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Diets composed of whole flint corn grain (WCG) without any roughage source are often used in South American countries. The primary source of protein in theses diets is soybean meal. We hypothesized that the combination of different protein sources improves ruminal fermentation and nutrient digestibility. This study was carried out to assess the impacts of replacing 50% of the soybean meal by other protein sources on voluntary dry matter intake (DMI), digestibility, efficiency of N utilization, efficiency of grain use, metabolic characteristics, and ingestive behavior of Nellore cattle fed WCG diets. Five rumen-cannulated Nellore Bulls (average BW = 651.6 ± 31.83 kg) were used in a 5 x 5 Latin square design, randomly assigned to five diets consisting of 85% of WCG and 15% of pellet supplement with combination of different protein sources: SM - pellet supplement with soybean meal only; CM - soybean meal and cottonseed meal; SFM - soybean meal and sunflower meal; DDG - soybean meal and DDG; DDGS - soybean meal and DDGS. The replacement of 50% of soybean meal by DDG increased (P0.05) by protein sources. Protein sources also did not affect the grain-use efficiency (P>0.05), with an average value of 96.6% and only 3.4% of the corn grains recovered in the feces. The concentration of GGT enzyme was greatest (P

This study evaluated the influence of the quantitative traits measured by real-time ultrasound (adjusted longissimus muscle area [AdjLMA], adjusted rump fat thickness [AdjRFT], and adjusted marbling [AdjMAR]) as well as age at first breeding [AFB] and adjusted weight [AdjWeight], on the probability of occurrence of early pregnancy (EP) in 55 Nellore heifers, and also performed an economic analysis. All calves received supplementation in creep-feeding (ad libitum), and at weaning (average age= 210 ± 30 days; average weight= 241 ± 33 kg) until first breeding by artificial insemination (May to November) all heifers were managed in the same group (two paddocks of 25 ha each evenly covered with Urochloa Marandu Grass) and received protein-energy supplementation (1% of average BW per animal/day). The quantitative variables were collected immediately after timed artificial insemination (average age= 392 ± 27 days; average weight= 431.90 kg), and the pregnancy diagnosis was completed at 30 days following insemination. For economic analysis, two systems were compared (age at first breeding at 13 and 24 months). The greater adjusted weight on the first breeding increased the probability of occurrence of early pregnancy, while the greater adjusted longissimus muscle area reduced. In addition, intensive meat production systems provide greater economic return throughout cow-calf operation.

Objetivou-se avaliar a qualidade espermática do sêmen de touros suplementados com selênio (Se) na dieta. Foram utilizados 16 touros Brangus, igualmente distribuídos em grupo controle (GC) e grupo Se (GSe − 0,1mg de Se/kg de MS de dieta). O experimento teve duração de 75 dias, e os animais foram suplementados por 60 dias. Foram realizadas quatro coletas de sêmen durante o período (0, 30, 60 e 75 dias) por animal. As amostras foram avaliadas quanto a motilidade e vigor espermáticos, integridade e funcionalidade da membrana plasmática (teste de expansão hiposmótico – HIPO) e viabilidade espermática e reação acrossomal (coloração tripla ̶ TRI). Após avaliação, estas foram diluídas em meio Tris-gema com 5% de glicerol, envasadas (40x106 espermatozoides/palheta), resfriadas, congeladas e armazenadas em nitrogênio líquido até a análise. Após descongelação, foram submetidas às mesmas avaliações descritas para o sêmen fresco. Não houve interferência da suplementação com Se nas variáveis vigor espermático, HIPO e TRI do sêmen fresco e descongelado. Porém, constatou-se queda na motilidade espermática do GSe comparativamente ao GC no sêmen fresco (P=0,0035) e descongelado (P=0,0067) após 60 dias de suplementação. Portanto, a suplementação de Se na dieta não foi efetiva na promoção de melhorias dos parâmetros espermáticos de touros Brangus. Palavras-chave: antioxidantes, criopreservação, espermatozoide.

