Effect of Methionine Source and Level on Performance of Growing Beef Calves Consuming Forage-Based Diets1

The effects of level and source of supplemental sulfur-containing amino acids (SAA) on the performance of growing beef calves were evaluated. In Exp. 1, 128 calves (BW = 277 ± 20 kg) were offered supplements containing 0, 2, 4, and 6 g/d of SAA from corn gluten meal (CGM), or 2, 4, 6, or 8 g/d of SAA using 88% 2-hydroxy-4-methylthio butanoic acid (Alimet, Novus International Inc. St. Louis, MO) in liquid molasses slurries for 113 d. Hay was offered as large round bales; supplements were limit-fed at 2.1 kg DM/d. Calf ADG was greater (P < 0.05) for calves supplemented with CGM or 2 and 6 g/d from Alimet than for control calves. Calves provided 2, 4, and 6 g/d of SAA from Alimet and 4 g/d of SAA from CGM had greater (P < 0.05) TDN intake than control calves. In Exp. 2, 72 heifers (BW = 371 ± 3 kg) were assigned to 1 of 3 soybean hull-based supplements that provided 0, 7.5, or 15 g/d of Alimet, which supplied 0, 2.5, or 5.3 g/d of additional SAA. Heifers were offered ad libitum access to water and hay; supplements were limit-fed at 2.3 kg DM/d. Reproductive tract score and pelvic area were measured on d 85. Supplementing 15 g/d of Alimet increased (P < 0.05) ADG during the first 30 d compared with the control diet. Heifers fed 15 g of Alimet daily tended to have greater (P = 0.08) reproductive tract scores. Alimet was effective as a source of supplemental SAA for improving the performance of growing beef calves provided forage-based diets.