Peanut skin as a fed ingredient in dairy cow?s diet: Effect on milk yield, composition and antioxidant activity

MASIA FERNANDO; MARTINEZ LUQUE LUCIANA; LARRAURI MARIANA; MARIAN BELEN PEDRAZA

Kansas

Congreso; ADSA Annual Meeting 2022; 2022

ADSA

Peanut skin is a by-product from blanched processing of peanut kernels. Peanut skin is rich in tannins and phenolics compounds with antioxidant property that can be a source of natural antioxidant to be used as supplement in diets of dairy cows. The aim of this work was to evaluate the effect of feeding peanut skin to dairy cows and measure milk yield, milk solid composition, and antioxidant activity. Twelve Holstein cows, balanced by milk yield and parity, were randomly assigned to 2 treatments in two periods during the first 60 DIM: control (CON), fed a basal diet composed by alfalfa hay (8.5%), corn silage (49.5%), soybean expeller (20%), corn cracked grain (21%), and peanut skin (PS) fed a diet composed by alfalfa hay (6.8%), corn silage (48.3%), corn cracked grain (17.2%), soybean expeller (19.8%) and peanut skin (6.8%) as antioxidant supplement. Diets were formulated to balance energy (Mcal NEl/kg DM) and protein (g PM/ kg DM) contents in both groups. Milk yield was measured daily throughout all the experimental periods. Total protein and fat milk, dornic acidity, pH, phenolic compound, and SCC was measured once a week from individual milk samples. Data were analyzed using a mixed linear model with treatment, block and interactions as fixed effects, and time correlation effect for repeated measures. No differences in milk yield were observed (PS 27.39 and CON 26.81 milk L/d; P = 0.8698). Total phenolic concentration in milk was higher in PS (18.26 vs 16.62 mg GAE/mL; P = 0.0143). There were no differences between groups in pH and dornic acidity (PS 6.67 vs CON 6.63; P = 0.2281 and PS 17.8 vs. CON 18.06; P = 0.7884). Total solid compound (12.27 vs 11.46; P = 0.0010), fat and total protein milk (3.97 vs. 3.39; P = 0.0089 and 3.13 vs. 2.82; P = 0.0251 g/mL respectively) was lower in PS. Peanut skin can replace concentrates in diets without affecting milk production, but solids are probably affected due to tannins bioregulation of ruminal activity. In addition, PS antioxidant content was higher in milk so improve its functional properties as a healthy milk.