3 October 1997


HIGH yielding cows must be fed 3.5kg of concentrates in the last three weeks of the dry period for optimum lactation performance.

According to Dorset-based independent nutritionist Ivor Bending, Holstein cows and heifers capable of producing more than 7500-litres cannot be fed like 5500-litre cows during the dry period.

In the early dry period feeding is not too critical, he says. "Keep the gut extended and the rumen working by feeding plenty of high fibre forage, such as mature grass."

The most critical stage, however, affecting performance throughout the entire lactation is the 20 days pre-calving and 10 days post-calving.

"In the last two weeks before calving cows suffer hormonal changes and the calf is growing quickly, reducing space for the rumen," says Mr Bending. The calf can restrict intake by as much 30% so to ensure the cow, rumen bacteria and calf are still fed adequately rations must be altered.

The cow needs higher energy feeds, including some concentrate, and she has an increasing crude protein requirement. Cows intakes must be measured by weighing in silage during this period, he adds. The mineral balance fed must also be correct for the farm.

Dietary crude protein level should be 15% in the last few weeks before calving and ideally increased to 16% for the last week. But the source of protein does not seem important, stresses Mr Bending.

To make a ration high enough in energy and balanced in protein he has found that cows need 3.5kg of concentrate for the last three weeks of the dry period. But this must be split into at least two feeds a day, or fed as part of a mixed ration. These cows must be checked three or four times a day and feeding them gives an opportunity to check them closely to see they have full rumens. Feed silage or a mixed ration in the evening to prevent cows calving at night, he advises.

Concentrate fed could be just maize gluten, but ideally offer 1.5kg of it as ground cereals. He cites German research to show that this stops the papillae on the rumen wall shrinking, keeping the rumen in good working order. This can help to prevent acidosis, fatty liver and ketosis before and after calving.

As an alternative to ground cereals, Mr Bending suggests 16kg of maize silage could be fed – equivalent to 2kg of grain – and an extra 1.5kg of concentrates.

"Care is needed to ensure calving dates are right on this feeding regime; cows fed this amount of concentrate for too long will have calving difficulties," he warns. "Heifers, therefore, should only be brought into the close to calving group a week before they are due as it is difficult to reliably predict their calving date." Heifers that will only receive 3.5kg of concentrate in the last week before calving must be fed some concentrate beforehand.

For a few days before calving cows should have ad-lib access to a high quality milking ration and clean water.

Immediately after calving ensure the cow is offered fresh water and given palatable food. She does not need any setbacks at this stage, advises Mr Bending.

"Fresh calvers should be kept out of the milking herd for three days, and until they are eating well. They should also comes over when offered fresh feed. Check temperature is normal as a routine and that the rumen is full and working. The first 24 hours are critical for treating subclinical problems."

Mr Bending advises against building up concentrates too quickly after calving. On a complete diet the cow eats a balanced ration, but when concentrate is fed separately, increase rates slowly over two weeks, he suggests. The cow may not reach her maximum dry matter intake for a few weeks.

After calving the cow will also need a high level of calcium, which must be kept low before calving.

When management is good during two weeks before and the few days after calving cows should not suffer milk fever or subclinical metabolic diseases and should milk to their potential. &#42

Milk fever cases should be a thing of the past provided that management is good during the critical 20 days pre and 10 days post calving.


&#8226 Offer 3.5kg of concentrate for 21 days before calving.

&#8226 Include cereals in concentrate.

&#8226 Feed concentrate at least twice-a-day.

&#8226 Measure forage intakes.

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