FONTES DE NITROGÊNIO NÃO PROTÉICO NA DIETA DE BOVINOS CONFINADOS

Abstract

The use of non-protein nitrogen (NPN) in the diet of cattle, such as extruded urea, has been widely tested as an alternative to improve feed efficiency and reduce costs in protein supplementation. Extruded urea, due to its more gradual release in the rumen, promotes a more efficient synchronization between the availability of ammonia nitrogen and the addition of carbohydrates, favoring microbial protein synthesis. NFeed® is a commercial extruded urea product containing essential oils derived from garlic - Allium sativum, and cinnamon - Cinnamomum sp. The objective was to evaluate the substitution levels of livestock urea (LU) by extruded urea (NFeed®) as sources of non-protein nitrogen in the diet of finishing feedlot steers. Twenty-four Nellore steers (Bos taurus indicus L.), with an average live weight (LW) of 394.60 ± 53 kg and an approximate age of 24 months, were used. The treatments were: diet 1 - 100% LU, diet 2 - 50% LU and 50% NFeed®, diet 3 - 25% LU and 75% NFeed®, and diet 4 - 100% NFeed®. The experimental design was completely randomized with four treatments and 6 replicates. There was a difference in the intakes of dry matter (DMI), organic matter (OMI), crude protein (CPI), ether extract (EEI), neutral detergent fiber (NDFI), and non-fibrous carbohydrates (NFCI) of the steers, with the highest averages (p