17 April 1997

Cutting culling rates could lift profits

REDUCING culling rates by 10% will increase dairying profits by £30 a cow, according to a new ADAS report.

Dairy breeding specialist Nick Holt-Martyn recognises that genetic progress will be lower if replacement rates are reduced. "The paradox is that higher replacement rates help genetic progress, but also increase herd depreciation," he says.

His key concern is that with cull values down to £280 net of costs there is now a significant difference between the cost of a replacement – assumed to be £700 – and cull cow value.

To determine what strategies should be employed to maximise genetic gain without reducing farm profit, he has carried out a modelling exercise. This is based on a typical ADAS herd, with 100 cows, averaging 7000 litres, and with a £20 herd PIN index.

It has shown that reducing herd replacement rates from 30% to 20% will add £30 a cow to profits. "Cow depreciation from culling more animals reduces profit in the long-term," says Mr Holt-Martyn. This is due to the greater annual costs of bringing in, for example, 30 heifers valued at £700 a piece and culling 30 animals for just £280. The burden is too much compared with the producer culling only 20 animals a year.

Mr Holt-Martyn cautions, therefore, against pursuit of index alone. "You cant justify the higher replacement rates unless you are doing something other than driving PIN index."

As well as trying to reduce replacement rates by 10%, other measures can make a contribution to profits, says Mr Holt-Martyn.

"Increasing cull values by selling poorer performing heifers and/or middle aged cows rather than culls at £280 will lift profits. Every increase is worth £30 a cow at 30% replacement rate." The same is true of replacement rearing costs. "Reducing the cost by £100 through cheaper concentrates or better use of forage is worth £30 a cow at 30% replacement rate."

Mr Holt-Martyn suggests setting benchmarks for heifers to achieve within one month of calving, and selling those that fail.

He also urges producers to use bulls with at least £100 PIN, and on only the best animals in the herd to maximise genetic gain.

Axient consultant Giles Coley suggests producers can tighten fertility management – particularly by being better focused on nutrition – and target somatic cell counts to help reduce culling rates.

He advises aiming for a replacement rate of 18% on the basis that the £8 increase in PIN values of each new heifer crop fails to cover herd depreciation at high replacement rates. &#42

Extra herd replacements help genetic progress but are costly… increasing herd life will pay in the long-term.