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A meta-analytic study was conducted to develop and evaluate models for the prediction of pasture dry matter intake (DMIpasture) by beef cattle in tropical conditions. 804 individual observations of DMIpasture were used, taken from 23 studies through analysis of mixed models, including the study as a random effect. To evaluate the accuracy and precision of the new models proposed as well as for the models of Azevedo et al., (2016) and Minson and McDonald (1987), an independent databank with 87 means from treatments of 21 experiments (n = 888 animals) was used. Three prediction models were adjusted: Model I (Animal Information), Model II (Animal Information + Supplement) and Model III (Animal Information + Supplement + Pasture). The proposed models presented similarity for the average square root of the prediction error. The inclusion of the predictive variables for supplementation (supplement dry matter intake - DMIsupplement - % of the body weight and crude protein intake through supplement) with the variables for the animal (BW0,75 and average daily gain) and of the pasture (% of crude protein) in Model III improves accuracy and precision and provides higher determination and correlation coefficients, and agreement than the other proposed models. Similarly, it was found to be more accurate and precise than the equations of Azevedo et al., (2016) and Minson and McDonald (1987), which presented lower precision and accuracy than the proposed models. The DMIpasture for beef cattle in tropical conditions is more accurate and precise when the information for the animal, supplement and pasture is included.

The objective of this study was to evaluate diets containing monensin (MON) associated or not with virginiamycin (VM) or functional oil based on cashew nut shell and castor beans (FOcc) for beef cattle in feedlots on nutritional (intake and digestibility) and productive parameters. A total of 1410 non-castrated Nellore cattle were selected, with an average age of 18 months and with an initial mean body weight (BW) of 305 ± 41.52 kg. The diet showed a roughage to concentrate ratio of 23:77, with the supply of corn silage as a source of roughage. The following additive inclusions in the diet were evaluated: (1) MON: 27 mg MON/kg dry matter (DM); (2) MON + VM: 22 mg MON/kg DM + 19 mg VM/kg DM; and (3) MON + FOcc: 22 mg MON/kg DM + 500 mg FOcc/kg DM. Statistical analyses were obtained through a linear model using initial BW and days of feedlot as covariables and comparisons between treatments using mutually orthogonal linear contrasts with a 5% significance level. The association or not of MON with VM or FOcc does not affect any of the nutritional and productive parameters evaluated. Animals that receive diets with MON + VM have higher average daily gain and feed efficiency (FE) than those that receive MON + FOcc without showing differences in nutritional parameters. The supply of MON associated with VM or FOcc does not increase intake and productive performance and, consequently, efficiency of feedlot beef cattle. However, in the case of use associated with MON, the VM provides greater performance than FOcc without changing food intake.

Context Cupuassu is frequently cultivated in Brazil as well as in the warm lowlands of other tropical American countries. Cupuassu nut contains high levels of theobromine and ether extra ct, which could negatively affect the intake and digestibility of nutrients, when included in livestock diets. Aims The present study was undertaken to evaluate how replacing maize with cupuassu nut affects feed intake, efficiency of microbial synthesis and nitrogen (N) balance in Nellore bulls at pasture. Methods Five Nellore bulls with an initial bodyweight of 336.7 ± 12.8 kg (mean ± s.d.) were kept in individual paddocks of Urochloa brizantha cv. Marandu. Concentrate supplements containing equal amounts of N and different concentrations of dried whole cupuassu nut (0%, 25%, 50%, 75% or 100% replacement of maize) were fed to bulls in a 5 × 5 latin square design, with each animal allocated to each diet for a period of 20 days, including a 14-day period of adaptation. Key results Intake of all dietary components and total digestible nutrients, except ether extract, theobromine and neutral detergent fibre corrected for ash and protein, decreased linearly with the addition of cupuassu. Theobromine intake varied from 13.86 (25% cupuassu nut) to 36.67 (100% cupuassu nut) mg/kg bodyweight. The inclusion of cupuassu in the supplement led to a linear decrease in ruminal ammonia-N concentration, N balance, and efficiency of microbial synthesis. Conclusion Replacing maize with dried whole cupuassu nut in concentrate supplements reduces the intake of DM from both supplement and pasture, the efficiency of microbial synthesis, and the N balance in grazing beef cattle. Implications The replacement of maize by dried whole nut of cupuassu in concentrate supplements for grazing cattle is not recommended because it reduces supplement intake and nitrogen retention, and it is likely to decrease liveweight gain.

