Effect of oral potassium and sodium chloride on plasma composition of cattle: a grass tetany related study.

M ANY factors have been implicated in the etiology of grass tetany including hypomagnesemia, hypocalcemia, class of animal, stage of production and various dietary factors. Hypomagnesemia has been the most consistent clinical symptom. Elevated levels of dietary potassium (K) (Kunkel, Burns and Camp, 1953; Ward, 1966a) and nitrogen (Redmond, 1950; Metson et al., 1966) have lowered plasma magnesium (Mg). Studies by Burt and Thomas (1961), Burau and Stout (1965) and Stout, Brownell and Burau (1967) have suggested a possible role of plant organic acids (namely citric and trans-aconitic) in the development of the tetany syndrome. An experimental tetany resembling grass tetany has been induced by Bohman et al. (1969) by the oral administration of trans-aconitic or citric acid plus potassium chloride (KC1). This tetany responded to intravenous treatment with calcium (Ca)---Mg gluconate. The purpose of this study was to measure at various intervals the effect of KC1 and sodium chloride (NaC1) on plasma citric acid and certain cations associated with grass tetany. Since splenectomized cattle failed to respond to intravenous Ca-Mg gluconate when tetany was induced in earlier studies (Bohman et al., 1969), a second objective was to ascertain if the blood composition of these animals differed from intact cattle under similar conditions related to tetany.