Can using food waste as feed reduce the environmental footprint of Canadian beef production? A case study of cull potatoes

Abstract

Context

Food loss and waste (FLW) originating from food production and subsequent agro-industrial processing and distribution is receiving increased attention as it impacts social, economic and environmental sustainability. It also results in inefficient use of land, water, and energy, contributing to greenhouse gas (GHG) emissions and habitat degradation. The use of FLW as livestock feed is one solution to address these environmental concerns as well as reducing the food-feed competition.

Objective

This study was designed to evaluate the feed conversion ratio (FCR), land use requirements and GHG emissions of cattle management systems (calf-fed, yearling-fed and yearling-grass fed) offered: i) barley- and corn-based standard (STD) diets or ii) STD diets in which cull potatoes replaced barley and corn at 15 % and 30 % dry matter (DM) basis.

Methods

Feed conversion was calculated as kg DM intake (DMI)/kg beef protein (BP; R₁); kg human-edible (HE) DMI/kg BP (R₂); kg protein DMI/kg BP (R₃) and kg HE protein DMI/kg BP (R₄). Corn and barley grain were either assumed to be grown on-farm (Scenario 1) or transported (Scenario 2) from an adjacent Ecodistrict. Further, in each scenario, emissions were estimated by considering no emissions from potato productions or 10 % emissions based on economic allocation. The Holos model and published coefficients that impact GHG emissions were used to estimate GHG emissions including those from diversion of cull potatoes from landfill.

Results and conclusions

Among FCR metrics, R₂ and R₄ provide meaningful measure of the value of cull potatoes in feedlot diets, representing the portion that would not be consumed by humans and wasted otherwise. Compared to STD diets, inclusion of cull potatoes at 15 % and 30 %, led to a 12–15 % and 24–30 % reduction in land use, respectively. Total GHG emissions were also reduced by up to 5 % and 22 % in Scenarios 1 and 2, respectively. In conclusion, incorporating cull potatoes in feedlot diets can improve FCR, reduce land requirements and GHG emissions, and avoid the CH₄ emissions that would arise if they were sent to landfill.

Significance

Inclusion of non-conventional feeds such as FLW could serve as a first step in addressing the FLW challenge as well as providing alternative feedstuffs during feed shortages resulting from flood or drought.