Abstract #T375
Section: Ruminant Nutrition
Session: Ruminant Nutrition: Beef II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
Session: Ruminant Nutrition: Beef II
Format: Poster
Day/Time: Tuesday 7:30 AM–9:30 AM
Location: Gatlin Ballroom
# T375
Effects of starch content and processing method on in situ rumen digestibility of barley grain in beef heifers.
Yanli Zhao1,2, Sumei Yan2, Uchenna Y. Anele1, Mary-Lou Swift3, Tim A. McAllister1, Wenzhu Yang*1, 1Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada, 2College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China, 3Alberta Agriculture and Rural Development, Lethbridge, AB, Canada.
Key Words: barley starch content, in situ rumen digestion, beef heifer
Effects of starch content and processing method on in situ rumen digestibility of barley grain in beef heifers.
Yanli Zhao1,2, Sumei Yan2, Uchenna Y. Anele1, Mary-Lou Swift3, Tim A. McAllister1, Wenzhu Yang*1, 1Lethbridge Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada, 2College of Animal Science, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China, 3Alberta Agriculture and Rural Development, Lethbridge, AB, Canada.
The inherent variability in barley chemical composition leads to differences in animal performance. The objective of this study was to investigate the effects of starch content of barley grain and processing method on in situ rumen digestion of DM and starch. Barley samples (n = 120) were collected monthly from 10 feedlots in Southern Alberta for one year. Samples were ranked according to their starch content into low (<60%) and high (>60% of DM). Ten barley samples with 5 low (57.1 ± 1.7%) and 5 high (66.0 ± 0.7% of DM) starch were either ground 2 mm or dry-rolled with processing index (PI) of 75% (PI = 100 × bulk density processed/bulk density whole). Three beef heifers (650 BW) fitted with rumen cannulas and fed diet consisting of 70% barley silage and 30% barley grain were used for in situ incubation. The study was arranged in a 2 (low and high starch) × 2 (ground and rolled) factorial design. Digestion kinetics of DM after 0, 3, 6, 12, 24, and 48 h of incubation was estimated using the model: y = a + b(1-e-ct). Effective rumen digestibility (ED) was estimated using ED = a + bc /(c + k) with k = 6%/h. Particle size distribution of rolled barley differed between low and high starch barley; the particles retained on the 3.35-mm sieve was less (17.8 vs. 25.3%; P < 0.01) but the particles on 2.36-mm sieve was greater (40.5 vs. 32.1%; P < 0.01) for low vs. high starch barley. Starch content × processing interactions were not noted. Low starch barley had less (P < 0.01) a (12.2 vs. 14.8%) and ED of DM (60.4 vs. 64.8%) versus high starch barley. The low starch barley also had less (P < 0.01) a (14.2 vs. 23.1%) and ED of starch (68.4 vs. 74.6%) but had greater (P < 0.03) b (75.5 vs. 70.5%) compared with high starch barley. As expected, rumen digestion kinetics of DM and starch differed between ground and dry rolled (PI = 75%) samples. Ground samples had greater (P < 0.01) a (21.6 vs. 5.4%), c (33.1 vs. 10.1%/h) and ED (71.6 vs. 53.6%) of DM but smaller b (59.8 vs. 77.8%; P < 0.01) compared with rolled barley. These results indicated that starch content of barley grain and manipulating processing method could effectively alter rumen digestion of barley grain.
Key Words: barley starch content, in situ rumen digestion, beef heifer
