Effects of diet and housing density on growth and stomach morphology in pigs

Two experiments were conducted to evaluate the impact of housing density on the stomach morphology of growing pigs and determine whether there was an interaction between housing density and diet. All diets were corn-soybean m eal based. In Exp. 1, 42 barrows (41.0 +/- .95 kg BW) were allotted either individually or three pigs per pen to evaluate the effects of crowding on s tomach lesions. Pen space per pig was 1.54 and .51 m(2), respectively. All pigs were fed a finely ground and pelleted diet (610 mu m) for 6 wk. The AD G decreased (P < .05) for the pigs housed three per pen during wk 4 to 6 on ly. There was no effect of housing density on feed intake or gainlfeed rati o. Neither visual nor histological ulcer score differed between the two tre atment groups. No stomachs were graded as normal. In Exp. 2, 80 barrows (39 .8 +/- .95 kg BW) were allotted either two or four pigs per pen. Pen space per pig was .77 and .39 m(2), respectively. Half of the pigs in each housin g situation were fed a coarse meal diet (1,050 mu m), and half of the pigs were fed a finely ground and pelleted diet (577 mu m) throughout the 49-d e xperimental period. Throughout the trial, pigs housed two per pen gained at a greater rate (P < .05) than pigs housed four per pen. From d 14 to the e nd of the trial, pigs consuming the finely ground and pelleted diet gained at a greater rate (P < .05) than pigs fed the coarse meal diet. The differe nces in ADG were reflected in final body weight. Stomach weight as a percen tage of body weight was higher for animals on the coarse meal diet. Visual and histological ulcer scores were similar, and both were higher (P < .001) on the finely ground and pelleted diet, indicating greater damage. There w as no effect of space restriction on stomach morphology. These data show th e major effect of diet type on stomach lesions with no interaction with spa ce restriction.