The objective of this study was to evaluate the inclusion of different levels of 0.0%; 0.7%; 1.4% and 2.1% of Noni (Morinda citrifolia) in the feeding of lambs regarding ingestive behavior and physiological variables. The experiment was carried out in a double Latin (4x4) experimental design with eight animals, consisting of four periods and four experimental rations. Eight lambs with no defined racial pattern were used, with mean initial body weight (BW) of 23.74 ± 1.00 kg. The ingestive behavior was performed during 24 hours, always on the last day of each experimental period. The physiological variables and the environmental variables were measured during three days of each period. Data were submitted for analysis of variance and, when significant, regression equation was applied at 5% of probability. Statistical analysis was performed considering the subdivision of the plot, which consisted of the diurnal and nocturnal evaluation times for the ingestive behavior and the morning and afternoon periods for the physiological variables. The inclusion of Noni in fed lambs did not change (p > 0.05) the time spent with ingestive behaviors for dry matter intake (DMI), rumination (RUM), idleness (IDL), water intake (WIN) and other activity (OAC). However, the daytime During the period there was gr eater (p < 0.05) time use for DMI, WIN and OAC. Inclusion of Noni to diets provided higher (p > 0.05) time use during the night time for RUM and IDL. The physiological variables were not influenced (p > 0.05) by the inclusion of Noni in the diets of lambs. However, higher mean (p < 0.05) body temperature of the front and rear, rectal temperature and respiratory rate of the lambs were observed during the afternoon. The inclusion of up to 2.1% of Noni in lamb feed does not alter ingestive behavior and physiological variables. However, the consumption of dry matter and water is higher during the diurnal period, while rumination and idleness are more active during the night period.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:07:52Z No. of bitstreams: 1 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) Made available in DSpace on 2013-08-22T19:07:53Z (GMT). No. of bitstreams: 1 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) Previous issue date: 2012-02-01 Made available in DSpace on 2013-09-30T20:12:37Z (GMT). No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Previous issue date: 2012-02-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:18:22Z No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Made available in DSpace on 2014-05-20T15:18:22Z (GMT). No. of bitstreams: 2 S1516-35982012000200023.pdf: 46654 bytes, checksum: 30965eba025aed84fff84c6dd7ef8ce0 (MD5) S1516-35982012000200023.pdf.txt: 26582 bytes, checksum: 58a4225e0eb7844e6898ca66458e29f7 (MD5) Previous issue date: 2012-02-01 The objective of this study was to determine requirements of calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K) and sodium (Na) for grazing zebu bovines. The experiment area was composed of Brachiaria decumbens paddocks. Twenty-seven non-castrated animals, with initial live weight of 311.0 kg and at an average age of 14 months were used. Three animals were slaughtered, after adaptation period, so they were used as control for estimates of empty body weight and initial body composition of animals in the experiment. Out of the 24 remaining animals, four were sent to the maintenance group with restrict grazing time to limit energy intake close to the maintenance level. The other 20 animals were distributed in four treatments: mineral mixture, self-control intake and three-times-a-week-offer frequency (offered on Mondays, Wednesdays and Fridays) and daily. Concentrations of all studied macro elements in empty body and empty body gain decreased as live weight increased. The ratios obtained for g Ca/100 g of retained protein and g P/100 g of retained protein were 9.18 and 4.72, respectively. Total dietary requirement of calcium was lower than the one recommended by NRC (2000), but P requirement was very close to that. UFMT ICAA UFV DZO UNESP UNESP

Made available in DSpace on 2018-11-12T17:26:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-09-01. Added 1 bitstream(s) on 2021-07-14T17:51:18Z : No. of bitstreams: 1 S1519-99402015000300699.pdf: 187811 bytes, checksum: 1df3cc94ee7fb2fa1e66eadd2d7a0cfa (MD5) ResumoObjetivou-se avaliar o consumo de matéria seca, o ganho de peso total e a eficiência bioeconômica de bovinos de corte terminados em confinamento com diferentes pesos corporais ao início do confinamento nos períodos de seca e de chuvas. Registros de CMS, ganho de peso total (GPT), conversão alimentar (CA), eficiência alimentar (EA), tamanho de lote e tempo de permanência (TP) no confinamento de 13.686 bovinos de corte machos com predominância de sangue nelore terminados no ano de 2009, foram utilizados para discriminar possíveis diferenças quanto ao peso de entrada (até 350kg ou acima de 350kg) e da época do ano (seca ou águas). Observou-se ausência de efeitos da época do ano (chuvas x seca) para o CMS e o GPT dos animais independente da classe de peso que apresentaram diferenças, com os animais mais leves apresentando menores CMS e maiores GPT e, consequentemente, maior eficiência que os animais mais pesados ao início do confinamento. O valor de compra por cabeça interfere altamente sobre valor por cabeça na saída do confinamento que é dependente do consumo de matéria seca e do ganho de peso total para maximização da receita. AbstractIt was aimed to evaluate the dry matter intake (DMI), total weight gain (TWG) and the bioeconomic efficiency of feedlot beef cattle with different body weights in dry and rainy season. Records of DMI, TWG, feed conversion (FC), feed efficiency (EA), lot size and feedlot length of stay (LS) of 13,686 beef cattle males with predominance of Nelore blood finished the year 2009, were used to discriminate possible differences in input weight (up to 350kg or above 350kg) and the season (dry or water). There was no effect on the season (rainy x dry) to DMI and TWG of independent animals, regardless of weight class that showed differences, with the lighter animals presented lower DMI and higher TWG and therefore higher efficiency than animals with higher higher starting weights of feedlot. The purchase price per head affects highly on value per head for the exit of feedlot which is dependent on dry matter intake and total weight gain for maximizing revenue. Universidade Federal de Mato Grosso Universidade Federal de Mato Grosso Instituto de Ciências Agrárias e Ambientais Universidade Estadual Paulista Universidade Estadual Paulista

