Effects of Kemtrace Cr Level and Feeding Regimen on Finishing Pig Growth Performance and Carcass Characteristics

A total of 1,206 pigs (PIC 337×1050; initial BW=48.9 kg) with 27 pigs per pen and 15 pens per treatment were used in an 84-d study to evaluate the effects of Cr supplementation (KemTRACE Chromium propionate, Kemin Industries Inc., Des Moines, IA) and feeding regimen on growth performance of finishing pigs housed under commercial conditions. Pigs were placed in mixed gender pens and blocked by BW in a randomized complete block design. Diets were corn-soy-DDGS-based and were fed in 4 phases. Treatments were: 1) Control; no Cr in grower or finisher, 2) 200 ppb of Cr fed in both grower and finisher, and 3) 200 ppb of Cr fed in grower and 100 ppb fed in finisher. The grower phase was from 49 to 92 kg and the finisher phase was from 92 to 124 kg. Data were analyzed using PROC GLIMMIX of SAS and are presented as least square means ± SEM. There was no evidence (P≥0.197) of Cr supplementation effect in the grower period. In the finishing period, addition of Cr resulted in a quadratic increase (P=0.023) in ADG with the greatest performance observed at 200 ppb Cr (0.92, 0.92, 0.94±0.010 kg/d; Control, 100, 200 ppb added Cr, respectively) with no evidence of differences on ADFI or G:F. Overall, the addition of 200 ppb Cr in both grower and finisher tended to increase (P=0.086) ADG compared to Control (0.89, 0.90, 0.91±0.006 kg/d; Control, 200/100, 200/200 ppb added Cr, respectively). There was no evidence (P≥0.523) of Cr supplementation effect on overall ADFI and G:F. Backfat was lowest (P=0.028) for pigs fed 200 then 100 ppb Cr, and greatest for pigs fed 200 ppb Cr in grower and finisher, with Control pigs intermediate (18.4, 18.0, 18.7±0.23mm; Control, 200/100, 200/200 ppb added Cr, respectively). Percentage lean was greatest (P=0.028) for pigs supplemented with 200 then 100 ppb Cr (55.1, 55.4, 55.0±0.16%, Control, 200/100, 200/200 ppb added Cr, respectively). Dressing percentage was lowest (P=0.018) for pigs fed 200 ppb Cr in both grower and finisher, with no difference between the other treatments (77.1, 77.1, 76.8±0.001%, respectively). There was no evidence of differences (P>0.10) in HCW or loin depth. In summary, adding 200 ppb of Cr in both grower and finisher increased finishing ADG. Carcass characteristics were optimized with supplementation of 200 ppb Cr in grower followed by 100 ppb Cr fed in finisher.