Sequential use of nutritional additives in diets for finishing Nellore steers in confinement.

The objective was to evaluate the effect of using prebiotics (Saccharomyces cerevisiae boulardii) or Monensin in the confinement initial phase and replacing monensin with probiotics (Bacillus toyonensis) in the final phase. Forty-eight Nellore steers were used, with an initial mean body weight of 356.2 ± 17.98 kg, distributed in a completely randomized design. Two animals per pen were confined in 80 m2 pens. The experiment was divided into two stages. The first phase lasted from day 1 to the 30th day, during which the animals were divided into two groups of 24 animals each. The treatments were the nutritional additives added to the diet: monensin or prebiotics (Saccharomyces cerevisiae boulardii). In the second phase, each group was subdivided into 12 animals by treatment, which received monensin or probiotics (Bacillus toyonensis). Dry matter intake (DMI), animal performance, and economic evaluation of the use of additives were evaluated. There was no additive effect on DMI, average daily gain, and total weight gain of the animals in the first experimental stage (0-30th day). Likewise, in the second stage (31st-100th day), there was no treatment effect for the variables of intake and performance. There was no effect of the use of different nutritional additives on carcass characteristics. The use of prebiotics sequentially to probiotics promoted gross and net yield that was superior to that of the animals that consumed monensin. Yeasts and bacteria respectively in the first and second phases of confinement can replace monensin in confinement diets.

Effect of whole oilseeds in the diet on bacterial diversity in the solid fraction of the ruminal content of steers.

Our hypothesis was that different whole oilseeds included in the diet for steers confined could alter the diversity of rumen bacteria compared to a diet without oilseeds or an exclusively forage diet. It was aimed to evaluate the effects of oilseeds inclusion in the diet on bacterial diversity in the solid fraction of the ruminal content of steers, by gene sequences of the conserved 16S rDNA region. Six crossbred steers castrated males, fitted with ruminal cannula were used in a 6 × 6 Latin square design, using 21-day period. At the start of the experiment, the live weight of the animals averaged 416 ± 9.7 kg (mean ± SD). A total of 2,180,562 16S rDNA sequences were generated for the Bacteria domain by MiSeq sequencing. The bacterial diversity was composed of 24 bacterial phyla, with the most abundant being Firmicutes, Bacteroidetes, and Proteobacteria. Other phyla with less diversity were also identified including Eurychaeota, Tenericutes, SR1 Absconditalbacteria, Synergistetes, Actinobacteria, Saccharibacteria, Elusimicrobia, Cyanobacteria, Verrucomicrobia, Fusobacteria, Lentisphaerae. The similarity in the bacterial community averaged 50% for all the experimental diets. Steers-fed corn silage exhibited a great diversity of bacteria of the Firmicutes phylum. The steers-fed oilseeds in the diet had a great diversity of bacteria from the phylum Bacteroidetes and Proteobacteria. The inclusion of whole oilseeds in the steer diets can alter the rumen bacteria population by up to 50% of total diversity.

Bacterial species in the ruminal content of steers fed oilseeds in the diet.

The aim of this study was to evaluate bacterial species and diversity of methanogenic Archaea in the solid fraction of the ruminal content, through the gene sequences of the conserved 16S rDNA region, in response to the following diets: canola, cottonseed, sunflower, soybean, corn silage, and control diet. Six rumen-fistulated crossbred steers, with body weight (BW) of 416.33 ± 93.30 kg, were distributed in a 6 × 6 Latin square design. Regardless of the diet provided, amylolytic, proteolytic, and lactic bacteria were identified in the rumen fluid. Cellulolytic bacteria were predominant for all diets, reaching 47.75% of operational taxonomic units (OTUs) in animals fed with the cottonseed diet. Amylolytic bacteria reach 62.51% of OTU in animal fed sunflower diet, while proteolytic bacteria correspond to 65.96% of OTU in this same diet. Also, Megasphaera elsdenii bacterium was identified for all diets, with a greater percentage of OTU in steers fed the cottonseed diet. The diversity analysis of the species identified the methanogenic Archaea Methanobrevibacter ruminantium in all diets. We conclude that the control and corn silage diets have the most similar bacterial flora; diets with oilseeds had 47.5% similarity in rumen flora bacteria species. Animals fed with soybean showed a reduced number of methanogenic Archaea in the rumen content, which could be an alternative feed for cattle due to their low potential for energy losses with the production of methane.

Characterization and in vitro evaluations of Baru pulp from almond production waste ensiled with different additives.

The silage process is an efficient way of storing nutrients for animal nutrition. Our hypothesis was that the Baru pulp can be preserved in the form of silage, regardless of the use of additives to aid the process. Silages of Baru pulp containing different additives were evaluated through in vitro analysis, fermentation parameters, and composition and thermal analysis including differential scanning calorimetry and thermogravimetry. The treatments consisted of (1) silage with Baru pulp (BP) in natura without additive; (2) BP in natura with acetic acid; (3) BP in natura with formic acids; and (4) BP in natura added with microbial inoculums in a randomized experimental design with three replications per treatment and analyzed in duplicate. The ensiled material was kept in anaerobic conditions for a period of 30 days. BP before and after the silage process presented averages of 67.31 and 66.24% for in vitro digestibility of DM (IVDMD). Microbial inoculant additive was the most effective in reducing pH, followed by acetic acid and formic acid. There were effects of additives on silages for all degradation parameters in ruminal liquid in vitro. It was observed that BP before ensiling had the highest A fraction (7.9 mL gas/100 mg DM), without differing from the silage treated with formic acid (7.1 mL gas/100 mg DM). Similar effects were observed on mass loss (TG) and heat flux (DSC) between the silages. Our findings suggest that Baru pulp with formic acid is more efficient in the conservation and preservation of fermentable carbohydrates as well as in silage production.

Effect of injectable trace mineral at weaning on growth and physiology of Nellore calves under feed restriction.

Calves are susceptible to a wide variety of stressors besides the seasoning low forage availability during their weaning phase. Thus, it is ideal if they receive adequate trace mineral supplementation during this period. This study evaluated the effect of injectable trace minerals (ITM) on performance, concentration of oxidative stress enzymes, and biochemical plasmatic parameters in Nellore calves during the weaning phase and under feed restriction. A total of 30 Nellore calves were used at the age of 7 ± 1 month and 176.23 ± 21.68 kg of initial body weight (BW). These animals were allocated in Urochloa decumbens pasture for 28 days and transferred to Urochloa brizantha cv Marandu pasture for another 28 days. The treatments were: Saline (saline solution; 0.9% NaCl) and ITM (Multimin®, providing: 15 mg Cu/mL, 60 mg Zn/mL, 10 mg Mn/mL, and 5 mg Se/mL). Both treatments were applied subcutaneously in the ratio of 1 mL/45 kg of BW. At the end of the experiment (d 56), animals were lighter than on d 0 in both treatments (P < 0.05). However, calves that received the ITM treatment presented lower body weight (P < 0.05) on d 56, compared to those in the control group. No significant difference (P > 0.05) was observed on the concentrations of oxidative stress enzymes. Moreover, no significant difference (P > 0.05) was observed in the plasmatic parameters; these were at normal range or slightly below the concentrations described for the species. We concluded that, in a feed restriction condition, the use of ITM in weaned calves did not improve performance, and the concentration of oxidative stress enzymes, and biochemistry variables. Therefore, we do not recommend using injectable trace minerals in the concentrations used in this study in animals under such stressful conditions.