Partial replacement of broom sorghum panicle residue and tallow with whole cottonseed in growing-finishing diets for lambs

Sixty-four Pelibuey × Katahdin male lambs (14.3± 2.2 kg initial live weight) were used in an 84-d growing-finishing trial to evaluate optimal levels of inclusion of whole cottonseed (WCS) in a broom sorghum panicle residue-based diet. Dietary treatments consisted in partial replacement of broom sorghum panicle residue (SPR) and tallow with 0, 10, 20 or 30% WCS. Control diet contained 66.5% PSR and 3% tallow, and replacing were as follows: 10% of WCS replaced 9% SPR and 1% tallow (WCS10), 20% WCS replaced 18 SPR and 2% tallow (WCS20), and 30% WCS replaced 27% SPR and 3% tallow (WCS30). Inclusion of WCS increased (quadratic component, P=0.03) average daily gain (ADG), dry matter intake (DMI) and gain efficiency. However, with increasing level of WCS substitution the observed/expected dietary net energy ratio decreased (linear effect, P