Potassium

Function:

Potassium (K) regulates osmotic pressure and water uptake by organs. It has a role in skeletal integrity and muscle function. K is involved in neuromuscular excitability.

Sources:

Forages and oilseed meals generally contain 1-2% potassium on a dry matter basis. Cereals are relatively poor sources : 0.3-0.4% potassium. Normally, K intake greatly exceed requirements due to the high K concentrations in most types of forage. K chloride and K carbonate are effective sources of supplemental K.

Daily requirements (NRC, 2005):

Maintenance : 0.05 g /kg body weight (BW)

Exercising horse : 0.05g to 0.11g /kg BW

Deficiency:

Reduced appetite, depressed growth rate, muscular dystrophy and stiffness of the joints, fatigue, weakness, lethargy, weight loss.

Excess:

The excess of K ahs not been studied in horses. However, hyperkalemia, induced by parenteral administration, would be expected to cause cardiac arrest. Excess dietary K is excreted readily, primarily via the urine, when water intake is unrestricted. So, excess due to the fed is likely not to occur.

When problems may occur?

Losses during sweating or diarrhoea increase the K need considerably. Young foals with persistent diarrhoea are particularly at risk. Be careful with animals in heavy work : they generally consume more cereals, thus lowering dietary K when losses in sweat would normally be increasing. Dietary intake of K may not be sufficient in hard working horses in warm, humid climates when supplementation is not provided. Excess of sodium restricts K intake.