Avaliação de taninos na dieta de vacas em lactação

Abstract

Five crossbred Dutch / zebu cows were distributed in a 5 × 5 latin square. In order to evaluate the effect of tanninipherous diets based on sorghum (Sorghum bicolor sorghum (l.) Moench) (condensed tannin) and increasing levels of tannic acid (hydrolyzable tannin) on intake, digestibility, milk production, blood parameters, N balance and protein production microbial lactating cows. The diets contained 35 kg of corn silage as roughage and 6.38kg of concentrate. The diet 1 (control) contained sorghum contained sorghum cultivar black tip, which was replaced on the other diets by sorghum cultivar A9904. The tannic acid levels added to diets were based on analysis of the condensed tannin amount constituent in A9904 sorghum cultivar. In this way, in the diets 2, 3, 4 and 5 was added 1.5, 79.5, 157.5 and 235,5g of tannic acid respectively. Natural and dry matter consumption did not differ (P> 0.05) between treatments. The consumption as a function of body weight did not differ (P> 0.05) for DM and NDF and differed significantly (P <0.05) for EE. The apparent digestibility of DM, CP, EE, NDF, and NFC, CHOT did not differ (P> 0.05) with increasing dietary tannin. To all blood parameters analyzed only the AST and hemoglobin levels showed significant differences (P <0.05). The urinary excretion of urea, allantoin and derivatives of purine absorbed purine, N-microbial synthesis and allantoin concentrations in the milk did not differ. The N balance was positive and did not differ (P> 0.05) between treatments. The average creatinine excretion was 72.16 mmol / day, and increased linearly (P <0.05) between diets evaluated with minimal point of 59.23 mmol / day and a maximum of 83.05 mmol / day. No toxic effects were observed with the addition of tannin in diets. The levels of AST (Aspartate transaminase) have a linear behavior (with a minimum point of 72.29 U / L and maximum 84.60 U / l), without however presenting toxicity. The inclusion of tannin in the diet did not cause depression in the intake or digestibility. The inclusion of tannin in the diet did not cause depression in the effective consumption or digestibility of animal, and as little significant effects on the animals blood parameters, indicating that the cows health was not depreciated. Milk production was decreased linearly on average 0.350 kg as increased tannin inclusion in the diet.