Table 4.
Summary of published studies evaluating the effect of N-carbamoylglutamate supplementation to ruminants on the potential to mitigate environmental nitrogen pollution
| Animals | Dose | Delivery method | Duration | Outcome | Reference |
|---|---|---|---|---|---|
| 60 Chinese Holstein multiparous dairy cows; 78 ± 17 DMI, 635 ± 60 kg BW and 42 ± 8 kg/d milk yield | 0, 10, 20, 30 g/NCG/d; 50:50 mix with corn starch | Top dressed on TMR twice daily |
10 d adaptation and 7 weeks treatment (3 times daily milking) |
↓ Plasma ammonia N (1200 vs. 595 μmol/L) ↓ MUN (12.4 vs. 11.5 mg/dL) ↓ BUN (7.06 vs. 6.24 mg/dL) ↓ UN (1071 vs. 794 mg/dL Greatest ↓ in 20 g/d group vs. control |
[39] |
| Cattle (Holstein bulls; 408 kg 450 d old); n = 24 (6/group) | 0, 20, 40, 80 mg NCG/kg BW | Mixed in feed |
Best in 40 g/d group: ↓ BUN (2.54 vs. 1.99 mmol/L) ↓ Plasma ammonia (64.8 vs. 34.4 μmol/L) ↓ (trend) faecal N (70.5 vs. 62 g/d) ↓ (trend) urinary N (80.2 vs. 68.3) ↑ N retention (46.6 vs. 61.5 g/d) ↑ N utilization % (23.6 vs. 32.1) |
[75] | |
| Holstein bulls (490 kg BW; n = 24 (6/group in individual pens) | Control diet (0) vs. Control diet + NCG (40 mg/kg BW) vs. urea diet vs. urea diet + NCG (40 mg/kg BW) | Mixed in feed |
2-week diet adaptation 7-week treatment (2 times daily feeding) |
Control vs. Control + NCG: ↓ Faecal N (8.2 vs. 69.9 g/d) ↓ Urinary N (105 vs. 95.2 g/d) ↑ N retention (62.2 vs. 73.3 g/d) ↑ N utilization (0.24 vs. 0.31 g/d) ↓ BUN (3.52 vs. 3.14 mmol/L) ↓ Plasma ammonia (55.1 vs. 45.5 μmol/L) |
[76] |