343 Effect of Ruminally-Protected Lysine Supplementation to Limit-fed Growing Cattle on Growth and Subsequent Finishing Performance

Abstract Lysine may be limiting for cattle fed diets based on corn products. Our objective was to supplement ruminally protected lysine limit-fed a corn-based diet during the growing phase and assess performance subsequent finishing phases. The 77-d growth trial used 338 crossbred steers allocated 32 pens 2.4% of body weight daily. Steers were implanted (40 mg trenbolone acetate, 8 estradiol) at initiation. Diets contained 39.5% grain, 40% wet gluten feed, 13% hay, 7.5% supplement. Treatments included: no supplemental amino acids (control), 3 g/d metabolizable from Smartamine ML (Adisseo, Alpharetta, GA; Lys-3), 6 (Lys-6), blood meal (Aadvantage; Perdue Agribusiness, Kings Mountain, NC) 0.89% dietary dry matter plus 2 methionine M (BM). Individual weights measured d 0 77. After 77 d, shipped commercial feedlot, commingled in pens, common 185 or 206 slaughtered commercially. Performance using carcass data slaughter facility. During phase, Lys-3 tended improve average daily gain by 0.11 kg/d (P = 0.12) feed efficiency 0.08) compared with control. finishing, Lys-6 have gains 0.05 greater than control 0.17). Carcass 7.1 3.4 kg heavier Lys-3, respectively. BM did not affect period resulting weight. Ruminally supplementation and/or phases, as well weights.