Cowley, Frances

Jennings, Jenny

Cole, Andy

Beauchemin, Karen

2019-09-16

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).

Animal Production Science, 59(11), p. 2082-2092

1836-5787

1836-0939

https://hdl.handle.net/1959.11/28029

en

CSIRO Publishing

Attribution-NonCommercial-NoDerivatives 4.0 International

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

Journal Article

Publication