Okara meal can completely replace soybean meal in diets of early to mid-lactation dairy cows

Abstract Text: Okara meal is a byproduct from the production of soy milk and tofu that can potentially replace soybean meal due to its high CP concentration. We aimed to evaluate the effects of okara meal as a replacement for soybean meal on performance and plasma concentration of metabolites in lactating dairy cows. Twelve multiparous (65 ± 33 DIM; 451 ± 45 kg of BW) and 8 primiparous (100 ± 35 DIM; 370 ± 51 kg of BW) Jersey cows were used in a crossover design with 21-d periods (14 d for diet adaptation and 7 d for data and sample collection). Diets were fed as TMR and formulated to be isonitrogenous and isofibrous and contained (DM basis) 50% grass-legume baleage, 2% liquid molasses, 2% minerals-vitamins premix, and: 1) 8.1% soybean meal, 10% soyhulls, and 27.9% corn meal (SBM treatment); 2) 15% okara meal, 8% soyhulls, and 23% corn meal (OKM treatment). The dietary nutrient composition averaged 15.4 vs. 15.9% CP, 35.3 vs. 36.3% NDF, and 24.1 vs. 24.1% ADF for SBM and OKM, respectively. Cows were fed and milked twice daily, and milk (d 15-16) and blood (d 16-17) samples were collected and analyzed for components and plasma metabolites [AA, urea-N (PUN)], respectively. Results are shown in Table 1. No significant differences were observed for DMI (mean = 18.0 kg/d), milk yield (mean = 20.7 kg/d), 4% FCM (mean = 24.2 kg/d), and ECM (mean = 26.0 kg/d) in cows fed SBM or OKM. Whereas milk fat concentration was not affected by treatments, milk true protein concentration was greater (P = 0.02) in cows fed SBM than OKM. Yields of milk fat and true protein did not differ significantly between treatments and averaged 1.06 and 0.78 kg/d, respectively. However, MUN (P < 0.01) and PUN (P = 0.03) were greater in cows fed SBM compared with those fed OKM suggesting an improvement in N use efficiency. Plasma concentrations of Met, Lys, and His did not differ significantly in cows fed SBM or OKM. Conversely, the plasma concentration of Leu was greater (P = 0.02), and that of total EAA tended (P= 0.09) to be greater in cows offered SBM vs. OKM, which may explain the observed increase in milk true protein concentration when feeding SBM. Overall, replacing soybean meal with okara meal maintained animal performance and appeared to improve N use efficiency.

Keywords: dairy cows, okara meal, soybean meal