Floor Feeding Sows Their Daily Allocation over Multiple Drops per Day Does Not Result in More Equitable Feeding Opportunities in Later Drops

SIMPLE SUMMARY: Floor feeding is one of the cheapest and simplest methods of feed delivery for groups of commercial gestating sows, but results in high levels of competition for feed. Consequently, feed intake and weight gain are reduced for low-ranking sows in floor-feeding systems. More equitable feeding opportunities may be achieved by providing floor fed sows their daily allocation over multiple feed drops per day. This study recorded (over two gestations) the aggressive and feeding behavior of sows that were floor fed four times a day. High-ranking sows spent the most time feeding where the majority of feed was distributed. All other sows fed opportunistically, consuming what they could from between and around high-ranking females. The lowest ranking sows spent more time than middle and highly ranked sows avoiding the feeding area. These relationships were true regardless of day, feed drop, or gestation. Further research is necessary to ensure that all sows are able to feed with less risk to their welfare, or, alternatively, determine whether variation in feed intake is a feature of floor feeding systems per se. In terms of accessing the feeding area, this research has broad implications for most feeding systems. ABSTRACT: This research studied whether floor feeding group-housed sows their daily allocation over multiple feed drops per day provides more equitable feeding opportunities in later drops. Over four time replicates, 275 sows were mixed into groups of 10 for both their first and second gestations (200 sows/gestation, 126 sows observed in both gestations). The feeding behavior of individual sows was recorded for 10 min following each of four feed drops per day (0730, 0900, 1100, 1500 h) on days 2, 9 and 51 post-mixing. The location of feeding sows (i.e., feeding in areas associated with high, reduced or little/no food availability) was also recorded. Sow aggressive behavior on day 2 was used to classify sows as dominant (D), subdominant (SD), or submissive (SM). Dominant sows spent the most time feeding in areas of high-food availability (gestation 1, p < 0.001; gestation 2, p = 0.023); SD sows fed more frequently than D sows from areas of reduced food availability (gestation 1, p = 0.001; gestation 2, p = 0.025); and SM sows performed more feeding behavior in areas of little/no food availability (gestation 1, p < 0.001; gestation 2, p < 0.001). These relationships did not change over feed drops or days in either gestation (p > 0.05). Further research on the management and design of floor feeding systems is required, with a particular emphasis on increasing accessibility to sows that avoid the feeding area.