Comparison between conventional urea and slow-release urea on concentration of ammonia in the rumen: A meta-analysis

Abstract

Urea is a source of Non-Protein Nitrogen (NPN). The utilization of urea in the ration is useful for increasing digestibility, dry matter intake, and increasing protein content. This study aims to compare the utilization of conventional urea and Slow Release Urea (SRU) to reduce ammonia concentration by in vivo study using meta-analysis. A total of 13 studies were obtained that consisted of 41 data points. The parameters in this study include pH, Dry Matter Intake (DMI), Volatile Fatty Acid (VFA), ammonia concentration, and nitrogen intake. The database compiled was statistically analyzed using a mixed model method. Different studies were considered as random effects, and the level of urea was treated as fixed effects. The model statistics used were the p-values and the Akaike information criterion. The significance of an effect was stated when its p-value was <0.05. The results revealed that level SRU and conventional urea had a significant linear effect on ammonia concentration, DMI, VFA, pH and nitrogen intake. However, the effect of giving SRU was better than conventional urea. It can be concluded that SRU can control ammonia concentration, DMI, VFA, pH and nitrogen intake better than urea.