02 lactations, a 33% culling rate, with 45% of cows culled by the end of their third lactation.

Of cows studied, 62% were culled for forced reasons such as infertility or disease. Disease is the reason given for 17.6% of culls, with an additional 7.5% culled for high cell counts. Infertility accounts for a further 24.8% of culls – almost half of which are repeat breeders (see graph).

Data from the first six months of the study, 18,000 culls, shows that 17% of culls were first lactation animals. A further 15% were in their second lactation and 14% were culled by the end of their third lactation, said Mr Forbes.

The most common reason for culling animals in their first three lactations is infertility – accounting for over 20% of primary reasons for culling animals in their first, second and third lactations.

In later lactations an increasing % of culls are due to mastitis and cell counts, but fertility remains the main reason for culling until cows reach their seventh lactation.

Mr Forbes told delegates cows must milk for three years to pay off their rearing or purchase costs.

"When losing half the herd within three lactations only half the herd is contributing to profit. You are losing young animals which are your best genetic material."

There is considerable scope for reducing culling rates and cost savings, he added. In a typical 100-cow, 6500-litre herd reducing culling rate from 33% to 25% in the current economic climate is worth £4500 a year or 0.7p a litre.

This gives more control, reducing forced culling through infertility and poor health, said Mr Forbes. "This gives more scope for selection of best quality animals, enhancing genetic progress." &#42

CULLINGSTUDY

&#8226 33% of herds culled/year.

&#8226 17% go in first lactation.

&#8226 Infertility major cause.