Table 1 Summary of published studies evaluating the effect of N-carbamoylglutamate supplementation to ruminants on lactation performance
From: The significance of N-carbamoylglutamate in ruminant production
Animals | Dose | Delivery method | Duration | Outcome | Reference |
|---|---|---|---|---|---|
60 Chinese Holstein multiparous dairy cows; 78 ± 17 DIM, 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 (17.6% CP) twice daily | 10 d adaptation and 7 weeks treatment (3 times daily milking) | ↑ Milk yield (2 kg/d) – trend in 20 g/d ↑ Milk protein content (2.8% vs. 2.7%) and yield (1.12 vs. 1.02 kg/d) in 20 g/d ↑ Lactose and milk solids (linear ↑ with NCG dose) No change DMI, milk fat %/yield | [39] |
60 Mid-lactation Holstein dairy cows 176 DIM 669 kg BW, milk yield 26 kg/d | 0, 10, 20 or 40 g/hd/d NCG | Top dressed on TMR (13.9% CP) 3 times daily 0600, 1400 and 2000 h | 2-week adaptation, 12 weeks treatment | ↑ Fat yield (linear; 0.97 vs. 0.91, 40 g/d) ↑ Fat % (linear and quadratic; 4.24 vs. 3.93, 40 g/d) ↑ Protein % (linear; 3.74 vs. 3.62, 40 g/d) ↑ Total solids (linear; 13.3 vs. 13.0, 40 g/d) ↑ Lactation persistency (linear and quadratic; 99.4% vs. 89.2%, 20 g/d) No change DMI or milk, protein, lactose, fat, energy corrected milk yield or feed efficiency | [40] |
Subset of 30 cows from 0 and 40 g/d group from [40] | 0 vs. 40 g/NCG/cow/d | Top dressed on TMR 3 times daily 0600, 1400 and 2000 h | 8 weeks | ↑ Milk NCG concentration (6 times) No NCG in cheese in control, < 1.0 μg/kg in NCG group (in whey stretch water, brine during cheese production) No effect on cheese texture and colour but NCG group lower in hardness | [41] |
30 Chinese Holstein dairy cows- multiparous; individual tie stalls; BCS 3.39 (5-point scale), 657 kg BW, 2.73 parity, 8692 kg 305d milk yield | 0 and 20 g/d NCG | Top dressed on TMR (12.6% CP dry period and 17.3% CP lactation) 1 time daily at 14:00 | 4 weeks pre-calving to 10 weeks post-calving | ↑ Milk yield (40.9 vs. 37.7 kg/d) ↑ Protein yield (1.2 vs. 1.13 kg/d) ↑ Fat yield (1.74 vs. 1.55 kg/d) Trend for ↑ fat, milk solids and lactose % over time Trend for ↓ protein % over time ↑ Liver function No change feed conversion efficiency No change SCC – numerical ↓ (3.82 vs. 4.2, P = 0.12) | [42] |
48 heat stressed Holstein lactating dairy cows; 154 DIM, 1–3 parity | 0, 15, 20, 25 g NCG/d | Mixed in TMR (CP not reported) diet – frequency not stated (milked 3 times daily) | 60 d | ↑ Milk yield (linear and quadratic; 31.5 vs. 29.9 kg/d) ↑ Protein % (3.49 vs. 3.27) ↓ SCC (3.33 vs. 4.65 × 104/mL, 20 g/d best) ↓ Pulmonary hypertension Improved immune function and antioxidant capacity No change lactose %, fat %, DMI | [43] |
14 Jersey cows 385 ± 46 kg body weight | 0, 20 g NCG/d | Mixed in ad libitum TMR diet (8.8% CP) | 60 d | ↑ DMI (trend) ↑ Blood oxygen saturation (trend) ↑ Milk fat % (trend) ↓ Milk protein % (trend) ↓ Markers of high-altitude stress ↓ Molar proportion of butyric acid (trend) but no other change in rumen fermentation No change in nutrient digestibility, plasma immunity and antioxidant capacity Altered lipid and amino acid metabolism | [44] |
Lactating cross-bred Boer × Yangtse River Delta White goats with twin male suckling kids | 0, 1, 2 or 3 g/d/goat | Mixed in TMR diet (15.9% CP) – frequency not stated | 0–42 d lactation | ↑ Milk yield at 21 (6.12 vs. 5.12 kg) and 42 d (8.62 vs. 6.99) in 2 g/d group only ↑ Milk protein % (2 g/d group only) | [45] |