The effects of increasing doses of three exogenous enzymes preparations with fibrolytic activity (FIB - 0, 0.6, 1.2, 1.8, and 2.4 mg mL-1liquid volume incubated), amylolytic activity (AMZ - 0, 0.05, 0.10, 0.15, and 0.20 mg mL-1liquid volume incubated), and proteolytic activity (PRO - 0, 0.05, 0.10, 0.15, and 0.20 mg mL-1 liquid volume incubated ) on gas production (GP), kinetic parameters, and fermentation profile of Brachiaria brizantha cv. Marandu were evaluated using the in vitro gas production technique. Ruminal liquid was obtained from two rumen-cannulated Santa Inês sheep maintained on pasture. Accumulated gas production was measured during 96 hours of incubation, measured at 18 different time points. The determined parameters were pH, asymptotic gas production (mL g-1), rate of gas production (h-1), lag time (h), organic matter digestibility (OMD, g g-1 DM), metabolizable energy (ME, MJ kg-1 DM), and neutral detergent fiber digestibility (NDFD, mg g-1 DM). Increasing the FIB dose linearly increased (P < 0.05) the asymptotic gas production. However, the rate of gas production and the lag time showed linear decreases (P < 0.05). Addition of FIB also linearly increased (P < 0.05) the GP at all incubation times, as well as the OMD, NDFD and ME. Addition of AMZ linearly increased (P < 0.05) the asymptotic gas production, but GP linear increased (P < 0.05) only at the 6-hour and 12-hour time points. The rate of gas production and the lag time decreased linearly (P < 0.05) in response to increasing AMZ addition. Inclusion of PRO did not affect (P > 0.05) asymptotic gas production, but there was quadratic effect (P < 0.05) on the rate of gas production, the lag time, and the GP at the 6-hour and 12-hour time points. The OMD, NDFD and ME were not affected by PRO addition. Thus, fibrolytic, amylolytic and proteolytic enzymes are effective in reducing the lag time and increasing the in vitro gas production from Brachiaria Brizantha cv. Marandu forage, and fibrolytic enzymes improve the in vitro fermentation profile.

This study was designed to evaluate the effects of different supplementation plans on the nutrient intake, apparent total-tract digestibility, grazing behavior, growth performance, and carcass characteristics of beef cattle under grazing conditions from ages 4 to 18 months old. The beef calves grazed Brachiaria decumbens in four seasons: rainy-dry transition, dry, dry-rainy transition, and rainy. Forty-four animals (11 per treatment) were randomly assigned to one of four nutritional plans of supplementation defined by the quantity of supplement offered: control, low, medium, and high supplementation. There was no difference (P > 0.10) in dry matter intake (DMI). However, animals receiving medium and high supplementation had decreased (P < 0.10) forage dry matter intake (FDMI) compared with those under non- and low supplementation. The DMI and FDMI were lower (P < 0.10) in the dry season. During the rainy season, the grazing time decreased (P < 0.10) for animals receiving supplementation compared with non-supplemented ones, but was similar between medium and high supplementation. The performance and carcass characteristics were greater (P < 0.10) for high and medium supplementation compared with low and control. In conclusion, increasing the supplementation plans for beef cattle in tropical pastures increases the nutrient intake but decreases FDMI. The performance also increases with the supplementation plan; however, the growth rate is affected by the grazing season.

The objective of this study was to evaluate the effects of tannins versus Monensin on in vitro ruminal fermentation of a feedlot diet. The treatments were: control (no additives); low tannin (2 mg g DM-1); medium tannin (4 mg g DM-1), high tannin (6 mg g DM-1), and Monensin (0.02 mg g DM-1). The substrate was a feedlot diet composed by hay and concentrate (15:85 w/w; DM basis). Ruminal fluid was obtained from three rumen-cannulated male Santa Inês sheep. In vitro incubations were carried out during four consecutive weeks (run). Gas production (GP) was recorded at 1, 2, 3, 4, 5, 6, 8, 10, 12, 18, 24, 30, 36, 42, 48, 60, 72, 84, and 96 h of incubation. At 48 and 96 h, two bottles per treatment were withdrawn to measure pH, ammonia concentration (NH3), volatile fatty acid (VFA), in vitro dry matter digestibility (IVDMD), and in vitro neutral detergent fiber digestibility (IVNDFD). Addition of tannin or Monensin did not affect (P > 0.05) the kinetics parameters. Tannin supplementation reduced (P < 0.05) the GP at 24 h compared to Monensin. Addition of Monensin decreased (P < 0.05) IVDMD at 96 h and IVNDFD at 48 and 96 h compared to the control. The IVNDFD was lower (P < 0.05) with Monensin than with tannin at 48 and 96 h. The NH3 was lower (P < 0.05) with tannin compared with Monensin. By increasing tannin dosage, NH3 levels changed quadratically (P < 0.05). The inclusion of tannin in vitro reduced the NH3 concentration considerably when used in low dose.

