Calcium (Ca)

Calcium or lime is an earth alkali mineral. Below, we distinguish between the role of calcium in animal husbandry and calcium in soil and crops. 

Calcium in animals

More than 95% of calcium (Ca) in the body is found in the bones. The calcium in bones, as well as in milk, occurs in the form of calcium phosphate (Ca3(PO4)2). Thus, both calcium and phosphorus (P) are required for bone formation and milk production. The ratio of calcium to phosphorus in the ration is therefore of great importance, although in recent years, there has been more emphasis on optimizing/minimizing phosphorus in the ration.

Dairy cows require a large amount of calcium to produce high volumes of milk. The bones provide the largest buffer. Vitamin D, with the help of hormones, regulates the absorption and reabsorption of calcium to and from the bones. As the animal ages, it becomes more difficult to mobilize calcium from the bones, which also increases the risk of milk fever.

In addition, calcium is responsible for the transmission of nerve impulses (and therefore muscle contractions), the production of hormones, blood clotting, pH regulation of the blood, fertility, and the regulation of membrane activities.

Calcium Requirements (CVB, 2016).
Category g/kg dry matter g/animal/day
Young cattle from 4 months 5.6 22
Young cattle from 9 months 3.5 20
Young cattle from 16 months 2.8 21
Dry 8-3 weeks to calving 2.4 27
Dry 3-0 weeks to calving 2.8 31
Milking (20 kg) 3.2 60
Milking (40 kg) 4.2 100

By performing a Ration Check from Eurofins Agro, you will know the levels contained in your mixed ration and can make any necessary adjustments.

Calcium deficiency
A calcium deficiency can structurally lead to osteoporosis and leg problems. It also increases the risk of milk fever and muscle cramps can also occur. A high magnesium content, through mutual competition, lowers calcium absorption and can thus cause an indirect calcium deficiency. In the diet of dry cows, higher magnesium levels are used to stimulate calcium absorption.

Calcium surplus
Calcium excess is rare because the body has several mechanisms at its disposal to excrete excess calcium. A temporary excess calcium level has no consequences. A prolonged elevated calcium intake through feed can cause kidney problems and lead to the calcification of soft tissues, such as the kidneys, liver and vessel walls. The CVB (2005) gives a toxicity limit of 15g of calcium per kilogram of dry matter (for chronically high levels).

Calcium in soil and crop

Calcium is an indispensable mineral for plants. It provides strength to the cell walls and promotes the quality of the crop. Its importance has been demonstrated for potatoes, asparagus, apples, lettuce and onions, among others. In addition, calcium ensures good soil structure and a lower susceptibility of the soil to sludge.

But not every crop has an equal need for calcium; cereals consume about 5 kg of calcium per hectare, whereas crops such as corn, grass (first cut) and onions consume 20 to 50 kg per hectare. Cabbage, clover, tomato, apple and sugar beet require more than 80 kg of calcium per hectare.

Roughage high in calcium include grass and grass silage, alfalfa, beet press pulp and red clover, while maize silage, Corn Cob Mix (CCM), potato products and brewer grains contain relatively low levels.

Calcium content (g/kg dry matter); Eurofins Agro 2009-2013
  Fresh grass Grass silage Maize silage Lucerne
Average 5.4 5.0 1.6 14.2
Target range 4.5-6.5 4.5-6.5 1.3-2.2 12-18


It seems that in recent years, the calcium content in grass has decreased somewhat. Spring grass in particular tends to contain too little calcium but a lot of phosphate. Moreover, not all the calcium present in the soil is available; this depends on, among other things, the acidity of the soil. For fertilization, specific crop characteristics must be taken into account, such as the Ca requirement, sensitivity to quality deterioration, and the crop type. The presence of substances that hinder calcium absorption and the impact on soil structure are also important to include in a fertilization plan. Eurofins Agro's analysis Fertilization Manager considers the various factors and provides the information needed for a sophisticated fertilization plan.

Why do we measure Calcium?


Ration Check

Fertilization Manager