Growth performance, reproductive parameters and fertility measures in young Nellore bulls with divergent feed efficiency

The growth, sexual maturity and fertility-related parameters related of young Nellore bulls with divergent residual feed intake (RFI) raised on pasture were evaluated. After classification of 48 young males as low and high RFI (more and less efficient, respectively), the animals were evaluated for growth and reproductive parameters at 28-day intervals from 14.3 to 24.6 months of age. The semen was cryopreserved in the last sampling and fresh and post-thaw semen samples were evaluated. Low RFI bulls exhibited higher initial and final body weight (P < 0.05), but feed intake, body condition score and growth measures evaluated by carcass ultrasound were unaffected by RFI (P > 0.05). The scrotal circumference, sperm concentration, defects, and quality of fresh semen, and ultrasonographic testicular characteristics were unaffected by RFI (P > 0.05). However, velocity parameters such as average path and curvilinear velocities determined by computer-assisted sperm analysis of thawed semen submitted to the rapid thermoresistance test were improved (P < 0.05) in low RFI bulls, but this improvement in quality did not enhance in vitro sperm fertilizing ability. Our results demonstrated significant differences in metabolism and growth performance between bulls of divergent RFI. In addition, there was slight improvement in the semen quality of bulls with low RFI bulls, but this did not enhance in vitro fertilizing ability. Selection of beef bulls for RFI can be performed, which will result in economic benefits by improving the growth performance of the animals without affecting reproductive parameters.(AU)

Development and evaluation of prediction equations for methane emission from Nellore cattle

Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore cattle (392 ± 27 days of age). Equations were generated from intake data and evaluated using root mean square prediction error (RMSPE), and validated by cross-validation. Equations that included DMI and hemicellulose intake (HEMI) [ CH4(MJd−1)=4.08(±1.65)+11.6(±2.34)DMI(kgd−1)−33.4(±7.21)HEMI(kgd−1)] ; DMI and total carbohydrate intake (TCHI) [CH4(MJd−1)=5.26(±1.69)−6.3(±1.47)DMI(kgd−1)+8.8(±1.81)TCI(kgd−1)]; metabolizable energy intake (MEI) and cellulose intake (CELI) [CH4(MJd−1)=5.16(±1.72)−0.13(±0.048)MEI(MJd−1)+7.37(±1.53)CELI(kgd−1)] , and non-fiber carbohydrate intake (NFCI) [CH4(MJd−1)=3.14(±1.48)+3.65(±1.05)NFCI(kgd−1)] resulted in the lowest RMSPE (14.3, 14.1, 14.3 and 14.7%, respectively). When literature equations were evaluated using our database, the most accurate predictions were obtained with equations that included DMI and lignin intake (RMSPE = 15.27%) and MEI, acid detergent fiber intake and lignin intake (RMSPE = 15.7%). The mean error of predicting enteric CH4 emission with the equations developed in this study based on DMI and nutrient intake is 17% and the most accurate predictions are obtained with equations including DMI, carbohydrate intake and MEI.(AU)  

Development and evaluation of prediction equations for methane emission from Nellore cattle

Dry matter intake (DMI), nutrient intake and enteric CH4 emission were evaluated in 48 Nellore cattle (392 ± 27 days of age). Equations were generated from intake data and evaluated using root mean square prediction error (RMSPE), and validated by cross-validation. Equations that included DMI and hemicellulose intake (HEMI) [ CH4(MJd−1)=4.08(±1.65)+11.6(±2.34)DMI(kgd−1)−33.4(±7.21)HEMI(kgd−1)] ; DMI and total carbohydrate intake (TCHI) [CH4(MJd−1)=5.26(±1.69)−6.3(±1.47)DMI(kgd−1)+8.8(±1.81)TCI(kgd−1)]; metabolizable energy intake (MEI) and cellulose intake (CELI) [CH4(MJd−1)=5.16(±1.72)−0.13(±0.048)MEI(MJd−1)+7.37(±1.53)CELI(kgd−1)] , and non-fiber carbohydrate intake (NFCI) [CH4(MJd−1)=3.14(±1.48)+3.65(±1.05)NFCI(kgd−1)] resulted in the lowest RMSPE (14.3, 14.1, 14.3 and 14.7%, respectively). When literature equations were evaluated using our database, the most accurate predictions were obtained with equations that included DMI and lignin intake (RMSPE = 15.27%) and MEI, acid detergent fiber intake and lignin intake (RMSPE = 15.7%). The mean error of predicting enteric CH4 emission with the equations developed in this study based on DMI and nutrient intake is 17% and the most accurate predictions are obtained with equations including DMI, carbohydrate intake and MEI.

