Effect of substituting steam winged bean tuber for cassava chips in the diet of Holstein Friesian dairy cows.

The winged bean tubers (WBT) are from leguminous plants abundant in protein (pods, seeds, leaves, blooms) and energy (roots), characteristics that makes them attractive as alternative feed sources in ruminant diets. With the use of steaming techniques to modify starch in WBT, the formation of resistant starch is enhances resistant starch formation and slows its ruminal digestion rate. This processing technique can serve as a cost-effective approach to feeding alternative feeds. The aim of this study was to assess the impacts of substitution cassava chips (CSC) with WBT steamed (WBTS) in the total mixed ration (TMR) of lactating cows. Sixteen multiparous Holstein Friesian lactating dairy cows (4 years old, 55 ± 20 days in milk, 490 ± 50 kg body weight) were used. Cows had a 21-day period of acclimation to stalls and rations, followed by a 60-day treatment period. Cows were fed twice daily a TMR that did not include WBTS (control group) or a TMR that contained 10% WBTS on a dry basis to replace CSC. The data were assessed as a completely randomized design using PROC GLM in SAS. The average daily intake of dry matter and crude protein was not affected (P > 0.05), and averaged 15.4 and 15.6 kg/day, including 13.1 and 13.2 kg/day, respectively. Feeding WBTS led to greater intake of neutral detergent fiber and acid detergent fiber (P < 0.01) but did not alter apparent total tract digestibility (P > 0.05). Ruminal concentration of ammonia-nitrogen and propionic acid (C3), and the level of plasma glucose were greater with WBTS. No difference was observed in the average milk output (19.7 and 19.9 kg/day). However, concentration of lactose was greater (P < 0.05) due to feeding WBTS. In conclusion, replacing CSC with 10% WBTS in the TMR may be a suitable strategy for maintaining optimal levels of milk production while enhancing fiber intake, ruminal C3, blood glucose, and milk lactose.