Effect of the beta-adrenergic agonists, ractopamine hydrochloride and salbutamol, on the performance of finisher pigs

The efficacy and safety of beta-adrenergic agonist use in modern swine production are controversial. This study aimed to determine the effect of dietary ractopamine hydrochloride and salbutamol on the performance of 440 male and female finisher pigs (Topigs Norsvin TN70), housed in 40 pens of 11 animals each, with five treatments and four replicates per treatment. The dietary treatments included a negative control, containing 16% crude protein and no feed additives; ractopamine-16 (negative control plus 6 mg ractopamine/kg); ractopamine-13 (13% crude protein and similar essential amino acid concentrations to the negative control, plus 6 mg ractopamine/kg); salbutamol-6 (negative control plus salbutamol 10% at 6 mg/kg); and salbutamol-4 (negative control plus salbutamol 10% at 4 mg/kg). At 6 mg/kg feed, ractopamine had no effect on pigs’ growth and carcass indices compared to the negative control, regardless of the dietary crude protein concentration. However, gilt carcasses had lower lean percentages on the ractopamine-13 diet than on the negative control diet. Pigs fed 4 mg and 6 mg salbutamol/kg had higher lean percentages than the negative control group. The crude protein content of a diet containing ractopamine can thus be decreased from 16% to 13% for boars, whereas gilts may still benefit from a higher crude protein concentration. Salbutamol supplementation suppressed feed intake and growth in boars and enhanced feed efficiency and lean percentage in gilts. Hence, salbutamol supplementation at 4 mg/kg may be a viable alternative to ractopamine for finisher pigs, producing a higher lean percentage and return on investment, and reduced production costs, despite not enhancing growth. (Submitted 20 June 2025; Accepted 13 January 2026; Published 13 March 2026)