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The objective was to evaluate the associative effect of monensin sodium to virginiamycin on the performance, dry matter intake, apparent digestibility and ingestive behavior of steers in the initial feedlot phase. The experiment lasted for 30 days, divided into two experimental periods. Thirty-six Angus Nellore steers, non-castrated, with a mean age of 10 months and an average weight of 300 kg, were divided into 18 pens. Animals were assigned to three treatments with six replications each, with the inclusion of the following additives: T1-monensin sodium, dose of 200 mg day-1; T2-monensin sodium, dose of 125 mg day-1 + virginiamycin, dose of 125 mg day-1; and T3-monensin sodium, dose of 200 mg day-1 + virginiamycin, dose of 125 mg day-1. All experimental procedures were previously submitted to the UNICENTRO Committee for Ethics in Animal Experimentation (CEUA), and were approved for execution (Official Letter 021/2019). The combination of monensin sodium with virginiamycin at a dose of 200 mg + 125 mg animal day-1 showed greater (P < 0.05) average daily weight gain (1.919 kg day-1) and better feed conversion (4.27 kg DM kg of weight gain-1) compared to diets with monensin alone (200 mg animal day-1) or monensin combined with virginiamycin (125 mg + 125 mg animal day-1), even with no significant (P> 0.05) difference in DM intake, with a mean value of 7.88 kg animal day-1. Regardless of the isolated or combined supplementation of the additives, no significant differences were detected in the analysis of the feeder and feces scores, ingestive behavior, and rectal temperature or infrared thermography during the evaluation period. The combination of monensin sodium with virginiamycin at 200 mg + 125 mg animal day-1 proved to be efficient in the initial feedlot period, determined by the greater weight gain and better feed conversion observed in this study.

he objective of this study was to evaluate the production and physical composition of three maize hybrids (Zea mays, L.) for silage production at six maturity stages. The hybrids evaluated were Maximus VIP3, Defender VIP and Feroz VIP. The experiment was conducted in a completely randomized block design with four replicates. The mean plant heights observed at harvest time (2.33 m, 2.45 m and 2.40 m) demonstrated that all materials were medium-sized hybrids. A positive correlation was observed between plant height and height of the ear insertion, varying from 0.86 for the Feroz VIP hybrid to 0.88 for the Maximus VIP3 hybrid, but these two variants had no correlation with the productivity data. There was a significant difference for the production of fresh biomass at the R1, R2 and R5 stages, with Maximus VIP3 obtaining the highest yields. The proportion of grains in the physical composition of plant varied between hybrids, where Maximus VIP3 and Defender VIP (482.2 and 461.7 g kg-1, respectively) were superior to Feroz VIP (429.7 g kg-1). With the advancement of maturity, there was a decreasing linear behavior for stem and leaf participation, with reductions of 3.8 g kg-1 and 4.5 g kg-1, respectively, per day (R2 = 0.79 and 0.80, respectively), quadratic behavior for bracts and corncob and a linear increase in grain participation in the plant structure, with an increase of 7.7 g kg-1 per day (R2 = 0.88). In general, the three hybrids present good characteristics for silage production and permit harvesting in the hard grain stage, allowing the addition of starch in relation to the farinaceous grain stage.

The Brazilian livestock activity is undergoing constant evolution, and aiming at its maximum efficiency, it is necessary to have available to the animals food in quantity and quality all the year. To this end, the cultivation of winter forage is carried out. The present study aimed to evaluate the productive and qualitative agronomic traits of ryegrass forage. The experiment was a randomized block design in a 3 x 2 factorial arrangement consisting of six treatments, three plant stands (525, 1050 and 2095 plants m-2) associated with two successive cutting times (vegetative and full vegetative), and four repetitions. There was no interaction between population stand and cutting times for the variables studied. The stand of 525 plants m-2 had a higher participation of green leaves (50.52 %), higher digestibility of the whole plant dry matter (84.81 %) compared to the stands of 1.050 and 2.095 plants m-2, and dry biomass production per unit area equivalent to the others (6087, 7243 and 6989 kg ha-1, respectively). The first harvest season presented higher participation of green leaves and better leaf/stem ratio, 58.62 % and 3.41 % respectively, as well as higher digestibility of green leaves (77.26 %) and stem (80.82 %).

