The Environmental Impact of Lowering Dietary Crude Protein in Finishing Pig Diets—The Effect on Ammonia, Odour and Slurry Production

Excess nitrogen excretion, ammonia and odour are environmental pollutants associated with pig production. Reducing dietary crude protein (CP) will lower the amount of excreted, reducing potential for emissions, if diets adequately formulated to supply amino acids production performance is maintained. Crude content in finishing pigs has been lowered recently, but quantitative effect this reduction on ammonia, odour, slurry output not well-established. The relationship between equivocal, unclear. objective study was investigate lowering CP emission, emission pigs. Thirty entire boar were individually housed groups six, from 10 weeks age (30 ± 3.0 kg) offered standard diets. At 75 kg (±1.5 assigned one three treatment diets; (1) 180 g/kg CP, 11.0 total lysine (High CP), (2) 150 11.1 (Medium (3) 130 9.0 (Low CP). After experimental moved, six each week, individual calorimetry chambers measure emissions. Pigs ad libitum. end recording period, removed chamber, weighed feed disappearance recorded calculate intake. chamber collected analysed. diet resulted a 22% 47% (p < 0.001). Slurry reduced by 39% 0.001) dry matter increased 35% compared 0.05). Water usage = 0.017), phosphate 0.05, respectively) found decrease linearly decreasing content. There no significant or hydrogen sulphide emissions decreased 0.010) CP. weak positive (linear: R2 0.25, p 0.005) as reduced. could reduce water nutrient