22 August 1997

Ensuring condition counts

Blood testing and forage analysis have helped to improve fertility of autumn calving sucklers for one Norfolk beef producer. But this years extra grass has forced him to concentrate on condition management. Jonathan Riley reports

TWO years ago 11% of the autumn calving Gelbvieh cross sucklers at Chris Cookes 160ha (400-acre) Manor Farm, Oby, were barren.

Fertility fell below the farms target calving rate of 95%. This was despite careful condition management and offering a good quality silage supplemented with a general purpose mineral.

To establish the cause of the infertility, Mr Cookes vet blood tested the cows and a metabolic profile showed they were short in all minerals except iron.

Forage analysis showed the silage was at fault. Although it was good quality in terms of energy and protein, it was short in all essential minerals, particularly selenium and copper.

To counter this a specific mineral mix high in selenium and copper has been formulated. This is offered ad lib as a powder in troughs at grass and 120g is sprinkled on silage during the winter.

"The new mineral was introduced for the first time last winter and early indications are promising – only two cows failed to get in calf. Also our 70 spring calvers and 35 pedigree Gelbviehs had a similarly low fertility rate two years ago. But after improving the minerals have improved fertility performance this spring," says Mr Cooke.

But the biggest threat to next years calving rate could be this summers extra grass.

Mr Cooke aims for a condition score of 2 at calving to minimise calving difficulties and to avoid the detrimental effect of poor calving on conception rates.

"After calving cows are put onto a higher plane of nutrition, using sugar beet tops and silage aftermaths. This ensures condition at bulling is rising which has a positive effect on conception rates," he explains.

When cows are weaned in poorer condition it is easy to achieve a target score of 2. But grass growth has taken condition over 3.5 for some of our autumn calvers this summer," says Mr Cooke.

Because condition is lost more quickly while cows are still milking Mr Cooke will delay weaning – normally nine weeks before calving – until cows were only six weeks off calving in September.

In addition he has split paddocks using electric fencing. This has enabled him to increase dry cow stocking rates to 15 cows/ha (6/acre).

"In contrast the bulls, have benefited from the extra grass and are in fit condition already. Up to bulling they will be offered 2kg to 3kg of concentrate," he adds.

For Norfolk producer Chris Cooke, this summers extra grass is the biggest threat to next years calving rate. Inset: Condition of some autumn calvers is over 3.5 – stocking rates have been increased to slim them down.

MAXIMISING FERTILITY

&#8226 Ensure essential minerals are provided.

&#8226 Restrict dry cow condition to about 2.

&#8226 After calving increase condition up to bulling.