Avaliou-se o efeito da substituição do milho pela glicerina bruta (GB) sobre o desempenho e a viabilidade econômica em bovinos de corte mantidos a pasto no período das águas. Foram utilizados 30 animais com peso corporal médio inicial de 238,6±21,24kg distribuídos em delineamento inteiramente casualizado entre os tratamentos: suplementação mineral e suplementação concentrada (1,0kg/animal, 30% PB) com 0; 33; 66 e 100% de GB em substituição ao milho. O fornecimento de suplementos proteico-energéticos proporcionou maior ganho médio diário (GMD) e peso corporal (PC) final em relação aos que receberam suplementação mineral. O incremento no GMD foi em média de 0,200 kg por dia. Não houve efeito dos níveis de substituição do milho sobre o GMD cujos ganhos foram de 0,817; 1,042; 1,064 e 1,005, respectivamente, para os níveis 0, 33, 66 e 100%. O fornecimento de 1,0kg de suplementos proteico-energéticos contendo 30% de proteína bruta melhorou o desempenho de bovinos de corte a pasto no período das águas, reduzindo o tempo de ocupação da pastagem quando comparado com animais que recebem apenas suplementação mineral. Pode-se substituir 100% do milho pela GB sem que haja queda no desempenho dos animais sendo que a substituição de até 66% do milho pela GB mostrou-se economicamente viável. The effect of replacing corn by crude glycerin (GB) on the performance and economic viability of beef cattle at pasture in the rainy season was evaluated. A total of 30 animals with average body weight (BW) of 238.6 ± 21.24 kg in a completely randomized design between treatments: mineral supplement and concentrate supplementation (1.0 kg/animal, 30% CP) with 0, 33, 66 and 100% of GB replacing corn. The supply of protein-energy supplements increased average daily gain (ADG) and final BW than those who received only mineral supplements. The increase in ADG was 0.200 kg/day. No effect of the levels replacement of corn on ADG that provided gains of 0.817, 1.042, 1.064 and 1.005, respectively, for 0, 33, 66 and 100%. The supply of 1.0 kg of protein-energy supplements containing 30% CP improves the performance of the pasture beef cattle during the wet, reducing the pasture occupation time compared to animals receiving only mineral supplementation. The crude glycerin can replace 100% of the corn in supplements offered in the proportion of 0.45% of BW without decrease animal performance. When the price of crude glycerin represent 54% of the price of corn to replace up to 66% of the corn showed to be economically viable.

The objective of this study was to evaluate the effects of frequency of concentrate supplementation on the daytime feeding behavior (grazing, rumination, drinking, and idle times), production performance, and economic viability of grazing cattle in the rainy season. A total of 120 uncastrated Nellore animals with an average body weight (BW) of 382.5 ± 32.2 kg were allocated to palisadegrass (Brachiaria brizantha) paddocks for the experiment. We evaluated supplements provided in the amount of 2.0 kg/animal, supplied three times weekly (3tw) or daily (7X). Animals supplemented 3X (5.46%) spent more time (%) drinking water than those supplemented 7X (3.72%). Grazing time and animal performance were not influenced by the frequency of supplementation. Average daily gain was 1.00 and 1.02 kg/animal for the groups under 3X and 7X, respectively. Expenditures on transportation and labor are lower (43%) when animals are supplemented 3X. Supplementation provided three times per week does not affect the grazing time or the performance of beef cattle in the rainy season, but rather implies an expressive reduction of expenditures on labor and distribution of supplements. Objetivou-se avaliar os efeitos da frequência de suplementação concentrada sobre o comportamento ingestivo diurno (tempos de pastejo, de ruminação, de bebedouro e de ócio), o desempenho produtivo e a viabilidade econômica de bovinos de corte em pastejo no período das águas. Foram utilizados 120 animais da raça Nelore não-castrados com peso corporal (PC) médio de 382,5 ± 32,2 kg alocados em piquetes formados com capim Marandu (Brachiaria brizantha). Avaliaram-se suplementos ofertados em quantidade de 2,0 kg/animal distribuídos três vezes por semana (3X) e diariamente (7X). O tempo gasto (%) no consumo de água foi maior para os animais que receberam suplementação 3X (5,46%) do que os animais que receberam suplementação 7X (3,72%). O tempo gasto com pastejo e desempenho dos animais não sofreram influência da frequência de oferta do suplemento. O ganho médio diário foi 1,00 e 1,02 kg/animal, respectivamente, para a suplementação 3X e 7X. Os gastos com transporte e mão-de-obra são menores (43%) quando suplementos são ofertados 3X. O fornecimento de suplementos três vezes por semana não afeta o tempo de pastejo e o desempenho de bovinos de corte no período das águas e implica em expressiva redução nos custos com a mão-de-obra e com a distribuição de suplementos.

