The influence of whole-corn feeding method during the finishing stage on the performance of overfed mule ducks

The aim of this trial was to compare 2 feeding systems based on whole corn, a loose-mix and a free-choice feeding system, during the finishing stage on the performance of ducks. Five hundred sixteen day-old male mule ducks (Muscovy drake × Pekin duck) were divided into 3 groups that differed in the presentation of the diet they received between 58 and 88 d of age: a complete pelleted diet (Control (CON) group; AMEn 12.1 MJ/kg, CP 15.0%) containing 500 g of corn per kg; or whole corn (AMEn 13.9 MJ/kg, CP 7.3%) and protein-rich pellets (AMEn 10.3 MJ/kg, CP 22.7%) in equal quantities mixed in the same feeders (loose-mix feeding [LMF] group) or in 2 separate feeders (free-choice feeding [FCF] group). From 89 to 99 d, 72 birds/group were overfed with a mixture containing mainly corn and water and then slaughtered to determine the weight and commercial value of the fatty liver. Feed intake was measured daily. Body weight (BW) was measured at 58, 88, and 99 d of age. From 58 to 88 d, total feed intake of the FCF group was +7% and +9% (+558 g and +672 g) higher than in the groups CON and LMF, respectively (P = 0.005). At 88 d, the BW was higher in the CON group than in the FCF group (4,959 vs. 4,778 g, P < 0.001), the LMF group being intermediate (4,874 g). During the experimental stage, the feed conversion ratio was higher in the FCF group than in the 2 others (+32%, P = 0.024), but the energy intake was similar between the 3 groups (92.6 MJ/duck, P = 0.353).After overfeeding (99 d), the BW (6,593 g), weight (642 g), and commercial grading of fatty liver were similar (P > 0.05) in the 3 groups. The present results suggest that loose-mix feeding during the finishing stage using whole corn is a solution for reducing feed cost.