The DCAB refers to the relative amounts of cations (the positively charged ions - Na, K) to anions (the negatively charged ions – Cl, sulphur (S) ). To Convert from % to mEq per kg, multiply by: High potassium, lowered calcium and lowered magnesium can all cause the tetany ratio to increase and predispose animals to tetany. Table 1 shows how to calculate mEq/kg from dietary percentages.

charge) because acid-base balance is affected by electrical charge rather than mass. Milliequivalents take into account both molecular weight and valence (i.e. The incidence of tetany increased to 6.66% of 1908 animals when the tetany ratio was above 2.2 The tetany ratio is expressed as K / (Ca+Mg) in milliequivalents (mEq) per kg of dry matter. In 1957, research showed that when the ratio of K to the sum of Ca and Mg (the tetany ratio) was less than 2.2, there were very few cases of tetany (0.77% of 4658 animals). Tetany ratios and dietary cation : anion balance (DCAB) are both used to describe electrolyte balance. Along with sodium, calcium (Ca) and magnesium (Mg), K acts to maintain nerve and muscle activity. K plays an important role in the transportation of oxygen and carbon dioxide through the blood. Along with sodium (Na) and chlorine (Cl), K is one of the three major electrolytes in the body and functions to maintain cation-anion balance (blood pH). It is found primarily in skin and muscle and is important for maintaining proper osmotic balance within cells. K is the third most abundant mineral in the body. This article will deal with beef cattle and K. Information on K and dairy cows can be found in previous Nutrition Update articles: Potassium in Dairy Cow Diets, May 2001 Preventing Udder Edemas, May 2002. This has created difficulties in balancing rations for cattle. They are often over 2% and in some cases, over 3%. Potassium (K) levels in some forages, e.g. Potassium and Tetany Ratios (Nutrition Update, Volume 15)

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