Calf - Rumen Development

• The rumen must be fully functional for the calf to digest forage
• The epithelial layer inside the rumen contains many small finger-like projections called papillae, where absorption takes place
• At birth, these papillae are small and nonfunctional; it is important to promote their development as they give increased surface area for absorption of nutrients and provide a good environment for beneficial bacteria to live and grow
• Adding live yeast to a calf’s diet
• encourages the growth of cellulolytic bacteria and fungi
• greatly increases fiber digestion
• encourages the production of acetic and butyric acids
• promotes the growth and development of papillae
• improves digestion of solid feeds and efficient absorption of nutrients
• leads to earlier dry feed intake

• Pre-ruminant calves need to be fed concentrates containing digestible fiber sources for optimum papillae development, and live yeast for improved fiber digestibility; straw, rather than hay, works to develop the “scratch factor” in the rumen
• Calf can only be successfully weaned when a good level of dry feed intake is achieved, during which live yeast ensures performance is achieved by maximizing dry feed intake and feed conversion ratio

Undeveloped papillae

Developed papillae