RESUMO

This study aimed to evaluate the effects of supplementation with non-protein nitrogen (NPN) or ruminal undegradable protein (RUP) on intake, digestibility, and amino acid (AA) use efficiency of Nellore cattle grazing during the dry season. Eight Nellore steers (12 ± 2 months old) were used in quadruplicate Latin squares (2 × 2). The animals were placed on Urochloa brizantha cv. Xaraés under continuous grazing. The treatments included the following: (1) urea supplementation (NPN) and (2) supplementation of corn gluten meal 60 (CGM, RUP). Animals supplemented with CGM showed higher intakes of dry matter (DM) supplement, total AA, essential AA, and individual AA. The supplementation did not affect the total AA digestibility, total AA flux, and the AA fluxes of microbial origin and RUP from the diet (p > 0.05). The ruminal microorganism origin flux of total AA to the duodenum was 44.5% and 52.7% for animals supplemented with NPN and CGM, respectively. Animals supplemented with CGM showed an increase in blood concentrations of isoleucine (+19.09 µmol/L), cystine (+27.29 µmol/L), and albumin (+0.11 g/dL) (p < 0.05), but this increase was not accompanied by an improvement in N use efficiency of steers (p > 0.05). RUP supplementation via CGM can be an efficient nutritional strategy to enhance the intake and absorption of AA by Nellore cattle grazing low-quality forage during the dry season.

RESUMO

The objectives were to evaluate the effects of monensin and virginiamycin, alone or combined, on supplemented Nellore cattle grazing tropical grass during the rainy season. Two experiments were conducted simultaneously to evaluate intake, digestibility, CH4 emissions, blood parameters, performance, and carcass characteristics (Exp. 1), and ruminal fermentation and relative abundance of ruminal microorganisms (Exp. 2). Animals (n = 92 Exp. 1 and n = 12 Exp. 2) were distributed in a completely randomized design and allocated in twelve paddocks composed of Urochloa brizantha (A. Rich.) Stapf. cv. Xaraés. A protein-energetic supplementation of 3 g/kg of BW per day was provided to all animals. Supplements were: without additives (WA), monensin alone at 80 mg/kg of product (MN), virginiamycin alone at 150 mg/kg of product (VM), and monensin (80 mg/kg of product) combined with virginiamycin (150 mg/kg of product; MNVM). Treatments did not affect intakes of total dry matter (DM), supplement DM, and nutrients. However, the intakes of forage DM and crude protein decreased in cattle fed MNVM compared with animals fed WA, MN, and VM. Total volatile fatty acids increased in animals fed VM. Ruminal NH3-N decreased, and pH increased in animals fed MN, VM, and MNVM. Relative abundance of total F. succinogenes and S. ruminantium decreased and R. flavefaciens increased in animals fed MN and VM at d 118. Treatments had no effect on enteric CH4 emissions. The average daily gain (ADG) and total gain were greater in cattle fed MNVM than in cattle fed MN. Combination of monensin and virginiamycin altered the rumen microbial populations but did not decrease enteric CH4 emissions. However, it decreased forage dry matter intake without altering the ADG and total weight gain, leading to an increase in feed efficiency. Results from this study indicate an advantage in including feed additives combined in the diet of supplemented Nellore cattle grazing tropical grass during the rainy season.

Assuntos

RESUMO

The effects of sources of rumen undegradable protein (RUP) in diets on methane (CH4), nitrous oxide (N2O) and ammonia (NH3) emissions from the manure of feedlot-finished cattle were evaluated. We hypothesized that the use of different RUP sources in diets would reduce N loss via urine and contribute to reduced N2O, CH4 and NH3 emissions to the environment. Nellore cattle received different diets (18 animals/treatment), including soybean meal (SM, RDP source), by-pass soybean meal (BSM, RUP source) and corn gluten meal (CGM, RUP source). The protein source did not affect the N and C concentration in urine, C concentration in feces, and N balance (P > 0.05). The RUP sources resulted in a higher N2O emission than the RDP source (P = 0.030), while BSM resulted in a higher N2O emission than CGM (P = 0.038) (SM = 633, BSM = 2521, and CGM = 1153 g ha-2 N-N2O); however, there were no differences in CH4 and NH3 emission (P > 0.05). In conclusion, the use of RUP in diets did not affect N excretion of beef cattle or CH4 and NH3 emission from manure, but increased N2O emission from the manure.

