49. Estimated Greenhouse Gas Emissions of Individually Housed Beef X Holstein Steers and Holstein Steers Fed to Finish.

Abstract Industry stakeholders, including the Canadian Roundtable for Sustainable Beef and the Dairy Farmers of Canada, along with the federal government have all made commitments to reduce greenhouse gas (GHG) emissions. These commitments have created the need to identify sustainable management practices within the cattle sector. There is increasing use of beef-on-dairy crossbreeding to improve the value of dairy calves. However, the environmental value of this breeding strategy has not been evaluated in Canada. The objective of this research was to estimate land use and GHG emissions of beef × Holstein (B×H) steers as compared to purebred Holstein steers. Existing data was obtained from a feeding trial conducted at the Agriculture and Agri-Food Canada Lethbridge Research Centre, in which 39 individually housed steers (n = 19 Holstein, 165 kg starting weight, 20 B×H, 180 kg starting weight) were fed barley grain/corn silage-based diets containing 15% CP and 69% TDN during the backgrounding phase and 13% CP and 78% TDN during the finishing phase. The backgrounding and finishing phases were 106 and 219 days for Holstein steers and, 84 and 204 days for B×H steers. Final body weights for the Holstein steers and B×H steers were 734 kg and 774 kg, respectively. Dressing percentages were 60.1% and 61.1% for the Holstein steers and B×H steers, respectively and kg of boneless beef were 322 and 345, respectively. Land requirements (ha breed−1) were calculated using the inclusion rate of ingredients (dry matter, DM%), DM intake, days on feed (DOF), number of head, and feeding and storage losses. The Holos model was used to estimate whole farm GHG emissions. Crossbred B×H steers had an 11% decrease in land use (ha treatment−1) for feed crops as a result of the shorter DOF and increased feed efficiency compared to Holstein steers. Emission intensities (kg CO2e kg boneless beef−1) for B×H steers were 8% lower than the Holstein steers. In conclusion, cross breeding of dairy cattle with beef resulted in decreased land use and GHG emissions suggesting that this breeding strategy can result in both productivity and environmental benefits.