Effect of adding urea, limestone or biuret to maize silage cut at two stages of maturity:

Dry matter digestibility of maize silage ensiled three weeks later than the hard dough stage (42,6 % dry matter) was higher than that of silage ensiled at the hard dough stage (35,0% dry matter). Ensiling with 1% urea resulted in a significant (P < 0,01) increase in total nitrogen, ammonia nitrogen content and apparent digestibility of protein in comparison with control silage and 1%-limestone silage. Non-significant differences in N-retention indicated that the additional N in the urea-silage was not utilised optimally by experimental sheep. The pH-value of urea-silage was also undesirably high. Ensiling with 1% biuret had the same effects but to a lesser extent. Concentration of total fatty acids was significantly (P < 0,01) increased in silage ensiled with 1% limestone. This treatment also caused an undesirable increase in concentration of butyric acid coupled with an undesirable decrease in acetic acid concentration.