PSI-22 Effects of supplementing sugar beet processing by-products in low-quality forage diets on in vitro fermentation characteristics and dry matter digestibility

Abstract

Abstract Sugar beet processing by-products can be used to increase nutrient supply in beef cattle fed low-quality forages. However, information on the effectiveness of the different byproducts on modulating ruminal fermentation is still limited. Our objective was to determine the effects of providing supplemental molasses, concentrated seperator by-product, liquid feed-grade (32% purity) and crystalline betaine (97%) on in vitro fermentation and dry matter digestibility (IVDMD). A batch culture system was used to evaluate volatile fatty acid (VFA) production (3 h), pH (24 and 48 h), and IVDMD (24 and 48 h). A low-quality hay (7.5% crude protein; 58% total digestible nutrients) was used as a substrate and the inclusion level was 10% (dry matter [DM] basis) for all by-products except for crystalline betaine. Because it is a solid, a solution of crystalline betaine was made such that the betaine inclusion level was similar to that of feed-grade betaine. Data was analyzed using PROC MIXED in SAS. Total VFA concentration was lower (P < 0.01) for crystalline and liquid betaine compared to molasses and concentrated seperator by-product. Molar proportion of propionate was lower for concentrated seperator by-product (P = 0.04) than for the other treatments whereas the molar proportion of butyrate was lower (P = 0.04) for crystal betaine compared to molasses and concentrated seperator by-product. However, although pH was lower (P < 0.01) at 48 than 24 h, whereas DMD was greater (P < 0.01) at 48 than 24 h, there was no treatment effect (P ≥ 0.18) on pH and in vitro dry matter digestibility (DMD) at both 24 and 48 h. In summary, although adding different by-products from sugar beet processing resulted in changes in the VFA profile at 3 h of in vitro incubation, it had no effect on 24 and 48 h pH and IVDMD.