The economic and environmental value of genetic improvements in fattening pigs: An integrated dynamic model approach1

Abstract

The selection of animals for improved performance affects the profitability of pig fattening and has environmental consequences. The goal of this paper was to examine how changes in genetic and market parameters impact the biophysical (feeding patterns, timing of slaughter, nitrogen excretion) and economic (return per pig space unit) results describing pig fattening in a Finnish farm. The analysis can be viewed as focusing on terminal line breeding goals. An integrated model using recursive stochastic dynamic programming and a biological pig growth model was used to estimate biophysical results and economic values. Combining these models allowed us to provide more accurate estimates for the value of genetic improvement and, thus, provide better feedback to animal breeding programs than the traditional approach, which is based on fixed management patterns. Besides the benchmark scenario, the results were simulated for 5 other scenarios. In each scenario, genotype was improved regarding daily growth potential, carcass lean meat content, or the parameters of the Gompertz growth curve (maturing rate [], adult weight of protein [α], and adult weight of lipid mass []). The change in each parameter was equal to approximately 1 SD genetic improvement (ceteris paribus). Increasing , , daily growth potential, or carcass lean meat content increased the return on pig space unit by €12.60, €7.60, €4.10, or €2.90 per year, respectively, whereas an increase in decreased the return by €3.10. The genetic improvement in and resulted in the highest decrease in nitrogen excretion calculated in total or per kilogram of carcass gain but only under the optimal feeding pattern. Simulated changes in the Gompertz growth function parameters imply greater changes in ADG and lean meat content than changes in scenarios focusing on improving ADG and lean meat content directly. The economic value of genetic improvements as well as the quantity of nitrogen excreted during the fattening period largely depends on feeding. Improved genotypes can require changes in pig management pattern. Estimating the influence of the genotype on the nitrogen excretion without considering changes in the management pattern can result in flawed conclusions. To improve overall economic performance and to decrease the environmental footprint of fattening pig production, the pig producer can adjust the herd management pattern according to the pigs' genetics.

Environmental Impacts and Their Association With Performance and Excretion Traits in Growing Pigs

“…The selection of animals for improved production traits has been, for a long time, the major driver of pig breeding ( 1 , 2 ). More recently, because of the increasing concern with environment, new selection criteria have been explored, such as nitrogen (N) or phosphorus (P) excretion, which are related to both feed efficiency and environmental impact ( 3 ).…”

Analyses of body weight patterns in growing pigs: a new view on body weight in pigs for frequent monitoring

“…For pigs observed during short time intervals, growth has been defined simply by linear functions with the intercept representing initial BW and the slope expressing an increase in BW (Toft et al, 2005). For pigs observed over longer time intervals, periods with faster and slower growth rates have been expressed in the form of Gompertz functions (Niemi et al, 2015). Such description of growth is adequate for traditional BW monitoring, which involves, for example, moving pigs from pens to a weighing crate on a daily, weekly or monthly bases.…”

Effect of growth rate on live performance, carcass and green thigh traits of finishing Italian heavy pigs

“…The benchmark value for the finishing GR of Italian heavy pigs is placed at around 650 g/d (BPEX 2016), although studies dealing with Italian heavy pig production show considerable variation in GR (ranging for instance from 590 g/d in Corino et al 2008, to 820 g/d in Prandini et al 2013 initial BW between 80 and 100 kg). Growth rate impacts on feed efficiency, carcass weight and composition and herd profitability (Nguyen & McPhee 2005;Yang et al 2012), and is recognised as one of the most important traits in pig production (Niemi et al 2015). Feeding strategy and diet composition can affect GR (Lebret 2008), and as the growth potential of pigs has increased as a consequence of selection procedures (Lo Fiego et al 2005), it is now time to reconsider the target GR for Italian heavy pigs.…”