Objetivou-se avaliar o desempenho produtivo, a eficiência econômica e a taxa de ingestão do suplemento em novilhos mestiços em pastejo no período da seca. Foram utilizados 20 novilhos Holandês × Zebu, não-castrados, com 19 meses de idade e peso médio inicial de 315,0 kg distribuídos em quatro piquetes de Brachiaria decumbens com 3,0 ha cada. Cada animal recebeu 4,0 kg/dia de suplemento, constituído de milho moído, farelo de algodão, mistura mineral e ureia/sulfato de amônia em quatro níveis: 0; 1,2; 2,4 ou 3,6% na matéria natural. O peso final e o ganho médio diário apresentaram comportamento quadrático, com respostas máximas estimadas obtidas para os níveis de ureia de 1,67% (399,9 kg) e 1,60% (0,956 kg/dia), respectivamente. O peso de carcaça quente, o rendimento de carcaça, as proporções de tecidos muscular, adiposo, ósseo e a relação músculo:osso na carcaça não foram influenciados pelos níveis de ureia. À medida que se elevou o nível de ureia, houve maior tempo para o suplemento ser totalmente consumido. A avaliação econômica dos suplementos, de forma diferencial ao tratamento sem ureia, comprovou maior eficiência econômica no nível de 2,4% de ureia. The objective was to evaluate productive efficiency, economic performance and supplement intake rate in crossbred steers on pasture during the dry season. Twenty 19-month-old Holstein × Zebu steers with 315±25 kg of live weight were alocated into four paddocks of Brachiaria decumbens with 3.0 ha each. Each animal received 4.0 kg/day of supplement based on ground corn grain, cottonseed meal, mineral mixture and urea/ammonium sulfate in four levels (0, 1.2, 2.4 and 3.6%) as fed basis. Final live weight and average daily gain presents quadratic behavior. Maximum responses estimated were observed at levels 1.67% (399.9 kg) and 1,60% (0.956 kg/day) urea, respectively. Hot carcass weight, carcass yield, the proportions of muscular, fat and bone tissues and the muscle:bone in the carcass ratio were not influenced by the levels of urea in the supplements. The economical evaluation of the supplements, unlike the treament without urea, showed greater economic efficiency for supplement containing 2,4% of urea. As urea levels were increased, more time was observed for total consumption of the supplements.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T19:07:35Z No. of bitstreams: 1 S1516-35982010000300021.pdf: 239389 bytes, checksum: 171248ed553818a6ff99d539a0bab740 (MD5) Made available in DSpace on 2013-08-22T19:07:35Z (GMT). No. of bitstreams: 1 S1516-35982010000300021.pdf: 239389 bytes, checksum: 171248ed553818a6ff99d539a0bab740 (MD5) Previous issue date: 2010-03-01 Made available in DSpace on 2013-09-30T20:12:08Z (GMT). No. of bitstreams: 2 S1516-35982010000300021.pdf: 239389 bytes, checksum: 171248ed553818a6ff99d539a0bab740 (MD5) S1516-35982010000300021.pdf.txt: 39089 bytes, checksum: f54a4dd3baa3b1937bbb593a857eb187 (MD5) Previous issue date: 2010-03-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T15:18:17Z No. of bitstreams: 2 S1516-35982010000300021.pdf: 239389 bytes, checksum: 171248ed553818a6ff99d539a0bab740 (MD5) S1516-35982010000300021.pdf.txt: 39089 bytes, checksum: f54a4dd3baa3b1937bbb593a857eb187 (MD5) Made available in DSpace on 2014-05-20T15:18:17Z (GMT). No. of bitstreams: 2 S1516-35982010000300021.pdf: 239389 bytes, checksum: 171248ed553818a6ff99d539a0bab740 (MD5) S1516-35982010000300021.pdf.txt: 39089 bytes, checksum: f54a4dd3baa3b1937bbb593a857eb187 (MD5) Previous issue date: 2010-03-01 Objetivou-se avaliar o efeito da frequência de oferta de suplementos proteicos sobre as características nutricionais de bovinos de corte em pastejo durante o período de seca. Utilizaram-se cinco novilhos mestiços Nelore nãocastrados, com peso médio inicial de 290 kg, fistulados no esôfago e rúmen e distribuídos em delineamento quadrado latino 5 × 5. A área experimental foi composta de cinco piquetes de Brachiaria decumbens, cada um com 0,40 hectare. O experimento foi composto de cinco períodos experimentais de 15 dias, com os sete primeiros dias destinados à adaptação dos animais. As estratégias estudadas foram autocontrole de consumo e oferta de suplementos (1,0 kg/dia) em três frequências: 3 vezes/semana (às segundas, quartas e sextas-feiras), 5 vezes/semana (de segunda a sexta-feira), 6 vezes/semana (de segunda a sábado) e diariamente. Não houve efeito das frequencias de suplementação sobre os consumos expressos em kg/dia ou % PV. A frequência de suplementação teve efeito nas