Increasing demand for food coupled with higher environmental standards is shaping agricultural activities toward ecologically sustainable and efficient systems ( McGuire, 2015). However, food waste remains a global dilemma, with negative environmental, social, and economic consequences ( Spang et al., 2019) associated with estimated annual losses of approximately one-third of all edible food (1.3 billion metric tonnes, MMT) across the supply chain ( FAO, 2011). More recently, the FAO (2019) has defined food waste using two indices: food lost in production or in the supply chain before it reaches the retail level (Food Loss Index) or food that is subsequently wasted by consumers or retailers (Food Waste Index). Fourteen percent of the world’s food is lost before it reaches the retail level, but the contribution associated with the Food Waste Index is still being explored ( FAO, 2019). In the United States alone, food loss streams have been estimated at 35.9 MMT from production/processing of vegetables, fruit, and meat/poultry/fish, whereas total retail and consumer waste are estimated at 19.5 MMT and 40.8 MMT, respectively ( Dou et al., 2016). In Canada, total annual loss and waste along the food value chain equates to 35.5 MMT, of which 11.2 MMT (32%) is avoidable, valued at $49.5 billion, and representing 51.8% of the food dollars spent in retail stores in 2016 ( Gooch et al., 2019).

In Canada, approximately 11.2 million metric tons of avoidable food waste (FW) is produced per year. Preservation of a greater proportion of this FW for use as livestock feed would have significant environmental and socioeconomic benefits. Therefore, this study blended discarded fruits, vegetables, and bakery products from grocery stores into silage to assess the ability to preserve their nutritional value and contribute to the feed supply. Two treatments for reducing the water content of FW were evaluated, sun-dried (SD) and passive-dried (PD), and compared to control (C) using laboratory mini-silos over 60 days of ensiling. Although dry matter (DM) was increased by 1–5% for PD and SD, respectively, up to 41.9% of bread products were required to produce a targeted silage DM of 38%. All mature silages were high in crude protein (15.2 to 15.7%), crude fat (6.0 to 6.3%), sodium (0.48 to 0.52%), and sugars (0.95 to 1.53%) and were low in neutral detergent fiber (6.2 to 7.6%) as compared to traditional silages used as livestock feed. Mold and other signs of spoilage were visible on FW, but mycophenolic acid was the only mycotoxin above the limit of detection in material prior to ensiling. Plate counts of molds and yeasts declined (p < 0.001) by 5–7 log colony-forming units (CFU) over 60 days of fermentation and were not detected in mature silage. All silages were aerobically stable over 20 days. This study indicates that FW can produce good-quality silage but approaches other than SD and PD are required for increasing silage DM as insufficient bread products may be available for this purpose in all batches of FW.

Global drivers such as the growing human population, evolving consumer preferences, globalization, and climate change have put pressure on the agri-food sector to produce more livestock products with less land, feed, and water. Taste, nutritional value, cost, convenience, source, animal welfare, and environmental sustainability of food are criteria upon which purchasing decisions are made. In response, an environmental footprint analysis composed of greenhouse gas emissions, nutrient and water use efficiency, water quality, carbon storage, and biodiversity has been completed for many commodities. However, as livestock production systems occur within complex agro-ecosystems, it is extremely challenging to formulate a single overall sustainability metric. There is no “silver bullet” to solve the environmental concerns of all livestock production systems as they operate under different constraints on different landscapes, with different water and nutrient cycles, and soil types. Furthermore, the lack of scientific evidence regarding the interactions between livestock production, human nutritional adequacy, and the health of our environment makes it difficult for consumers to interpret this information and make informed food choices. This review examines these complex interactions and trade-offs, as well as the potential impacts of changes in consumer dietary choice on environmental sustainability, nutritional adequacy, and land use.

