Switch from grass to maize boosts yields
Moving from a grass-based
to maize-based diet has
boosted milk production by
800 litres a cow on one
Hants college farm.
Hannah Velten reports
IN autumn 2000, the 130-cow herd at Sparsholt College, Winchester changed from an extended grazing system to a maize/concentrate ration.
Over the past 12 months cows have responded by producing an extra 800 litres a head.
According to the units dairy consultant, Mike Bray of Kite Consulting, the reason for increasing yields is purely to improve farm margins (table 1).
"Feeding more concentrate a cow increases yield and milk incomes and reduces the amount of forage needed in the ration, allowing increased stocking rates. Dairy grassland can then be used by the arable enterprise or reliance on rented land reduced."
The decision to increase herd performance was also helped by higher milk prices from United Milk, no adjustment on quota this year and high genetic merit cows. Improved milk income also allows dilution of the high fixed costs on the college unit. These costs include buildings, diet feeder and slurry towers, adds Mr Bray.
Increasing yields means looking closely at quota needs. The dairy currently holds 848,000 litres at 4.29% butterfat, but increasing yields mean an estimated quota shortage of 295,000 litres. Whether to lease or buy quota has yet to be decided, but Mr Bray believes quota must be bought before Christmas.
The change in philosophy has meant a complete overhaul of land and cow management, with the full commitment of dairy staff.
Fodder beet was eliminated from the crop rotation and grass silage area reduced, allowing more maize to be grown (table 2). "Fodder beet is a wet feed and grass silage quality notoriously variable. To achieve our target yield of 9200 litres a cow means greater dry matter intakes, hence the increase in more dependable, drier maize."
Cropping plans for next year include 28ha (70 acres) of forage maize, 7ha (17 acres) of whole-crop peas and 9ha (22 acres) of whole-crop winter wheat. "Growing whole-crop peas and wheat on the spare dairy land could reduce ration cost and also maximises arable area aid," he adds.
Fresh autumn calvers are now housed, rather than keeping them out during the day well into October. "Because of the extended system, fresh calvers were unable to reach their potential milk yield and some cows body condition scores fell to 2.2, which caused fertility problems."
Muddy cows paddling into the parlour increased milking times because more cleaning was necessary and the potential for mastitis increases when cows are dirty, adds Mr Bray.
Late lactation cows are kept out at grass because they are capable of using autumn grazing.
Focus has also turned to heifer condition at service so they can cope with lactation demand. "Heifers should be 380kg at service and calve at 24-25 months weighing 625kg. This means they are growing in their rearing period rather than during the first lactation," says Mr Bray.
Attaining milking potential means cow management is crucial. "Silage clamp management must be improved to avoid presenting cows with unpalatable feed. Enough feed must be available to satisfy 105% of appetite, so they can pick out the best bits.
"Cubicles should be comfortable to encourage cows to lie down for at least eight hours a day. Water must be plentiful and fresh and buildings must be adequately ventilated."
Plans for the future include increasing the herd to 160 cows and calving all year round.
"Throughout the year, autumn-calving herds have peaks and troughs of milk yields and numbers in milk. We are aiming for a flatter production profile, which the liquid milk market requires," says Mr Bray. *
Table 1:Past, present and future dairy costings
Mar 2000 Aug 2001 Mar 2002
Yield (litres a cow) 7,117 7,879 8,100
Concentrate feed rate (kg/litre) 0.23 0.3 0.3
Concentrate cost (£/t) 107 128 124
Milk price (p/litre) 17.9 18.6 19.6
Margin over purchased feeds (£ a cow) 1,096 1,125 1,297
Stocking rate (cows/ha) 2.08 2.52 2.5
Table 2: Past and present
winter dairy rations*
Maize silage 22 24
Grass silage 22 14
Fodder beet 16 0
Wheat 0 4
Rape 1.5 2.25
Soya 1.5 2
Hi Phos mineral 0 0.10
Maize gluten in parlour up to 7.5 0
18% compound in parlour 0 6.5
*Fresh weight kg a head a day.