Assuntos

RESUMO

This study evaluated the effect of phosphorus (P) supplementation on the intake, digestibility, and quality of aged meat from Nellore young bulls fed on high-grain diets finished in feedlot. Forty young bulls (30 months old) with an initial body weight (IBW) of 296 ± 25 kg were used. It was distributed in a completely randomized experimental design. The treatments were: without P supplementation (CO), commercial mineral supplement (CM), and supplementation with dicalcium phosphate (DP) with 2.4, 4.2, or 5.0 g of P per kg of dry matter (DM), respectively. Diets were composed of sugarcane bagasse (200 g kg-1) plus concentrate (800 g kg-1) on a dry matter (DM) basis. The meat quality parameters analyzed were pH, color, cooking losses, shear force, and water-holding capacity. P supplementation did not affect the intake and digestibility of nutrients There was no interaction (p > 0.05%) between diets and the aging time for the meat quality parameters. However, bulls fed with DP exhibited lower pH (5.98) compared to CO and CM (6.19 and 6.14, respectively). The longer aging time increased the cooking losses and intensity of yellow (b*). Under Brazilian conditions, feedlot Nellore cattle fed with high-grain diets do not require additional mineral supplements.(AU)

Assuntos

RESUMO

This study evaluated the effect of phosphorus (P) supplementation on the intake, digestibility, and quality of aged meat from Nellore young bulls fed on high-grain diets finished in feedlot. Forty young bulls (30 months old) with an initial body weight (IBW) of 296 ± 25 kg were used. It was distributed in a completely randomized experimental design. The treatments were: without P supplementation (CO), commercial mineral supplement (CM), and supplementation with dicalcium phosphate (DP) with 2.4, 4.2, or 5.0 g of P per kg of dry matter (DM), respectively. Diets were composed of sugarcane bagasse (200 g kg-1) plus concentrate (800 g kg-1) on a dry matter (DM) basis. The meat quality parameters analyzed were pH, color, cooking losses, shear force, and water-holding capacity. P supplementation did not affect the intake and digestibility of nutrients There was no interaction (p > 0.05%) between diets and the aging time for the meat quality parameters. However, bulls fed with DP exhibited lower pH (5.98) compared to CO and CM (6.19 and 6.14, respectively). The longer aging time increased the cooking losses and intensity of yellow (b*). Under Brazilian conditions, feedlot Nellore cattle fed with high-grain diets do not require additional mineral supplements.

Assuntos

RESUMO

Two experiments were conducted to evaluate the effects of inclusion of crude glycerin (CG) in the supplement (0, 70, 140, 210, and 280 g kg-¹ dry matter (DM) of supplement) of Nellore cattle grazing tropical grasses during dry season. In Experiment 1, intake, digestibility, ruminal fermentation, and the rumen microbial profile were evaluated in two simultaneous 5 × 5 Latin squares, using 10 ruminally cannulated Nellore steers (408.8 ± 38.5 kg of body weight (BW)). In Experiment 2, cattle growth performance was evaluated in 50 young Nellore bulls (279.52 ± 16.3 kg of BW) distributed in a randomized complete block design. The increasing inclusion of CG did not affect intake (P= 0.813), diet digestibility (P = 0.895), however linearly increased pH (P=0.001), butyrate concentration (P < 0.001) and Fibrobacter succinogenes (P=0.003) population. CG inclusion linearly decreased total ruminal volatile fatty acids (VFA) (P < 0.001), acetate concentration (P < 0.001) and quadratically affected (P=0.009) acetate: propionate ratio. In experiment 2, the inclusion of CG quadratically affected DM intake (DMI) (P=0.005), DM total-tract apparent digestibility (P < 0.001), linearly increased additional gain (P > 0.001), average daily gain (P > 0.001) and feed efficiency (P > 0.001). CG in the supplement of Nellore steers grazing tropical grass during dry season doesnt affect intake and digestibility but alters ruminal fermentation, without negative effect on relative proportion of cellulolytic bacteria population. The increasing replacement of corn grain by CG in the supplement of pasture-raised growing Nellore bulls (up to 280g/kg DM) improved BW gain and consequently feed efficiency.(AU)