digestibilidades aparentes total e ruminal da MS e da PB, que foram maiores nos animais do grupo autocontrole. Os valores médios de pH observados no dia em que os animais não receberam suplemento foram de: 6,54±0,13; 6,48 ± 0,15 e 6,61 ± 0,07, respectivamente, para as frequências 3 vezes/semana, 5 vezes/semana e 6 vezes/semana. A concentração do NH3 foi 14,65 ± 5,78; 13,57 ± 5,30 e 15,30 ± 4,98 mg/dL de líquido ruminal, respectivamente, para as frequências 3 vezes/semana, 5 vezes/semana e 6 vezes/semana nos dias em que os animais não receberam suplemento. As eficiências microbianas e as concentrações de nitrogênio na urina e no soro sanguíneo são afetadas pelas estratégias estudadas e maiores nos animais alimentados com suplemento autocontrole. The objective of this study was to evaluate the effect of the frequency of protein supplementation on the nutritional characteristics of beef cattle during the dry season. Five Nellore crossbred steer were used 290.0 kg LW, fistulated in the rumen and esophagus, distributed in a 5 × 5 Latin square design. The experimental area consisted of five 0.40 ha Brachiaria decumbens paddocks. The experiment consisted of five 15-day experimental periods, with the first seven days for the animals to adapt. The strategies studied were: self-feed supplementation and supplementation (1.0 kg/animal/day) offered at three frequencies: three times/week (Monday, Wednesday and Friday), five times/week (Monday to Friday) and six times/week (Monday to Saturday) and daily. There were no effects of the different strategies on the intake expressed in kg/day or LW percentage. The supplementation frequency affected the total DM apparent digestibility and ruminal crude protein apparent digestibility that were higher in the self-feed supplementation group. The mean pH values, observed on the day when the animals were not supplemented were: 6.54 ± 0.13; 6.48 ± 0.15 and 6.61 ± 0.07, respectively for, the frequencies 3 times/week, 5 times/ week and 6 times/week. The NH3 concentration was: 14.65 ± 5.78; 13.57 ± 5.30 and 15.30 ± 4.98 mg/dL ruminal liquid, respectively, for the frequencies 3 times/week, 5 times/week and 6 times/week, on days without supplementation. The microbial efficiency and nitrogen concentrations in the urine and serum are affected by the strategies studied and are higher in the animals fed self feed supplementation. UFMT ICAA Departamento de Zootecnia UFV Departamento de Zootecnia UNESP UNESP

Objetivou-se determinar as exigências proteicas de bovinos anelorados sob pastejo em cinco piquetes de Brachiaria decumbens. Utilizaram-se 27 animais não-castrados, com peso corporal (PC) médio inicial de 311,0 kg e idade média de 14 meses. Três animais foram abatidos após o período de adaptação para servirem como referência para as estimativas do peso de corpo vazio (PCVZ) e da composição corporal iniciais dos animais mantidos no experimento. Dos 24 animais restantes, quatro foram designados ao grupo mantença, que teve tempo de pastejo restrito. Os 20 demais foram distribuídos em quatro tratamentos: mistura mineral, autocontrole e duas frequências de alimentação: três vezes/semana (às segunda, quartas e sextas-feiras) ou diariamente. As exigências líquidas de proteína para ganho diminuíram com o aumento do peso vivo (PV) dos animais. A exigência líquida de proteína encontrada para um animal com peso corporal de 250 kg foi de 153,71 g/kg GPCVZ, enquanto para um animal de 400 kg foi de 141,86 g/kg GPCVZ. A seguinte equação foi obtida para estimativa da proteína retida em relação ao ganho de peso vivo em jejum (GPVJ) e da energia retida (ER): PR (g/dia) = -34,6109 + 257,956*GPVJ – 17,01*ER. As exigências de proteína metabolizável estimadas para mantença e ganho de peso foram de 357,77 e 288,33 g/kg PC, respectivamente, para um bovino não-castrado de 400 kg de PC sob pastejo. Animais que consomem suplementos proteicos apresentam maiores exigências de proteína degradável no rúmen (PDR) em comparação a animais sem suplementação, em virtude do maior consumo de nutrientes digestíveis totais. Para um animal de 400 kg de PV sob suplementação, as exigências de proteína degradável no rúmen e proteína não-degradável no rúmen são de 764,22 e 73,89, respectivamente, que correspondem à exigência de proteína bruta de 838,10 g/dia. The objective of this study was to determine the protein requirements of Zebu sterrs grazing grazing five Bracharia decumbens paddocks. Twenty-seven steers averaging initial body weight (BW) of 311.0 kg and 14 months