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

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.

Reducing supplementation frequency for Nellore beef steers grazing tropical pastures

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)

Estimation of fecal production, digesta flow and digestibility in dairy heifers with different indicator / Estimativa de produção fecal, fluxo de digesta e digestibilidade em novilhas leiteiras com utilização de diferentes indicadores

This study evaluated fecal excretion by means of the internal indicator indigestible neutral detergent fiber (iNDF) and external indicators such as chromium complexed with ethylenediaminetetraacetic acid (Cr-EDTA) and ytterbium chloride (YbCl3), in addition to estimating the duodenal flow of dry matter and the total, ruminal and post-ruminal apparent digestibility coefficients. Eight crossbred Holstein x Zebu heifers were distributed into a 4 x 4 Latin square. Indicators Cr-EDTA, YbCl3 and iNDF did not efficiently estimate the fecal production (p < 0.05), with results of 1.64, 1.71 and 2.71 kg day

Objetivou-se com este trabalho avaliar a produção fecal por meio do indicador interno, fibra em detergente neutro indigestível (FDNi), e externos, cromo complexado com ácido etilenodiaminotetracético (CrEDTA ) e o cloreto de itérbio (YbCl3), além de estimar o fluxo duodenal da matéria seca e os coeficientes de digestibilidades aparentes total, ruminal e pós-ruminal, de diferentes nutrientes. Foram utilizadas oito novilhas mestiças Holandês/Zebu, distribuídas em duplo quadrado latino 4 x 4. Os indicadores Cr-EDTA, YbCl3 e o FDNi não estimaram produção fecal de forma eficiente (p < 0,05), obtendo resultado de 1,64; 1,71 e 2,71 kg dia

Reutilization of chemical waste in methodologies for analyses of neutral detergent fiber and acid detergent fiber / Reutilização de resíduos químicos em metodologias para análises de fibra em detergenteneutro e fibra em detergente ácido

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.

Reutilization of chemical waste in methodologies for analyses of neutral detergent fiber and acid detergent fiber / Reutilização de resíduos químicos em metodologias para análises de fibra em detergenteneutro e fibra em detergente ácido

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)

Estimation of fecal production, digesta flow and digestibility in dairy heifers with different indicator / Estimativa de produção fecal, fluxo de digesta e digestibilidade em novilhas leiteiras com utilização de diferentes indicadores

This study evaluated fecal excretion by means of the internal indicator indigestible neutral detergent fiber (iNDF) and external indicators such as chromium complexed with ethylenediaminetetraacetic acid (Cr-EDTA) and ytterbium chloride (YbCl3), in addition to estimating the duodenal flow of dry matter and the total, ruminal and post-ruminal apparent digestibility coefficients. Eight crossbred Holstein x Zebu heifers were distributed into a 4 x 4 Latin square. Indicators Cr-EDTA, YbCl3 and iNDF did not efficiently estimate the fecal production (p < 0.05), with results of 1.64, 1.71 and 2.71 kg day <->1, respectively, compared with the total feces collection, which resulted in 1.39 kg day <->1. The estimated values of dry matter flow, both for the methodologies of single and double indicator, can be considered biologically acceptable. However, the value obtained by the Cr-EDTA/YbCl3 association, used as a double indicator, was the most reliable, due to better recovery of the external indicators (Cr-EDTA and YbCl3), which have had averages of 89 and 85%, respectively, in comparison with the internal one (iNDF), which averaged 67%. The ruminal and post-ruminal digestibility coefficients, estimated by the Cr-EDTA/YbCl3 association, were considered the best indicators owing the dry matter flow estimated by this association.(AU)

