Chloride Requirements of Lactating Dairy Cattle

Abstract

Chloride is the third most abundant mineral element in milk and the most common anion in the extracellular body fluids of mammals (Coppock and Fettman, 1977). An early study at Cornell found that cows fed a low chloride diet, containing .18% chloride, had lower chloride excretion in urine and feces (Coppock et al., 1979). Significant reductions in chloride concentrations of blood plasma, urine, saliva and synovial fluids were reported in young calves fed a diet containing .038% chloride (Burkhalter et al., 1979; Burkhalter et al., 1980; and Neathery et al., 1981).  A trial was designed to examine the potential affects of a chloride deficiency in dairy cows (Fettman et al., 1984b, I 984c). Diets were formulated containing either . 1 (low), .27 (medium) or .45 (high) % chloride on a dry matter basis. No differences in dry matter intake, milk production or body weight changes were detected between the medium and high diets (Fettman et al., 1984b, 1984c). However, significant decreases in these three measures were noted for cows on the low chloride diet. Cows on the medium and high chloride diets did not differ in the metabolic parameters monitored. The results of this study indicate that a dietary chloride content of . l % is too low for early lactation dairy cows. It would appear that a dietary chloride level of .25 to .3% on a dry matter basis should be used in practical ration formulation.