The objective of this study was to evaluate the productive performance, ingestive behavior, apparent digestibility of the diet, rectal temperature, superficial thermography of skin and hull, and the carcass traits of heifers finished in confinement under the effect of inclusion of live yeasts (Saccharomyces cerevisiae as probiotic) in the diet. The treatments were: Control: diet without the inclusion of live yeasts, and Yeast: diet with the inclusion of live yeasts (7 g animal day-1, at the concentration of 107 CFU g-1. The diets were composed of corn silage at a constant forage: concentrate ratio of 50: 50, on a dry matter basis. The experimental design was completely randomized, composed of two treatments and nine replicates, wherein each replicate was represented by a stall with two animals. Thirty-six heifers, ½ blood Angus, from the same herd, with an average age of 11.9 months and an initial average body weight of 317 kg, were used in the experiment. Supplementation of live yeasts in the diet for finishing heifers proved to be efficient in the feedlot finishing phase because it provided improvement in the apparent digestibility of DM. In relation to the productive performance, ingestive behavior, rectal temperature, superficial thermography of skin and hull and carcass traits, no statistical difference was found between the treatments. The animals have already come from the property adapted to the feedlot system, defining small challenge against the presence of live yeasts included in the experimental diet, justifying the lack of expression on some results obtained.

The objective of this study was to evaluate the associative effect of monensin sodium to virginiamycin and/or essential oils on performance, consumption of nutrients and dry matter, apparent digestibility, feeding behavior and carcass characteristics of feedlot finished steers. The experiment lasted 106 days with 10 days of adaptation and 96-day trial, and had 32 crosses angus steers, average age 12 months and average weight of 376 kg, divided into 16 stalls, the weighing took place every 21 days and at the end of the experiment. The treatments consisted of the combination of the following additives to the diet included: Monensin sodium, 200 mg day-1 (MO); Monensin sodium, a dose of 200 mg day-1 + essential oil dose of 1.5g day-1 (MO+EO); Monensin sodium, a dose of 200 mg day-1 + virginiamycin, 200 mg day-1 (MO+VI); Monensin sodium, 200 mg day-1 + essential oil dose of 1.5g day-1 + virginiamycin day, 200 mg day-1 (MO+EO+VI), each treatment had four repetitions, where each repetitions consisted of a bay with two animals. The MO+VI association in relation to MO only increase in average daily gain (ADG) of 24.44%, 22.35%, 21.10% and 17.31% in weighing 42, 63, 84 and 96 days, similar the combination of MO+EO+VI which provided an improvement of 21.94%, 13.59%, 15.45% and 14.75% respectively in the same weightings. The daily carcass gain and carcass overall gain were higher in associations MO+VI and MO+EO+VI and provided an average gain of 16.67 kg more compared to MO and MO+EO. In the parameters feed efficiency, dry matter intake and nutrient expressed in kg day-1 and percentage of live weight were not observed differences (P > 0.05) between treatments. Data on apparent digestibility, feeding behavior and carcass characteristics did not show statistical difference between treatment, except for fat thickness which was higher when associated with any of the additives to the MO, and farm weight was higher in associations containing VI. Associating MO+VI or MO+EO+VI proved to be best in this work compared to MO+EO or only MO in the diets of steers in termination.

Monensin is an ionophore antibiotic, the inclusion of which in the feed of beef cattle favors the best use of feed nutrients, via ruminal modulation. However, there are concerns regarding the residence of residues in the carcass from metabolism of monensin. The objective of this study was to evaluate the productive performance, carcass characteristics, serum parameters, tissue residual depletion and economic benefit of finishing of young bulls in confinement with monensin in the ration. Thirty-six animals were confined, and given 50% corn silage feed and 50% more concentrated feed. The experimental design was completely randomized, with two treatments (with or without monensin) and 10 replicates for the control group and eight for the monensin group. The use of monensin reduced the dry matter intake in relation to live weight (2.36% vs 2.55%), and improved feed conversion (8.61 vs 10.06 kg kg?1); the animals presented higher live weight (511 vs 494 kg), higher warm carcass weight (285 vs 272 kg) and an increase in fat thickness (4.97 vs 4.25 mm) compared to control animals. These increases in performance gave higher economic results, with a profit margin of R$ 122.84 per animal. A waiting period of 16 h before slaughter resulted in monensin concentrations below 0.25 µg kg?1 in edible organs and tissues, values well below those permitted by legislation. The use of monensin for young bulls in confinement promoted improvements in productive and economic performance, without leaving residues in edible tissues.

