Live yeast should not raise the body temperature as it will serve as a source of nutrients and remain viable in the rumen as it develops for several hours. Yeast and yeast culture products are commonly added to calf starters to improve performance. Research has shown that 2% inclusion of yeast in a calf starter (dry matter basis) gives good response.
Mike Hutjens, Extension Dairy
Specialist, U of IL - Illini DairyNET
Hugh Chester-Jones, U of MN dairy and beef specialist