N-fertilization level
Low Medium High s.e.m. P
(100 or 200 kg N/ha) (400 kg N/ha) (600 or 800 kg N/ha)
April - July
12-month-old lambs:
DM (%) 14.8 14.2 14.2 0.190 0.30
CP (%) 21.3 22.4 24.3 0.54 0.09
NO3-N (%) 0.14a
0.16a
0.27b
0.019 0.03
TNSC (%) 17.3 16.0 13.0 1.04 0.25
DMI (g/day) 1 544 1 596 1 558 27.1 0.72
Digestibility trial
DMI (g/day) 1228 1450 1472 53.5 0.18
N% of feed 3.88a
4.09a,b 4.41b
0.079 0.062
IVDOM (%) 70.5 70.5 70.7 0.34 0.978
N intake (g/day) 53.4 58.1 61.9 1.58 0.10
Rumen ammonia concentrations
NH3-N (mg/100 ml) 20.1a
24.3a,b 28.0b
0.171 0.02
August - November
Weaner lambs:
DM (%) 16.0 14.8 14.5 0.40 0.27
CP (%) 18.6a
20.5a
24.2b
0.64 0.003
NO3N (%) 0.24a
0.27a
0.46b
0.30 0.007
TNSC (%) 12.7b
10.0a,b 7.9a
0.69 0.02
DMI (g/day) 1 047 1 302 1 163 46.3 0.09
Digestibility trial
DMI (g/day) 1 300 1 273 1 189 113.1 0.916
N% of feed 3.6a
4.3b
4.7c
0.071 0.001
IVDOM (%) 70.3 70.3 68.4 0.674 0.431
N intake (g/day) 30.4a
41.9b
45.0b
1.71 0.002
Rumen ammonia concentrations
NH3-N (mg/100 ml) 18.6a
26.4ab 35.7b
2.67 0.06