Raw nicotinamide supplementation increased slightly lactation production of Holstein cows under heat stress

摘要

Introduction Nicotinamide (NAM) and nicotinic acid (NA) can be synthesized in the rumen (Santschi et al.,2005),while absorption through the rumen wall has been shown to occur by increasing dietary levels of NA or NAM (Campbell et al.,1994).External NAM would be converted rapidly to NA by microorganisms m the reticulorumen,and duodenal NA concentrations are higher for cows supplemented with NAM than for cows receiving NA (Campbell et al.,1994).It is well known that NA could decrease heat stress in dairy cow owing to the flush response (Di Costanzo et al.,1997),while effects of supplemental NA on heat stress are not consistent recently (Zimbelman et al.,2010) (Wrinkle et a1.,2012) (Zimbelmanet al.,2013).Therefore,the objective was to value effects of supplemental raw NAM on lactation production of Holstein cows under heat stress.