The Intergovernmental Panel on Climate Change overestimates annual nitrogen excretion from pigs in Korea

This study aimed to validate the accuracy of representative body weight (BW) and annual nitrogen (N) excretion (Nex) of pigs suggested by the Intergovernmental Panel on Climate Change (IPCC) and to estimate the annual Nex from pigs in Korea.

Seven crossbred barrows (initial BW = 56.6±2.3 kg) were used to determine apparent total tract digestibility (ATTD) of dry matter and N, and the fresh-to-dry fecal weight ratio. Daily BW, feed intake, and age data were collected from the National Research Council and the Korean Feeding Standard for Swine. Models for daily BW, feed intake, and fresh fecal excretion of pigs were developed to calculate the representative BW. Daily fecal Nex from a market pig was calculated using ATTD of N and daily N intake, and daily urinary Nex was estimated. Total Nex was calculated as the sum of fecal and urinary Nex.

The ATTD of dry matter and N was 88.4% and 88.8%, respectively, and the fresh-to-dry fecal weight ratio was 3.55. Based on the average daily feed intake of 1,602 g/day and fresh fecal excretion of 587 g/day, the representative BW for market pigs was determined to be 35.3 kg at 85 days of age. The daily fecal, urinary, and total Nex at the representative BW were 5.6, 15.3, and 20.9 g/day, respectively. The annual total Nex for a market pig was 7.6 kg/year. The annual Nex for a reproductive sow was 14.5 kg/year. Assuming a population of 91% market pigs and 9% breeding sows, the annual total Nex for all pigs in the Korean swine industry was 8.23 kg/year which is less than 18.0 kg/year suggested by the IPCC (p<0.001).

The IPCC overestimated the representative BW of pig and Nex from pigs in Korea. The annual Nex from pigs is 8.23 kg/year in Korea.