Effect of a low chloride diet on lactating Holstein cows.

Twenty primiparous lactating Holstein cows were fed diets supplemented with either .5% sodium chloride or .75% sodium bicarbonate. Those fed the latter diet conserved chloride by reducing the chloride concentration in urine, feces, and, to a small but nonsignificant amount, in milk. The low chloride diet did not affect consumption of feed dry matter and water or milk production and composition. There was no indication of pica or other aberrant taste behavior. One half of the cows in each diet group was given free choice salt block of trace elements. Those fed the low chloride diet consumed more salt (337 versus 149 g/cow per wk). When chloride requirements have been established and data on chloride composition become more widely available, it will be possible to include both sodium and chloride in diet formulations and omit salt. This will reduce the amount of salt needed as either a sodium or chloride supplement.