Objetivou-se com este trabalho avaliar a produção fecal por meio do indicador interno, fibra em detergente neutro indigestível (FDNi), e externos, cromo complexado com ácido etilenodiaminotetracético (CrEDTA ) e o cloreto de itérbio (YbCl3), além de estimar o fluxo duodenal da matéria seca e os coeficientes de digestibilidades aparentes total, ruminal e pós-ruminal, de diferentes nutrientes. Foram utilizadas oito novilhas mestiças Holandês/Zebu, distribuídas em duplo quadrado latino 4 x 4. Os indicadores Cr-EDTA, YbCl3 e o FDNi não estimaram produção fecal de forma eficiente (p < 0,05), obtendo resultado de 1,64; 1,71 e 2,71 kg dia <->1, respectivamente, quando comparado à coleta total de fezes, que obteve resultado de 1,39 kg dia <->1. Os valores estimados de fluxo de matéria seca, tanto para a metodologia de único, quanto para de duplo indicador, podem ser considerados biologicamente aceitáveis. Contudo, o valor obtido pela associação Cr-EDTA/YbCl3, utilizada na forma de duplo indicador, foi o mais confiável, pela melhor recuperação dos indicadores externos (Cr-EDTA e YbCl3), que obtiveram médias de 89 e 85%, respectivamente, em comparação ao interno (FDNi), que obteve média 67%. Os coeficientes de digestibilidade ruminal e pós ruminal, estimados pela associação Cr-EDTA/YbCl3, foram considerados melhores, em consequência do valor de fluxo de matéria seca estimado por esta associação.(AU)

Effects of different lipid levels on protozoa population, microbial protein synthesis and rumen degradability in cattle / Efeito de teores de lipídeos sobre a população de protozoários, síntese de proteína microbiana e a degradação ruminal em bovinos

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.

Desempenho de bovinos em pastejo submetidos a duas frequências de suplementação no período da seca / Steers performances in grazing submitted by two supplementation intervals during dry season

Com o objetivo de avaliar diferentes frequências de suplementação no período da seca foram utilizados 48 bovinos da raça Nelore com peso médio inicial de 320 kg, em pastagem de Brachiaria brizantha cv. Marandu, submetidos aos tratamentos: suplementação diária e suplementação três vezes por semana, a fim de avaliar o ganho médio diário de peso corporal dos animais nesse período. Os animais de ambos os tratamentos receberam, semanalmente 7,0 kg de suplemento animal-1 e foram pesados em intervalos de 28 dias. Os dados foram analisados pelo procedimento MIXED do SAS (2004) com medidas repetidas no tempo. Observou-se oferta de forragem média de 4,2 toneladas de MS ha-1, com teores médios de 3,5% de PB, 82,24% de FDN e 64,97% de FDA na forragem. Não foi observada diferença (p > 0,01) nos ganhos de peso médio diário entre os animais que receberam o suplemento diariamente (0,23 kg dia-1) e aqueles que receberam três vezes por semana (0,13 kg dia-1). Portanto, as frequências de suplementação não influenciaram no ganho diário de peso corporal dos animais no período da seca.(AU)

This work was carried out to evaluate different frequencies of supplementation during the dry season. Forty-eight Nellore steers with 320 kg of initial live weight were fed with Brachiaria brizantha cv. Marandu pasture on a continuous stocking rate. The animals were submitted to following treatments: daily supplementation and supplementation three times a week. The animals in both treatments received 7 kg of supplementation animal-1 weekly, and were weighted at 28-day intervals. The data were analyzed by the MIXED procedure in SAS (2004), with measurements repeated over time. The study observed average forage allowance of 4.2 tons of DM ha-1, with 3.5% CP, 82.24% NDF and 64.97% ADF. There was no difference (p < 0.01) among daily weight gains of animals who received daily supplementation and those received supplementation three times a week (0.23 and 0.13 kg day-1, respectively). Therefore, the supplementation intervals did not influence steer performance during the dry season.(AU)

