Global demand for animal proteins is foreseen to increase by 22% (Figure 1). Thus, one of the main challenges for 2050, in addition to meeting the high expectations in terms of food production, is facing the various issues which threaten food quality and safety, as well as land management and sustainable beef production. This will directly influence how we will raise and feed our animals to meet consumers needs.
Pasture production, adopting supplementation technologies, as well as an adequate pasture management, are tools for the production of “green” beef, which allows land use optimization, increased stocking rates as well as higher gain rates per area and individual. Among the technologies available for pasture supplementation, nutritional additives play a key role. Nutritional additives are chemical or natural substances such as antibiotics / ionophores and natural additives such as polyphenols. In general, the use of additives improves weight gain and feed conversion rates by 3 to 5%, by improving animal health and rumen function.
However, there is a growing demand for antibiotic-free animal protein production, either coming from direct consumer market or by government legislation. With these restrictions, which technological alternatives are left to the producer? The answer lies in nature, or better in plants, where research shows great potential for plant extracts, or rather tannins, as additives that may help improve animal performance and health (Mueller-Harvey, 2006).
Among these natural solutions, tannins stand out for their scientifically proven effects, which have an impact on feed intake, protein metabolism, ruminal function, and antimicrobial activities, working as ruminal flora modulator with reduction in enteric methane emissions.
The best-known effect of tannins is associated with their ability to complex proteins (Zelter et al., 1970), and reduce protein degradation by increasing the flow of metabolizable protein to the intestines (Mezzomo, et al. 2011), as well as lower rumen urea activity (Carrasco et al. 2017). All this allows nutritionists to manipulate diet formulas or supplements, reducing plant protein and increasing NNP usage, reducing formula costs. Carrasco et al. 2017, also observed a strong change and balance in the rumen microbiota, with a reduction in methanogenic bacteria and an increase in Firmicutes family bacteria, especially Ruminococcaceae bacteria, which are associated with higher energy efficiency. All these characteristics make tannins performing additives in protein / energy supplements for grazing animals, with superior results to antibiotics.
In this context, a field work was developed comparing the use of Monensin (MN) and Virginiamycin (VM), with Silvafeed® ByPro, a blend of plant bioactives, rich in tannins, specifically formulated for ruminants nutrition. Sixty Nellore cattle were used, 20 animals per treatment, in Brachiaria Brizantha pastures from May to September (dry season). The supplementation was protein based, with an estimated consumption of 0.1% live weight and 45% crude protein.
As shown in Table 1, the supplementation with Silvafeed® ByPro resulted in greater weight gains compared to MN and VM, respectively (0652 x 0.531 and 0.579 g / day), which represented significantly greater total gains (89.95 x 73.3 and 79.9 kg). Ingestion of Silvafeed® ByPro supplements as well as VM were similar, however MN did not reach the expected consumption, probably due to palatability.
Growth performance of animals was better in Silvafeed® ByPro group, which was 12% more than VM and 22% more than MN. These results demonstrate that ionophores or antibiotic additives can be replaced by this blend of plant bioactives, and it will provide better gains in the rearing of grazing calves with low protein supplements.
Another trial, assessing 465 commercial farm steers feeding on Brachiaria Brizantha pastures, during the rainy season, was focused on the comparison between an untreated control group and a group fed a Silvafeed® ByPro diet, at the finishing of grazing beef cattle. The feedlot included 465 Nellore or Nellore crossbred animals, with an initial average weight of 430 kg, distributed on 17 paddocks, and supplemented with 0.5% of the live weight of an energy protein supplement (25% CP), with or without the use of Silvafeed® ByPro.
The above results highlight the absence of interaction between treatment and breed groups. Silvafeed® ByPro treated steers showed higher daily and total weight gain than control (1,181 x 0.842 kg / d and 127.46 and 79.13 kg, respectively). These gain rates reflected significantly in higher final weight (548.74 x 517.04) and carcass weight (297.21 x 277.84 kg).
The inclusion, within the diet of grazing animals, of Silvafeed® ByPro, a blend of plant bioactives rich in tannins, proved to be an excellent natural solution to improve weight gain in the rearing and finishing of grazing beef cattle. Most of these effects can be attributed mainly to the improvement in protein utilization, as well as the better balance of the rumen microbiome, also causing greater digestibility of forage.