Maize has made the single biggest difference to feeding and performance in the dairy herd for Devonshire farmer Bill Blake. It is all down to the consistency of quality that the maize silage provides year after year that has seen his increasing dependency on the crop.

From nine acres in the mid-1980s maize is now grown on 150 acres and forms the largest part of the forage ration for the farm's 300-cow pedigree Harpoon herd. The aim is to grow 0.5acre/cow, yielding about 6t dry matter/acre of silage.

Bill, who is in partnership with his wife Jan and brother Rob, manages 600 acres, two-thirds of which is at Appledore Farm, Bow, near Crediton. Part of Bill's enthusiasm for maize stems from the fact that Appledore Farm is one of Grainseed (Maize)'s farm trial sites, so a wealth of information has been built up over the past ten years.

"I like to keep on top of the new varieties and to see what's coming through and that's an advantage of being a trial site. There's been an enormous change to varieties since we first started growing maize and that's been of benefit to us," he said.

Each year the farm grows a trial site with up to 15 varieties in small plots, all treated in the same way as his own crops. Last year, Bill was one of the few farmers who had some of the new early variety Sibylis seed on trial and this produced the largest yields on the site. This backs up NIAB trials that have shown Sibylis to have exceptionally high yields.

This year, commercially he has grown about 45 acres each of Sophy, Soldier and Wallis - three varieties that do well on the farm. Soldier, in particular, is suited to the higher land at 420ft on the farm and produces early high dry matter yields with an early cob maturity.

The cold, wet spring and early summer gave Bill huge concerns about germination and early growth but eventually the crop pulled through with the sunshine and has grown well. Yields are predicted to be as high as usual, although possibly a little later maturing this year.

A local contractor normally starts the maize harvesting at the end of September and Bill makes the most of his early maturing, high yielding varieties to get the crop in early. "Getting the contractor when you want is easier if you are first to be ready," he said, "and the trial site together with taking weekly dry matter samples in September allows us to be ahead of the pack."

Maize silage goes into a mixer wagon in a ratio of two-thirds maize and one-third grass, together with soya, rape, citrus pulp and caustic treated wheat. Feeding is once a day into troughs and is supplemented by only 1kg/day of concentrate in the parlour. Herd average annual yield is around 8000 litres at 3.85 per cent butterfat and 3.34 per cent protein.

Last year the Blakes built new silage pits to hold the larger maize yields that they have produced in the past years and converted the old silage pit into cubicles for 100 cows to accommodate the herd expansion up to 300 cows. With 100 beef animals and 150 heifers and calves the farm supports a total of 550 head of stock.

A strong reliance on home-grown feeds, particularly maize, is helping the Blake family to achieve its commitment to dairying, an enterprise that was set up by Bill's father when he first came to the farm 40 years ago.