The drum on calcium and phosphorus ratios

Written by Antoinette Foster BSc Nutrition, Equine Nutritional Therapist and Medical Herbalist

©Hi Form Australia PL 2022

Calcium and phosphorus

Calcium and phosphorus are extremely important for the horse’s health and wellbeing. The horses’ bones and teeth contain approximately 99% of the calcium in the horse's body. The horse’s health is very reliant on calcium and phosphorus. Calcium supports brain and neuromuscular function, blood clotting and the activity of enzymes.

The attributes of phosphorus are as follows: the regulation of muscle contraction, integrity optimisation of glucose for energy conversion.

35% of the average bone is made up of calcium whereas phosphorus is approximately 14 -17%. This ratio is roughly 2:1. Based on this ratio, we suggest that it is ideal to maintain this in the horse’s diet.

Table 1. Average daily values of calcium and phosphorus needed for horses at different life stages with different activity levels. (Supplied table from various sources)

What suits each individual horse?

We understand that the calcium and phosphorus ratio is especially important but the amounts of each mineral in the horse’s diet is also important. Calcium and phosphorus are macro-minerals which means that horses must receive a number of grams per day per body weight. Whereas milligrams per kilo are called micro minerals.

What you will supply your horse depends entirely on individual needs. For example, there are different requirements for pregnant and lactating mares and young growing horses. It makes sense that these  horses require a higher level of these minerals.

Calcium should be at least 0.6% and the phosphorus 0.4% of the total ration to ensure that the joints, muscles etc are supported for these types of horses.

Mature horses require the lowest amounts for maintenance, these types of horses are those that are in work and only require adequate levels to support physical function. it has been proven scientifically that horses undergoing intense exercise require higher levels of calcium. The higher the work level, the higher the requirement for calcium, this is necessary due to bone and tissue repair, but a high level is lost through sweat. By increasing the intake 1.5-2 times the maintenance requirements should support the horse efficiently

 

Make sure you calculate the total feed ration.

The ratio of Ca and P is always important when looking at horse rations. A ratio of two parts Ca: one part P is ideal, with a range of 1:1 to 6:1 being acceptable. Because phosphorous competes with Ca for absorption in the gut, total diets that are less than 1:1 or contain more P than Ca should be avoided. If only one part of the diet has an inverted ratio, the total feed ration may be perfectly adequate. in some cases, you may have the correct ratio, but still be deficient in these minerals if there are inadequate quantities within the feed. It is rare to have excessive amounts of calcium in the feed ration however if this does occur it can interfere with absorption of some trace minerals. These can include iron, zinc and copper and can have an impact on kidney function.

 

What can happen if the ratios are inverted

I am sure everyone has heard from time to time about the importance of feeding a correct calcium to phosphorus ratio! There is a reason for this because if the ratio is inverted and there is a calcium deficiency it can cause serious issues which include muscle trembling and neurological conditions. If your horse’s diet is deficient in calcium or there is too much phosphorus this can impair the calcium's absorption. overtime the skeleton will weaken and this can cause many orthopaedic diseases. One of the most common all these diseases is big head. Young horses have a higher risk with developmental orthopaedic disorders, especially those younger than the age of two.

Developmental orthopaedic disease can consist of osteochondrosis lesions, physitis, angular limb deformities and even wobbler syndrome. Symptoms of these conditions include pain, stiffness, joint swelling, lameness and unevenness. other conditions associated with an inverted calcium to phosphorus ratio can be hyperparathyroidism.

It is essential to ensure that your horses are fed a well-balanced diet according to the horses age and work requirements. By managing your horse’s diet efficiently, you will ensure that your calcium to phosphorus ratio is correct.

Most horse feed manufacturers provide sufficient calcium and phosphorus within their feeds; however, the form of minerals is also a topic of discussion. I personally prefer the use of mineral tissue salts if you are supplementing with at vitamin and mineral formula as they are more readily absorbed and used by the horse.

Mineral Tissue Salts: broadening the horse owner’s view about mineral and trace element use.

