Effects of Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite zeolite compared with tylosin phosphate and negative control on health, performance, carcass outcomes, and liver abscesses of dairy-beef cross feedlot cattle*

Our objective was to evaluate the effects of in-feed, non-antibiotic alternatives (Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite zeolite) on health, growth performance, carcass characteristics, and liver abscesses in dairy-beef cross composites in a commercial feedlot. Dairy-beef, intact heifers (n = 2,088; average BW = 334.8 kg) were assigned to 1 of 3 treatment groups: (1) Negative control (no feed-grade antimicrobials for control of liver abscesses; NC); (2) Saccharomyces cerevisiae CNCM I-1077 (0.5 g/heifer per day to provide 1 × 1010 cfu/heifer per day) and calcium clinoptilolite zeolite (replacing flaked corn at 1.2% on a DM basis; LB), or (3) tylosin phosphate (targeted at a rate of 68 mg/heifer per day; TY). Heifers averaged 228 d on feed at harvest. Individual carcass outcomes and liver scores were captured at harvest. Heifers in the TY treatment had reduced DMI, increased G:F, and reduced cost of gain compared with the other treatments. Carcass characteristics were not affected by treatments. Heifers offered LB tended to have fewer total liver abscesses compared with the TY group, whereas NC was intermediate. Feedlot performance improved for dairy-beef heifers offered tylosin; however, TY had the greatest percentage of liver abscesses compared with NC. Feeding the combination of Saccharomyces cerevisiae CNCM I-1077 and calcium clinoptilolite as a non-antimicrobial alternative for the mitigation of liver abscesses in dairy-beef females seems to be promising strategy; however, growth performance outcomes may be reduced compared with tylosin.