1 March 2002


Maize silages benefits in

cow diets are being seen in

north-east England, even

though it is classed as a

marginal area for the crop.

Wendy Owen reports

MOVING from the Midlands to Northumberland failed to deter a committed maize grower who has successfully grown the crop for two years.

Its inclusion in cow rations has average cow yields increase by 400kg.

Andrew Crewdson had worked for Sentry Farms on one of its Worcestershire farms for a number of years, where he grew 122ha (300 acres) of maize. When he was transferred to the companys 687ha (1700-acre) Blagdon Estate, Morpeth, as farm manager two years ago, he was determined to make maize a big part of the herd diet.

He was not put off by the location, which is so far north that the number of heat units falls about 25% short of the temperature usually recommended for growing the crop.

"The farm had tried to grow maize in the early 1990s, but it had not been successful. When I arrived cows were on a grass silage-based mixed ration and parlour-fed concentrates."

During the first year under Mr Crewdsons management, the farm grew 10ha (25 acres) of maize, rising to 19ha (47 acres) in 2001. He has also cut out bought-in parlour concentrates from the diet. Instead, cows are fed a total mixed ration, with 50% of the dry matter coming from maize silage.

The change in diet has produced a good response, with an increase of 400kg in milk yield to give a 7200kg herd average, as well as an increase in milk protein. Butterfat has remained unchanged.

Maize cheaper

"Maize is definitely cheaper to grow than grass silage. Harvesting is one of the biggest costs in any crop-growing operation and taking two to three cuts of grass adds extra expense.

"I do not expect to equal the yields achieved further south, but the crop can still produce a high quality feed. However, the odds are stacked against it here, so I have to do everything possible to give maize the best chance to perform."

Nancis and Soltis were the two main varieties at Blagdon last year and fields chosen for maize are the lightest possible on the mainly heavy loam land. They receive farmyard manure in autumn and are often ploughed during winter.

Before drilling, which is usually around the first week in May, land is sub-soiled and care is taken to produce a fine seed-bed. A pre-emergence herbicide application takes care of any competitive weeds.

"Seed rates for Nancis are 42,500/acre, with slightly less for Soltis, which is precision-drilled at 38,000/acre. Fertiliser is applied with the seed at the time of drilling. This is crucial to the crops later performance.

"Once seed has germinated, it needs fertiliser to give it a boost, particularly if soil temperature is low, as it tends to be in the north," says Mr Crewdson.

At the 5-6 leaf stage, the crop is sprayed again with herbicide and a decision is then taken on whether an extra 56kg/ha of nitrogen (45 units/acre) will be needed.

"Extra nitrogen at this stage will encourage growth, but it can delay maturing. Under normal growing conditions, it will produce a marked increase in yield and starch content. But in a very wet year it is best to leave it out in an attempt to bring forward crop maturity, even though it will mean a drop in yield."

By September, maize is being monitored carefully. Despite this, the target date for harvesting is never later than mid-October, he says.

Crop harvesting

"If the crop has not matured by then, there is nothing to be gained by waiting and the field is being tied up preventing the next crop going in. I look for cob maturity and I want the cob to be as fully-formed as possible before cutting."

In its first year, the crop did not perform up to standard and a corn-cracker was not necessary, as the plant was still green at harvest. But since then, management techniques have allowed the production of a more mature crop and the corn cracker is viewed as an essential part of harvest.

A minimum chop length of 8-10mm (0.3-0.4in) is aimed for, on the basis that shorter material will give better consolidation in the clamp. The entire crop is harvested and sheeted within a day, with about 750t of freshweight made in 2001. No additive is applied, other than salt on the top layer to seal the clamp.

Although he is a great fan of mixed ration systems and believes that maize is a valuable and uniform product to add to the dairy cows diet, Mr Crewdson warns that it has its pitfalls.

"One of the potential drawbacks is human error. It is all very well working out a precise diet, but it is easy to make a mistake when mixing it.

"We work on an audit system, where all feed is recorded on a spreadsheet and set against the amount of feed left in the shed at the end of the month. We also analyse random samples of the ration every now and then, as well as blood-profiling cows as a matter of routine." &#42

Growing maize for cows in Northumberland has proven beneficial with yields increasing by 400kg a cow, says Andrew Crewdson.

&#8226 Fine seed-bed needed.

&#8226 Fertiliser at drilling.

&#8226 Extra N at 5-6 leaf stage?

&#8226 Harvest by mid-October.

Year one Year two

Freshweight 12t/ha 15t/ha

yields (4.8t/acre) 6t/acre)

Dry matter 24% 29%

Starch 19% 26%

*Variety: Nancis.

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