Influência de fontes de nitrogênio no consumo e digestibilidade aparente total e parcial de novilhos alimentados com cana-de-açúcar / Effects of nitrogen sources in the intake, total and partial digestibility of steers feeding on sugarcane

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)

Influência de fontes de nitrogênio no consumo e digestibilidade aparente total e parcial de novilhos alimentados com cana-de-açúcar / Effects of nitrogen sources in the intake, total and partial digestibility of steers feeding on sugarcane

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.

Desempenho de bovinos em pastejo submetidos a duas frequências de suplementação no período da seca / Steers performances in grazing submitted by two supplementation intervals during dry season

Com o objetivo de avaliar diferentes frequências de suplementação no período da seca foram utilizados 48 bovinos da raça Nelore com peso médio inicial de 320 kg, em pastagem de Brachiaria brizantha cv. Marandu, submetidos aos tratamentos: suplementação diária e suplementação três vezes por semana, a fim de avaliar o ganho médio diário de peso corporal dos animais nesse período. Os animais de ambos os tratamentos receberam, semanalmente 7,0 kg de suplemento animal-1 e foram pesados em intervalos de 28 dias. Os dados foram analisados pelo procedimento MIXED do SAS (2004) com medidas repetidas no tempo. Observou-se oferta de forragem média de 4,2 toneladas de MS ha-1, com teores médios de 3,5% de PB, 82,24% de FDN e 64,97% de FDA na forragem. Não foi observada diferença (p > 0,01) nos ganhos de peso médio diário entre os animais que receberam o suplemento diariamente (0,23 kg dia-1) e aqueles que receberam três vezes por semana (0,13 kg dia-1). Portanto, as frequências de suplementação não influenciaram no ganho diário de peso corporal dos animais no período da seca.

This work was carried out to evaluate different frequencies of supplementation during the dry season. Forty-eight Nellore steers with 320 kg of initial live weight were fed with Brachiaria brizantha cv. Marandu pasture on a continuous stocking rate. The animals were submitted to following treatments: daily supplementation and supplementation three times a week. The animals in both treatments received 7 kg of supplementation animal-1 weekly, and were weighted at 28-day intervals. The data were analyzed by the MIXED procedure in SAS (2004), with measurements repeated over time. The study observed average forage allowance of 4.2 tons of DM ha-1, with 3.5% CP, 82.24% NDF and 64.97% ADF. There was no difference (p < 0.01) among daily weight gains of animals who received daily supplementation and those received supplementation three times a week (0.23 and 0.13 kg day-1, respectively). Therefore, the supplementation intervals did not influence steer performance during the dry season.

Steers performances in grazing submitted by two supplementation intervals during dry season - DOI: 10.4025/actascianimsci.v31i4.5918 / Desempenho de bovinos em pastejo submetidos a duas frequências de suplementação no período da seca - DOI: 10.4025/actascianimsci.v31i4.5918

This work was carried out to evaluate different frequencies of supplementation during the dry season. Forty-eight Nellore steers with 320 kg of initial live weight were fed with Brachiaria brizantha cv. Marandu pasture on a continuous stocking rate. The animals were submitted to following treatments: daily supplementation and supplementation three times a week. The animals in both treatments received 7 kg of supplementation animal-1 weekly, and were weighted at 28-day intervals. The data were analyzed by the MIXED procedure in SAS (2004), with measurements repeated over time. The study observed average forage allowance of 4.2 tons of DM ha-1, with 3.5% CP, 82.24% NDF and 64.97% ADF. There was no difference (p < 0.01) among daily weight gains of animals who received daily supplementation and those received supplementation three times a week (0.23 and 0.13 kg day-1, respectively). Therefore, the supplementation intervals did not influence steer performance during the dry season.

