Influence of Mechanical Processing on Utilization of Corn Silage by Lactating Dairy Cows

Abstract

We conducted three experiments to determine the influence of mechanical processing on corn silage utilization by lactating dairy cows. Total mixed rations contained either unprocessed or processed corn silage harvested between 1/4 and 3/4 milk line. In trial 1, 12 multiparous Holstein cows were used in a replicated double switchback design with 21-d periods. Intake of dry matter (DM) was increased 1.2 kg/d by processing, but milk yield was unaffected. Processing did not affect apparent total-tract DM digestibility, but processing tended to lower starch and corn excretion in feces and reduced concentration of sieved corn kernel particles in feces. In trial 2, 42 Holstein cows were used in an 18-wk randomized complete-block design. Intake of DM and milk yield were unaffected by processing, but milk fat percent was increased 0.35 percentage units by processing. Processing tended to increase total-tract digestibility of starch, but reduced organic matter, crude protein, and neutral detergent fiber digestibilities. In trial 3, 30 Holstein cows were used in a 15-wk randomized complete block design. There was no influence of mechanical processing on intake or lactation performance in this trial. Despite indications of increased starch digestion in two trials and increased DM intake in one trial, effects of processing corn silage on lactation performance were minimal with corn silage at the maturity and moisture contents used in these trials.

Effect of mechanical processing of corn silage on in vitro ruminal fermentation, and in situ bacterial colonization and dry matter degradation

“…1) could explain the higher VFA production and lower pH in the rumen of dairy cows fed MPCS (Dhiman et al 2000). A similar trend was observed in incubation with the Rusitec (Table 2), even though ruminal environments were different among these in vitro, in situ and in vivo experiments.…”

“…In fact, markedly enhanced VFA with feeding of MPCS was characterized by high acetate (Table 2), which is a representative end-product of cellulolytic bacteria (Ogimoto and Imai 1981). Higher acetate concentration and molar proportion with MPCS feeding, as shown by Johnson et al (2002) and the present Rusitec study, may cause elevation of milk fat production that has been documented in several reports (Dhiman et al 2000;.…”

“…able to digestion in the gastrointestinal tract, and such kernels are eventually excreted into feces (Dhiman et al 2000). This remains a disadvantage of feeding corn silage intensively.…”

Effect of roll clearance of mechanical processing of corn silage harvested at the black‐line stage of maturity on carbohydrate and protein utilization in dairy cows

“…2002a; Cooke & Bernard 2005) in which animals were fed CS harvested at the 3/4 milk line or black‐line stage also reported that MP had no effect on DM intake. However, some studies (Dhiman et al . 2000; Andrae et al .…”

“…Many studies reported that MP increased starch digestibility, the amount of total digestible nutrients (TDN), and animal performance (Bal et al . 2000; Dhiman et al . 2000; Johnson et al .…”