Abstract
High moisture (H-M, 18% dry matter) chopped silage, H-M unchopped silage, low moisture (L-M, 71% DM) silage, ammonia treated hay and field cured hay of first cut grass (timothy 70%, clover 30%) were prepared from the same field and fed to lambs to study the effect of fermentative quality of silage and ammonia treatment of moist hay on dry matter intake, animal growth and ruminant metabolism. H-M unchopped silage and hays were fed in chopped form. With H-M unchopped silage, large amount of butyric acid and ammonia was produced. The H-M chopped silage contained little butyric acid. The field cured hay contained more NDF and less CP than high moisture silage. TDN values were ranged from 61.4 for H-M unchopped (poor quality) to 71.0% DM for H-M chopped (good quality) silage. TDN value of ammonia treated hay was 64.9% DM and not significantly different from that of field cured hay. Nitrogen retention was highest for field cured hay. Dry matter intake for lambs fed H-M poor quality silage was only 2.3% of body weight and growth rate for five weeks was near zero. Lambs fed other forages consumed more than 3% of dry matter per body weight and gained about 10% of body weight. Feed efficiency (body weight gain/feed intake, %) of H-M poor quality silage was - 4.0%. Feed efficiencies of other forages were about 10% but that of H-M good quality silage was a little low. Ruminal ammonia concentration at 4 hr. post feeding were 20.4 mg/dl and 16.1 mg/dl for ammonia treated hay and H-M poor quality silage higher than for field cured hay and L-M silage. Feeding hays or L-M silage resulted in a high molar percentage of acetate in the rumen of lambs. Molar percentage of propionic acid in H-M good quality silage fed lambs was high. For H-M poor quality silage, ruminal butyric acid was higher and propionic acid was lower than other forages in each VFA. For lambs fed H-M poor quality silage, blood ketone level was high (10.2 mg/dl) and blood glucose level and blood protein level were low. Blood urea nitrogen levels were 28.5, 21.7 and 20.8 mg/dl for ammonia treated hay, H-M good quality silage and H-M poor quality silage higher than for field cured hay.
