Effect of ensiling a total mixed ration for dry cows on chemical composition, fermentative quality, aerobic stability and palatability

The experiment was carried out to investigate the effect of ensiling on the several feed characteristics of a total mixed ration (TMR) prepared for dairy dry cows. The TMR was composed of 36% (on a dry matter [DM] basis) whole plant corn silage (late yellow ripe stage), 32% grass silage (first cut at heading stage), 25% grass hay (first cut at blooming stage) and 7% compound feed. The contents of total digestible nutrient and crude protein were set at 63% and 12% on a DM basis, respectively. The TMR was ensiled using a roll baler for chopped material and opened after 4 months. The chemical compositions, fermentative characteristic, aerobic stability and palatability by pre-parturition animals were compared with those of TMR prepared using the same lot of ingredients. We found that TMR silage contained significantly but slightly more DM (by approximately one percentage point). No significant differences were observed in the lactate and ethanol contents between TMR silage and TMR. Although the TMR silage contained more acetate, propionate and volatile basic nitrogen, the fermentative quality was classified as fairy good based on V-score value (92 points). The TMR silage showed higher aerobic stability after exposed to air. When the TMR silage and TMR were offered simultaneously to 8 animals (4 dry cows and 4 pregnant heifers) and the daily intake of each diet was recorded, the palatability index of TMR silage (the proportion of TMR silage intake to total intake) was 61% which was significantly higher than 50%. These results indicate that, although several characteristics seem to differ from those of TMR silage for lactating cows which were demonstrated previously by several authors, the ensiling of TMR for dry cows which contains more roughage and less concentrate can improve the aerobic stability and palatability as known for TMR silage for lactating cows.