Calcium is the fundamental element for proper teeth and skeleton formation and, together with phosphorus, is the most copious mineral in a horse’s body (70%).
- What are the functions of calcium?
This macromineral has several functions and is essential for:
- blood coagulation;
- neuromuscular and mitochondrial function;
- cellular membranes function;
- enzymes regulation;
- glandular secretion;
- temperature regulation.
Muscle tone decreases in case of hypercalcaemia (high level of calcium in the blood) and increases in case of hypocalcaemia (low level of calcium in the blood).
In order to meet the subject’s needs, which change according to life phases (breeding, pregnancy, lactation etc.), diet has to provide the proper amount of all nutrients, including minerals. Another fundamental factor is the bioavailability of the elemental mineral contained in the related salt. For example, the main sources of calcium salts are:
- calcium carbonate from calcic rocks
- dicalcium phosphate
- calcium lactate
- calcium sulphate
Calcium salts from shells powder or seeweeds (lithotamnio) can be used too.
On the contrary, the following calcium sources should be avoided:
- calcium iodate (risk of iodine excess)
- calcium chloride (poorly appetizing)
- all forms of mixed tripolyphosphates (poor calcium availability).
What are the functions of phosphorus?
Phosphorus is essential:
- as a buffer;
- for several cellular functions;
- for energy metabolism (phosphocreatine)
What is the “Ca:P ratio”?
By “Ca:P ratio” we refer to the ratio between calcium and phosphorus in a specific product or diet: in adult horses it can range from 1:1 to 4:1, while in growing horses this ratio normally ranges from 1:1 to 3:1. In adult horses, the Ca:P ratio must be higher than 1:1 and lower than 4:1.
Generally, the Ca:P ratio in feeds and protein concentrates is quite low. In our feeds for adult horses (Unika Endurance and Unika Sport) this ratio is 3, while in Unika Foals (growth) and Unika Mares (pregnancy) it equals 2.
What happens when there is a calcium and phosphorus imbalance?
If the level of phosphorus in the body is too high, calcium will not be properly absorbed; on the other hand, an excessive amount of calcium does not influence the absorption of phosphorus. Calcium is absorbed by the small intestine: the eventual excessive amount of this mineral is eliminated via urine and, therefore, does not influence phosphorus absorption, which takes place in the large intestine.
Calcium and phosphorus are crucial for horses: a Ca:P ratio imbalance, due to inadequate levels of one or both of these minerals, can lead to skeletal alterations. In order to prevent an excessive tendency to fractures, the Ca:P ratio must be higher than 1.
Calcium and/or phosphorus inadequate levels (excess or deficiency) result in mineral deposits and mobilizations in bones, thus causing skeletal conditions. Luckily, thanks to the action of some specific enzymes, these minerals’ concentrations in plasma is constant. Therefore, non-skeletal function is not compromised.
Therefore, properly planning your horses’ diets with the help of a nutritionist is fundamental to avoid an imbalanced ratio between calcium and phosphorus.