VetSRev
Database of veterinary systematic reviews
Database of veterinary systematic reviews
PLoS ONE (2021) 16:
DOI: 10.1371/journal.pone.0246922
Slow-release urea (SRU) is a coated non-protein nitrogen (NPN) source for providing rumen degradable protein in ruminant nutrition. A meta-analysis was conducted to evaluate the effects of replacing vegetable protein sources with SRU (OptigenR, Alltech Inc., USA) on the production performance of dairy cows. Additionally, the impact of SRU supplementation on dairy sustainability was examined by quantifying the carbon footprint (CFP) of feed use for milk production and manure nitrogen (N) excretion of dairy cows. Data on diet composition and performance variables were extracted from 17 experiments with 44 dietary comparisons (control vs. SRU). A linear mixed model and linear regression were applied to statistically analyse the effect of SRU on feed intake and production performance. Feeding SRU decreased (P \textless 0.05) dry matter intake (DMI, -500 g/d) and N intake (NI, -20 g/d). There was no significant effect (P \textgreater 0.05) on milk yield, fat-corrected milk, energy-corrected milk, and milk fat and protein composition. However, SRU supplementation improved (P \textless 0.05) feed efficiency (+3%) and N use efficiency (NUE, +4%). Regression analyses revealed that increasing SRU inclusion level decreased DMI and NI whereas increasing dietary crude protein (CP) increased both parameters. However, milk yield and feed efficiency increased in response to increasing levels of SRU inclusion and dietary CP. The NUE had a positive relationship with SRU level whereas NUE decreased with increasing dietary CP. The inclusion of SRU in dairy diets reduced the CFP of feed use for milk production (-14.5%; 373.13 vs. 319.15 g CO_\textrm2 equivalent/kg milk). Moreover, feeding SRU decreased manure N excretion by 2.7% to 3.1% (-12 to -13 g/cow/d) and N excretion intensity by 3.6% to 4.0% (-0.50 to -0.53 g N/kg milk). In conclusion, feeding SRU can contribute to sustainable dairy production through improvement in production efficiency and reduction in environmental impacts.
Salamiid, S. A., Moranid, C. A., Warren, H. E., & Taylor-Pickard, J. (2021). Meta-analysis and sustainability of feeding slow-release urea in dairy production. PLoS ONE, 16(2). https://doi.org/10.1371/journal.pone.0246922 cattle, cows, dairy cattle, dairy cows, meta-analysis, Animal Nutrition (Production Responses) [LL520], effects, Food Composition and Quality [QQ500], Animal Nutrition (Physiology) [LL510], butterfat, cattle feeding, Dairy Animals [LL110], diets, Mathematics and Statistics [ZZ100], milk fat, rumen, feeding, crude protein, feeding stuffs, feeds, milk, Milk and Dairy Produce [QQ010], milk production, urea, yields, dry matter, feed conversion efficiency, feed intake, excretion, milk yield, milk products, sustainability, protein sources, cattle manure, Feed Composition and Quality [RR300], production, dairy products, Animal Wastes [XX100], United States of America, USA, milk components, milk composition, milk constituents, milk quality, milk fat percentage, milk protein percentage, controlled release, nonprotein nitrogen, slow release