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This study aimed to evaluate intake, animal performance and carcass traits with the inclusion of corn dried distiller grains (DDGs) replacing cornmeal (Zea mays L.) in non-forage-based diets for finishing feedlot Nellore cattle. Sixty-four uncastrated Nellore cattle weighing 267.22 ± 20.4 kg and 18 ± 3 months old were distributed in 16 pens. Experimental diets were based on cornmeal, cottonseed cake, a mineral mixture and increased levels of DDG replacing cornmeal (0, 10, 20 and 30% on a dry matter basis). The study lasted 135 days, and the intake of nutrients and body weight gain were monitored. At the end of the study, the animals were slaughtered to measure their carcass traits. During the first 34 days of the study, the DDG levels linearly increased dry matter intake and intake of all nutrients. In other phases of the feedlot, the DDG levels did not have any effect on DMI or ADG but caused a quadratic effect on hot carcass weight. Thus, DDG can replace cornmeal in non-forage diets fed to feedlot Nellore cattle without any negative effect on intake or animal performance.

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The effect of the association of non-protein nitrogen, yeast, and bacterial probiotics on the ruminal microbiome of beef cattle intensively finished on pasture was evaluated. The experiment was carried out in a completely randomized design with five treatments and four replications. The treatments consisted of a group of animals kept on pasture that received low consumption supplementation (LS) and four groups that received for 98 days, 17.5 g concentrate kg-1 body weight. The supplements were composed of the association of additives: urea (U), slow-release non-protein nitrogen (U+SRN), yeast (Saccharomyces cerevisiae; U+SRN+Y), and bacterial probiotics (live strains of bacteria; U+SRN+Y+BP). All supplements also contained salinomycin and virginiamycin. After slaughtering the animals, samples of ruminal content were collected to quantify groups of fibrolytic bacteria (Ruminococcus albus and Fibrobacter succinogenes), non-fibrolytic (Prevotella ruminicola, Selenomonas ruminantium, and Streptococcus bovis), Archaea, and ciliate protozoa, using the qPCR technique. The abundance of F. succinogenes was the same for the LS animals and those that received the supplement U+SRN+Y (1.42×108 copies mL-1) but higher than the other treatments. Supplementation reduced by 90% the abundance of S. bovis compared to the LS. The inclusion of yeast increased the abundance of fibrolytic bacteria by 2.2-fold. For animals that received the supplement U+SRN+Y+BP and the LS, there was no difference for non-fibrolytic bacteria (3.07×109 copies mL-1). The use of yeasts and sources of non-protein nitrogen in high-concentrate diets for beef cattle stimulates the growth of fibrolytic bacteria, which can contribute to the reduction of digestive disorders and metabolic diseases in animals that receive diets with high concentrate in pasture intensive termination systems.

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The objective of this study was to evaluate increasing levels of inclusion of dry distillery grains (DDGs) in substitution of corn and urea in multiple supplements for beef cattle of Urochloa brizantha cv. Marandu on the consumption, digestibility, and efficiency of microbial synthesis and use of nitrogen. We used four Nellore bulls cannulated in the rumen with an average age of 24 months and 445.12 ± 34.4 kg of body weight (BW), in a 4 × 4 Latin square design. Supplements differed by the inclusion level of DDG (0%, 31.5%, 63.0%, and 94.5%). Increasing levels of DDG inclusion decreased dry matter intake (DMI) (P = 0.002), forage (P = 0.002), organic matter (OM) (P = 0.001), crude protein (CP) (P = 0.037), and total digestible nutrients (TDN) (P < 0.001) and had a quadratic effect on the intake of non-fibrous carbohydrates (NFC) (P = 0.002). It was observed an increase in the digestibility of ether extract (EE) (P = 0.005), however a decrease in the digestibility of NFC (P = 0.001). Inclusion of DDG did not influence ruminal pH. There was a quadratic effect at collection times for ruminal ammoniacal nitrogen (P < 0.05), except for the supplement with 94.5% DDG where the effect was linear (P = 0.002). Nitrogen intake was 10.9% higher when there was no DDG in the supplement, compared with the supplement with 94.5% DDG (P = 0.039). The excretion of N by feces was greater when there was a greater amount of DDG in the supplement (P = 0.027), the opposite occurred with urine excretion of N, being higher when there was less amount of DDG in the supplement (P = 0.027). Increasing levels of DDG did not affect ruminal microbial protein yield (P > 0.05). Replacing corn and urea with up to 94.5% DDGs in multiple supplements resulted in no adverse effect efficiency of microbial synthesis, although nutrient intake, total digestible nutrients, and use of nitrogen were reduced at 94.5% DDG inclusion.

