Forage rations need the right supplements

28 December 2001

Forage rations need the right supplements

Producing milk economically

should start with the herds

heifer-rearing enterprise.

Richard Allison reports on

a unit dedicated to

rearing high quality heifers

LOW forage stocks and high straw prices have forced some producers to reassess their heifer feeding management this winter.

High growth rates can be achieved with either straw or silage based rations, says ADAS consultant Christine Turner.

"But the forage component must be adequately supplemented with concentrates." This must include sufficient vitamins and minerals, particularly with vets reporting a rise in mineral deficiencies for youngstock. Calcium deficiency is the most damaging, leaving heifers with brittle bones that are prone to fracture.

One of her clients, Peter Appleton, of East Sussex, always feeds a mineral and vitamin supplement mixed with either maize gluten or soyabean meal to heifers. "Heifer rearing is carried out at Primrose Farm, which is dedicated to calf and heifer rearing," he says

Keeping them separate from the 300-cow herd focuses attention on their management. They are one of the most important enterprises, he adds. "Without a supply of high quality heifers, the herd manager cannot do his job of producing milk economically properly."

Heifers are traditionally fed third-cut grass silage and maize gluten. Maize silage is included in the ration for two months around service to boost energy levels and maximise conception rates, says Mr Appleton.

"But silage stocks were tight last year and heifers were fed straw and maize gluten. Growth rates of 0.85-0.95kg a day were achieved with straw. The secret is to feed at least 4kg a head a day of maize gluten."

Straw is less attractive this winter because many units are having to pay premium prices. Mr Appleton regards straw and maize gluten as a back-up during years when forage stocks are low.

"There is plenty of maize silage this winter, but grass silage stocks are low. Heifers are receiving self-feed maize silage balanced with soyabean meal and a mineral and vitamin pre-mix fed in troughs."

These heifers have achieved liveweight gains of 0.95kg a day with an average liveweight of 420kg at first service. This is 40kg above target and Mr Appleton is concerned these growth rates may be too high. Straw has now been included in the ration to bring gains back to 0.85kg a day.

"It is important to ensure daily gains are not excessive. Research shows heifers with higher gains may lay down excess fat in the udder area. This has detrimental effects on subsequent milk production."

Grazing is an important part of heifer nutrition in spring and summer, but daily gains can easily fall to 0-0.2kg a day during a wet autumn, even with maize gluten supplementation. It is difficult to recover from low gains over a 4-6 week period and this can cause lower liveweights and poor milk yields.

Their second grazing season is usually spent on tightly grazed swards plus straw to make sure they are fit, not fat. Over-fat heifers tend to have more calving difficulties and those failing to make a second lactation will be a major cost to the business, says Mr Appleton.

Last years heifers yielded 31kg a day during December, helped by them hitting the target liveweight of 630kg at calving. The secret to high production heifers is to keep management simple and focus on their progress, says Mr Appleton.

Another key part of heifer management is providing young calves with an ideal start. Calves are fed waste milk and colostrum until eight weeks of age. They are then offered self-feed 50:50 grass and maize silage. The clamp is a thin wedge and calves appear to eat sufficient to avoid spoilage.

Straw has been included in the Primrose Farm heifer ration to bring daily gains back to 0.85kg.

&#8226 Ensure adequate minerals.

&#8226 Regularly monitor liveweight.

&#8226 Avoid over-fat heifers.

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