Effect of corn particle size on mucosal morphology and digesta pH of the gastrointestinal tract in growing goats

A slaughter experiment was conducted to determine the effect of corn particle size on mucosal morphology and digesta pH in the gastrointestinal tract of goats. Twelve Guanzhong wether goats aged 9 months (23.5 ± 0.3 kg) were randomly fed diets containing 55% corn silage and 28% finely cracked, coarsely cracked or whole corn. After a 35 d feeding period, goats were slaughtered to obtain digesta samples for pH determination, and gastrointestinal mucosa for morphological analyses. Corn particle size did not affect (P > 0.05) digesta pH in the rumen, the abomasum and the small intestine. In the ventral ruminal sac, corn particle size did not affect (P > 0.05) papillae density, height, width, and muscle depth, and finely cracked corn increased (P < 0.05) the papillae surface area compared with coarsely cracked and whole corn. In the dorsal ruminal sac, whole corn tended to decrease (P < 0.10) papillae height and width, and decreased (P < 0.05) papillae surface area compared with finely and coarsely cracked corn. There was no effect (P > 0.05) of corn particle size on the morphology of the abomasum and total small intestine. These data suggest that finely cracked corn significantly enhanced the absorption surface area of the rumen papillae, and did not affect mucosal morphology and digesta pH of the abomasum and the small intestine in growing goats fed diets containing 35% of starch.