Proposed Use of Adjusted Intake Based on Forage Particle Length for Calculation of Roughage Indexes

Effect of forage addition to the diet on rumen development in calves

“…The same trend is also observed in mature animals fed diets with differing particle size. Rumen pH is also lower in mature cows receiving decreasing levels of TMR particle size (0.31, 0.43, and 0.51 cm) (Santini et al, 1983). Thomas and Hinks (1982) showed that chopping roughage into 20-mm lengths does not alter rumen-buffering characteristics of long roughage.…”

“…As particle size of a ration, particularly the forage component, decreases, acetate to propionate ratios also decrease (Santini et al, 1983;Kerley et al, 1985).…”

“…By 6 to 8 weeks of age most calves are actively ruminating solid feed of sufficient particle size (Conrad et al, 1958). A decrease in ration particle size is associated with a decrease in rumination and saliva flow into the rumen Santini et al, 1983). Long roughage takes longer to eat than pellets and requires 7 times the amount of rumination.…”

“…Forage that is chopped or ground to fine particle sizes decrease rumen pH and cellulolytic bacteria populations . This decrease in pH is caused by a lack of rumination and saliva flow into the rumen Santini et al, 1983). Several investigations have observed decreases in the acetate to propionate ratio as a result of decreasing rumen pH and cellulolytic populations (Santini et al, 1983;Kerley et al, 1985).…”

“…Forage chopped or ground to fine particle sizes decrease rumen pH and cellulolytic bacteria populations . This decrease in pH is caused by a lack of rumination and saliva flow into the rumen Santini et al, 1983). Rumen papillae are also influenced by the particle size of the ration.…”