EVALUATION OF BARLEY GRAIN PROCESSING METHOD AND SEVERITY OF PROCESSING ON FINISHING CATTLE PERFORMANCE, CARCASS CHARACTERISTICS, STARCH DIGESTIBILITY, AND ECONOMIC VALUE
Date
2024-01-25
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0009-5104-9908
Type
Thesis
Degree Level
Masters
Abstract
The objectives of this research were to evaluate the effects of barley grain processing methods and severity on feed intake, ruminal fermentation, and digestibility, growth, and carcass characteristics. For Study 1, a total of 420 steers (initial BW ± SD; 375 ± 26 kg), blocked by BW, were randomly assigned to 1 of 4 treatments (15 steers/pen) in a 111-d finishing study. Steers were transitioned to a diet containing either: 1) dry-rolled barley (DR; 522.1 g/L); 2) temper rolled barley (TR; 539.7 g/L); or 3) steam-flaked barley at a moderate (MF; 361.0 g/L); or 4) coarse flake densities (CF; 450.3 g/L). Dry matter intake, average daily gain (ADG), fecal starch, and carcass data were collected. For Study 2, five ruminally cannulated heifers were used in a 5 × 5 Latin square design with 21-day periods. Each period consisted of 17 d for dietary adaptation followed by 4 d of sample and data collection. Treatments included a dry-rolled barley with a processing index of 72% (CON) or barley that was steam-flaked by conditioning at 95ºC for 5 min and passed through a roller mill to achieve a thin (5THIN; 285 g/L), moderate (5MID; 339 g/L), or coarse flake (5C, 466 g/L). The final treatment was conditioned for 20 min at 95ºC and flaked to yield a thin flake (20THIN; 272 g/L). In Study 1, feeding MF (10.8 kg/d) and CF (11.6 kg/d) decreased DMI relative to DR (12.7 kg/d) and TR (12.7 kg/d). Steers fed MF had lesser ADG (2.16 kg/d; P = 0.009) relative to DR (2.34 kg/d) and TR (2.30 kg/d), while CF (2.28 kg/d) was intermediate but not different. The G:F was greater for MF (0.201 kg/kg; P < 0.001) and CF (0.197 kg/kg) than for DR (0.185 kg/kg) and TR (0.181 kg/kg). Estimated starch digestibility was greatest for flaked treatments, intermediate for DR, and least for TR. Carcass characteristics were not affected except for a greater marbling score (P= 0.002) for DR relative to all other treatments. In Study 2, no differences were observed among treatments for dry matter intake (DMI), mean, minimum, or maximum pH. A linear increase in duration that pH was < 5.5 was detected with decreasing flake density (P = 0.029). A quadratic relationship (P = 0.044) was detected for area that pH was <5.5. Total short chain fatty acid (SCFA) concentration was not affected by steam flaking or conditioning duration, but there was a quadratic response for the molar proportion of propionate with increasing flaking density, with the 20 minute thin and 5 minute thick flakes creating the highest molar proportion of propionate and the other two (5THIN and 5MID) being more moderate. Total tract digestibility was not affected by treatment. Based on the results of this research, steam flaking barley may reduce DMI, likely due to greater ruminal digestibility. However, steam-flaking conditions that result in a coarse flake may improve gain to feed (G:F) without compromising carcass weight or carcass characteristics.
Description
Keywords
Barley grain, Grain processing, Carcass characteristics, steam flaking
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science