Minerals

More than 99% of the calcium and about 80% of the phosphorus in the animal body is bound to the skeleton, indicating a close relationship between these two elements. This is why they should be discussed together.

Calcium ions are primarily absorbed in the upper and middle sections of the small intestine, with adequate vitamin D levels greatly enhancing this absorption process. Calcium is excreted through the intestines and kidneys, and its excretion rate can vary significantly. Particularly in young animals, calcium excretion is extremely low despite adequate intake, as most of the calcium is used for skeletal development.

Phosphorus ions are mostly absorbed in the small intestine and to a lesser extent in the stomach. The absorption of phosphorus is also supported by the presence of calcium and vitamin D.

The main function of calcium is in the construction of the skeleton (bones and teeth), and in birds, it also plays a role in the formation of egg shells. Calcium, along with other elements, is involved in muscle and heart function.

In 100 ml of animal blood, approximately 10 mg of calcium is found. If this value decreases, calcium is withdrawn from the bones, which serve as a calcium reservoir.

In addition to being a component of bones, phosphorus plays several roles in the animal’s metabolic processes. Phosphorus is crucial in energy metabolism and is also involved in the metabolism of amino acids and fats.

Due to the close interrelationship between calcium and phosphorus metabolism, the correct balance of these two elements—known as the calcium-phosphorus ratio—is of utmost importance in animal feeding. For mammals, an optimal calcium-phosphorus ratio is considered to be 1.2 – 1.5:1, while for birds, a ratio of 1.6 – 2:1 is ideal.

A deficiency in calcium primarily affects the skeletal system, leading to leg weakness, rickets, and osteomalacia. It can also result in heart and circulatory problems.

A phosphorus deficiency can cause symptoms such as diarrhea, weight loss despite high food intake, and reduced fertility, among others.

More than half of the magnesium present in the animal body is a component of bones and teeth.

Magnesium plays a crucial role in maintaining blood levels and the normal function of essential nerve sensations. Additionally, magnesium activates important enzymes involved in the entire carbohydrate metabolism.

Magnesium is absorbed in the small intestine of the animal organism. Its excretion occurs via the kidneys and digestive tract.

A magnesium deficiency can lead to decreased nutrient utilization, muscle cramps in various muscle groups, and heart and circulatory problems.

These three major elements are grouped together because, not only in terms of their quantity, they ensure the proper functioning of all metabolic processes, but also because they are closely related in their functions within the organism.

In the gastrointestinal tract, sodium is almost 100% absorbed from all salts. Potassium ions are also absorbed in the intestinal tract. Chloride is usually almost completely absorbed in the digestive tract of the animals, mainly in the form of common salt. The excretion of these three elements occurs primarily through the kidneys.

Sodium is crucial for regulating fluid volume and maintaining the acid-base balance in the animal organism. While sodium performs this role outside the cells, potassium is responsible for the acid-base balance and the maintenance of osmotic balance inside the cell.

Chloride metabolism is inseparably linked to sodium metabolism. Chloride is considered the dominant anion to sodium and is thus involved in maintaining osmotic pressure in the extracellular fluid space. An excess of chloride can inhibit growth but can be compensated by sodium and potassium. Similarly, excess sodium and potassium can inhibit growth unless this is counteracted by chloride. This highlights the close relationship between these three elements.

A sodium deficiency causes loss of appetite with significant weight loss, rough coat, low blood pressure, and circulatory problems. Potassium deficiency is rare since most of the offered feed contains an excess of potassium. In fact, overconsumption of potassium often leads to an extremely high potassium-to-sodium ratio of more than 10:1, which can only be corrected by increasing sodium intake and water. Chloride deficiency leads to growth disturbances, tissue dehydration, and nervous disorders in the animal.

In the animal body, the majority of sulfur is a component of sulfur-containing amino acids. Inorganic sulfate sulfur is very difficult for animals (except ruminants) to absorb. Easily soluble sulfates (such as sodium sulfate or magnesium sulfate) are rarely ingested by animals due to their very unpleasant taste and their laxative effects (such as Glauber’s salt or Epsom salt). For this reason, sulfur in the feed and feed supplements used today is present as a component of the sulfur-containing amino acids cysteine, cystine, and methionine.