BLOOD TESTING - WHY - WHAT - HOW
Blood testing can be useful when the right testing is carried out. Here we are going to discuss electrolyte levels in your horses blood.
Testing can give you a base point from which to keep track of essential parts of your horses well being. Excessive or deficient levels of minerals such as potassium, sodium, calcium and selenium can have a dramatic effect on your horses health and behavior.
Your local vet will need to come and collect the samples. If you want potassium levels to be tested for you will need to book your vet in at such a time that they can get the blood back to the clinic or lab within 2-3 horses to obtain a correct result. After this time potassium leaks from the cells, artificially increasing potassium levels in the blood sample. Checking levels around 6 monthly is a good idea.
Electrolytes in the blood are – potassium (K), sodium(Na), calcium(Ca), chloride(Cl),magnesium(Mg).
Potassium is one of the most problematic minerals for horses. It can be very easily over supplied in the diet resulting symptoms such as tight muscles, short stepping and not tracking up, spooking and shying, excessive sweating and seeming lack of fitness to name a few. The recommended range for riding horses is 3.3-3.9. Readings over or below this can result in difficult behaviour and health issues such as colic, dehydration and in extreme cases heart failure.
Magnesium levels in the blood should not be used to diagnose body magnesium levels. The homeostasis mechanism gives blood priority for magnesium, while nerves and muscles can be deficient. Magnesium toxicity is unknown as it is not stored in the body and therefore it is one of the most important minerals a horse owner can give their horse. Magnesium deficiency is very common and very often overlooked.
Calcium range is narrow and readings outside this should be addressed.
Chloride is essential to digestion, acid balance and osmotic pressure.
Sodium is essential and is a major electrolyte. It drives the thirst reflex, is important in the nervous system, aiding movement signals and transporting key nutrients such as amino acids and glucose. A horse deficient in sodium but high in potassium can become very unwell as the only way excessive potassium can be excreted is via the kidney and therefore drinking is essential.
One other key mineral recommended for testing that is not under the electrolyte heading is selenium. Our soils are very often deficient. Low selenium levels affect muscle development, and hoof and hair growth but excessive levels can be very toxic. It is also important to know where your horses level is before supplementing with selenium as toxicity is very nasty and should be avoided. Feeding multiple sources of selenium can also lead to toxicity so great care needs to be taken with supplements and premixed feeds.