Live Yeast Supplementation and Heat Stress on Ruminal Fusobacterium necrophorum Counts

Abstract

Reduced average daily gains and feed efficiencies, as well as liver condemnations associated with severe liver abscesses in feedlot cattle, are economic liabilities to producers and packers. Fusobacterium necrophorum, a Gram-negative ruminal bacterium, is the primary etiological agent of liver abscesses in grain-fed cattle. F. necrophorum survives elevated rumen temperatures during heat stress and exploits ruminal acidosis in conjunction with rumenitis as an opportunity to invade ruminal epithelium and enter portal circulation to reach the parenchyma of the liver. Live yeast supplementation has been shown to stabilize ruminal pH levels away from acidotic conditions during heat stress in dairy cattle.