Abstract #W29

# W29
Survey of physical and chemical characteristics of sorghum silage in California.
J. Heguy*1, N. Clark2, D. Meyer3, 1University of California Agriculture & Natural Resources, Modesto, CA, 2University of California Agriculture & Natural Resources, Tulare, CA, 3University of California Davis, Davis, CA.

The aim of this study was to describe sorghum silage quality and density of silage in storage structures in California’s San Joaquin Valley. Silage in 15 structures was sampled (7 piles, 8 bags). Open faces were cored once during feed out. Each coring event consisted of sampling 3 pre-marked locations which were 0.25, 0.50, and 0.75 of the distance across the face at approximately 1.5 m above grade. Bags were cored twice at the 0.50 location, at approximately 0.30 m above the original core location, to ensure enough material for chemical analysis. Immediately upon removal of each 25.4 cm core sample, the sample was weighed and a small portion of silage from each core was used for pH determination. Within each structure, samples were pooled across coring locations for nutrient analysis (Table 1) and berry processing score (BPS). The overall density for each silage structure was calculated as an average of the coring locations. Descriptive statistics were calculated in Excel. Average density of sorghum piles was 609 kg of WW/m3, with a range of 432 to 705 kg of WW/m3. Bagged sorghum averaged 513 kg of WW/m3, with a range of 433 to 561 kg of WW/m3. Average sorghum silage pH was 3.9, with a range of 3.5 to 4.7. Berry processing score of sorghum, the percent of starch passing a 1.18mm screen, averaged 28%, with a range of 12 to 41%. Four of the 7 sorghum piles met the minimum density required (640 kg of WW/m3) by current California air district regulations (bagged silage is exempt). Variable BPS results may justify current recommendations to adjust starch availability to zero when incorporating sorghum silage into rations. There is a need to describe sorghum silage quality in California, as sorghum is a minor agronomic crop gaining interest due to water shortages and future water regulation. Table 1 (Abstr. W29). Sorghum nutrient composition (n = 15) in California’s San Joaquin Valley
DM %% of DMNDFD 30, % of NDF
CPADFNDFStarchNFCAsh
Mean29.38.533.949.113.128.911.748.9
Median29.78.934.247.710.129.310.948.6
Minimum22.85.628.442.21.415.38.932.2
Maximum35.211.841.359.429.341.214.557.5
SD3.41.84.35.28.27.91.86.6

Key Words: sorghum, silage, California