Foram realizados dois experimentos para avaliar os efeitos da inclusão de glicerina bruta (GB) no suplemento (0, 70, 140, 210 e 280 g kg-¹ de suplemento) de bovinos Nelore pastejando gramíneas tropicais durante a estação seca. No experimento 1, o consumo, digestibilidade, fermentação ruminal e o perfil microbiano do rúmen foram avaliados em dois quadrados latinos 5x5 simultâneos, usando 10 novilhos Nelore canulados no rúmen (408,8 ± 38,5 kg de PC). No Experimento 2, o desempenho do crescimento do gado foi avaliado em 50 novilhos Nelore (279,52 ± 16,3 kg de PC) distribuídos em delineamento em blocos casualizados. A inclusão crescente de GB não afetou o consumo (P = 0,813), a digestibilidade da dieta (P = 0,895), mas aumentou linearmente o pH (P=0,001), a concentração de butirato (P < 0,001) e a população de Fibrobacter succinogenes (P = 0,003). A inclusão de GB diminuiu linearmente os ácidos graxos voláteis totais (AGVs) no rúmen (P < 0,001), a concentração de acetato (P < 0,001) e afetou quadraticamente a relação acetato: propionato (p = 0,009). No experimento 2, a inclusão de GB modificou quadraticamente o consumo de matéria seca (CMS) (P = 0,005), a digestibilidade aparente total (P < 0,001), aumentou linearmente o ganho adicional (P > 0,001), o ganho médio diário (P > 0,001) e a eficiência alimentar (P > 0,001). GB no suplemento de novilhos Nelore pastejando gramíneas tropicais durante a estação seca não afeta a ingestão e digestibilidade, mas altera a fermentação ruminal, sem efeito negativo sobre a proporção relativa de bactérias celulolíticas. A crescente substituição do grão de milho por GB no suplemento touros Nelore em crescimento criados em pastagem (até 280g / kg de DM) melhorou o ganho de peso e consequentemente a eficiência alimentar.(AU)

Assuntos

RESUMO

Two experiments were conducted to evaluate the effects of inclusion of crude glycerin (CG) in the supplement (0, 70, 140, 210, and 280 g kg-¹ dry matter (DM) of supplement) of Nellore cattle grazing tropical grasses during dry season. In Experiment 1, intake, digestibility, ruminal fermentation, and the rumen microbial profile were evaluated in two simultaneous 5 × 5 Latin squares, using 10 ruminally cannulated Nellore steers (408.8 ± 38.5 kg of body weight (BW)). In Experiment 2, cattle growth performance was evaluated in 50 young Nellore bulls (279.52 ± 16.3 kg of BW) distributed in a randomized complete block design. The increasing inclusion of CG did not affect intake (P= 0.813), diet digestibility (P = 0.895), however linearly increased pH (P=0.001), butyrate concentration (P 0.001), average daily gain (P > 0.001) and feed efficiency (P > 0.001). CG in the supplement of Nellore steers grazing tropical grass during dry season doesn’t affect intake and digestibility but alters ruminal fermentation, without negative effect on relative proportion of cellulolytic bacteria population. The increasing replacement of corn grain by CG in the supplement of pasture-raised growing Nellore bulls (up to 280g/kg DM) improved BW gain and consequently feed efficiency.

