THE IMPORTANCE OF CLEAT SPACING IN RAMP DESIGN FOR YOUNG PIGS

Four ramp designs were tested for acceptance by pigs aged 7–8 wk and weighing about 16 kg. The designs included one ramp with a 22° slope and cleats spaced 100 mm apart, and three ramps with slopes of 28° and cleat spacing of either 100, 75 or 50 mm. Forty-eight litters were used in the study, each providing four pairs of pigs. Each of the four pairs was exposed to a different ramp design for 1 h, with ramp acceptance determined by whether a pig tried the ramp or not. Acceptance was much higher for the 22° ramp than the 28° ramp when the cleats were spaced at 100-mm (0.56 vs. 0.36, respectively; P < 0.01). However, there was a strong linear trend towards greater acceptance of the 28° ramp as cleat spacing was reduced (P < 0.001), so much so that acceptance of 50-mm spacing tended to surpass that of the 22° ramp with 100-mm spacing (0.70 vs. 0.56, respectively; P < 0.07). The results show that narrowly spaced cleats can compensate for steepness of slope in ramp designs for young pigs. Key words: Pigs, behavior, ramp design, cleat, spacing, slope