being undervalued

26 December 1997


being undervalued

Maize growers surveyed last

winter were found to

be failing to realise

the potential of maize.

Jessica Buss met up with

a herdsman, farm manager

and consultant to find out

how to make more of

this forage

IMPROVING use of forage maize in dairy cow diets by reducing concentrates could increase margin over concentrate by £44 a cow on one Dorset dairy unit.

That is despite the 150-cow herd at Drayton Dairy, Lulworth Castle Farms, Winfrith Newburg, producing more than 3200 of its 7150 litre average from forage, off an 85% maize silage diet.

About 120 cows calve from December to March, with 30 calving in summer.

Axient consultant Quentin Straghan cited CEDAR, University of Reading, studies to show that forage maize could support yields of 4000 litres from forage.

But the Maize Growers Association and Milk Development Council survey last winter revealed that on average about 2000 litres from forage was being achieved.

The gross margin for maize growing farms surveyed was £36/cow higher than for all grass farms but this was only a small proportion of the £180 to £230 increase in gross margins by feeding maize predicted by CEDAR studies.

Drayton Dairy was making good use of its maize. But with its high genetic merit cows and the ability to grow more maize, Mr Straghan believed profit could be increased further by reducing concentrates.

In winter cows had received no more than 8kg, with an average of 6kg a cow, of a 26% concentrate which was fed to yield over 12 litres in the parlour, said herdsman Mike Wilkinson.

Feeding less – about 4kg a cow – of a higher crude protein 34-35% concentrate, would be worth £44 a cow in margin over concentrate, estimated Mr Straghan.

But farm manager Bruce Guthrie is concerned about reducing output, which he wants to maintain. Fresh calvers must also peak well to milk at grass, and have good fertility to maintain a good calving interval.

However, Mr Straghan believed that cutting back on concentrate should not reduce yield dramatically. Response to extra concentrate, as found in the CEDAR maize study, was low at 0.8kg of milk/kg of concentrates between 6 and 9kg fed.

However, cows at Drayton would eat more forage to compensate for less concentrate and the maizes energy level at 11 to 12 ME was not much lower than that of the concentrate.

"Currently as yield drops, cows concentrate is cut, they eat more silage and their diet is lower in protein, so yield drops again. Its a vicious circle. But research shows that if concentrates are reduced and the protein % is increased yields are maintained.

"At worst, cow yields will fall by 250 litres – and that would save on quota leasing," said Mr Straghan. And the herd would still have a good profit/litre because its overheads are low.

He advised cutting back concentrate in stages, increasing the protein % of the concentrate as rates are cut, to assess the impact on yield.

However, to adopt this strategy successfully, adequate supplies of forage would needed. More maize would need to be grown, on the farm that currently grows 200ha (500 acres) for its 880 cows in four herds. The farm totals 1450ha (3600 acres) and could grow more maize, and the units clamp could hold more. Maize silage also yields 1.5 times more than grass on the farms drought prone, black sand, soils.

Mr Straghan estimated the cost of growing maize at £60/t of dry matter, so the extra forage eaten would cost £15-20 a cow. Cows at Drayton Dairy find maize very palatable and could eat more, he added.

Mr Wilkinson currently restricts maize to ensure cows eat some chopped straw, big bale silage and concentrate.

"We cannot feed maize ad-lib or cows wont eat concentrate, gorging themselves on maize to the detriment of other feeds needed for a balanced diet," said Mr Guthrie.

Before milking cows are shut in the cubicles, while feed is put out. When maize was fed up until milking, cows were not tempted into the parlour and did not clear up concentrate, explained Mr Wilkinson.

Feeding maize as 85% of the forage allows cow intakes to benefit fully, but cows need some long fibre and this is provided using chopped straw. This is placed in feed bunkers on top of the maize, so cows have to dig through it to reach maize – providing mixed mouthfuls.

Fresh calvers should also give the best response to maize and calving the majority of the herd in winter means they are receiving maize when they can make best use of it.

Cutting back on concentrate should not reduce yield, but will increase profits, Quentin Straghan told Bruce Guthrie (left) and Mike Wilkinson (centre).




&#8226 Maize growers achieve 25% more profit/cow than grass only farms – with the best maize growers doubling that.

&#8226 Only a small proportion of maize benefits identified by research are realised.

&#8226 Attention is needed to concentrate allocations, feed analyisis, diet formulation and forage supply.


&#8226 Reduce concentrate feed rates

&#8226 Offer a higher protein cake

&#8226 Will need to grow more maize

Margin comparison of Drayton and maize surveys

DraytonSimple systemsMixed ration

averagefed average

Yield litres/cow715956535956

Milk price p/l23.7123.1723.44

Yield from forage320020321245

Margin over conc £/cow139610611109

DraytonSimple systemsMixed ration

averagefed average

Yield litres/cow715956535956

Milk price p/l23.7123.1723.44

Yield from forage320020321245

Margin over conc £/cow139610611109

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