Foram realizados dois experimentos para avaliar os efeitos da inclusão de glicerina bruta (GB) no suplemento (0, 70, 140, 210 e 280 g kg-¹ de suplemento) de bovinos Nelore pastejando gramíneas tropicais durante a estação seca. No experimento 1, o consumo, digestibilidade, fermentação ruminal e o perfil microbiano do rúmen foram avaliados em dois quadrados latinos 5x5 simultâneos, usando 10 novilhos Nelore canulados no rúmen (408,8 ± 38,5 kg de PC). No Experimento 2, o desempenho do crescimento do gado foi avaliado em 50 novilhos Nelore (279,52 ± 16,3 kg de PC) distribuídos em delineamento em blocos casualizados. A inclusão crescente de GB não afetou o consumo (P = 0,813), a digestibilidade da dieta (P = 0,895), mas aumentou linearmente o pH (P=0,001), a concentração de butirato (P 0,001), o ganho médio diário (P > 0,001) e a eficiência alimentar (P > 0,001). GB no suplemento de novilhos Nelore pastejando gramíneas tropicais durante a estação seca não afeta a ingestão e digestibilidade, mas altera a fermentação ruminal, sem efeito negativo sobre a proporção relativa de bactérias celulolíticas. A crescente substituição do grão de milho por GB no suplemento touros Nelore em crescimento criados em pastagem (até 280g / kg de DM) melhorou o ganho de peso e consequentemente a eficiência alimentar.

Assuntos

RESUMO

Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG), efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI), dry matter and organic matter digestibility (DMD and OMD), BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg) were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD), once daily except Saturdays and Sundays (SS), or on alternate days (AD), at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.(AU)

Assuntos

RESUMO

Reduced supplementation frequency is a broadly applied management practice. Ruminants consuming low quality forages/pastures, supplemented less than once daily are able to maintain body weight gain (BWG), efficiency of use of dry matter, nitrogen and other nutrients, as compared with animals supplemented once daily. We evaluated the feeding behavior, dry matter intake (DMI), dry matter and organic matter digestibility (DMD and OMD), BWG, Longissimus muscle area and backfat depth of Nellore steers raised on Brachiaria brizantha cv. Marandu pastures during the dry season, with different supplementation patterns. Thirty six animals (338 ± 40.7 kg) were distributed over nine paddocks according to a completely randomized design. Treatments were based on supplementation frequency: once daily (OD), once daily except Saturdays and Sundays (SS), or on alternate days (AD), at 1.0 %, 1.4 % and 2.0 % BW, respectively. Average total DMI accounted for 1.6 % BW day-1, with no effect of supplementation frequency. Supplementation frequency had no effect on BWG or grazing time during the day. There was no difference in Longissimus muscle area animals supplemented daily, SS and AD. The backfat depth was thinner in animals supplemented AD, but even in this case, it was within the standards considered satisfactory for a finishing steer. Reducing supplementation frequency seems a good option to lower labor costs without affecting feed efficiency or carcass quality in beef cattle grazing tropical pastures.

Assuntos

RESUMO

The disposal of chemical waste and the precision of analyses of the neutral (NDF) and acid (ADF) detergent fiber contents were evaluated utilizing conventional (Van Soest) and alternative methods of analyses. The recovery of acetone promoted both economic and environmental gains, with a recovery rate of 84.12%. The precision of the analyses was not observed in most of the determinations with reutilization of chemical waste in all the analytical methods tested, in spite of promoting decrease in cost, time invested in the preparation of solutions and the disposal of chemical waste.(AU)

Foram avaliados descarte de resíduos químicos em análises dos teores de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA), utilizando métodos convencional (Van Soest) e alternativos de análises. A recuperação da acetona promoveu ganhos tanto econômico como ambiental, observando-se taxa de recuperação de 84,12%. A precisão das análises não foi observada na maioria das determinações com reutilização de resíduos químicos, em todos os métodos analíticos testados, apesar de promover redução no custo, no tempo investido no preparo das soluções e no descarte de resíduos químicos.(AU)

Assuntos

RESUMO

The disposal of chemical waste and the precision of analyses of the neutral (NDF) and acid (ADF) detergent fiber contents were evaluated utilizing conventional (Van Soest) and alternative methods of analyses. The recovery of acetone promoted both economic and environmental gains, with a recovery rate of 84.12%. The precision of the analyses was not observed in most of the determinations with reutilization of chemical waste in all the analytical methods tested, in spite of promoting decrease in cost, time invested in the preparation of solutions and the disposal of chemical waste.