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The objective of this study was to evaluate the effects of rumen-protected oil (soybean and palm oil) in supplements for beef cattle during the fattening phase in pastures on the intake and digestibility of nutrients, animal performance, and carcass characteristics. Forty-eight noncastrated male Nellore cattle (15 ± 2 months and 389.5 ± 20 kg of body weight) were used in a completely randomized design to evaluate the following treatments: protein-energy supplement (PES) without rumen-protected oil (control: CO), PES containing palm rumen-protected oil (PRPO), PES containing soybean rumen-protected oil (SRPO), and PES containing a mixture of soybean and palm rumen-protected oil (SPRPO). The study lasted 112 days, and there was a decrease in crude protein intake (P < 0.05) and an increase in ether extract intake (P < 0.05) when rumen-protected oil was included in the supplements. In comparison to the palm rumen-protected oil supplement, the soybean rumen-protected oil supplement promoted a lower average daily gain (ADG) (P < 0.05); however, regardless of the rumen-protected oil source, an increase in the fat thickness of the subcutaneous tissue was observed. In addition, there was no difference in carcass gain (P > 0.05) regardless of oil source. Rumen-protected oil is a tool to increase the finishing of pasture-finished young beef cattle in the dry season.

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We tested the hypothesis that supplementation with protein improves fermentation parameters without damaging the rumen microbial populations of beef cattle grazing Urochloa brizantha cv. Marandu during the dry season. Four rumen-cannulated Nellore bulls (571 ± 31 kg of body weight) were used in a 4 × 4 Latin square design. The treatments were not supplemented with concentrate (only free-choice mineral salt ad libitum) and supplemented (supplements with low-LPSU, medium-MPS, and high protein supplement-HPS), supplying 155, 515, and 875 g/animal/day of crude protein (CP), respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. There was no difference (P > 0.05) across treatments for intakes of dry matter (DM), forage and neutral detergent fiber (NDF), digestibility of DM and NDF, and ruminal pH. Animals supplemented with concentrate had greater (P < 0.05) intakes and digestibility of CP, ether extract and non-fibrous carbohydrate contents of the substrates (EE + NFC), and ruminal ammonia nitrogen (RAN) compared to control. Bulls that received only mineral salt had lower proportions of Butyrivibrio fibrisolvens and had greater (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus albus, Ruminococcus flavefaciens, Methanogen archaea than bulls supplemented with concentrate. The MPS animals had greater (P < 0.05) intake and digestibility of CP, RAN concentration, and had lower (P < 0.05) proportions of Fibrobacter succinogenes, Ruminococcus flavefaciens, and Selenomonas ruminantium than LPSU animals. The HPS provided higher (P < 0.05) intake of CP, RAN and proportion of Ruminococcus albus when compared with MPS. In conclusion, supply of 515 g/animal/day of protein via supplement provides better ruminal conditions for the growth of cellulolytic bacteria of bulls on pasture during dry season.