A monensina é um antibiótico ionóforo, cuja inclusão na alimentação de bovinos de corte favorece o melhor aproveitamento dos nutrientes da ração, via modulação ruminal. Porém há preocupações no que tange a permanência de resíduos na carcaça, provenientes da metabolização da monensina. Assim, objetivou-se avaliar o desempenho produtivo, as características de carcaça, os parâmetros séricos, a depleção residual tecidual e a economicidade da terminação de tourinhos em confinamento com monensina na ração. Foram confinados 36 animais com ração 50% de silagem de milho mais 50% concentrado. O delineamento experimental foi inteiramente casualizado, com 2 tratamentos (com ou sem monensina) e 10 repetições para o grupo controle e 8 para o grupo com monensina. O uso de monensina reduziu o consumo de matéria seca em relação ao peso vivo (2,36 vs 2,55%), melhorou a conversão alimentar (8,61 vs 10,06 kg kg-1), os animais apresentaram maior peso vivo (511 vs 494 kg), maior peso de carcaça quente (285 vs 272 kg) e aumento na espessura de gordura (4,97 vs 4,25 mm) comparativamente aos animais da ração controle. Tais acréscimos em desempenho conferiram maiores resultados econômicos, com margem de lucro de R$ 122,84 por animal. O período de carência de 16 horas antes do abate apresentou concentrações de monensina inferiores a 0,25 µg kg-1 nos órgãos e tecidos comestíveis, valores muito abaixo dos permitidos na legislação. O uso de monensina para tourinhos em confinamento promoveu melhorias no desempenho produtivo e econômico, sem deixar resíduos nos tecidos comestíveis. ; Monensin is an ionophore antibiotic, the inclusion of which in the feed of beef cattle favors the best use of feed nutrients, via ruminal modulation. However, there are concerns regarding the residence of residues in the carcass from metabolism of monensin. The objective of this study was to evaluate the productive performance, carcass characteristics, serum parameters, tissue residual depletion and economic benefit of finishing of young bulls in confinement with monensin in the ration. Thirty-six animals were confined, and given 50% corn silage feed and 50% more concentrated feed. The experimental design was completely randomized, with two treatments (with or without monensin) and 10 replicates for the control group and eight for the monensin group. The use of monensin reduced the dry matter intake in relation to live weight (2.36% vs 2.55%), and improved feed conversion (8.61 vs 10.06 kg kg?1); the animals presented higher live weight (511 vs 494 kg), higher warm carcass weight (285 vs 272 kg) and an increase in fat thickness (4.97 vs 4.25 mm) compared to control animals. These increases in performance gave higher economic results, with a profit margin of R$ 122.84 per animal. A waiting period of 16 h before slaughter resulted in monensin concentrations below 0.25 µg kg?1 in edible organs and tissues, values well below those permitted by legislation. The use of monensin for young bulls in confinement promoted improvements in productive and economic performance, without leaving residues in edible tissues.

The goal of the present study was to evaluate the biomass and grain yield, the morphological and chemical composition, production costs and the ruminal disappearance of the whole corn plant and grain-free corn plant harvested at different reproductive stages. The experimental design was completely randomized, consisting of six treatments, where each treatment corresponded to a stage of corn maturity. The advance of plant cycle promoted an increase in dry biomass and grain yields per unit area, reducing production costs. Higher participation of grains and lower participation of structural components promoted a reduction in NDF and ADF, with the lowest values in dough grain (R4) and dent grain (R5) stages. The advancement of stages promoted an increase in production and a reduction in costs, but significantly reduced the quality of grain-free plants, increasing the NDF, ADF and ADL; but R4 and R5 presented NDFd of 84.80 % and 82.79 %, respectively, showing to be a good quality fiber. R4 stage had the highest rumen disappearance values after 24 and 48 hours of incubation. Based on chemical data, ruminal disappearance, ruminal degradation kinetics of the whole corn plant and without grains, the R4 stage of the evaluated hybrid is the stage at which the plant had the best quality, representing the appropriate stage to harvest the material for making silage, aiming at the production of a silage with good chemical quality.