Foram avaliados descarte de resíduos químicos em análises dos teores de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA), utilizando métodos convencional (Van Soest) e alternativos de análises. A recuperação da acetona promoveu ganhos tanto econômico como ambiental, observando-se taxa de recuperação de 84,12%. A precisão das análises não foi observada na maioria das determinações com reutilização de resíduos químicos, em todos os métodos analíticos testados, apesar de promover redução no custo, no tempo investido no preparo das soluções e no descarte de resíduos químicos.

Assuntos

RESUMO

Protozoa population, microbial synthesis efficiency and rumen degradability of dry matter and neutral detergent fiber in cattle fed on diets with different lipid rates were evaluated. Nine 16-monthold Nelore young bulls, cannulated in the rumen and duodenum, weighing 232 ± 35 kg, were used in the trial. Experimental design consisted of a 3 x 3 square in triplicate, comprising the following treatments: 2, 4 and 6% lipid in diet. In situ degradability was assessed by rumen incubation of corn silage, soybean, soybean meal and citrus pulp during 0, 3, 6, 12, 24, 48, 72 and 96h. The flow of microbial nitrogen and microbial efficiency were not influenced (p > 0.05) by the inclusion of lipid levels in the diet. When the animals received diet with 4% lipid, there was a reduction (p < 0.05) in the potential and effective degradation of dry matter of corn silage (64.10 and 55.04%, respectively), soybean meal (94.55 and 60.83%, respectively) and soybeans (98.45 and 76.44%, respectively). Since the degradability of neutral detergent fiber was not affected, 4 and 6% lipid levels in the diet may be used without altering the parameters of rumen degradation of fiber.

Avaliaram-se a população de protozoários, a eficiência de síntese microbiana e a degradabilidade ruminal da matéria seca e da fibra em detergente neutro, em bovinos que consumiram dietas contendo diferentes teores de lipídeos. Foram utilizados nove novilhos da raça Nelore, canulados no rúmen e duodeno, com idade inicial 16 meses e 232 ± 35 kg de peso corporal. O delineamento experimental utilizado foi quadrado latino 3 x 3 triplicado, sendo os tratamentos: 2; 4 e 6% de lipídeos na dieta. A degradabilidade "in situ" foi avaliada por meio da incubação ruminal da silagem de milho, soja grão, farelo de soja e polpa cítrica por 0, 3, 6, 12, 24, 48, 72 e 96h. O fluxo de nitrogênio microbiano e a eficiência de síntese microbiana não foram (p > 0,05) influenciados pela inclusão de teores de lipídeos nas dietas. Quando os animais receberam 4% de lipídeo na dieta ocorreu redução (p < 0,05) da degradação potencial e efetiva da matéria seca da silagem de milho (64,10 e 55,04%, respectivamente), farelo de soja (94,55 e 60,83%, respectivamente) e soja grão (98,45 e 76,44%, respectivamente). Teores 4 e 6% de lipídeos na dieta podem ser utilizados sem alterar os parâmetros de degradação ruminal da fibra.

Assuntos

RESUMO

Objetivou-se, com este trabalho, avaliar os efeitos de fontes de nitrogênio, utilizando-se como volumoso a cana-de-açúcar, suplementada com ureia, glúten de milho- 60 ou farelo de soja, sobre o consumo e a digestibilidade aparente total e parcial, em novilhos mestiços. Os tratamentos foram: cana-de-açúcar, cana-de-açúcar suplementada com ureia, glúten de milho-60 ou farelo de soja. Foram utilizados oito novilhos canulados no rúmen e duodeno, distribuídos em dois quadrados latinos 4 x 4. Para se determinar a digestibilidade aparente no trato digestivo total foi utilizada a coleta total de fezes. As determinações das digestibilidades ruminal e intestinal e dos fluxos diários de matéria seca foram estimadas por meio da fibra em detergente ácido indigestível (FDAi) como marcador de fluxo duodenal. Os consumos de MS, MO, PB, EE, ED, FDN, FDA e CT foram influenciados (p < 0,05) pelas fontes de nitrogênio, sendo observado consumo inferior nos animais alimentados exclusivamente com cana-de-açúcar em relação aos animais alimentados com as demais rações experimentais. Entretanto, as fontes de nitrogênio não afetaram o consumo de NDT. As digestibilidade aparente total, ruminal e intestinal dos nutrientes não foram influenciadas pela adição de fontes de nitrogênio, com exceção da matéria seca e da proteína bruta.(AU)

