Evaluating a Growth Model to Predict Amino Acid Requirements for Commercial Turkey Toms with and Without Feed Additives

Estimating dietary requirements is resource-intensive and often excludes common commercial practices, such as the use of feed additives (FA). The objective of this study was to evaluate whether a factorial–mechanistic growth model-derived feeding program would improve performance and economic efficiency compared to the 1994 NRC recommendations for commercial turkey toms. This applied study used 5248 Nicholas Select toms (day 0 to 140) in a 2 × 2 factorial design comparing two nutrition programs (growth MODEL versus 1994 NRC recommendations) with or without feed additives (FA). Hatch-mate toms were placed across two research farms, with eight replicate pens per treatment at each farm. Growth and efficiency measurements were collected throughout the trial, and carcass yield was measured at 140 days. Data were analyzed using mixed linear models with nutritional model, FA, phase, location, and all interactions as fixed effects. The main effect of the nutritional model was different for body weight, feed intake, feed conversion ratio, and lysine to gain (p < 0.030), with the MODEL program demonstrating favorable outcomes except for body weight through the first 42 days, which was the only variable impacted by FA (p = 0.014). Nutritional program by FA interactions affected breast meat yield, feed conversion ratio, and lysine conversion, with FA improving outcomes for toms fed the MODEL feeding program but not the NRC feeding program. These findings support the use of factorial growth models over traditional NRC feeding programs.