The study was carried out in a greenhouse with a 4X4 factorial arrangement randomized block design in order to evaluate the effects of nitrogen rates (0, 50, 100 and 150 mg dm-3) associated with cutting heights (10, 15, 20 and 25 cm) on dry matter production and the chemical composition of Massai grass. The seeding was done in pots with 11 kg of soil. 10 plants were kept per pot, and there were two cuts every 35 days. Nitrogen fertilization was split between the two cuts, where the first N application occurred after the uniformity cut and the second after the first cut. In each cut the plants were separated and weighed for botanical component evaluation: leaf blade and stem + sheath. After this, the samples were homogenized and analysed for dry matter (DM), crude protein (CP) and neutral detergent fibre (NDF) content. In the first cut, the N fertilization caused a linear increase in DM production of 0.058 g pot-1 per each 1 mg dm-3 of N applied, as well as causing an increase of 0.549% in CP percentage, a 0.0124 pot-1 g increase in CP production and a reduction of 0.055% in NDF. In the second cut, N rates promoted a quadratic effect on DM production. A maximum DM production of 16.48 g pot-1 with 107.27 mg dm-3 of N was observed while CP production content was increased by 0.0092 g pot-1 for each 1 mg dm-3 N applied. In terms of linear responses to DM and PB, as well as the use efficiency calculated for Massai grass, recommended N doses range between 50 and 100 g dm-3.

The objective was to evaluate performance and economic viability of protein supplementation of grazing beef cattle in the wet and dry-wet transition season. Eighty non-castrated Nellore steers, body weight of 371 ± 11.3 kg were used in the experiment. The treatments were the following: SM – Mineral supplement; Protein mineral supplements (SMP 20% FS - soybean meal: 410 g/animal; SMP 40% UR - urea: 223 g/animal; and SMP 40% UP - protect urea: 236 g/animal). It was used a complete random design with 20 replicates per treatment. There was a difference in the results (Plongissimus dorsi muscle (Tx.EGLD) between treatments. The PMS 40% UP supplement showed an accumulation of fat 0.018 mm/day while the SMP 40% UR had a lower rate of fat 0.011 mm/day. There was no effect (P> 0.10) of treatments on the rate of accumulation of fat in the rump region. All treatments presented a positive net margin. The best net margin was observed for treatment PMS 40% UP, that is, R$123.92 per animal/period, whereas the smallest was observed in treatment PMS 20% FS, that is, R$98.91 per animal/period. Protein supplementation with a source of protected nitrogen can be used as a strategy to increase the performance of beef cattle on pasture of Brachiaria brizantha cv. Xaraés during the wet and dry-wet transition.

Avaliou-se os efeitos de doses crescentes de três enzimas exógenas: fibrolíticas (FIB), 0; 0,6; 1,2; 1,8 e 2,4 mg mL-1 volume de líquido incubado; amilolíticas (AMZ), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-1 volume de líquido incubado, proteolíticas (PRO), 0; 0,05; 0,10; 0,15 e 0,20 mg mL-1 volume de líquido incubado, sobre a produção de gases (PG), parâmetros cinéticos e perfil da fermentação da Brachiaria brizantha cv. Marandu usando a técnica in vitro de produção de gases. O líquido ruminal foi obtido de dois ovinos Santa Inês canulados no rúmen, mantidos em regime de pastejo. A produção de gases acumulada foi obtida durante 96h00 de incubação, mensurada em 18 tempos. Ao final da incubação foram determinados o pH, produção de gás assintótica (mL g-1), taxa de degradação fracional (h-1), lag time (h), digestibilidade da matéria orgânica (DMO, g/g MS incubada por 24h00), energia metabolizável (EM, MJ kg-1 MS) e a digestibilidade da fibra insolúvel em detergente neutro (DFDN, mg g-1 MS). As doses de FIB aumentaram linearmente (P < 0,05) a produção de gases assintótica. Entretanto, a taxa de degradação fracional e lag time reduziram linearmente (P < 0,05). A adição de FIB também aumentou linearmente (P < 0,05) a PG em todos os tempos de incubação, DMO, DFDN e EM. A inclusão de AMZ aumentou linearmente (P < 0,05) a produção de gases assintótica, e a PG somente nos tempos 6 e 12 horas após a incubação. A taxa de degradação fracional e lag time reduziu linearmente (P < 0,05) com a inclusão de AMZ. A inclusão de PRO não modificou (P > 0,05) a produção de gás assintótica, mas promoveu efeito quadrático (P < 0,05) na taxa de degradação fracional, lag time, e PG nos tempos 6 e 12. No entanto, PRO não afetou DMO, DFDN e EM. As enzimas fibrolíticas, amilolíticas e proteolíticas são efetivas em reduzir o lag time e aumentar a produção de gases in vitro da Brachiaria Brizantha cv. Marandu, e as enzimas fibrolíticas melhoram o perfil da fermentação in vitro.

