Effects of starch sugar by-product on rumen in vitro digestibility, in situ disappearance rate, and milking productivity of the lactating dairy cow

OBJECTIVE: The purpose of the present study was to determine the effects of starch sugar by-product (SSB) feeding on the rumen in-vitro digestibility, in situ disappearance rate, and lactating dairy cow. METHODS: To determine the rumen in vitro digestibility, 50 mL of the buffer-rumen fluid mixture was dispensed into a 125 mL serum bottle containing 0.5 g of dry matter (DM) of substrates. Nitrogen gas (N(2), 99.9% pure) was flushed into the serum bottles and three replications were incubated at 0, 2, 4, 8, 16, 24, and 48 h. To determine the in-situ disappearance rate, SSB was incubated for 0, 2, 4, 8, 16, 24, and 48 hours in nylon bags (5 × 10 cm, 45*m pore size) placed within the ventral sac of two cannulated Holstein cows.. A total of sixteen Holstein Friesian cows (60.5 ± 20.4 months old, 706.8 ± 3.4 kg initial body wieght) fed experimental diets during the experimental periods. The treatments were basal diet (control) and 3.0% DM of SSB, with the diet formulated according to national research council (NRC) nutrient requirements of dairy cattle guideline. An experiment was conducted with a randomized block design for six weeks based on body weight. RESULTS: Soluble fraction (fraction a) of DM and crude protein (CP) was 28.99 and 11.92%DM, fraction b of DM and CP was 44.63 and 31.61% DM, and c value of DM and CP was 26.38 and 56.47%DM. As an increase SSB level in total mixed ration (TMR), there was a decrease in gas production at 0, 16, and 48 h (p < 0.05). As an increase SSB level in TMR, there was a decrease in acetate to propionate ratio at 8, 16, 24, and 48 h (p < 0.05). Dry matter intake, milk production, and milk composition did not differ between the treatments. All blood profile contents did not differ between treatments. CONCLUSION: A diet containing 3.0% SSB could be fed to ruminants without adverse effects on rumen fermentation.