The objective of this study was to evaluate the effects of using conventional productivity-enhancing technologies (PETs) with or without other natural PETs on the growth performance, carcass traits, and environmental impacts of feedlot cattle. A total of 768 cross-bred yearling steers (499 ± 28.6 kg; n = 384) and heifers (390 ± 34.9 kg; n = 384) were offered a barley grain-based basal diet and divided into implanted or non-implanted groups. Steers were then allocated to diets that contained either: (i) no additive (control); natural feed additives including (ii) fibrolytic enzymes (Enz), (iii) essential oil (Oleo), (iv) direct-fed microbial (DFM), (v) DFM + Enz + Oleo combination; conventional feed additives including (vi) Conv (monensin, tylosin, and beta-adrenergic agonists [βAA]); or Conv with natural feed additives including (vii) Conv + DFM + Enz; (viii) Conv + DFM + Enz + Oleo. Heifers received one of the first three dietary treatments or the following: (iv) probiotic (Citr); (v) Oleo + Citr; (vi) Melengesterol acetate (MGA) + Oleo + βAA; (vii) Conv (monensin, tylosin, βAA, and MGA); or (viii) Conv + Oleo (ConvOleo). Data were used to estimate greenhouse gas (GHG) and ammonia (NH₃) emissions, as well as land and water use. Implant and Conv-treated cattle exhibited improvements in growth and carcass traits as compared to the other treatments (P < 0.05). Improvements in the performance of Conv-cattle illustrated that replacing conventional feed additives with natural feed additives would increase both the land and water required to satisfy the feed demand of steers and heifers by 7.9% and 10.5%, respectively. Further, GHG emission intensity for steers and heifers increased by 5.8% and 6.7%, and NH₃ emission intensity by 4.3% and 6.7%, respectively. Eliminating the use of implants in cattle increased both land and water use by 14.6% and 19.5%, GHG emission intensity by 10.5% and 15.8%, and NH₃ emission intensity by 3.4% and 11.0% for heifers and steers, respectively. These results demonstrate that the use of conventional PETs increases animal performance while reducing the environmental impacts of beef production. Restricting use would increase the environmental footprint of beef produced for both domestic and international markets.

Use of productivity-enhancing technologies (PET: growth hormones, ionophores, and beta-adrenergic agonists) to improve productivity has recently garnered public attention regarding environmentally sustainability, animal welfare, and human health. These consumer perceptions and increased demand for PET-free beef offer opportunities for the beef industry to target niche premium markets, domestically and internationally. However, there is a need to critically examine the trade-offs and benefits of beef raised with and without the use of PETs. This review contains a summary of the current literature regarding PET products available. The implications of their use on resource utilization, food safety and security, as well as animal health and welfare are discussed. Furthermore, we identified gaps in knowledge and future research questions related to the sustainability of these technologies in beef production systems. This work highlights the tradeoffs between environmental sustainability of beef and supplying the dietary needs of a growing population.

A study was conducted in 2009 at two locations in Manitoba (Killarney and Souris), Canada to determine the impact of off-stream waterers (OSW) with or without natural barriers on (i) amount of time cattle spent in the 10 m buffer created within the riparian area, referred to as the riparian polygon (RP), (ii) watering location (OSW or stream), and (iii) animal performance measured as weight gain. This study was divided into three 28-day periods over the grazing season. At each location, the pasture—which ranged from 21.0 ha to 39.2 ha in size—was divided into three treatments: no OSW nor barriers (1CONT), OSW with barriers along the stream bank to deter cattle from watering at the stream (2BARR), and OSW without barriers (3NOBARR). Cattle in 2BARR spent less time in the RP in Periods 1 (p = 0.0002), 2 (p = 0.1116), and 3 (p < 0.0001) at the Killarney site compared to cattle in 3NOBARR at the same site. Cattle in 2BARR at the Souris site spent more time in the RP in Period 1 (p < 0.0001) and less time in Period 2 (p = 0.0002) compared to cattle in 3NOBARR. Cattle did use the OSW, but not exclusively, as watering at the stream was still observed. The observed inconsistency in the effectiveness of the natural barriers on deterring cattle from the riparian area between periods and locations may be partly attributable to the environmental conditions present during this field trial as well as difference in pasture size and the ability of the established barriers to deter cattle from using the stream as a water source. Treatment had no significant effect (p > 0.05) on cow and calf weights averaged over the summer period. These results indicate that the presence of an OSW does not create significant differences in animal performance when used in extensive pasture scenarios such as those studied within the present study. Whereas the barriers did not consistently discourage watering at the stream, the results provide some indication of the efficacy of the OSW as well as the natural barriers on deterring cattle from the riparian area.