The objective was to evaluate the substitution levels of protein from soybean meal by high energy cottonseed (CS) meal in multiple supplements for beef cattle grazing in the dry season on the average daily gain (ADG) and economic viability. Twenty Nellore steers with initial body weight of 351.25±35.38 kg and average initial age of 24±0.8 months were used, divided into four paddocks of Brachiaria brizantha cv. Marandu with 1.6 ha each incompletely randomized design with four animals and five supplements to assess the following supplements: 0CS, 25CS and 50CS corresponding to the level of 0,25 and 50% high energy cottonseed meal to replace the meal soybean, provided the amount of 2 kg/animal/day, which were compared to mineral mixture (MM). The supplement 25CS provided higher (P

The objective was to evaluate thein take and digestibility of nutrients, ammonia nitrogen (NH3-N) in the rumen and serum urea nitrogen (BUN) in Nellore heifers in grass Marandu recreated during the transition period dry energy supplement receiving waters, protein and multiple. We used four heifers with average body weight and initial age of 189.5 kg and 12 months respectively, distributed in four paddocks of 0.25 ha each. The design was a 4x4 Latin square (four supplements and four periods of 14 days). The supplements were: energy supplement (ES) protein (PS) and multiple (MS), provided the amount of 1 kg animal day-1 in addition to supplement containing commercial mineral mixture ad libitum (MM). The concentrate supplementation did not increase intakes of dry matter, total organic matter and forage. The additional SP provided greater (P

The objective of this study was to evaluate the body weight gain and the economic viability of Nelore heifers reared on pasture grass Marandu during transition dry-waters receiving energetic, proteic and multiple supplements. Twenty Nelore heifers were used, with average initial body weight of 189.75 ± 21.55 kg distributed in four paddocks of 1.6 ha each. The experimental design was completely randomized (four supplements and five replicates) to evaluate the following supplements: energetic supplement (ES) proteic supplement (PS) and multiple supplement (MS), provided that the amount of 1 kg animal day-1, beyond the exclusive supplement with mineral mixture (MM) ad libitum. The economic evaluation was conducted considering the return of invested capital by dividing the profit margin for the total investment involved in the process of supplementation. The average daily gain (ADG) was higher (P

It was aimed at to evaluate the effect of the degradable protein in the rumen (RDP) and the supplementation frequency on the average daily gain weight, final body weight and economic viability of cattle in pasture of Brachiaria brizantha cv. Marandu during the rainy/dry transition period. 25 Nellore steers withinitial body weight of 287.96 ±7.47 kg and average initial age of 18 months, distributed into eight paddocks of 1.6 ha each, were used. The experimental design was completely randomized with five replicates and five supplements. The supplements were: SAL - mineral mix supplied ad libitum (Controls); daily RDP: supplement formulated to meet the requirements RDP, with daily supply; frequency RDP: supplement formulated to meet the requirements RDP, supplied three times on week (Mondays, Wednesdays and Fridays); RDP+: supplement formulated with increment of 10% of the requirements of RDP supplied 3X; RDP-: supplement formulated with less 10% of the requirements of RDP supplied 3X. The supplemented animals showed average daily gain (ADG) greater (P = 0. 0010) to control supplement. The RDP daily supplements and RDP frequency showed no significant difference (P> 0. 05) for the GMD. There was a significant difference in ADG of frequency RDP (P = 0. 0189) compared to the RDP- supplement. In the economic evaluation revealed positive economic return to the supplements: frequency RDP, daily RDP, RDP + and RDP-. The strategy of supplying the frequency RDP supplement provided the best economic return. Supplementation in alternate day for grazing steers provides greater gain final and higher body weight ADG, which are effective in promoting economic profitability and higher growth performance to those obtained in the pasture systems daily supply of supplement.

