Resumen: 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. Idioma: Inglés DOI: 10.4081/ijas.2014.3207 Año: 2014 Publicado en: Italian Journal of Animal Science 13, 3 (2014), 568-575 ISSN: 1594-4077 Factor impacto JCR: 0.718 (2014) Categ. JCR: VETERINARY SCIENCES rank: 83 / 133 = 0.624 (2014) - Q3 - T2 Categ. JCR: AGRICULTURE, DAIRY & ANIMAL SCIENCE rank: 32 / 57 = 0.561 (2014) - Q3 - T2 Financiación: info:eu-repo/grantAgreement/ES/INIA/PET2007-05-C03 Financiación: info:eu-repo/grantAgreement/ES/INIA/RZP2009-005 Financiación: info:eu-repo/grantAgreement/ES/INIA/RZP2012-00002 Financiación: info:eu-repo/grantAgreement/ES/INIA/UDL-P09014 Tipo y forma: Artículo (Versión definitiva)