22 August 1997

Selecting suitable sire is top priority

GETTING the basics right enables Devon dairy producer Roger Broomfield to rear productive heifers with good fertility.

Sire selection is his first priority. He uses high indexing dairy sires on cows used to breed replacements to maximise genetic progress. Emphasis is on production and functional type traits such as udders and feet and legs.

"Herd replacements arent cheap so we aim for longevity as well as production when were selecting which sires to use."

AI sires are also used on heifers and heat synchronisation allows them to be treated as a group making heat observation and AI easier.

Mr Broomfield aims to calve his heifers at about 28 months to ensure they are well grown. Ideally service is at 350kg when the heifers are about 14-15 months. Two months before service they are on a rising plane of nutrition. "Build up to service is crucial," he says.

At this stage heifers also receive a mineralised bolus to provide selenium and copper – both minerals are deficient on his 52ha (128-acre) Little Landside Farm, Westleigh, Tiverton.

After service and in the run up to calving growth rates are up to 1kg/day. Growth is restricted, however, pre-puberty to ensure heifers grow frame and strength. "This will help them compete when they enter the herd and survive for longer," he says.

Heifers join the 66-cow milking herd a month before calving so they are acclimatised to the cows and the milking ration, he says.

"Allowing enough time to adjust to the herd reduces stress at calving, and puts the finishing touches to our rearing management."n

Roger Broomfield grows heifers for frame and strength to maximise survivability.That means calving them at two-and-a-quarter years of age.