High salt inclusion reduces concentrate intake without major effects on renal function in young bulls

Abstract

Beef producers prefer to feed concentrates on an ad libitum basis to increase the flexibility of their work. Including salt, which is a self-limiting supplement, could control or reduce concentrate intake without increasing the workforce. The aim of the study was to evaluate the effect of including 10%NaCl in the concentrate on intake, growth, blood ions (sodium, potassium and chlorine), renal function (through creatinine and urea concentrations in blood), and daytime behaviour of bulls over 6 weeks. Bulls consuming the control concentrate (Control bulls) had greater weight gain (P<0.05) and concentrate intake (P<0.001) than those consuming the concentrate with 10%NaCl (10%NaCl bulls). Lower plasma sodium concentration was found in Control bulls after 6 weeks (P<0.05), while potassium concentration was lower after 4 (P<0.05) and 6 weeks (P<0.01). Blood urea did not differ between the groups, and creatinine only differed at week 4 (P<0.01). Control bulls spent less time eating hay (P<0.001) and more time idling (P<0.01) during daylight hours. In conclusion, the inclusion of 10%NaCl in the concentrate for short periods could be used to reduce concentrate intake without major effects on renal function; however, a concomitant decrease in weight gain should be expected.