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New Entrants to Farming: Health & Nutrition Planning (Argyll) – Event Summary

29 January 2018


During the meeting we calculated rations for a spring calving suckler cow (700 kg) as shown on the QMS Timeline leaflet (which can be found in the deownload section below). This summary shows methods of calculating the basic ration.

What you need to know before you start;

  • Weight of animal
  • Stage in production cycle (pre-calving, peak lactation, etc.)
  • Feeds available to you and their analysis (own silage analysis, purchased feeds analysis from label/manufacturer/tables)

For the basic ration you need Dry Matter % (DM)

Energy content as Metabolisable Energy (ME) measured as MJ/kg DM

Crude protein (CP) shown either as % in the dry matter (i.e. 10%), or as grams per kilogram DM (i.e. 100g/kg DM)

Remember; the feed value is in the dry matter, not the water. For example, a tonne of silage at 25% DM contains 250 dry matter kilograms and 750 kg of water.

What does the animal require?

Energy. This can be calculated (as demonstrated at the meeting) or taken from tables.

Using the QMS leaflet our 700 kg cow, 30 days pre-calving needs 90 MJ ME/day


Protein. Some table include this, otherwise use;

Energy supplied (MJ) x 11.8 = Protein required (grams)

So our QMS cow needs; 90 MJ x 11.8 = 1,062 g CP


How much can it eat?

This varies with breed and level of production but for basic ration use;

Intake = 2.5% of bodyweight in dry matter per day

700kg x 0.025 = 17.5

So our QMS cow can eat 17.5 dry matter kilograms.


Our 700 kg cow, 30 days before calving, needs;

90 MJ ME/day

1,062 g CP/day

And can eat up to 17.5 kg DM/day.

Calculation Example

700 kg cow, 30 days before calving, needs;

90 MJ ME/day

1,062 g CP/day

Can eat up to 17.5 kg DM/day.


There are 2 ways to start a basic ration calculation.

One way is to see what ad lib (unlimited) silage would give her.

If, for example, your silage is 25% DM,   ME 11 MJ/kg DM,   CP 120 g/kg DM (CP 12%)


Our cow can eat max 17.5 kg DM

17.5 kg x 11 MJ = 192 MJ

17.5 kg x 120g = 2,100 g CP

So unlimited  silage gives twice what she needs!


If 9 dry matter kg of silage fed, then;

9 kg x 11 MJ = 99 MJ

9 kg x 120g = 1,080 g CP


9 dry matter kg of silage @ 25%=  9/0.25 = 36 wet kilograms of silage.

She has appetite for more and would also eat straw or rough grazing if available.


Alternatively, you may already be feeding a ration and want to check if it enough/too much.

If you are feeding 25 wet kg of our silage (25% DM,  ME 11 MJ/kg DM,  CP 120 g/kg DM (CP 12%)) and 1.5 kg beef nuts (86%DM,   ME 12 MJ/kg DM,   CP 180 g/kg DM (18% CP)), then;


25 wet kg silage at 25% DM = 25 x 0.25 = 6.25 dry matter kilograms

6.25 kg x  11MJ = 68.75 MJ

6.25 kg x 120g = 750 g CP


Plus 1.5 kg nuts @ 86% DM = 1.5 x 0.86 = 1.29 kg DM

1.29 kg x 12 MJ = 15.48 MJ

1.29 kg x 180g = 232.2 g CP


Total being fed in this ration

ME 68.75 + 15.48 = 84.23 MJ ME/day

CP 750 + 232.2 = 982 g CP/day

Dry matter intake = 6.25 + 1.29 = 7.54 kg DM.


The ration is not enough and will need increasing or an additional foodstuff included. You could feed all silage but you may not have enough to last the winter and so need to supplement it, or you are going to feed concentrates later to meet peak lactation demand and so are including some now for acclimatisation. You may need better quality protein (DUP) at peak times.

Mineral + vitamins needed.

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