The production of novel beef products is crucial to ensuring the sustainability of British Columbia’s beef industry as it increases product differentiation in the beef marketplace. This research has evaluated the impacts of supplementing cattle finishing rations with winery by-products (WB), mainly wine lees, at a feedlot in the South Okanagan region of British Columbia. To accomplish this, 69 Angus cross feedlot steers (live weight; 51.3 ± 27.9 kg) were randomly allocated to one of two pens, two per treatment, and fed finishing rations supplemented with either 6-7 % WB (WB; n = 18, 17) or water (control (C); n = 17, 17) for 143 d. Over the course of the study the impacts of WBsupplemented feed rations on the weight and flight speeds of cattle were evaluated, as well as the impacts of this feed on the frequency of fecal samples harbouring antimicrobial resistant Escherichia coli (EC) and the diversity of fecal bacterial communities. Cattle fed WB-supplemented feeds were found to require less feed than C fed steers to reach the same slaughter weight, while producing meats with no changes to the colour or composition than the control, save for the colour of ground steak meat, which was found to be darker in meats from WBfed animals. WB-supplemented feeds did not alter cattle temperament, however cattle became habituated to handling over the feeding period. WB-fed cattle had elevated EC loads compared to C-fed animals, however no changes to the proportions of antimicrobial resistant EC were observed between treatments. Similarly, diet was not found to alter the bacterial communities of cattle feces, however these communities were found to change with time on feed. In conclusion, supplementing cattle feeds with WB can provide economic incentives to producers through reduced feed demands, without altering the loads of fecal pathogens or temperament of cattle.
