Effect of cattle diet and manure storage conditions on carbon dioxide, methane and nitrous oxide emissions from tie-stall barns and stored solid manure

The diversity of beef cattle production systems in terms of diet, manure management and building design results in variation in greenhouse gas (GHG) emissions and the opportunities to reduce them. Within this context, we studied the effect of the varying proportions of concentrate (37–85% of DM) in the diet of Belgian Blue heifers on CH4 and N2O emissions from a tie-stall system (barn and solid manure storage). Trials were conducted over two consecutive periods in which manure was stored mainly in winter and spring. Increasing the proportions of concentrate in the diet reduced the GHG (CH4 + N2O) emissions from the barns from 8.5 ± 1.6 to 1.9 ± 0.4 kg CO2 eq/kg live-weight gain, but had not significant influence on the emissions from the stored solid manure. Seasonal variation in gas emissions was observed, with lower emissions from stored solid manure in winter than in spring (159 ± 25 and 314 ± 49 mg CO2, 0.14 ± 0.02 and 2.47 ± 0.78 mg CH4, and <0.01 and 0.24 ± 0.09 mg N2O/kg of fresh manure stored/d of storage, respectively), indicating that manure storage in the warmer season should be avoided. The GHG (CH4 + N2O) emissions from stored solid manure, however, were less than 11% of the total emissions (barns + manure storage). The emphasis in these systems should therefore be on modelling and reducing direct CH4 emissions from cattle but feed production impact should also be included. The GHG emissions were validated using nutrient (C, K, P and ash) balances including CO2 and CH4 emissions for the C balance.