Feeding of wheat middlings in lamb total mixed rations: Effects on growth performance and carcass traits

Little scientific information is available that evaluates wheat middlings (WM) as corn grain substitute in lamb diet. The objective of this work was to evaluate the effect of feeding WM in total mixed rations (TMR) on lamb performance and carcass characteristics. Forty Comisana breed male lambs (13 ± 0.5 kg BW) were allocated randomly to two isocaloric and isonitrogenous diets. Two pelleted TMR were formulated: control diet contained 400 g/kg of dry matter (DM) of corn as main starch source, whereas experimental diet contained 600 g/kg DM of WM. Lambs were slaughtered after fifty days of feeding trial and carcass data were collected. In order to evaluate in vivo digestibility of TMR, four adult Comisana rams were placed in metabolic cages and their individual faeces and urine were collected, and indicated differences for NDF and ADF fractions. Results from growth trial of lambs showed that final live weight and gain as well as feed conversion ratio were improved by WM in diet (P=0.035). In slaughter trial, none of the parameters studied were influenced by dietary treatment, except for slaughter weight and cold-carcass dressing that were improved in lambs fed WM (P=0.047 and P=0.042, respectively). Additionally, WM diet had no effect on lamb carcass traits. As result, WM maintained lamb performance and had no negative effect on lamb performance and carcass traits. Maximizing the use of WM may become economically feasible for lamb feeders when prices turn favorable compared to conventional dietary ingredients such as corn.