Evaluating the Addition of Water to a Barley-Based Finishing Diet on Feed Sorting Behaviour, Digestibility, Steer Performance, and Carcass Characteristics
Date
2025-01-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0003-5085-0935
Type
Thesis
Degree Level
Masters
Abstract
The objectives of the studies within this thesis were to evaluate the effects of adding water to a dry-rolled barley grain-based finishing diet on dry matter intake (DMI) and feed sorting behaviour. In Chapter 3, 8 ruminally cannulated beef steers (341.5 ± 25.1 kg starting body weight (BW)) were used in a study designed as a replicated 4 × 4 Latin square, with 21-d periods consisting of 16 d for diet adaptation and 5 d for data and sample collection. Chapter 4 utilized 120 beef steers (331.0 ± 31.0 kg starting BW) that were stratified by BW and randomly assigned to 1 of 20 pens (6 steers/pen, 5 pens/treatment) in a finishing growth performance study lasting 150 to 181 d. Dietary treatments for both studies included water at 0% (CON), 10% (10W), 20% (20W), and 30% (30W) relative to the barley grain weight. Both studies used barley-based finishing diets consisting of (dry matter (DM) basis) barley grain (88%), barley silage (7.7% in Chapter 3, 9.6% in Chapter 4), mineral and vitamin premix (4.1% in Chapter 3, 2.4% in Chapter 4), and titanium dioxide (0.2% in Chapter 3 only). The major difference between experiments was that Chapter 3 utilized aggressively processed barley grain with a processing index (PI) of 62.2 ±2.1% and 3.2 ±1.0% percent fines, whereas the barley grain in Chapter 4 had a PI of 84.2 ± 3.4% and 2.1 ± 1.0% percent fines. In Chapter 3, increasing water inclusion linearly increased DMI and water intake (P < 0.01 and P = 0.04, respectively). As water inclusion increased, the sorting index for the pan approached 100% (P < 0.01) indicating that steers consumed more fine particles. The increase in DMI and fine particle consumption led to linear decreases for mean (P < 0.01) and maximum ruminal pH (P = 0.02), and linear increases for the duration that ruminal pH was <5.5 (P = 0.02) and the ruminal lipopolysaccharide concentration (P < 0.01). In Chapter 4, DMI, average daily gain, and the gain:feed ratio were not affected by water inclusion (P ≥ 0.46). Sorting index values for particles retained on the 19-, 4-, and 1.18-sieves, and the pan were quadratically affected by the addition of water (P ≤ 0.02) such that the magnitude of the sorting decreased (values moved towards 100%) at a decreasing rate as water inclusion increased. Carcass characteristics (hot carcass weight, cold carcass weight, dressing percentage, and ribeye area) did not differ among treatments (P ≥ 0.15). However, increasing water linearly reduced variability within a pen for marbling scores (P = 0.05). Collectively, these results are interpreted to suggest that adding water to a barley-based finishing diet may be an effective strategy to reduce feed sorting behaviour without altering digestibility, thereby reducing the variance for carcass marbling scores.
Description
Keywords
cattle, beef, barley grain, sorting behaviour, feedlot diet, metabolism, feedlot, carcass characteristics
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science