Tr. Dhiman et al., PARTICLE-SIZE OF ROASTED SOYBEANS AND THE EFFECT ON MILK-PRODUCTION OF DAIRY-COWS, Journal of dairy science, 80(8), 1997, pp. 1722-1727
Fifteen cows were used in an experiment with a 5 x 5 replicated Latin
square design to quantify the effect of particle size of roasted soybe
ans on milk production and fecal excretion of soybeans. The five exper
imental periods were each 2 wk long. Diets contained (percentage of dr
y matter) 33% alfalfa silage, 17% corn silage, 30.6% high moisture ear
corn, 18% soybeans, and 1.4% mineral supplement. The five dietary tre
atments included raw whole soybeans or roasted soybeans in four partic
le sizes (whole and half, half and quarter, quarter and smaller, and c
oarsely ground). Mean particle sizes of the raw soybeans and of the ro
asted soybeans in whole and half sizes were >4.75 mm. Mean particle si
zes of the roasted soybeans in half and quarter, quarter and smaller,
and coarsely ground roasted soybeans were 2.92, 2.01, and 1.59, respec
tively. During the normal handling of roasted soybeans, a large number
of seeds was broken into halves in the treatment with whole and half
sizes (36%, wt/wt basis). Production of 3.5% fat-corrected milk was 35
.4, 37.7, 37.2, 35.1, and 35.4 kg/d for cows fed raw soybeans; roasted
soybeans in whole and half, half and quarter, and quarter and smaller
sizes; and ground roasted soybeans, respectively. Cows that were fed
raw soybeans excreted the largest amount of visible soybean particles
in feces, and cows that were fed ground roasted soybeans had the least
amount of soybeans in the feces (61.3 vs. 10.6 g of soybeans/kg of fe
cal dry matter). Roasted soybeans in half and quarter sizes are optima
l for milk production.