Effects of replacing soybean meal with slow-release urea on milk production of Holstein dairy cows

The study investigated the effects of replacing soybean meal (SBM) with slow-release urea (SRU) on milk production, composition, and rumen fermentation Holstein dairy cows. Sixteen cows weighing between 550 680 kg in mid lactation were randomly assigned to four dietary treatments a 12-week study. consisted T1: diet containing 16.7% crude protein (CP), T2: T1 0.5% SRU plant protein, T3: 0.75% T4: 1.00% protein. Animals fed three times day feed being offered ad libitum. Dry matter intake (DMI) average daily gain (ADG) not affected by level SRU. Feeding did affect production composition significantly, but fat nitrogen (MUN) levels increased. Significant differences observed ruminal volatile fatty acid (VFA) concentration. increased butyrate concentration no significant concentrations acetate or propionate. cholesterol, triglyceride, high-density lipoprotein (HDL), low-density (LDL), nonesterified (NEFA) concentrations, glucose, very-low-density (VLDL) β-hydroxybutyrate (BHB) significantly treatments. Thus, feeding altered release rate ammonia provided more (NH3-N) for microbial synthesis rumen.