Detailed analysis of the individual feeding behavior of male and female mule ducks.

The feeding behavior of 19 mule ducks (males and females) bred in a group was studied during their growth phase (between 3 and 8 wk of age) using the recording system for waterfowl feeding behavior developed in our lab. The basic feeding behavior data obtained allowed us to confirm on the one hand the reliability of our tool and, on the other hand, to compute food intake traits per day (ADFI, number of visits, and time spent feeding per day), per visit (feed intake per visit, visit duration, and visit feeding rate), and per meal (meal size, meal duration, and meal feeding rate). Daily feed intake increased with age (130 to 248 g/d) while the time spent feeding decreased from 14 to 5.5 min/d. Because the duration of visits remained stable (average 45 s), this reflected a decrease in the number of visits per day. At the same time the feed intake per visit and the feeding rate per visit increased sharply with age. The same trend was observed at the meal level for both the feed intake and the feeding rate. Feed intake did not differ between males and females, but the time spent feeding was significantly greater for females than for males (10.8 and 8.9 min per day and 53 and 37 s per visit for females and males, respectively), leading to significantly greater feeding rate for males (30 g/min) than for females (24 g/min). Grouping visits in meal events minimized the differences between genders as the meals tended to comprise fewer visits for females. Under the hypothesis of a genetic link between feeding behavior during growth and force-feeding ability of ducks, genetic selection of these behavioral traits could be included in breeding programs to improve the force-feeding capacity of mule ducks.