Dairy cow ration formulation

Feed is the largest cost item on a dairy farm, and it is also the factor with the greatest effect on yield. A good ration covers the cow's needs while preventing waste. Below we set out the logic step by step.

A ration is not really a complicated calculation. You answer three questions in order: How much can the cow eat in a day? How much of that will be forage? How much extra energy and protein does her milk require? In this article we have reduced every step to something you can do in the barn, with the bucket and the scale you already have.

1. Start with dry matter (DM) intake

In a day a cow can consume roughly 3% of her body weight in dry matter. For example, a 600 kg cow eats about 18 kg of dry matter a day. This figure is the starting point of any ration plan, because that is all the animal can digest.

This proportion is not the same in every animal or in every period. A dry cow makes do with about 2% of her body weight, while at peak lactation a high-yielding cow's dry matter intake can climb to 3.5–4%. A young heifer cannot eat as much as a mature cow of the same weight. So rather than feeding the whole herd off a single figure, the most practical place to start is to separate at least fresh cows, high yielders, cows past peak and dry cows.

Dry matter is what is left once you take the water out of a feed. A cow eats feed by weight but takes her nutrients from the dry matter. Most of the weight of a bucket of maize silage is water, whereas almost all of the same weight in straw is dry matter. Unless you build the ration on dry matter rather than on what the scale says, your figures will always be off.

How much dry matter is in the feed you have?

For an exact figure, a feed analysis is the right answer. If you cannot have one done, the approximate values below are enough to build a rough plan; the dry matter of your own silage may fall outside these ranges depending on when it was harvested and how well it was packed.

A practical check: squeeze a handful of silage. If water runs out of your hand the silage is too wet; you will not get the dry matter you expect from that bucket, and the cow stays hungry on a full belly.

2. The forage and concentrate balance

The base of the ration is forage (maize silage, hay, straw, alfalfa). Forage is essential for rumen health and, on a dry matter basis, should usually make up more than half of the ration. Concentrate (dairy or compound feed) is the energy and protein supplement added according to milk yield. Too much concentrate with too little forage upsets the rumen (acidosis).

The point most often confused here is this: forage is by fresh weight the larger part of the ration, but by dry matter the split is far more even. 20 kg of silage looks heavy on the scale; in a silage of 30% dry matter that comes to roughly 6 kg of dry matter (varying between about 5.6 and 7.0 kg with the dry matter of the silage). As a general rule forage holds more than half of the ration's dry matter; a concentrate share approaching half applies only to high-yielding groups and under expert supervision. Letting the dry matter share of forage fall below 40% of the ration is risky for the rumen.

It is not only the amount of forage that matters but also its length. Forage ground to dust does not make a cow chew her cud. Cudding means saliva, and saliva is the natural system that buffers acid in the rumen. The ration must contain a coarsely chopped forage that the cow is forced to chew.

3. Protein and energy

Making milk takes protein and energy. Dairy concentrates are sold in different grades; the protein content usually ranges from 16–21%, so check the figure on the label of the feed you buy. The more milk a cow gives, the more energy and protein she needs, which is why a high-yielding cow gets more concentrate.

But protein alone does not make milk. When energy falls short the cow turns the surplus protein into urine rather than milk; the money goes up in smoke and the liver is put under strain. The reverse also holds: with plenty of energy but too little protein, yield never reaches its ceiling and the cow puts on fat. Think of the two together. In a ration, energy usually comes from grain and good silage, and protein from oilseed meals and legume forages (alfalfa, vetch).

Do not put off minerals and vitamins; salt, calcium, phosphorus and trace elements affect everything from conception to hoof health. If you use a compound dairy feed, read the label: does it already contain minerals and vitamins, or do you need to give them separately?

4. An example daily ration

The table below is an example prepared to show how the dry matter calculation is built for a moderate-yielding dairy cow; it is not a recipe to be applied directly. Minerals, vitamins and free water are added on top of it.

Note this: on the scale the forage reads 27 kg and the concentrate 7 kg. In dry matter, though, forage is ~11 kg and concentrate ~6.2 kg, a total of ~17 kg of dry matter, with forage holding roughly two thirds. If you keep giving the same concentrate to a cow whose yield has fallen, you lose money and she puts on fat. In a high-yielding cow the concentrate share rises; but concentrate must not exceed half of the ration's dry matter, and every increase must be made gradually over several days.

These figures are only an example. A ration must be calculated for the individual animal according to her body weight, her stage of lactation, her milk yield and the quality of the feeds you have. For the right balance, get support from a veterinarian or an animal nutritionist.

Build the ration in the barn in 6 steps

1. Weigh or measure the cow. If you have no scale, a heart girth tape will do the job. Do not guess: the difference between 550 kg and 650 kg is 3 kg of dry matter in the ration.
2. Write down the daily dry matter target. Start at about 3% of body weight and pull it up or down for her stage.
3. Place the forage first. Give the best forage you have, as much as the cow will eat. The better the forage, the less concentrate you need.
4. Fill the remaining gap with concentrate. Add it according to milk yield; never let forage fall below 40% of dry matter. Do not pile the concentrate into a single meal; spread it through the day.
5. Add minerals, vitamins and salt. Follow the rate on the label; do not raise it on the reasoning that a bit more will do good.
6. Run it for 10 days and measure. Watch milk yield, what is left in the trough and the manure. If you are going to change something, change one thing at a time, or you will never know what worked.

