19 May 1995

Team effort puts Devon herd on top figure track

By John Burns

TARGETS of £2000 a cow margin over concentrates and a 10,000-litre herd average while maintaining a 365-day calving index are in sight on an East Devon estate.

The 150-cow Rolle herd of Holstein Friesians, at Dalditch Farm, Budleigh Salterton, part of the Clinton Devon Estate, already has a rolling average of nearly 9200 litres at 3.96% fat and 3.29% protein. Calving index is 365 days and rolling margin over purchased feed £1800 a cow or £3500/ha (£1416/ acre). Rolling cell count is 59,000/ml, TBC just over 1 and clinical mastitis stands at 4%.

Herd manager Nigel Lock attributes the herds success to a team effort, including the vet and nutrition advisers.

Vet Richard Sibley told visitors to a farm open day that they were tackling lameness and trying to improve conception rate in high-yielders, particularly the second-calvers. "It is easy to assume both problems are the result of mineral deficiencies but I do not believe they are," said Mr Sibley.

"We have had two causes of lameness in this herd: Foul-in-the-foot and sole ulcers. The foul we are tackling by improving cow tracks and the sole ulcers by giving the cows more comfortable lying conditions."

A special cow track laid alongside the existing one, to dairy consultant John Hughes specification, and used over the past winter, has proved excellent. "It used to take me an hour to get the cows in," said Mr Lock. "They just did not want to walk on the old track. But they are off like greyhounds on this new one." Although only 0.7m (30in) wide so the cows walk in single file, it is so comfortable that they walk quickly.

Mr Sibley is almost certain current difficulties getting high yielders back in calf result from failure to provide enough dietary energy.

Pure sand soil

But Mr Sibley said their soil was almost pure sand. Grass and maize silages showed very low levels of all minerals and trace elements and without supplementation there would be deficiencies.

Satisfactory results had been obtained with one in-water product but it could not supply iodine and copper at the same time. It was also costly. Asked to cut mineral costs, Mr Sibley had tried other methods without success and at considerable cost in cows culled because they were not in calf.

Aquablend, a liquid formulation containing iodine, copper, cobalt, manganese, selenium, phosphorus, magnesium and zinc proved successful. Mr Sibleys evidence is the low incidence of milk fever and retained cleansings, acceptable-to-low stillbirths, low non-visible oestrus, and blood profiles showing normal levels of minerals and trace elements.

Aquablend was metered into the drinking water and could supply iodine and copper at the same time. It was expensive but cost-effective. Mr Lock said the mineral bill was only two-thirds of the previous in-water system.

But it did affect the taste of the water and to ensure adequate intakes cows had to be kept away from other sources such as streams. Although Aquablend proved cost-effective on this farm, Mr Sibley said it may not be so for every farm. He advised anyone who suspected mineral-related problems to seek vet advice.

"I am against free-access dry minerals," he said. "Even if they do no harm they are almost always wasteful." &#42