It was aimed to evaluate the effect of the rumen degradable protein (RDP) and supplementation frequency on the consumption and digestibility of the nutrients, concentration of amoniacal nitrogen (N-NH3), ruminal pH and nitrogen compounds excreted in the urine (NUR) and serum (NS) in bovine in pasture of Brachiaria brizantha cv. Marandu during the rainy/dry transition period. Five crossbred steers, castrated, with average body weight of 350 kg, cannulated in the rumen, were used. The experiment used in Latin square design 5 X 5, with duration of 21 days each experimental period. The treatments were: SAL - mineral mix supplied ad libitum (Controls); daily RDP: supplement formulated to meet the requirements RDP, with daily supply; frequency RDP: supplement formulated to meet the requirements RDP, supplied three times on week (Mondays, Wednesdays and Fridays); RDP+: supplement formulated with increment of 10% of the requirements of RDP supplied 3X; RDP-: supplement formulated with less 10% of the requirements of RDP supplied 3X. There was statistical difference for dry matter intake (DMI), forage (CFO) and neutral detergent fiber (NDF) and apparent digestibility of DM and NDF with treatment effect (p 0.05) DMI and apparent digestibility of DM, CP and NDF. The ruminal pH was different between the frequency RDP supplements vs. RDP- time 4 hours on day no supplementation. The ruminal ammonia concentration of the supplemented animals showed a difference between the RDP daily supplements vs. RDP frequency; RDP frequency vs. RDP +; RDP frequency vs. PDR-. The nitrogen serum concentration is larger (P

The objective was to evaluate the effect of inclusion levels of sunflower cake as protein source to replace soybean meal in multiple supplements for cattle grazing during dry season on nutritional parameters. Five steers were used, Nellore, non-castrated, with age and average initial weights of 20 months and 354.7 kg, respectively, divided into five paddocks of 0.25 ha each, consisting of Brachiaria brizantha cv. Marandu. The experiment was divided into 5 x 5 Latin square, composed of five experimental periods of 15 days each and five animals. The strategy adopted was the inclusion of sunflower cake in increasing levels of zero, 270, 406, 540 g / kg supplement and mineral supplement composed only by the will provided in the trough (control). Supplements were formulated to be isonitrogenous (25% CP) and provided the amount of 1.5 kg / animal / day of natural material. The forage mass and the availability of dry matter digestible pontecialmente were 3,120 and 2,379 kg DM / ha respectively. Effect was observed (P 0.10). There was a significant difference in the concentrations of NH3-N between animals that received only mineral mixture (8.64 mg / dL) and cattle supplemented with 0 (12.61 mg / dL) and 27% (11.79 mg / dL ) of adding TG in time 4 hours after supplementation. However, the concentration of NH3-N, between supplemented animalsindependent of the inclusion of TG was not significant (P> 0.10), but was numerically lower for animals supplemented with 40.6 (10.81 mg / dL ) and 54% (10.50 mg / dL) inclusion of sunflower cake. We conclude that the inclusion of sunflower cake in the formulation of the supplements did not interfere with nutritional parameters can replace soybean meal in up to 100% without affect consumption of animals, this level of supplementation

The objective of this study was to evaluate the performance of F1 (Holstein × Zebu) cows in lactation according to different levels of substitution of soybean meal for a protein equivalent non-protein nitrogen originated from slow-release urea (SRU). Eight F1 (Holstein × Zebu) cows in the first third of lactation, with an average milk yield of 12.7 kg (±3.1 kg)/day and a live weight of 552 kg (±30 kg), were used. The experimental design was composed of two simultaneous 4 × 4 Latin squares, with the following treatments: 100% soybean meal and 0% SRU; 66% soybean meal and 34% SRU; 34% soybean meal and 66% SRU; and 0% soybean meal and 100% SRU. Sorghum silage, used as roughage, was supplied together with the concentrate. Feed intake and digestibility as well as milk yield and milk composition were measured. The obtained data were subjected to analysis of variance, adopting a 5% probability level. No intake variable showed significant differences among the treatments, and the mean values for the intakes of dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) were 18.35 2.62 and 5.85 kg/day, respectively. The results for apparent digestibility also did not show differences among treatments, with DM, CP and NDF averaging 58.16, 58.64 and 36.21%, respectively. Milk yield and composition were similar among the treatments. The average 4%-fat-corrected milk yield was 13.39 kg/animal day. Intake, digestibility and milk yield and composition variables are not changed according to the substitution of the soy protein for slow-release urea. Thus, for average-milk-yield crossbred.animals, this substitution depends on economic variables only.

