Abstract The study aimed to evaluate tannic acid's influence on lactating cows' diets on milk production and lipid composition. Five crossbred cows (Holstein x Zebu), distributed in a 5 × 5 Latin square, were used to evaluate the effect of increasing tannic acid (hydrolyzable tannin). The diets were composed of 35 kg of corn silage as bulking and 6.38 kg of concentrate. The treatments consisted of increasing levels of tannic acid added to diets (0%, 1.3%, 2.6%, 3.9% and 5.2%). It was observed a decreasing linear effect (P<0.05) of the inclusion of tannic acid in the concentration of saturated butyric fatty acids (C4:0) presenting a mean of (2.99), and quadratic effect in the concentration of saturated fatty acids lauric (C12:0) presenting mean (26.74). The addition of tannic acid had effects on saturated fatty acids, decreasing the concentrations of butyric acid and increasing the concentrations of lauric acid. Atherogenicity and thrombogenicity rates reveal the potential for the prevention of coronary heart disease. However, the observed changes do not compromise the milk's chemical composition and nutritional quality,the y nutritional quality of the milk, presenting possibilities of human health benefits, thus enabling the aggregation of value for these products.

Abstract The study aimed to evaluate the effect of adding tannic acid to the diet on the milk quality of cows. The five primiparous crossbred cows (Holstein x Zebu) were used, with about four years old, the average body weight of 420 ± 30 kg, 100 days of lactation initial average production of 18 ± 4 kg of milk/cow/day. The treatments consisted of increasing tannic acid (0; 1.3; 2.6; 3.9 and 5.2%) to replace corn bran in the diet, based on dry matter. The sensory attributes of odor had a significant effect (P < 0.05) of the inclusion of tannic acid in the diet. The odor attributes showed a lower average for the control treatment, and these attributes also showed orthogonal contrast, except the characteristic cow, that is, the control group differed from the treatments as the tannin was introduced, the attribute value became higher compared to the control group. The inclusion of 5.2% tannic acid in dairy cows’ diet promoted a slight variation in the taste of milk. However, it did not alter the quality or acceptance of this milk by consumers.