Understanding the unrecognised therapeutic action and the importance of effective absorption and utilization using mineral salts is important. Some salts have a much wider action and use in the human and animal body than is recognized by most veterinary and medical authorities. Knowledge of these wider uses means that these minerals can be used more selectively in the case of a need or symptoms. Much of the known yet overlooked therapeutic information regarding common natural mineral salts... such as silica, calcium fluoride, calcium sulphate, sodium sulphate, sodium chloride, iron phosphate, calcium phosphate, potassium phosphate, potassium chloride, magnesium phosphate, and zinc sulphate, comes from discoveries made in the 1800’s by German doctors, particularly by Dr. W. H.Schuessler in 1873. He obtained his data from homoeopathic clinical trials or ‘provings’ involving thousands of human volunteers, mostly university students, who imbibed both large and small doses of a variety of triturated (finely ground) mineral salts to establish optimal therapeutic effect. He found that the above minerals in small doses, often in combination with others, have repeatable therapeutic effects beyond the standard, widely known uses of these simple mineral salts. These minerals represent the core of the so-called ‘12 Tissue Salts’, originally described and utilized by Dr. Schuessler.

Of utmost importance is the form of the salt in which the mineral is delivered to the animal. As the saying goes, “oils aint oils”, meaning that not all calcium is the same, not all irons are the same, etc.   Different salts of one mineral can have significantly different effects both in terms of absorption/ utilization of the actual mineral, and in terms of a specific therapeutic action. 

Let us take calcium as an example, which is the mineral needed in the largest quantities in animals. We note that calcium does not occur naturally as the metal calcium but occurs in nature as various salts. The main natural-occurring calcium salts are calcium carbonate, the most generic form, (chalk, limestone, marble, and dolomite); calcium sulphate (gypsum); calcium fluoride (fluorspar); and calcium phosphate (complexed as apatite and organic bonemeal).

 Calcium carbonate is the cheapest and one of the most common forms used in feeds and supplements but is poorly absorbed in many cases, compared to calcium phosphate (hydroxyapatite complex), which is well absorbed and utilized, perhaps because its animal source gives it the inherent balance most suited to animal absorption. 

Calcium fluoride, on the other hand is toxic in large quantities and therefore is not suitable as a source of calcium. However, it has important therapeutic value when used as a trace element. This natural form of fluoride not only is useful in arthritis and ‘splints’, helping break up exostoses and indurated glands, but also strengthens prolapsed muscle and veins, helping to re-establish elasticity.

 Calcium sulphate, also is not well tolerated or absorbed as a bulk source of calcium. But, it also has therapeutic value in small-dispersed doses, particularly helpful in suppurative conditions such as chronic thick, yellow and lumpy mucus discharges, recurrent abscesses and poor healing after injury. 

Several laboratory prepared salts of calcium are also in wide use and some of these also show good absorption compared to calcium carbonate. Most useful of these are the chelated calcium’s, combined to amino acids and other organic nutrients such as calcium orotate and calcium gluconate. However, these do not provide the inherent needed phosphate balance found in the organic calcium phosphate complex.

Finding the right balance with your feed

Make sure when you are looking for a supplement for your horse no matter what age that you you read the label and the levels of calcium and phosphorus, but also the form of mineral that is being used. It is also important to remember that if you have a young growing horse you will need to be making changes prior to maturity.

Feeding hays such as alfalfa can be beneficial for young growing horses Alfalfa contains an excellent level of calcium and the ratios of calcium to phosphorus are also excellent. Grains tend to be higher in phosphorus then calcium, so make sure that you are formulating the correct balance between the two. Aim for a diet suited to the species, one that is packed full of natural nutrients. Horses have evolved to consume a high roughage diet this means, pasture, hays some grain and possibly some oils, plus the correct added vitamins and minerals.

Always contact a qualified nutritionist to assist with balancing your feed ration no matter what the age of the horse. We know that nutrition is essential for ongoing health and wellbeing, supporting skin, hoof growth, muscle, and joint health and one of my most favourite topics of discussion the gut microbiome.

Calcium and phosphorus % in feeds:

Feed	% Calcium	% Phosphorus
Alfalfa hay (legume)	1.27	0.24
Clover hay (legume)	1.38	0.24
Barley	0.06	0.39
Cracked corn (not recommended)	0.04	0.30
Oats	0.11	0.40
Rice bran (by-product)	0.07	1.78
Wheat bran (by-product)	0.13	1.18

 

For more detailed advice please contact us on enq@hiform.com.au or pm us on FB or Instagram giving us a little information about your horse and we will organise one of our nutritionists to contact you. 03 97756422