Urea ammoniation compared to urea supplementation as a method of improving the nutritive value of wheat straw for sheep

Author: S.W.P. Cloete & N.M. Kritzinger
Year: 1984
Issue: 2
Volume: 14
Page: 59 - 63

The ammoniation of wheat straw by urea in a stack method was investigated and compared to urea supplemented and untreated straw in an intake and in vivo digestibility trial. Ammoniation and supplementation significantly (P 0,01) improved the mean daily consumption of wheat straw by 46,7 and 35,6% respectively. The improvement of 8,1% in the voluntary intake of ammoniated wheat straw compared to urea supplemented wheat straw was not significant. Apparent digestibility of OM, OM, CWC, ADF and hemicellulose was significantly (P 0,01) improved by 17,5; 15,1; 24,1; 14,3 and 39,2% respectively, when ammoniated straw was compared to untreated straw. Corresponding improvements of 10,0;  8,4; 17,8; 8,7 and 29,2% were obtained when ammoniated straw was compared to urea supplemented straw. All these differences were significant at least at P 0,05. Similarly, urea supplementation tended to increase the digestibility of the above-mentioned fractions marginally. Both ammoniation and urea supplementation of wheat straw significantly (P 0,01) improved the apparent digestibility of CP as well as the N-balance. The apparent digestibility of CP of ammoniated wheat straw was significantly (P 0,01) reduced by 22,1 % compared to urea supplemented wheat straw. The N-balance of ammoniated wheat straw, on the other hand, was marginally higher than that of urea supplemented wheat straw, mainly owing to a higher level of urinary N-excretion observed on the latter treatment.



Keywords: Ammoniation, in vivo digestibility, nitrogen retention, urea supplementation, voluntary intake, wheat straw
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