04/07/2025
Is 10g per 100kg of Salt Excessive?
I have always said, if you can’t do much feed wise – just do salt and hay!! It’s not 100% ideal but we have all been in that situation at some stage whether its time, budget, grazing location, turned out on hills and so on. It will cover the two important nutrient aspects fibre and sodium chloride. And this still stands true to this day.
Many horse owners do not fully appreciate or understand the significance of providing adequate salt to their equines diet. In terms of cost to benefit ratio, it would be hard to think of another nutrient with such a low cost and so easily supplied, that provides the benefits that salt does.
Equine diets are naturally low in sodium (and chloride) especially on largely forage diets. That includes BOTH hay and grass forage.
Levels of sodium in the blood and body fluids are strictly controlled by hormones. It is also the major regulator of water balance in tissues. Sodium helps to “hold” water in the tissue, and it is what the brain “reads” to figure out when to trigger thirst, when to balance the sodium levels and therefore water in the body and what of each to discard (urine). What do you do when you eat something salty? Yep, you head for the water.
Actual loss studies have determined a figure of 0.02g sodium lost per kg bodyweight (NRC Plus Dr Eleanor Kellon) at MAINTENANCE (no exercising, no sweating, no running around the paddock, no sunny weather + woolie coats, no hot summer days + with no shade, no sweating under covers) which dictates the MINIMUM 0.02g per kg bodyweight daily needs.
A 500kg horse x 0.02g = 10g sodium DAILY = 25g salt (salt is 40% sodium) – a heaped tablespoon. Having 7 horses in my paddock, 9 at one stage, we all know horses don’t stand still (given the chance), they move, and they move a lot even when not in work. The sodium requirements of horses in moderate to heavy work are estimated to be twice as high, and does not consider even higher rates of sweat production in extremely warm weather.
Providing a salt block free choice is an option that people do, however its highly unlikely your horse is consuming enough of it. A 1kg plain salt block (the white one, not the red mineral ones) should be gone in around 1 MONTH for 1 HORSE (not plural) to determine they are getting enough for base line needs. Commercial feed also usually contains salt. Remember our recommendation aligns with OUR feeding regime which does not incorporate commercial feed.
When it comes to sodium you are much better off providing a LITTLE TOO MUCH than a little too little. If the horse has access to clean water, sodium is very easily excreted. Insufficient sodium inevitably leads to some dehydration. Blood testing? Won’t give a true picture of hydration. The brain ‘reads’ the sodium level in blood and will maintain its level by stealing sodium from outside the cell especially tissue (pinch skin dehydration test).
If sodium levels are too low, the kidneys will actively dump potassium and save sodium, even if blood potassium levels drop below normal. For horses with chronic problems relating to low potassium – give more salt – not potassium. This is a very common mistake. The rule of thumb is 2-3% dehydration can lead up to a 10% drop in performance. Excessive intakes however need to be avoided and strongly recommend to either learn or get someone who has, to balance your horses electrolyte output vs input.
Sodium gets all the glory and its rather neglected, yet important stable mate Chloride is often overlooked. Sodium is a Cation and Chloride is an Anion. A Cation has a positive charge and an Anion a negative charge and together Sodium and Chloride (among others) play a careful balancing act to regulate blood pH.
A 500kg horse at maintenance (remember statue horse) has a base requirement of 0.08g per kg bodyweight = 40g Chloride - 25g salt (40% salt, 60% Chloride) = 15g Chloride. 50g salt = 30g Chloride. This is where its important to ensure more than ADEQUATE levels of salt are provided in the diet to address BOTH sodium AND Chloride levels. Even with 50g salt for a 500kg, Chloride still falls short, although some is present in forage and levels increase with forage maturity.
As a side note, excessive urination in Cushings horses is due to high circulating levels of cortisol (especially when unmanaged) which stresses kidney function. It is of note, horses that consume excessive amounts of protein also have increased urination, which we find to be a more common issue than excessive sodium; highlighted by the high CP levels and low sodium and chloride levels in the many hay and pasture tests we have observed. It is partly why we also recommend to regularly detox your horses (horses with a compromised/sluggish liver often have an impaired ability to clear excess protein from the body) and especially why starting with our base feed BEFORE loading up on protein!!
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