Efficacy of tiamulin as a growth promotant for growing swine.

A study involving 244 pigs initially averaging 13 kg was conducted at two stations to evaluate tiamulin as a growth promotant for growing swine. In each experiment, four replicate pens of five (Exp. 1) or six (Exp. 2) pigs/pen were used to evaluate each treatment. In Exp. 1, pigs were fed 0, 11, 22 or 44 ppm tiamulin from 15 to 58 kg, then fed a nonmedicated control diet for the remainder of the experiment (to 95 kg). In Exp. 2, pigs were fed 0, 2.75, 5.5, 11 or 22 ppm tiamulin from 11 to 56 kg, followed by the nonmedicated control diet (to 95 kg). In each experiment, carbadox (55 ppm) was included as a positive control and was fed to an average weight of 35 kg, followed by the control diet. Averaged across all dietary levels, tiamulin resulted in a 14.1% improvement in gain and a 5.7% improvement in feed:gain ratio during the first 28 to 35 d of the experiment (to 30 kg). These improvements were slightly less than those resulting from the feeding of carbadox during the same period (21.5 and 6.9%, respectively). From 13 to 57 kg, pigs fed tiamulin gained 11.6% faster and 3.1% more efficiently than did controls. Over the entire experiment (13 to 95 kg), tiamulin-fed pigs gained 5.7% faster than did controls, even though the tiamulin was withdrawn at 57 kg body weight. Growth rate from 13 to 57 kg plateaued at the 11-ppm dietary level of tiamulin; whereas, feed:gain ratio plateaued at the 22-ppm level. The results indicate that tiamulin is an effective growth promotant for growing swine.