Abstract
The present study compared the greenhouse gas (GHG) emissions, and breeding herd and land requirements of Canadian beef production in 1981 and 2011. In the analysis, temporal and regional differences in feed types, feeding systems, cattle categories, average daily gains and carcass weights were considered. Emissions were estimated using life-cycle assessment (cradle to farm gate), based primarily on Holos, a Canadian whole-farm emissions model. In 2011, beef production in Canada required only 71% of the breeding herd (i.e. cows, bulls, calves and replacement heifers) and 76% of the land needed to produce the same amount of liveweight for slaughter as in 1981. Compared with 1981, in 2011 the same amount of slaughter weight was produced, with a 14% decline in CH4 emissions, 15% decline in N2O emissions and a 12% decline in CO2 emissions from fossil fuel use. Enteric CH4 production accounted for 73% of total GHG emissions in both years. The estimated intensity of GHG emissions per kilogram of liveweight that left the farm was 14.0 kg CO2 equivalents for 1981 and 12.0 kg CO2 equivalents for 2011, a decline of 14%. A significant reduction in GHG intensity over the past three decades occurred as a result of increased average daily gain and slaughter weight, improved reproductive efficiency, reduced time to slaughter, increased crop yields and a shift towards high-grain diets that enabled cattle to be marketed at an earlier age. Future studies are necessary to examine the impact of beef production on other sustainability metrics, including water use, air quality, biodiversity and provision of ecosystems services.
Generated Summary
This research, published in the journal *Animal Production Science*, undertakes a comparative analysis of greenhouse gas (GHG) emissions and resource utilization linked to Canadian beef production in 1981 versus 2011. Employing a life-cycle assessment (LCA) approach, the study focuses on “cradle to farm gate” emissions, using the Holos model, a Canadian whole-farm emissions model. The methodology incorporated temporal and regional variations in feed types, feeding methods, cattle categories, daily weight gains, and carcass weights to produce an accurate assessment. The primary aim of this study was to compare the GHG emissions and resource use associated with Canadian beef production in 2011 with that in 1981, to identify the factors that have contributed to the decline in emission intensity and resource requirements over the past three decades and explore the implications for future beef production.
Key Findings & Statistics
- In 2011, Canadian beef production required only 71% of the breeding herd and 76% of the land needed to produce the same amount of liveweight for slaughter as in 1981.
- The total beef production in Canada in 1981 was 1.05 billion kg from 3.80 million slaughtered cattle, whereas in 2011, it was 1.35 billion kg from 3.72 million cattle.
- The average carcass weights of steers, heifers, cows, and breeding bulls slaughtered in 2011 were 29%, 45%, 19%, and 28% heavier, respectively, than those in 1981.
- The steer carcass weights were 1.19 and 1.28 times the cow carcass weights in 1981 and 2011, respectively.
- Approximately 83% of the feed in 1981 and 78% of the feed in 2011 required by the Canadian beef cattle herd was forage.
- 29% less breeding stock was required to produce the same amount of beef in 2011 compared to 1981.
- The slaughter population required to produce a given amount of Canadian beef was reduced by 24%.
- The land use to produce a given amount of Canadian beef was reduced by 24%.
- The estimated GHG intensity was 14.0 kg CO₂e/kg liveweight in 1981 and 12.0 kg CO₂e/kg liveweight in 2011, a 14% decline.
- The total GHG emissions from Canadian beef production were 28% higher in 2011 than in 1981 (28.3 Tg CO2e vs 22.1 Tg CO2e).
- The study reports declines of 18% in CH4, 19% in N2O, and 16% in CO2 emissions.
- The GHG intensity was 12.0 kg CO₂e per kg liveweight for 2011 and 14.0 kg CO₂e per kg liveweight for 1981, a 14% decline.
- Enteric CH4, manure N2O, and soil N2O accounted for more than 92% of the total GHG emissions.
- The analysis showed that the area of land fertilized with commercial N for crop production in 1981 was assumed to be 14% lower than in 2011.
- The average weaning weights for 1981 and 2011 were based on values reported by Schaeffer et al. (1981) and Sheppard et al. (2015), respectively.
- The average daily gain of steers and heifers in 2011 was 1.35 kg/day and 1.17 kg/day, respectively.
Other Important Findings
- Enteric CH4 emissions contributed approximately 73% of total GHG emissions in both 1981 and 2011.
- The improvements in average daily gain and slaughter weight led to a dilution in the maintenance costs of the herd and overall nutrient demand.
- Advances in reproductive efficiency and productive performance signify that cow-calf producers adopted improved genetics and management practices, leading to increased weaning weights.
- A larger proportion of calves was sent to feedlots immediately after weaning in 2011 than in 1981.
- The study showed that the lower intensity of CO2 emissions from on-farm fuel use and manufacturing of fertilizers and herbicides are due to improvements in crop and animal productivity.
- The study confirms that the cow-calf system is the primary source of GHG emissions.
Limitations Noted in the Document
- The analysis depended on disparate datasets and assumptions regarding input parameters such as feed types, feeding practices, herd structure, and growth rates.
- Uncertainties are inherent, necessitating caution when interpreting the results.
- It was not possible to acquire reliable data regarding transportation of cattle and feeds among and within provinces.
- Emissions associated with culled dairy cows were estimated and entirely attributed to beef production, even though veal calves were not included in the analysis.
- The study’s land-use estimate might be higher than actual values under producer control, due to the stocking-rate assumptions in the analysis.
Conclusion
The primary goal of the study was to compare the greenhouse gas (GHG) emissions associated with Canadian beef production in 1981 and 2011. The research found a 14% decrease in GHG intensity, with the estimated intensity of GHG emissions per kilogram of liveweight dropping from 14.0 kg CO2 equivalents in 1981 to 12.0 kg CO2 equivalents in 2011. The key factors that contributed to the decline included increased average daily gain and slaughter weight, improved reproductive efficiency, reduced time to slaughter, increased crop yields, and a shift toward high-grain diets. These changes allowed cattle to be marketed at an earlier age, resulting in lower GHG emissions per unit of liveweight. The research showed that enteric CH4 emissions from cattle accounted for a large portion of overall emissions in both years, highlighting the importance of this area for mitigation strategies. The study also noted that the reduction in GHG emissions over the 30-year timeframe has been partially attributed to the amount of energy beef cattle require for maintenance. The study showed that the same amount of beef required 29% less breeding stock and 24% less land in 2011 compared to 1981 to produce the same beef output. The study’s data reveals that the Canadian beef industry has made significant advancements in reducing its environmental impact, with improvements in production efficiency leading to reduced emissions. This reduction is associated with a shift to more efficient practices within the beef production cycle, while also noting that opportunities for further mitigation lie within the cow-calf sector. The findings provide a basis for developing GHG policies for the Canadian beef industry and highlight the need for future research to examine the impact of beef production on sustainability metrics such as water use, air quality, and biodiversity.