Do not rush a feed change. When moving to a new feed, a gradual 10–15 day transition is needed for the rumen microbes to adapt. An abrupt switch made in a single day turns even the best ration into a cause of disease.

5. Do not forget water

Milk is about 87% water. Without clean water freely available 24 hours a day, no ration gives its full yield. When water intake falls, milk falls with it.

A rough figure in common use is that every kilogram of milk takes about 3–4 litres of water; on hot summer days that need rises sharply. Check the drinker by hand every day: one that has grown algae or lost its flow costs far more milk than it appears to. If a crowded barn has only one drinker, the timid cow waiting her turn never drinks enough.

Change the ration with the stage of lactation

Giving one cow the same ration all year round is among the most expensive mistakes there is. The stages divide roughly as follows:

• The first weeks after calving: Milk rises quickly but her appetite has not caught up yet. The cow covers the shortfall from her own body fat, which makes this the riskiest period for energy. Increase concentrate gradually and do not cut forage.
• Peak yield and after: Appetite is now where it should be. This is when the ration carries its heaviest load.
• The period of declining yield: Reduce concentrate in line with milk yield. Otherwise you produce fat rather than milk, and that makes the next calving harder.
• The dry period: The ration becomes forage-based. Do not let drying off tracking slip; a cow that gets too fat in this period causes far more trouble after calving.

Feeding heifers and young stock is a separate subject; for a plan of the period up to first calving see our heifer rearing article, and for a calf's first days our calf care article.

The most common mistakes in the field, and how to spot them

• Measuring concentrate by eye. On every farm that measures by the bucket, the amount drifts over time. Weigh your bucket once and write on it how much it holds.
• Feeding the whole herd one ration. If a cow giving 30 litres and one giving 10 litres face the same trough, one is underfed and the other overfed.
• Feeding all the concentrate in a single meal. A large amount at once drops rumen pH. Splitting it into meals makes the very same feed far safer.
• Letting the trough run completely empty. After a long empty spell the cow eats fast and eats too much, which causes digestive upset.
• Feeding mouldy or heated feed. Throw away the warm, mouldy or foul-smelling part of the silo. Mouldy feed given on the grounds that "it is only a small patch" is the silent cause of poor fertility and low milk.
• Glancing at the trough instead of checking it. Look at what is left in the trough in the morning. If nothing is left the cow is probably going hungry; if a lot is left, either the feed has spoiled or you are giving too much.

The cheapest way to tell whether a ration is working is to read the cow: when the herd is lying down, it is a good sign if most of them are chewing their cud. If the manure is very loose or shows undigested grain, there may be too much concentrate or too little forage. A drop in milk fat points the same way. Animals that are neither too thin nor too fat show that the ration has settled for the long run. To take yield as a whole, our increasing milk yield article will also help.

Which signs call for a veterinarian

Setting the ration is the farmer's job; diagnosing disease is the veterinarian's. In the situations below do not wait, call your vet:

• A cow going off feed suddenly and completely, especially in the first weeks after calving together with dullness and a rapid drop in milk.
• Swelling that develops quickly on the upper left side of the abdomen, with laboured breathing. This is an emergency.
• Watery diarrhoea that does not clear, blood in the manure, or a marked amount of undigested grain.
• A rising number of lame animals in the herd.
• Inability to stand, trembling, or going down after calving and not getting up.
• Weight loss alongside a marked drop in milk, with a dull, staring coat.

Telling these signs apart takes an examination and, where needed, laboratory work. Do not give on your own any medicine heard about online or from a neighbour.

6. Track cost and yield together

Getting the ration right matters, and so does watching what it costs and what it returns. If you record the monthly feed bill and the milk you get in return, you see in figures which ration is actually profitable.

A simple approach is this: divide the total feed cost for a month by the income from the milk you sold that month. If the ratio stays close from month to month, the business is in balance. When feed prices rise or milk falls the ratio breaks, and that is the moment to go back and look at the ration. Growing your own forage is the best-known way to improve it. Support schemes for forage production change from period to period; for current terms and the application calendar, contact your provincial or district directorate of agriculture and forestry and your veterinarian.

Why keeping records pays off

Records do not make a ration correct; what they change is how long it takes you to notice your mistake. Kept in your head, it comes out as "last month was better, I think". Written down, you can see which week and which feed change the yield fell after. The four records worth keeping at a minimum are: daily milk per animal, the type, amount and price of the feed you bought, the date of any change to the ration, and notes on body condition and health.

You can keep these four in a notebook. What matters is that it is regular. How to set up that routine is in our how to keep herd records article, and moving from the notebook to digital is in our digitalisation on the farm article. To follow milk data animal by animal, take a look at the milk tracking and cow tracking pages as well.

A short checklist

Track feed cost and milk with Alprivo

In Alprivo Herd Management, record the ration and the feed cost and see the milk income; follow from a single screen which period you made a profit in.