The objective was to evaluate the performance and production costs of Nellore steers growing on Brachiaria brizantha cv. Marandu during the dry season receiving mineral supplements with partial replacement of corn by residual glycerin. 40 Nellore steers with initial body weight of 203.12 ±20.10 kg and average initial age of 12 months, distributed into eight paddocks of 1.6 ha each, were used. The experimental design was completely randomized with five replicates and eight supplements. Supplements with levels of partial replacement of corn by glycerin were evaluated: 0% (G0), 10% (G10), 20% (G20), 30% (G30), 40% (G40), 50% (G50) and 60% (G60) provided on the amount of 1 kg/animal/day in the natural matter, and a mineral supplement (MS). The average daily gain (ADG) was higher (P

The objective was to evaluate levels of multiple supplement for beef heifers in restricted grazing on average daily gain (ADG), economic analysis and intakes of total dry matter (TDMI), forage dry matter (FDMI), crude protein (CPI) and total digestible nutrients (TDNI). For evaluation of performance and economic analysis, twenty Nellore heifers (328.45 kg) were used. The following supplements were evaluated as fed to the animals: control (mineral supplement) and supplementation levels of 2, 4 and 6 kg/animal/day, composing the following percentages of average body weight (ABW): 0.55, 1.11 and 1.66%, respectively. To evaluate the nutrient intake, additional five Nellore heifers with 344 kg, were used, which were submitted to same supplements previously mentioned, in addition to the level of 2.22% of ABW (8 kg/animal/day). Average daily gain showed quadratic behavior; TDMI, CPI and TDNI had increasing linear behavior; and FDMI showed decreasing linear behavior in function of the supplementation levels. The strategy of supplying 0.55, 1.11 and 1.66% of the ABW to heifers on restricted grazing provides additional weight gains of 608, 762 and 943 g/day, respectively, which are effective in promoting similar productive and economic performance to those obtained in grazing systems in the rainy period.

The objective was to evaluate intake and digestibility of nutrients, as well as milk production and composition of the milk from F1 Holstein × Gyr cows kept on pasture, supplemented with sugarcane and concentrate (28% CP). Five cows with 150±14 lactation days and average milk production of 7.1±2.1 kg/day were distributed in a 5 × 5 Latin square design. The treatments were: soybean meal-based concentrate; soy bean-based concentrate; ground soybean-based concentrate; roasted soybean-based concentrate; and ground, roasted soybean-based concentrate. Dry matter (DM), organic matter, crude protein (CP), neutral detergent fiber (NDF), total carbohydrates and total digestible nutrients intakes were not affected by the diet, but ether extract intake was higher for the animals fed soy bean-based diets than those fed soybean meal. The digestibility of DM, NDF and CP did not differ. The corrected milk yield differed between treatments; animals on the treatment with soy bean-based concentrate had the lowest production in relation to the others, which did not differ from each other. There was no difference between treatments for milk composition. Thus, soybean meal can be replaced by ground soy beans or roasted soy beans (ground or whole) in diets for low-yield cows reared on Brachiaria decumbens pastures with no harm to milkproduction or composition. Therefore, the use of these alternative raw materials is recommended whenever their inclusion represents lower feeding costs.

