Comparison of Nellore and Bos taurus × Nellore beef crosses at the same age on performance, carcass characteristics, and fecal starch content

Objective: Our objective was to evaluate the performance, carcass characteristics, and fecal starch content of castrated Nellore and Bos taurus x Nellore crossbred cattle raised on the same plane of nutrition from birth until slaughter. Materials and Methods: Forty-seven steers of similar age (22 mo +/- 23 d) and BW (310 +/- 30 kg) were divided into 4 genetic groups: 1/2 Angus + 1/2 Nellore (AN), 1/2 Canchim + 1/2 Nellore (CN), Nellore (NL), and 1/2 Simmental + 1/2 Nellore (SN). Diet contained 13.34% CP, 9.35% RDP, 18.18% of starch on DM, and 68.69% TDN. Results and Discussion: There was no difference in BW at the beginning of the feedlot period between AN and SN steers. However, AN were heavier than NL and CN. Groups AN and SN had the highest ADG (P < 0.0001), and AN had the highest DMI (kg/d and % of BW; P < 0.0001). The AN and SN steers had the highest initial-slaughter and final carcass weights. Group AN had higher fat thickness (P = 0.02) than the CN, NL, and SN groups but lower loin eye area. Group SN presented the lowest fecal starch content (P = 0.04), which suggests greater ability to use starch when compared with NL, AN, and CN groups. Implications and Applications: British Bos taurus x Nellore crosses allow for better performance and carcass finishing than purebred Nellore steers. Steers with a higher percentage of Zebu blood may have less ability to digest starch.