Effects of corn milling type on physical characteristics and dustiness of swine diets

Twenty samples of two commercial feedstuffs, one for fattening pigs and one for pregnant sows, half of them containing hammer-mill ground corn and the other half containing roller-mill ground corn, were analyzed under laboratory conditions to determine the effect of milled corn, as the main ingredient in swine diets, on the mean particle size, standard deviation, apparent density, and stability ratio of emitted dust. Higher levels of respirable dust were recorded from roller-milled diets than from hammer-milled diets. Persistently high dust concentrations were recorded throughout the period of observation for both mixtures of roller-milled feedstuffs, particularly the pregnant sow diet, which was characterized by high corn percentages. The type of formulation influenced the mean particle size, standard deviation, and apparent density. The type of corn milling significantly influenced mean particle size, standard deviation, and feedstuff stability. It can be concluded that although roller-milling of corn can have a positive effect on feed digestibility, as widely reported in the literature, large amounts included in the diet can reduce the quality of air inside piggeries, with higher levels of fine particulate matter.