Com o objetivo de avaliar diferentes frequências de suplementação no período da seca foram utilizados 48 bovinos da raça Nelore com peso médio inicial de 320 kg, em pastagem de Brachiaria brizantha cv. Marandu, submetidos aos tratamentos: suplementação diária e suplementação três vezes por semana, a fim de avaliar o ganho médio diário de peso corporal dos animais nesse período. Os animais de ambos os tratamentos receberam, semanalmente 7,0 kg de suplemento animal-1 e foram pesados em intervalos de 28 dias. Os dados foram analisados pelo procedimento MIXED do SAS (2004) com medidas repetidas no tempo. Observou-se oferta de forragem média de 4,2 toneladas de MS ha-1, com teores médios de 3,5% de PB, 82,24% de FDN e 64,97% de FDA na forragem. Não foi observada diferença (p > 0,01) nos ganhos de peso médio diário entre os animais que receberam o suplemento diariamente (0,23 kg dia-1) e aqueles que receberam três vezes por semana (0,13 kg dia-1). Portanto, as frequências de suplementação não influenciaram no ganho diário de peso corporal dos animais no período da seca.

Frequência da suplementação de bovinos da raça Nelore mantidos em pastagens

O objetivo deste estudo foi avaliar o efeito da frequência de suplementação no comportamento ingestivo animal, ingestão e digestibilidade da matéria seca, desempenho e características da carcaça; além de verificar o efeito da frequência de suplementação na, fermentação ruminal, fluxo de nutrientes, eficiência de síntese microbiana e produção de metano ruminal de bovinos Nelore, mantidos em pastagem de Brachiaria brizantha cv Marandu, durante o período da seca. O suplemento foi fornecido diariamente, de segunda a sexta-feira e suspenso aos sábados e domingos e em dias alternados, na ordem de 1%; 1,4% e 2,0% do peso corporal, respectivamente. O suplemento foi composto de polpa cítrica, farelo de algodão e uréia. Os dados foram submetidos à análise de variância com medidas repetidas no tempo, pelo procedimento MIXED do SAS, e as médias foram comparadas através do teste de Tukey. A frequência de suplementação não influenciou o desempenho, o comportamento ingestivo animal, a ingestão de matéria seca, a eficiência de síntese microbiana e a produção de metano ruminal. Os meses do ano exerceram efeito na massa e composição química da forragem, no desempenho e na produção de metano de bovinos em pastejo. Foram verificadas interações significativas entre as frequências de suplementação e meses avaliados na digestibilidade da matéria seca, pH e concentração de nitrogênio amoniacal ruminal, e na produção de ácidos graxos de cadeia curta. As características de carcaça foram influenciadas pelas frequências de suplementação, no entanto, encontraram-se no limite desejável de acabamento. Desta forma, a redução da frequência de suplementação torna-se uma boa opção no sistema de suplementação, pois permite diminuir custos com suplemento e equipamentos

The objective of this study was to evaluate the effect of supplementation frequency on behavior animal intake, dry matter intake, dry matter digestibility, performance and characteristics of the carcass; besides the effect of the supplementation frequency on the ruminal fermentation, flow of nutrients, microbial synthesis efficiency and ruminal methane production by Nellore steers grazing Brachiaria brizantha cv. Marandu pasture during dry season. The supplement was offered daily or from Monday to Friday or in alternate days, in the order of 1%, 1.4% and 2.0% of the body weight, respectively. This supplement was composed by citrus pulp, cottonseed meal and urea. The data were analyzed by analysis of variance (repeated measure in time), using the proc mixed procedure of SAS, and the averages were cooperated through Tukey test. The supplementation frequency did not influence the performance, behavior animal intake and dry matter intake, microbial synthesis efficiency and ruminal methane production. Months of the year affected the herbage mass and their chemical composition, performance and ruminal methane production of animals. They were verified significant interaction between supplementation frequency and months for dry matter digestibility, ruminal pH and concentration of ruminal ammonia nitrogen and short-chain fatty acids production. Carcass characteristics were influenced by the supplementation frequency, however, they were in the desirable limit of finish. This way, the reduction in the supplementation frequency became a good option in the production system, because of reducing costs and time with supplement and equipments