The effects of partial substitution of soybean with urea or slow-release urea on finishing performance, meat quality, and digestion parameters of Nellore steers

Abstract

The effects of substituting ~50% of the soybeans in the diet of finishing Nellore steers with either urea (U) and/or slow-release urea (SRU) on the steer performance and meat quality were assessed in two experiments. In the first experiment, 46 Nellore steers in a 104-day experiment (Exp. 1) were fed a Control diet with U or SRU or U+SRU. In Experiment 2 (Exp. 2), digestibility and microbial protein (MCP) synthesis were assessed in four steers by using a 4 × 4 Latin square design with 21-day periods. Four corn-based diets were used in both Exp. 1 and 2. (1) Control (CTL): 0% of non-protein nitrogen (NPN). (2) U: 1.66% of NPN. (3) SRU: 1.8% of NPN. (4) U+SRU: 1.72% of NPN. In Exp. 1, final bodyweight, average daily gain, dry matter intake, Gain to Feed ratio, carcass traits and steer meat quality were not influenced by the experimental diets. In Exp. 2, the apparent digestibility was similar for all diets, and the MCP synthesis was affected by dietary treatments (P = 0.065). The NPN treatments showed 25.5% more (P = 0.03) MCP efficiency (g microbial protein/kg of total digestible nutrient content consumed) than the CTL. We conclude that the partial replacement of SBM with U, SRU or U+SRU will provide similar animal performance without negatively impacting carcass and meat quality and improve the efficiency of microbial protein synthesis in Nellore cattle.

Ruminal fermentation and digestion of cattle diets with total and partial replacement of soybean meal by a slow-release urea product

“…Since the values of the ruminal digestibility are related to the availability of N during the ruminal fermentation, it can be inferred that U+SRU+AA was similar to SBM for the total N release for the ruminal bacteria as no differences were observed for the ruminal digestibility of N among the different sources of N. In addition, the lack of effects observed for the intestinal digestibility of the nutrients showed that the changes in the proportion of the non-protein N of the diets did not cause changes in the nutrient digestion after the abomasum. Therefore, the microbial protein likely met 100% of the metabolisable protein required by the steers (Benedeti et al 2014;Corte et al 2018). Similar to our data, Giallongo et al (2015) found no effect of the SRU supplementation and the SRU plus rumen-protected methionine on the NDF digestibility, the feed intake or the milk production and the quality in the dairy cows.…”

“…Slow-release urea (SRU) products to reduce the rate of ammonia release from U are currently available. Substantial research has been developed to evaluate the effects of these SRU products (Chegeni et al 2013;Benedeti et al 2014;Giallongo et al 2015;Gardinal et al 2017;Corte et al 2018) in cattle. Previous studies found that although SRU released more N than soybean meal (SBM), which induced a higher ammonia N concentration in the rumen, SRU can replace SBM in diets without affecting the growth performance of beef steers or milk production of dairy cattle (Pinos-Rodriguez et al 2010a;Pinos-Rodriguez et al 2010b).…”

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

“…In this experiment, the authors observed no significant differences in DMI in treatments (P >0.05) (Table 3), though DMI was higher in the cows fed diets containing SRU. Corte et al (2018) conducted the same research in Nellore steers and observed no difference in DMI. In contrast, Galina et al (2003) conducted similar research on sixty zebu steers and reported that supplementing 1.8 g/kg DM SRU improved DMI and digestibility.…”

Effect of soybean meal replacement by slow-release urea on ruminal parameter, blood metabolites, and microbial protein synthesis in Zel ram

“…When energy is available, the final products of protein breakdown (peptide, amino acid and NH 3 -N) can be used to make the microbial protein (Bach et al, 2005). It seemed that microbial protein increase in treatment 4, is due to slow and continuous release of nitrogen from SRU (Corte et al, 2018). Therefore, the ruminal NH 3 -N concentration has an impact on MPS, and a synchrony of these processes would improve the efficiency of NPN incorporation into microbial protein and thereby improving the overall efficiency of N use.…”