Effect of extracts from baccharis, tamarind, cashew nut shell liquid and clove on animal performance, feed efficiency, digestibility, rumen fermentation and feeding behavior of bulls finished in feedlot

Abstract There is a growing public concern on the use of antibiotics and ionophores in livestock and emerging antimicrobial resistance. Plant extracts and essential oils are natural alternatives having antimicrobial and antioxidant properties. This study evaluated the effects of a mixture of baccharis (Baccharis dracunculifolia) leaves and stems, tamarind (Tamarindus indica L.) seed, cashew (Anacardium occidentale) nut shell liquid, and clove (Syzygium aromaticum) essential oil on animal performance, feed intake, feed efficiency, apparent digestibility, molar concentration of volatile fatty acids and feeding behavior of bulls finished in the feedlot and fed high-grain diets. A total of 32 bulls (½ Angus vs. ½ Nellore) with a mean age of 24 ± 2.0 months and a mean body weight of 418 ± 4.51 kg were distributed in a completely randomized design with four diets and eight replications per diet. The four experimental diets were as follows: CONT – basal diet; MIX2 – basal diet and 2 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX4 – basal diet and 4 g/animal/d of extracts from baccharis, tamarind, cashew nut shell liquid, and clove; MIX6 – basal diet and 6 g/animal/d of extracts from baccharis, tamarind, cashew nut liquid shell liquid and clove. Animal performance, dry matter, and other nutrients intake were similar among diets. Dry matter, neutral detergent fiber, and organic matter digestibilities were greater for the MIX2 when compared to other diets. There was an increase in propionate and a decrease in the acetate/propionate ratio when MIX6 was used. A similar effect was observed when orthogonal contrasts comparing the CONT diets with the addition of MIX was used. Feeding behavior was similar among the four diets. Our findings indicated that supplementation of baccharis, tamarind, cashew nut shell liquid, and clove oil (2, 4, and 6 g/animal/d) may be fed to beef cattle once it showed no adverse effects on feed intake and nutrient digestibility. Moreover, it was observed a higher concentration of propionate, a reduction in acetate/propionate ratio, and a greater digestibility of dry matter, neutral detergent fiber, and organic matter. However, more studies should be carried out to determine the effect of higher levels of MIX aiming to use it as a feed additive to improve animal performance and ruminal fermentation in beef cattle finished in feedlot.