Abstract

CORONA-PALAZUELOS, Melissa B. et al. Influence of tannin extract addition on the amount of nematodes found in feedlot calves at the beginning of the fattening process. Agrociencia [online]. 2016, vol.50, n.8, pp.1013-1025. ISSN 2521-9766.

The diseases caused by nematodes affect the health and productivity of feedlot calves. The consumption of plants containing tannins reduce the burden caused by nematodes in grazing ruminants, but there is little information related to how the addition of tannin extracts (TE) to the diet of feedlot calves diet affects the amount of nematodes. The objective of this study was to evaluate the influence of TE addition on the amount of nematodes in calves at the beginning of the fattening process. Experiment 1: Thirty Brahman calves (227±13.9 kg) were housed in six pens (6×12 m) with 24 m2 roof, 2.4 m feed bunker, and a 0.6 m water trough. The experimental design was completely randomized and the treatments were: 1) 0 % of TE (control), 2) 6 g kg-1 DM TE condensed (TC), and 3) 6 g kg-1 DM of hydrolysable TE (TH). Feces samples were collected: 3 d before and 3 d after administering the treatment for 28 d. The value of the eggs per gram of feces (EGF) was transformed to Log10 (n+40), and was analyze using ANOVA. The TH decreased the EGF of Haemonchus spp by 58 % (p=0.10). Experiment 2: Using results of Experiment 1 as a base, the number of experimental units was duplicated and was increased 2.5 times to test the absence of the effect of TH in the egg excretion of Cooperia. The experimental design was completely randomized and we used 40 Brahman calves (212±8.8 kg), kept in 8 pens. The treatments were as follows: 1)0% de TE (Control), and 2) 15 g kg-1 DM ofT H. The procedure was similar to experiment 1, the EGF values were transformed to Log10 (n+17), and an ANOVA was carried out. The addition of 15 g kg-1 DM of TH decreased (p≤0.05) the amount of EGF of Haemonchus sp and Cooperia sp, by 61 and 68 % respectively. The results suggest that including the hydrolysable tannin extracts into the calves’ diets could be a sustainable alternative for controlling nematodes like Haemonchus in feedlot cattle.

Keywords : Calves; tannin extracts; nematodes; fattening.

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