old were used. Three animals were slaughtered after the adaptation peiod to serve as reference for the estimate of empty body weight (EBW), and the initial body composition of the animals kept in the experiment. Among the 24 remaining animals, four were placed in the maintenance group, with restricted grazing time. The other 20 were allotted to four treatments: mineral mixture, self-feed and two feeding frequencies (three times a week, Monday, Wednesday and Friday, or daily. The net protein requirements for gain decreased as body weight increased. The protein requirement detected for an animal with 250 kg BW was 153.71 g/kg EBW, while for an animal of 400 kg live weight it was 141.86 g/kg EBG. The following equation was obtained to estimate the retained protein (RP) in function of the fasting live weight gain (LWG) and the retained energy (RE): RP = -34.6109 + 257.956*LWG – 17.01*RE. The metabolizable protein requirements estimated for maintenance and gain were 357.77 and 288.33 g/kg BW, respectively, for a 400 kg BW grazing steer. The animals fed protein supplementation presented greater degradable protein requirements in the rumen than non-supplemented animals, due the greater intake of total digestible nutrients (TDN). For an animal with 400 kg BW fed protein supplementation, the daily requirements for degradable protein in the rumen and non-degradable protein are, respectively, 764.22 and 73.89 g that corresponded to a crude protein requirement of 838.10 g/day.

Foram utilizadas 12 vacas da raça Holandesa, entre puras e mestiças, distribuídas em três quadrados latinos 4 x 4, organizados de acordo com os dias em lactação, com o objetivo de avaliar o efeito de dois períodos de coleta de fezes (dois ou seis dias), em intervalos de 26 horas, e de dois indicadores (fibra em detergente neutro indigestível (FDNi) ou fibra insolúvel em detergente ácido indigestível (FDAi)) na estimativa da excreção de matéria seca fecal (EMSF), do coeficiente de digestibilidade dos nutrientes e dos teores de NDT. Avaliou-se também a eficiência do conjunto de equações somativas propostas pelo NRC (2001) para estimar o valor energético dos alimentos utilizando-se 60% de silagem de milho com base da MS total das dietas. Os concentrados foram constituídos de diferentes fontes protéicas (FS - farelo de soja; FA38 - farelo de algodão 38%PB; FA28 - farelo de algodão 28%PB e FSU - farelo de soja + 5% de uréia/sulfato de amônia na MS do concentrado). Não foram observados efeitos dos dias de coleta de fezes e dos indicadores sobre as estimativas da EMSF, dos coeficientes de digestibilidade dos nutrientes e dos teores de NDT. As equações propostas pelo NRC (2001) subestimaram os consumos de CNF e EE digestíveis e NDT e superestimaram os de FDN e PB digestíveis. Dois dias de coleta de fezes são suficientes para estimativa da digestibilidade dos nutrientes e, conseqüentemente, do consumo de NDT. A FDNi foi o indicador mais preciso para estimar a excreção de MS fecal. As equações propostas pelo NRC (2001) não foram adequadas para estimar o valor energético dos alimentos em condições tropicais. Twelve lactating dairy cows (Holstein and crossbred Holstein x Zebu) were blocked by days in milk and randomly assigned to three replicate 4 x 4 Latin squares to compare two schedules of total fecal collection (two versus six days) and the reliability of two internal markers [indigestible neutral detergent fiber (INDF) or indigestible acid detergent fiber (IADF)] to estimate fecal DM excretion (FDME), apparent total tract digestibility of nutrients, and the total digestible nutrients (TDN) content of the diets. The summative equations from the NRC (2001) model were also used to estimate the energy value of feeds. A diet containing 60% of corn silage (DM basis) plus one of the following proteins sources was fed to animals: soybean meal (SM), 38% CP cottonseed meal (CM38), 28% CP cottonseed meal (CM28), or SM plus 5% of urea/ammonium sulfate in the concentrate DM (SMU). Fecal collection schedule and markers had no effect on the estimates of FDME, nutrient digestibility, and dietary TDN. The summative equations from the NRC (2001) overestimated the intake of digestible CP and NDF and underestimated that of digestible NFC, EE, and TDN. It was concluded that INDF was the most precise marker and two days of total fecal collection was enough to estimate FDME, nutrient digestibility and dietary TDN. The NRC (2001) summative equations did not reliably predict the energy value of tropical feeds.

