When you add salt to feeds, you are actually supplying two of the major electrolytes – sodium and chloride:
Mammals are composed largely of salt and water with salt being one of the key enablers of life itself!
Horses are relatively large mammals and have a large requirement compared to we humans. They are not inclined to lick enough from salt licks to meet their daily requirements.
Due to the fact that plants are virtually devoid of salt, and salt is so vital to life, all mammals have an innate drive to seek it out. If there is not enough in the diet, they will lick your hands and/or dirt, ring-bark trees and wreck your wooden rails.
Make sure they get their quota (see below) in a daily feed and by all means have a salt lick available as well. You will notice the threshold at which your horses starts to sweat goes up.
1. A lack of sodium means the thirst response is not triggered and the horse will not drink as much water. If a salt deprived horse also sweats this can easily lead to dehydration. Hence packaged ‘electrolytes’ contain good levels of salt to replace what has been lost. Once sodium levels increase, the thirst response is triggered to ensure the body immediately takes on more water.
2. If a horse is not drinking well, offer him a bucket of salt water (add 150 grams of salt to a 20 litre bucket of water) With that initial drink of salt water, the salt concentration in the blood will be sufficiently elevated to activate the drinking triggers of the brain.
3. If your horse refuses to eat any salt, it could be a sign he has gastric ulcers or some kind of ulcerated or open wound in his mouth. Salt on an open wound stings! Further investigations by your vet are in order.
Here are the classic signs of a lack of salt:
• Loss of appetite, weight loss, no top-line (see Point 6)
• Dry, staring hair-coat
• Dehydration - skin stays tented when pinched (see point 4)
• Anhidrosis (inability to sweat at all see photos)
• Small, sunken eyes
• Pinning the ears when asked to ‘go’
• Having absolutely 'no go’ (see point 6)
• Sweating with little exertion
• Sweating in odd places (on top of the neck or rump)
• Reproductive problems (less capacity to produce milk, abortions, limb deformities)
• Retarded growth and bone development (see point 6)
• Staggering, wobbly especially in the hind-quarters (See Point 7)
• Abdominal bloating or cramping
• Increased risk of impaction colic (see point 8)
• Allergies (salt acts like an anti-histamine)
• EMS, Laminitis & Head-flicking (See points 4 & 5)
How does salt work?
4. The Sodium component has to be maintained at a certain concentration in the body fluids. The balance between how much the horse drinks and how much he urinates is the way the body maintains the correct sodium concentrations and fluid levels. Problems with this process caused by lack of salt sets off a cascade of metabolic malfunctions which include Equine Metabolic Syndrome, laminitis and head-flicking.
5. The Chloride component is required for both pH balance plus very importantly, the production of stomach acid.
6. If there is insufficient sodium available, the nutrients from food cannot be transported into the cells no matter how much you feed the horse. This is why lack of salt is a primary cause of ‘Ill-thrift’. This includes the transport of glucose for energy which is why lack of salt causes lack of energy.
7. Sodium, in conjunction with potassium, is key to normal nerve impulse transmission and muscle function, hence lack of salt predisposes the horse to becoming unco-ordinated, cramping, heavy on the forehand, stumbling or to ‘staggers’.
8. Inadequate salt intake means an increased risk of impaction colic because the reduced fluid consumption reduces the fluid content of the digesta. With good salt intake the digestive tract can act as a reservoir for both fluid and electrolytes in times of increased need.
9. In hot weather, while a human can sweat 2 litres an hour, a horse can sweat as much as 15 litres an hour. Horse’s sweat contains a lot more salt than human sweat.
How Much Salt are we Talking?
A good rule of thumb is to add a minimum of 10gms per 100 kgs live weight to feeds, preferably split am & pm. For example, if your horse weighs 500kg, he needs approximately 50gms of salt per day – this is approximately 2 good tablespoons. More if he is in hard work or sweats for any other reason. The requirement for salt can triple when the horse is exercising in hot weather!
Can you Feed Too Much Salt?
According to the NRC for Horses the “maximum tolerable concentration in the ration is 6% of total feed intake”. So this would equate to 600gms out of 10kgs of feed, way more than what we are talking.
Of course it is equally vital that your horse has access to clean fresh water because adding salt into the diet should make him want to drink more. In the hot weather, plastic water troughs, especially black ones get warm and yucky – bucket them out regularly.