Robert Wiseman Dairies unveiled its most important boardroom shake-up for more than 30 years as it milked the collapse of one of its biggest rivals to report record underlying profits.

Alan Wiseman, the son of the group's founder, revealed that he would be stepping down as chairman after 38 years in the post, and 43 at the company.

He will be succeeded as executive chairman by his brother, Robert, who will pass on many of his current responsibilities as chief executive to Billy Kean, who moves up from finance director to managing director.

A spokesman for group said that the change reflected Alan Wiseman's age – "he is in his 60^th year" – and had been planned "for some time".

With Alan Wiseman remaining on the company payroll, to provide, after he steps down from the board in July, the changes provided for a "smooth transition of management" to their new roles, the spokesman added.

Key contract

The announcement came as the group unveiled underlying profits up 37.8% to £48.4m for the year to April 3, fuelled by the pick-up of customers, including the Co-operative retail chain, from bankrupt milk supplier Dairy Farmers of Britain.

"The main contributing factor to our volume growth was the large gain with the Co-operative," the company said, reporting a 9.1% jump to 1.77bn litres in milk sales.

Group revenues rose by 4.5% to £886.2m.

Cost increases

However, the group sounded caution over prospects, warning that the market was "extremely competitive", and noting that a run up in packaging and transport costs, fostered by higher oil prices, had continued into recent weeks.

"Consideration will need to be to given as to how the impact of these cost increases can be mitigated," Alan Wisemans said.

Furthermore, a spike in takings last autumn from bulk cream, a byproduct of milk processing used by bakery companies, may not recur, although there were signs of a revival in prices last month.

'Cautious outlook'

In the City, analysts at Panmure Gordon left their forecast for Robert Wiseman Group shares unchanged, noting "strong results" but a "cautious outlook".

Investec kept a "buy" rating on the stock, with a price target of 560p, saying the company's newly-started 2011 financial year "should show further steady volume progress".

Margins, however, were "unlikely to match 2010 reported levels due to the windfall cream benefit last year".

Robert Wiseman shares closed 1.8p lower at 481.5p in London.