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We tested the hypothesis that supplementation with three protein levels improves fermentation parameters without changing the rumen microbial population of grazing beef cattle in the rainy season. Four rumen-cannulated Nellore bulls (432 ± 21 kg of body weight) were used in a 4 × 4 Latin square design with four supplements and four experimental periods of 21 days each. The treatments were mineral supplement (ad libitum) and supplements with low, medium (MPS), and high protein supplement (HPS), supplying 106, 408, and 601 g/day of CP, respectively. The abundance of each target taxon was calculated as a fraction of the total 16S rRNA gene copies in the samples, using taxon-specific and domain bacteria primers. Supplemented animals showed lower (P < 0.05) proportions of Ruminococcus flavefaciens and greater (P < 0.05) proportions of Ruminococcus albus and Butyrivibrio fibrisolvens than animals that received only the mineral supplement. The HPS supplement resulted in higher (P < 0.05) proportions of Fibrobacter succinogenes, R. flavefaciens, and B. fibrisolvens and lower (P < 0.05) proportions of R. albus than the MPS supplement. Based on our results, high protein supplementation improves the ruminal conditions and facilitates the growth of cellulolytic bacteria in the rumen of bulls on pastures during the rainy season.

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Supplementation of animals in the rainy season is essential to maximise weight gain. Thus, the objective was to evaluate the effects of supplementation with low-, medium- and high-protein levels on nutritional parameters of grazing beef cattle in the rainy season. Eight rumen-cannulated Nellore bulls (437 kg body weight) were used in a 4 × 4 double Latin square design with four supplements and four experimental periods. The treatments were mineral supplement (ad libitum) and supplements with low-protein (LPSU), medium-protein (MPS) and high-protein (HPS) levels, providing 106, 408 and 601 g/day of crude protein (CP), respectively. There was no difference (P > 0.05) between treatments for dry matter and forage intake, ruminal pH, ruminal ammonia nitrogen (RAN) at time 0 (before supplementation) and microbial protein yield. Animals on MPS had a higher (P > 0.05) intake and digestibility of CP, higher RAN levels (3 and 6 h after supplementation), increased nitrogen intake and a better nitrogen balance than animals on LPSU. The HPS provided higher (P > 0.05) RAN at time 6 and a better nitrogen balance when compared with MPS. We therefore infer that the high-protein supplement positively impacts nitrogen metabolism and efficiency in grazing beef cattle during the rainy season.

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SUMMARY The present work aimed to evaluate the effect of supplementation with different protein sources in the diets for dairy cows kept on Brachiaria brizantha MG5 grass pasture on serum levels of the glucose, triglycerides, cholesterol and urea as well as on enzymes gama grutamil transferase, creatinine quinase and aminotransferase. We have evaluated the following protein sources: bean byproduct, soybean meal, sunflower meal and cottonseed meal. Eight crossbred cows (Holstein x Gir) were used, weighing 500±60.33 kg, average milk production of 14.85±3.28 kg/day, between the 60th and the 90th day of calving, by a simultaneous double 4 x 4 latin square design 4 x 4. Each experimental period lasted 15 days, of which the first 10 days were designed to animal adaptation and the final five days for data collection. There was an interaction effect (P 0.05) among protein sources and sampling time on serum glucose. There was no effect (P>0.05) of protein sources for the triglycerides, cholesterol and urea levels, averaging 6.46±2.05, 182.43±37.52 and 38.20±12.29 mg/dL, respectively. There was a significant effect (P 0.05) of the sampling time on blood levels of triglycerides and urea. The different protein sources did not affect significantly (P>0.05) serum enzyme levels of glutamine transferase, creatinine quinase and aminotransferase, averaging 26.76±8.02, 112.13±20.13 and 58.79±31.72 IU/L, respectively. The protein sources promoted changes on blood glucose with the sampling time, while sampling time altered triglycerides and urea levels. Changes to other blood metabolites were not observed.

