Nitrogen budget estimated for 908 cow-calf, backgrounding and finishing beef operations across Canada

Effect of changes in management practices and animal performance on ammonia emissions from Canadian beef production in 1981 as compared with 2011

“…Emissions from cattle finished in feedlots were higher with about 45% of N intake lost as NH 3 -N. Calves had lower NH 3 -N losses as a proportion of N excreted and N intake because of their milkcontaining diet, lower feed intake per animal, and higher rate of N deposition. Our estimates are comparable with the values of 17.5 kg NH 3 animal −1 yr −1 , 18.5 kg NH 3 animal −1 yr −1 , and 15 kg NH 3 -N animal −1 yr −1 reported by Sheppard and Bittman (2012), Chai et al (2014), and Sheppard et al (2018), respectively.…”

“…For most of the Canadian winter, beef cows are commonly fed conserved forages in confinement, which leads to higher NH 3 losses as a percentage of excreted manure N compared with grazing systems. Grazing cattle can congregate near mineral, shade or water sources on pasture, and these areas are more susceptible to excess N as well as N 2 O, NO (nitric oxide), N 2 (molecular nitrogen), and NH 3 emissions (Sheppard et al 2018). However, these areas generally constitute a small proportion of the total grazing area.…”

“…Notwithstanding, strategies planned or implemented to mitigate NH 3 emissions can have unintended consequences in terms of the emissions of other greenhouse gases and airborne pollutants (Carew 2010;Sheppard et al 2018). For example, manure injection, which is adopted to mitigate NH 3 emissions, can cause leaching of nitrate and higher N 2 O emissions than surface application of manure (Sheppard and Bittman 2016).…”

“…Ammonia emissions from confined beef production systems represent an important loss of an essential crop nutrient (Sheppard et al 2018). Adopting manure tillage practices is one of the possible options to mitigate NH 3 emissions from feedlots, and thereby enhance air quality (Carew 2010).…”

Efficient use of nitrogen in agriculture

“…In animal production, feed and manure management are important factors for the farm N efficiency. Surveying more than nine hundred beef operations across Canada, Sheppard et al (2018) showed that N budgets and NUE varied significantly among different types of beef operations. Forage based operations showed the largest N surplus and lower NH 3 emissions than confinement housing, while finisher operations had the highest NUE, but also the highest NH 3 emissions.…”