Q: One of my horses (a 21-year-old TB) will literally eat his salt block, scraping it with his teeth. The other one, a seven-year-old crossbred, ignores the salt block completely. Why the difference, and is either behaviour unhealthy? Should I supplement the younger horse with salt in his feed?
Sam, via email
Vet Dave replies:
Sam, your older TB is showing the more unhealthy behaviour. It is unlikely that he is eating his salt block out of metabolic demand, and more likely that he is eating it because he likes the taste/texture/experience. The plus side is that if he is supplied with ad-lib fresh water, the salt intake from the block should be dealt with by his kidneys with the majority of excess salt ingested excreted in his urine along with the extra water required by the body to do this.
However, eating chunks of salt is less than ideal, as they can cause a physical obstruction such as a choke. My preference would be to remove the salt block and provide him with a small amount of salt in his daily feed. This should meet his nutritional requirements without any of the risks associated with eating large chunks of salt block.
The younger horse ignoring the salt block suggests that he has different grazing preferences. It does not really give you any information on his daily salt requirements or knowledge if he is receiving too little, the right amount or too much salt.
My personal preference for both your horses would be to feed a general purpose balanced electrolyte mix at the recommended dose rate in feed, rather than straight salt. A small excess or imbalance of electrolytes provided in feed can easily be corrected by the kidney through normal processes; however, a lack of any electrolytes in the diet makes maintaining an ideal balance much harder for the body.
Nutritionist Lucy replies:
Hi Sam, this is a common problem – one of my horses is prone to this behaviour. To prevent it, I use a sold form vitamin and mineral bucket in the paddock that is produced using a special manufacturing process which makes it set like concrete, so they cannot get their teeth into to. Sometimes the horse is not consuming the whole block, rather playing with it and scattering it around the paddock. This is still annoying when you have spent good money on blocks.
It may be that he has encountered poor mineral intakes at some time in his life, so he is over-compensating. I see a lot of this in laminitic ponies who have been deprived of a balanced diet for a long time. They typically overconsume vastly for a couple of months, and then settle down to regular intakes without gorging.
Mineral intake in the body is tightly regulated for both consumption and excretion, and animals will have the desire for more minerals if they have low levels of minerals stored in the body tissues. Such mineral reserves are kept in various tissues and organs in readiness for periods when more are needed for essential functions, such as sweating to regulate body temperature in hot conditions.
I would suggest using the supplement buckets, as these are harder for him to get his teeth into, and will supply both minerals and vitamins to both horses without extra supplementation.
As for the younger horse, he may be accessing it but only moderately and you may not see him doing so. Be careful if you want to supplement the younger horse further – always use a balanced mineral supplement especially if based on inorganic minerals, as this is very important to ensure these nutrients are kept in the correct balance.
