Akbar Nikkhah - Chief Highly Distinguished Professor, Department of Animal Sciences, Faculty of Agricultural Sciences, University of Zanjan

Early establishment of fibrolytic, amylolytic, and proteolytic capacities is influential for early expansion of the reticulorumen epithelia. This will enable a timelyhepatic adaptation to volatile fatty acids assimilation. The early nutrient release in the reticulorumen can thus facilitate early weaning, reduce labor costs, save milk, and lessen health issues associated with late weaning. The objective of this article is to delineate rolesof commercial exogenous carbohydrases (CEC) in stimulating fermentation developmentof the reticulorumen in young ruminants, to discuss the literature on nutrient digestibilityand calf performance response to dietary CEC, and to provide insights into future opportunities for using dietary CEC for young ruminants. Cow milk may reduce the risk ofcancer development and cardiovascular diseases. Therefore, nutritional implications forhumans of supplementing calf diets with CEC and its potential for milk savings is alsodiscussed. Dietary incentives leading to savings in milk would aid in meeting the risinghuman demands for well-distributed milk products. Applying CEC to pre- and postweaning starters would need to be evaluated before CEC for young ruminants could be expected on a large scale. Any benefits of nutritional strategies to the animal industry mustalso consider their implications for human health. As such, dietary use of CEC for young ruminants may be considered as an interface of animal nutrition, farm economics, and animal-human health.

Exogenous commercial carbohydrases, milk, starter, weaning, growing ruminant