Relationship between Various Physical and Chemical Measurements on Barley Grain and its Nutritive Value Measured by in sacco and in vitro Methods

Abstract

Brand, T.S. and Swart, C.J., 1999. Relationship between various physical and chemical measurements on barley grain and its nutritive value measured by in sacco and in vitro methods. J. Appl. Anim. Res., 15:153–163.

One hundred samples of 2-row barley (Hordeum vulgare cv. Clipper) were randomly collected from producers in the Southern Cape Region of South Africa. The study was conducted to determine the variation in the energy content of the grain for pigs and, ruminants and to relate the variation encountered to the chemical and physical composition of the grain. The hectolitre mass of the grain used in the study ranged from 45 kg hl⁻¹ to 68 kg hl⁻¹, while the amount of screenings (<2.2 mm) varied from 7 g kg⁻¹ to 706 g kg⁻¹ . The digestible energy (DE) content of the grain, as determined for pigs ranged, from 15.1 to 16.6 MJ kg⁻¹ DM, while in vitro digestible organic matter (TVDOM) content of the grain ranged from 796 to 881 g kg⁻¹ OM. With regard, to the physical characteristics of the samples, the amount of screenings and, hectolitre mass predicted the DE content for pigs the best, accounting for 66% and 57% of the variation. Every 1 kg hl⁻¹ decrease in hectolitre mass resulted in a reduction of 0.06 MJ DE kg⁻¹ DM. The chemical fractions, crude fibre (CF) and acid detergent fibre (ADF), were the best correlated to DE content and were associated with, respectively, 56% and 46% of the variation in DE. Hectolitre mass accounted for 51% of the variation in the IVDOM content, while the amount of screenings was associated with only 33%. IVDOM was reduced by 2.5 g kg⁻¹ with every 1 kg hl⁻¹ decrease in hectolitre mass. With regard to the chemical fractions, CF accounted for 41% and ADF for 35% of the variation in IVDOM. It was suggested in the study that practical measurements like hectolitre mass and the amount of screenings can be used to give an indication of the energy content of the grain for pigs and, ruminants. Crude fibre and/or ADF contents can also be used to predict the energy content of the grain to a certain extent.

Key words:

• Barley
• energy content
• chemical composition
• physical characteristics
• pigs
• ruminants