Essential oils and enzymes are alternatives to feed additives for ruminants that aim to replace the use of ionophores and improve animal performance, but their mechanisms of action are different. Therefore, the present study aimed to verify if there is a synergistic effect in the combined use of enzymes carbohydrates and essential oils on the performance, ingestive behavior and carcass traits of steers fed a high-energy diet. During the finishing period of 78 days, 40 steers were assigned to four treatments: CON- control; ENZ- enzymatic complex; EO- essential oil blend; ENZ+EO - enzymatic complex combined with essential oil blend. Regardless of the feedlot periods, the ENZ+EO treatment caused a reduction in the dry matter intake (12.48%) compared to the control. The ENZ+EO treatment resulted in the lowest mean fecal output and, consequently, the highest dry matter digestibility (DMD) and starch digestibility (SD), compared to the other treatments. Animals that received EO and ENZ+EO in the diet spent more time in feeding. As for the number of times animals visited the feeding trough, the highest values were presented by the animals in the EO, ENZ and ENZ+EO treatments. For the carcass parameters, only the subcutaneous fat thickness on the rib was significantly different between treatments, with the highest values obtained by adding EO and ENZ+EO (8.80 and 8.10 mm respectively). Thus, the combination of carbohydrate enzymes and essential oils proved to be synergistically beneficial in relation to better use of nutrients and productive performance of feedlot steers.

The objective was to evaluate the productive performance, ingestive behavior, apparent digestibility of the diet and carcass traits of beef steers finished in feedlot under the effect of including tannins and essential oils (TAN+EO) alone or combined with sodium monensin (MO) in the feed. For this purpose, 30 ½ blood Angus steers from the same herd, with an average age of 12 months and an average initial body weight of 367.8 kg were used. The experimental design was randomized blocks, consisting of three treatments: MO - diet with sodium monensin (25 mg kg DM-1); TAN+EO - diet with tannins and essential oils (1.5 g kg DM-1); and MO+TAN+EO - diet with sodium monensin + tannins and essential oils (25 mg kg DM-1 + 1.5 g kg DM-1), with five repetitions, where each repetition was represented by a stall with two animals. Diets were formulated and consisted of a mixture of 40% corn silage and 60% concentrate, which was fed to the animals twice a day, at 06h00 am and 05h30 pm. There was no difference (P>0.05) in average daily weight gain of animals between treatments, with an average of 1.392 kg day-1. Carcass yield was higher for animals that received the compound of essential oils and tannins (55.72%), compared to animals fed the combination of tannins, essential oils and monensin (54.54%) but did not differ from those supplemented with sodium monensin alone (55.58%). Supplementation with essential oils and tannins improved the apparent digestibility of the diet, however, did not promote changes in the ingestive behavior and carcass traits of steers. The combination of essential oils and tannins with sodium monensin did not show a potentiated effect on animal performance, digestibility of DM, digestive and ingestive behavior and carcass traits of feedlot finished steers compared to the combined use of essential oils with tannins.

Functional additives, such as autolyzed yeasts, have been used to achieve greater production efficiency and animal health. These compounds are also alternatives to the use of performance-enhancing antimicrobials. The objective was to evaluate the productive performance, ingestive behavior, apparent digestibility of feed DM and the carcass characteristics of beef steers finished in feedlot receiving autolyzed yeasts in the diet. The experimental design was randomized blocks, consisting of three treatments and six repetitions, where each repetition was represented by a stall with two animals. 36 bulls, ½ Angus × ½ Nelore blood, from the same herd, with an average age of 11 months and an average body weight of ± 330 kg were used.The treatments were as follows: CON - yeast-free diet; Y4 - yeast diet (4 g animal day-1) and Y7 - yeast diet (7 g animal day-1). The product used is a functional ingredient containing the yeast Saccharomyces cerevisiae. The inclusion of autolyzed yeasts resulted in greater daily body weight gain and better feed conversion in the initial feedlot phase. The apparent digestibility of DM of diets containing autolyzed yeast was superior to the control diet, and its use did not interfere with the animal ingestive behavior. Supplementation with autolyzed yeasts at the inclusion level of 4 g day-1 promoted better results in the finishing of feedlot steers, and that the supplemented groups (4 g animal day-1 and 7 g animal day-1) achieved the same degree of carcass finishing, higher than the control group.