In the journal, Professional Animal Scientist, this month, scientists led by G.D. Gerlemann of the University of Missouri reports their work aimed at evaluating pig performance, feed efficiency and carcass characteristics of finishing pigs fed ractopamine hydrochloride (RAC) in a single-phase (7.4mg per kg for 31 days) or step-up (5.0/10.0mg per kg) feeding programme when compared with a NRC control diet.

Working together with co-authors from Ohio State University, Elanco Animal Health and University of Pennsylvania School of Veterinary Medicine, barrows and gilts were divided into pens of approximately 22 pigs per pen and fed one of three dietary programmes when pigs reached approximately 103.5kg bodyweight. The five heaviest pigs per pen were marketed on day 17 of the trial (before the step-up initiation) and on day 31, the remaining 17 pigs per pen were marketed.

Pigs fed RAC and marketed after 17 days (1.195kg per day) of feeding had a 14.5 per cent improvement (P<0.0001) in average daily gain and a 13.2 per cent improvement (P<0.0001) in efficiency (0.385) compared with controls (1.04kg per day; 0.34).

On average, RAC-fed pigs had 0.43 percentage units greater (P=0.02) carcass yield.

During the entire 31-day feeding trial, RAC-fed pigs (1.20kg per day) gained 12 per cent more (P<0.0001) weight per day and were 14 per cent more (P<0.0001) efficient (0.365) at feed conversion than were controls (1.07kg per day; 0.32).

Ractopamine-fed pigs also had greater (P<0.0001) carcass yields, larger (P<0.0001) loin depths and greater (P<0.0001) estimated carcass lean values than did pigs not fed RAC.

Ractopamine can be fed in a step-up feeding programme, even in marketing strategies when pigs are marketed relatively soon after the RAC initiation with the same performance and carcass results normally observed in continuous-dose feeding programmes.

Reference

^{Gerlemann G.D., G.L. Allee, D.D. Boler, M.J. Ritter, M.K. Pierdon and S.N. Carr. 2013. The effects of ractopamine hydrochloride feeding programs on growth and carcasses of finishing pigs marketed in 2 different groups. Professional Animal Scientist. 29(3):271-277.}

June 2013