The objective of this work was to evaluate the effect of nitrogen sources, using sugarcane supplemented with urea, corn gluten meal- 60 or soybean meal. It was evaluated Intake, total and partial apparent digestibility were evaluated using four rumen and duodenal cannulated crossbred steers. The treatments were evaluated in a 4 x 4 Latin square design. The total feces were collected to determine the apparent digestibility on the total intestinal tract. The indigestible acid detergent fiber (iADF) was used as marker of duodenal flux to determine ruminal and intestinal digestibility and dry matter daily flux. The DM, OM, CP, EE, DE, NDF, ADF and TC intakes and digestibility rates were influenced by nitrogen sources, and lower intake was observed in animals fed exclusively with cane sugar compared to animals fed the other experimental diets. Meanwhile the sources of nitrogen did not affect the total digestible nutrients (TDN) values. The RDP sources did not affect the total, ruminal, and intestinal nutrients apparent digestibility. However, the total, ruminal, and intestinal dry matter, and protein apparent digestibility were affected by the RDP sources.(AU)

Assuntos

RESUMO

Objetivou-se, com este trabalho, avaliar os efeitos de fontes de nitrogênio, utilizando-se como volumoso a cana-de-açúcar, suplementada com ureia, glúten de milho- 60 ou farelo de soja, sobre o consumo e a digestibilidade aparente total e parcial, em novilhos mestiços. Os tratamentos foram: cana-de-açúcar, cana-de-açúcar suplementada com ureia, glúten de milho-60 ou farelo de soja. Foram utilizados oito novilhos canulados no rúmen e duodeno, distribuídos em dois quadrados latinos 4 x 4. Para se determinar a digestibilidade aparente no trato digestivo total foi utilizada a coleta total de fezes. As determinações das digestibilidades ruminal e intestinal e dos fluxos diários de matéria seca foram estimadas por meio da fibra em detergente ácido indigestível (FDAi) como marcador de fluxo duodenal. Os consumos de MS, MO, PB, EE, ED, FDN, FDA e CT foram influenciados (p < 0,05) pelas fontes de nitrogênio, sendo observado consumo inferior nos animais alimentados exclusivamente com cana-de-açúcar em relação aos animais alimentados com as demais rações experimentais. Entretanto, as fontes de nitrogênio não afetaram o consumo de NDT. As digestibilidade aparente total, ruminal e intestinal dos nutrientes não foram influenciadas pela adição de fontes de nitrogênio, com exceção da matéria seca e da proteína bruta.

The objective of this work was to evaluate the effect of nitrogen sources, using sugarcane supplemented with urea, corn gluten meal- 60 or soybean meal. It was evaluated Intake, total and partial apparent digestibility were evaluated using four rumen and duodenal cannulated crossbred steers. The treatments were evaluated in a 4 x 4 Latin square design. The total feces were collected to determine the apparent digestibility on the total intestinal tract. The indigestible acid detergent fiber (iADF) was used as marker of duodenal flux to determine ruminal and intestinal digestibility and dry matter daily flux. The DM, OM, CP, EE, DE, NDF, ADF and TC intakes and digestibility rates were influenced by nitrogen sources, and lower intake was observed in animals fed exclusively with cane sugar compared to animals fed the other experimental diets. Meanwhile the sources of nitrogen did not affect the total digestible nutrients (TDN) values. The RDP sources did not affect the total, ruminal, and intestinal nutrients apparent digestibility. However, the total, ruminal, and intestinal dry matter, and protein apparent digestibility were affected by the RDP sources.

Assuntos