2016-09-09   facebooktwitterrss

Effective Energy Values in Cow Rationing Plans

Think about effective energy values in your cow rationing plans – not the energy values calculated by computer. That’s the view of leading cow nutritionist Robert Cope, who describes effective energy as what happens inside the cow, once the product has been fed.

“Far from being the claims of what a product hopes to achieve, when it’s included in the ration, effective energy is the actual value,” he says. And the actual value can be very different from the expected value.

Robert Cope

Robert Cope

For example, Glycal Forte, a protected glycerol, fed at 250 grams per cow per day, costs just 55p. To get the same energy value from a more commonly used product, calcium soap, you would have to feed 1.5 kgs a day at a cost of £1.05 per cow per day.

He believes that there’s a large number of variables when feeding dairy cows – when using liquid glycerol or differing chop lengths of straw, for example, and this means that energy levels can sometimes deliver nearer to the opposite of what is expected.

“All of us compiling rations for the dairy industry are in the grip of a system that works on energy values derived from a chemical test,” he says, adding that computer programmes can only use equations from these figures to produce a result, and can’t be relied on in practice.

If we take calcium soaps (protected fats) as an example of a lower than book value energy, saying their inclusion in a ration has been shown to do almost the opposite of what is expected.

On a positive note, Glycal Forte, has a high effective energy and although it has a low book value, when it’s fed at a rate of 0.25kg, it raises rumen pH and increases dry matter intake, says Robert, who has had great results from using the product on farm, and has recorded increases of 1kg of dry matter intake on many occasions.

Robert believes that the protection allows the glycerol to be transported to the liver where it’s converted to glucose, in turn reducing bodyweight loss, aiding fertility, and lifting milk yields.

“The interesting lesson from all of this is that although Glycal Forte appears to be three times more expensive than calcium soap, it produces far better results making it great value for money. As always the proof is in the eating,” he says.

According to Robert, and judging from his own experience, the following feeds are either better, or worse, than what a trusted computer reveals:

Better than book value
Fodder beet, brewers’ grains and potatoes – unless diet is wet, then they are worse;
Wheat straw – chopped to thumb length;
Maize silage above 30% dry matter;
Glycal Forte (protected glycerol)

Worse than book value
Calcium soaps (protected fats)
Liquid glycerol
Wet maize silage
Vegetable waste such as carrots, brussel sprouts, cabbage
Sodium bicarbonate
Wheat straw chopped longer than thumb length
Barley straw

“Cows will eat more of what they like, just like us, and top of their list is fodder beet, brewers’ grains and potatoes. But, if these products are fed wet, they can depress intakes - something our computer programme doesn’t allow for,” explains Robert, who points to wet maize silage and vegetables too.

Moving on to liquid glycerol, which fizzes in the rumen causing a low pH, this can depress intakes and lead to possible ketosis. Adding sodium bicarbonate to the ration to raise rumen pH is not a panacea, as it doesn't raise the pH above 5.5, and the rumen needs to be at 6.0 to work properly.

Robert believes that dry matter intake is, of course, down to the dryness of the material fed and how it’s presented, but sometimes small adjustments can lead to significant improvements in milk yield.

“It's all down to what happens in the real world, and not what the computer programme suggests,” he says.

Bio energy

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