RESUMO Objetivou-se com este trabalho avaliar o efeito da suplementação com diferentes fontes proteicas na dieta de vacas leiteiras mantidas em pastagem de Brachiaria brizantha MG5 sobre os níveis séricos de glicose, triglicerídeos, colesterol e ureia e das enzimas gama glutamina transferase, creatina quinase e aminotransferase. Avaliaram-se diferentes fontes proteicas: coproduto de feijão, farelo de soja, farelo de girassol e farelo de algodão. Foram utilizadas 8 vacas cruzadas 5/8 (Holandês x Gir), peso médio 500±60,33kg, produção média de leite de 14,85±3,28kg/dia, entre 60 e 90 dias de lactação, em delineamento quadrado latino 4 x 4 duplo e simultâneo. Cada período experimental teve duração de 15 dias, sendo 10 dias iniciais para adaptação dos animais e os demais para avaliação e coleta de dados. Houve efeito de interação (P 0,05) das fontes proteicas e tempos de coleta sobre os níveis séricos de glicose. Não houve efeito (P>0,05) das fontes proteicas para os valores de triglicerídeos, colesterol e ureia dos animais, com média de 6,46±2,05; 182,43±37,52 e 38,20±12,29mg/dL, respectivamente. Houve efeito (P 0,05) dos tempos de coleta nos níveis sanguíneos de triglicerídeos e ureia. As diferentes fontes proteicas também não influenciaram (P>0,05) os níveis séricos das enzimas gama glutamina transferase, creatina quinase e aminotransferase, com médias de 26,76±8,02; 112,13±31,72 e 58,79±20,13 UI/L, respectivamente. As fontes proteicas promoveram alterações na glicemia com os tempos de coletas, sendo que estes alteraram os valores de triglicerídeos e ureia. Não foram observadas alterações para os demais metabólitos sanguíneos.

RESUMO

SUMMARY The objective was to assess the effects of rice meal over losses by gas and effluent, the fermentative profile and the chemical composition of Brachiaria decumbens cv. Basilisk silage in laboratory bags. Entirely random lining was used, with five treatments: 0; 10; 20; 30 and 40g/kg rice meal, based on natural grass matter. The values of losses by gas and effluents were reduced linearly in 0.11 and 0.39g/kg DM, while recovery of dry matter increased linearly in 0.32g/kg DM. There was quadratic behavior for pH values and linear decrease for the values of N-ammoniacal and buffering power estimated in 1.1 and 5g/kg DM. Concentrations of acetic, butyric and propionic acids were reduced linearly in 0.1; 0.008 and 0.006g/kg DM, while lactic acid increased linearly in 0.5g/kg DM. Each 1g/kg rice meal promoted linear increase of 4.3; 1.8; 7.1 and 7.0g/kg dry matter levels, crude protein, ethereal extract and total digestible nutrients and linear decrease of 6.9; 4.3 and 2.6g/kg DM of fiber in neutral detergent, fiber in acidic detergent and hemicellulose levels. Inclusion of 10g/kg rice meal already ensures lowering losses by gas and effluents, increase in dry matter recovery, allowing improvements on the fermentative profile and the chemical composition of silage.

RESUMO Objetivou-se avaliar os efeitos do farelo de arroz sobre as perdas por gases e efluente, o perfil fermentativo e a composição química das silagens de Brachiaria decumbens cv. Basilisk ensilado em silos de laboratório. Utilizou-se delineamento inteiramente casualizado, com cinco tratamentos: 0; 10; 20, 30 e 40g/kg de farelo de arroz, com base na matéria natural da gramínea. Os valores das perdas por gases e efluentes foram reduzidos linearmente em 0,11 e 0,39g/kg MS, enquanto a recuperação da matéria seca aumentou linearmente em 0,32g/kg MS. Houve comportamento quadrático nos valores de pH e, redução linear para os valores de N-amoniacal e poder tampão, estimados em 1,1 e 0,5g/kg MS. As concentrações de ácido acético, butírico e propiônico foram reduzidas linearmente em 0,1; 0,008 e 0,006g/kg MS, enquanto a de ácido láctico aumentou linearmente em 0,5g/kg MS. Cada unidade porcentual de farelo de arroz promoveu aumento linear de 4,3; 1,8; 7,1 e 7,0g/kg nos teores de matéria seca, proteína bruta, extrato etéreo e nutrientes digestíveis totais, e redução linear de 6,9; 4,3 e 2,6g/kg MS nos teores de fibra em detergente neutro, fibra em detergente ácido e hemicelulose. A inclusão de 10g/kg de farelo de arroz já assegura diminuição das perdas por gases e efluentes, aumento na recuperação de matéria seca, proporcionando melhorias no perfil fermentativo e na composição química das silagens.