Recent advances to improve nitrogen efficiency of grain-finishing cattle in North American and Australian feedlots

Citation

Cowley, F., Jennings, J., Cole, A., Beauchemin, K. (2019). Recent advances to improve nitrogen efficiency of grain-finishing cattle in North American and Australian feedlots, 59(11), 2082-2092. http://dx.doi.org/10.1071/AN19259

Plain language summary

Overfeeding of nitrogen to feedlot cattle is considered low-risk (in terms of cost and effects on production), but excreted excess dietary nitrogen is of significant environmental concern. Our ability to formulate the protein content of grain-finishing rations is becoming more precise but there are still barriers to adoption on-farm. Precision feeding of protein needs to account for variations in production system, and will enable us to improve nitrogen use efficiency, and reduce nitrogen intake and wastage in the feedlot.

Abstract

© CSIRO 2019 Open Access.Formulating diets conservatively for minimum crude-protein (CP) requirements and overfeeding nitrogen (N) is commonplace in grain finishing rations in USA, Canada and Australia. Overfeeding N is considered to be a low-cost and low-risk (to cattle production and health) strategy and is becoming more commonplace in the US with the use of high-N ethanol by-products in finishing diets. However, loss of N from feedlot manure in the form of volatilised ammonia and nitrous oxide, and nitrate contamination of water are of significant environmental concern. Thus, there is a need to improve N-use efficiency of beef cattle production and reduce losses of N to the environment. The most effective approach is to lower N intake of animals through precision feeding, and the application of the metabolisable protein system, including its recent updates to estimation of N supply and recycling. Precision feeding of protein needs to account for variations in the production system, e.g. grain type, liveweight, maturity, use of hormonal growth promotants and β agonists. Opportunities to reduce total N fed to finishing cattle include oscillating supply of dietary CP and reducing supply of CP to better meet cattle requirements (phase feeding).

Publication date

2019-01-01

Author profiles