Effect of Cimaterol (CL 263,780) as a Repartitioning Agent in the Diet for Finishing Pigs

Abstract

One hundred ninety-two crossbred pigs (61 kg) were allotted by weight to a randomized complete-block design of four treatments with six blocks per treatment and eight pigs per totally slatted, concrete pen. Pigs were allowed ad libitum consumption of either a corn-soybean meal control diet or the control diet plus cimaterol (CL 263,780) at .25, .50 or 1.00 mg/kg of diet. Cimaterol is a repartitioning agent recently identified by American Cyanamid Company. Pigs were slaughtered at an average pen weight of 105 kg. Average daily gain and feed conversion ratio were not affected (P>.10) by diet. Daily feed intake decreased linearly (P<.01) as cimaterol increased in the diet, but the response was inconsistent because pigs fed diets containing 0 and . 50 mg of cimaterol/kg of diet ate more feed than pigs fed diets containing .25 and 1.00 mg of cimaterol/kg of diet (cubic effect of diet, P<.01). Locomotive soundness scores were not affected (P>.10) by diet. The addition of cimaterol to the diet of finishing pigs resulted in a linear increase in longissimus muscle area (P<.05) and predicted kg of muscle (P<.01). Fat depth, average backfat and ham and loin fat decreased linearly (P<.01) as cimaterol increased in the diet. Pork carcass grade improved (P<.01) as cimaterol increased in the diet. Dressing percentage, carcass length, muscle score and color of lean score were not affected by diet. These results suggest that the addition of cimaterol to the diet resulted in an increase in muscle accretion and a decrease in fat deposition, resulting in a significant improvement in carcass leanness.