Dois experimentos foram realizados com o objetivo de avaliar níveis de PB em suplementos para novilhos mestiços em pastagem de Panicum maximum cv. Mombaça durante o período de transição seca/águas. Os suplementos, à base de milho e grão de soja triturados, foram formulados para apresentar 8,0; 16,0 e 24,0% de PB e foram fornecidos na quantidade de 1,0 kg/dia. No primeiro experimento, foram avaliados o desempenho produtivo e a eficiência econômica de 20 novilhos mestiços Holandês x Zebu, não-castrados, com 19 meses de idade e 339,4±14,8 kg de PV inicial. O ganho médio diário e o ganho de peso total aumentaram de forma linear de acordo com os níveis de proteína nos suplementos. Os ganhos observados foram de 0,992; 1,142 e 1,261 kg/dia, respectivamente, para os suplementos com 8,0; 16,0 e 24,0% de PB. A avaliação econômica dos suplementos comprovou maior eficiência econômica do suplemento com 24% de PB. No segundo experimento, quatro novilhos mestiços (peso médio de 400 kg) fistulados no rúmen e no esôfago foram utilizados para avaliar a influência dos níveis de proteína sobre o pH e a concentração de amônia ruminal. O pH não foi alterado, mas a concentração ruminal de N-NH3 aumentou de forma linear com os níveis de proteína do suplemento. Os níveis amoniacais médios observados com os suplementos contendo 8,0; 16,0 e 24,0% de PB foram de 8,41; 10,69 e 12,92 mg/dL, respectivamente. Two experiments were conducted to evaluate different crude protein (CP) levels of a mixture of mineral and concentrate (multiple supplement) fed to crossbreed steers grazing Panicum maximum cv. Mombaça pasture during the transition between the dry and the rainy season. The multiple supplement contained ground corn and soybean grains and was formulated to yield 8.0, 16.0 or 24.0% of CP. Each animal received 1.0 kg of the multiple supplement per day or only ad libitum mineral mix (control treatment). In the first trial, 20 crossbred steers averaging 19 months of age and 339.4±14.8 kg of body weight were used. The average daily gain (ADG) increased linearly from 0.992 to 1.258 kg/d when the CP level of the supplement increased from 8.0 to 24%. Total weight gain also increased linearly by increasing the CP level of the supplement. Economical analysis of the supplements showed greater gross income for the supplement containing 24% CP. In the second trial, four crossbreed steers fitted with ruminal and esophageal cannulas and averaging 400 kg of body weight were used to investigate different CP levels of the supplements on ruminal pH and ruminal ammonia ruminal concentration. The different CP levels of the supplement did not significantly change ruminal pH. However, ruminal ammonia increased linearly from 8.41 to 12.2 mg/dL when the CP level of the supplement increased from 8.0 to 24%.

Avaliaram-se os consumos e as digestibilidades dos nutrientes e a produção e composição do leite de cabras alimentadas com dietas com 47% de silagem de milho e 53% de concentrado, contendo níveis crescentes de PB (11,5; 13,5; 15,5 e 17,5%PB na MS). Foram utilizadas 12 cabras da raça Alpina em lactação, distribuídas em três quadrados latinos 4 x 4, compostos de quatro períodos de 15 dias (sete de adaptação às dietas e oito para coletas de amostras). Amostras de fezes e de leite foram analisadas e os resultados avaliados por meio de análises de variância e regressão. Os consumos de MS, MO, PB, PDR e NDT, assim com as digestibilidades da MS, MO, PB e CNF, aumentaram linearmente com os níveis de PB da dieta. A produção de leite aumentou linearmente com o incremento do nível dietético de PB, enquanto a produção de leite corrigida para 3,5% de gordura e as porcentagens de gordura e PB no leite não foram influenciadas pelos níveis de PB nas dietas. Concluiu-se que os níveis de 13,5% de PB ou 290 g de PB/dia atendem às exigências de proteína e parecem adequados para cabras com produção diária de até 2,7 kg de leite corrigido para 3,5% de gordura. Intake, apparent digestibility of nutrients, milk yield and milk composition were all evaluated in goats receiving diets with 47% of corn silage and 53% of concentrate. Dietary crude protein (CP) was increased as follows [dry matter (DM) basis]:11.5, 13.5, 15.5 and 17.5%. Twelve lactating Alpine goats were randomly assigned to three 4 x 4 Latin squares with 15 days experimental periods: seven days for diet adaptation and eight days for samples collection. Total collection of feces was done from day 8 to day 12 of each period while milk samples on day 10. Data were evaluated by analysis of variance and regression. Intakes of DM, organic matter (OM), CP, rumen degradable protein (RDP) and total digestible nutrients (TDN) increased linearly with the increment of dietary CP. Similarly, digestibilities of DM, OM, CP and non-fiber carbohydrates (NFC) increased linearly when the CP level increased from 11.5 to 17.5 of the diet. Milk production also increased linearly with the increase of CP in the diet but no significant effects were observed for 3.5% fat corrected (FCM) milk as well as for contents of milk fat and milk CP. It can be concluded that the diet with 13.5% of CP met the protein requirements of lactating goats and appeared to be adequate for animals yielding up to 2.7 kg of 3.5% FCM per day.

Validaram-se as equações desenvolvidas por Hankins e Howe (1946) para fins de predição da composição física e química da carcaça e desenvolveram-se equações a partir de corte da costela para se estimar a composição química do corpo vazio. Foram utilizados 19 novilhos anelorados, com peso vivo médio inicial de 270 kg e 24 meses de idade, castrados – quatro pertencentes ao grupo referência, três ao grupo mantença e 12 distribuídos uniformemente em três grupos, com diferentes níveis de concentrado na dieta (5, 35 e 65% na base da matéria seca total). Como volumoso, foi utilizado pré-secado de capim-braquiária (Brachiaria brizantha) e de capim-tifton 85 (Cynodon sp.). As dietas foram isoprotéicas e os alimentos foram fornecidos permitindo-se cerca de 5% de sobras. Os animais do grupo mantença e dos tratamentos com 5, 35 e 65% de concentrado foram alimentados por um período de, respectivamente, 84, 109, 104 e 102 dias, após o qual foram abatidos, apresentando peso vivo médio de 340,25; 360,55 e 374,50 kg, respectivamente. Após o abate, procedeu-se à dissecação completa da carcaça direita e do corte das 9-10-11ª costelas, retirado da carcaça esquerda. O corte das 9-10-11ª costelas estimou satisfatoriamente a composição física da carcaça dos animais e estimou adequadamente os conteúdos de proteína, água e minerais da carcaça, enquanto o teor de extrato etéreo foi superestimado em 7,8%. Foi desenvolvida uma equação para estimar a porcentagem de extrato etéreo na carcaça a partir da porcentagem desse componente no corte das 9-10-11ª costelas: % EE na carcaça = 1,0709 + 0,7854 * % EE no corte das 9-10-11ª costelas, r2 = 0,97. A composição química do corpo vazio pode ser estimada satisfatoriamente a partir da composição química do corte das 9-10-11ª costelas, entretanto, mais informações devem ser geradas para que se possa obter equações mais abrangentes e aplicáveis de forma confiável. The equations developed by Hankins and Howe were validated in order to predict the physical and chemical carcass composition and equations were developed aiming to estimate the body composition of zebu cattle from the 9-10-11th rib cut composition. Nineteen Zebu steers, with 270 kg of initial live weight (LW) and 2 years old were used. Four were slaughtered in the beginning of the trial, performing the reference group, three were fed to the maintenance level and the remaining were uniformly allotted into three treatments, with different levels of concentrate in the diets (5, 35, 65 %, in the total dry matter basis). Brachiaria brizantha and Cynodon spp haylage were used as the roughage source of the diets. The diets were isonitrogenous and the animals were fed ad libitum. The animals of the reference group and those of the treatments with 5, 35 and 65 % of concentrate were fed for a period of, respectively, 84, 109, 104 and 102 days, after which the animals were slaughtered, with average body weight of 340.25; 360.55 e 374.50 kg, respectively. After slaughter, the right side of all carcasses were totally dissected. The same was done to the 9-10-11th rib cut, obtained from the left sides of carcasses. The physical composition of the carcasses were well predicted by the 9-10-11th rib cut, which chemical composition predicted satisfactorily the contents of protein, water and minerals of the zebu cattle carcasses. The content of fat of the carcasses was overestimated in 7.8%. A regression equation was developed to estimate the percentage of ether extract (EE) of the carcasses, in function of this component in the 9-10-11th rib cut: % EE carcass = 1.0709 + 0.7854 * % EE 9-10-11th rib cut, r2 = 0.97. The empty body chemical composition can be predicted from the chemical composition of the 9-10-11th rib cut, however, more data should be gathered in order to develop equations that would be applicable in a wide range of situations, producing reliable estimates.