The objective was to evaluate levels of multiple supplements supplied to beef heifers in low supply of pasture on intake and nutrients digestibility, pH and concentration of ruminal ammonia nitrogen, nitrogen balance, synthesis and microbial efficiency. Five Nellore heifers with initial body weight of 344.00 ± 21.10 kg and average initial age of 22 months were used. The following supplements were evaluated as fed to the animals: control (mineral supplement) and supplementation levels of 2, 4, 6 and 8 kg/animal/day, composing the following percentages of body weight (BW): 0.55, 1.11, 1.66 and 2.22%, respectively. The experimental design was a Latin square with five replications and five supplements. Intakes of total dry matter, crude protein (CP) and total digestible nutrients, and total apparent digestibility of dry matter, crude protein, total carbohydrates and no fiber carbohydrates increased linearly (P

The objective of this study was to present some factors affecting feed efficiency in dairy goats. To develop our work, individual and average data from performance experiments with lactating goats were used. The following variables were evaluated: gross feed efficiency, adjusted feed efficiency, dry matter intake, milk-yield, 3.5% fat-corrected milk yield, dry matter digestibility, dietary neutral detergent fiber content, different roughage-to-concentrate ratios and body weight. The statistical analyses involved the application of descriptive and dispersion measures besides Pearson's correlation coefficient and linear regression analysis. The analyzed variables were highly correlated with feed efficiency. The feed efficiency of lactating goats was affected by the milk fat correction, dry matter digestibility, dietary fiber content, proportion of roughage in the diet and body weight. Among these factors, standardization of the milk fat appeared to be the most efficient in correcting the feed efficiency in lactating goats. Correction of some of these factors implies greater precision in the measurement of feed efficiency.

The objective was to evaluate the effect of mineral salt (MS), multiple (MS), energy (ES) and protein supplements (PS) on performance, behavior and production cost of the cattle in Marandu grass pasture. The experiment lasted 84 days, conducted in the experimental area consists of four paddocks of 1.45 ha. Twenty steers were used with age and initial body weight of 172 kg and 10 months, respectively. It used a completely randomized design with four treatments and five replicate. The energy, multiple and protein supplements was supplied on 1.0 kg day-1. The animals were weighed at the beginning and end of the experiment, to determine the average daily gain (ADG). The weight gain of animals was 0.380, 0.600, 0.750 and 0.730 kg/day, respectively, for treatments MS, ES, MS and PS, have been verified statistical difference between supplemented animals and animals than received only mineral salt. The multiple supplement produced ADG 49.33% and 20.00% higher than the mineral salt. The multiple and protein supplements permitted average performance 18.92% higher than the energy supplement. There was no difference in behavior of grazing (P> 0.05). Animals receiving the mineral mixture had time to 8.40 hours of grazing animal day-1. The multiple supplement provided better economic performance considering the sale of animals to 350 kg body weight.

The objective of this study was to evaluate the effect of five nitrogen doses on the productive and quality characteristics and the use efficiency of Brachiaria brizantha cv. Marandu grass. The treatments consisted of four doses of nitrogen (0, 60, 120, 180 and 240 kg ha-1), distributed through a completely randomized design with four replicates. Samples of the material were collected to analyze productivity variables, concentrations of neutral detergent fiber, crude protein and neutral detergent insoluble nitrogen, and in vitro dry matter digestibility. The nitrogen use efficiency, recovery of the applied nitrogen (RAN) and agronomic efficiency of the applied nitrogen (AE) were calculated. Dry mass production increased by 1,624.67 (kg/ha) as the nitrogen doses were increased. The doses of nitrogen affected the concentrations of neutral detergent fiber (from 294.6 to 381.4 g.kg-1, in the leaf), crude protein (from 86.1 to 99.6 g.kg-1, in the leaf) and neutral detergent insoluble protein (from 402.9 to 396.2 g.kg-1 CP, in the leaf). Nitrogen use efficiency increased, whereas RAN and AE were not affected by the nitrogen doses. Nitrogen fertilization promotes improvement in productivity and chemical composition of Marandu grass, also improving the efficiency with which the grass utilizes the nitrogen.

The objective of this study was to evaluate the processing of millet grain provided at two supplementation frequencies for grazing beef cattle during the dry season on nutritional parameters. Five rumen-cannulated crossbred steers, with 24 to 26 months of age and average body weight of 428.6±26.06 kg, were assigned to a Latin square design (5 × 5) in a 2 × 2 + 1 factorial arrangement, as follows: two forms of millet grain (whole grains - or ground; WG - GG), two strategies of concentrate supplementation (daily distribution - 7X; or three times a week - 3X) and a control treatment (mineral mixture - MM). Animals were kept in five paddocks of 0.24 ha each with Marandu grass pastures. Concentrate supplements were supplied at 2.00 and 4.66 kg/animal/day for treatments 7X and 3X, respectively. The concentrate supplementation enhanced the intake of total dry matter (DM) and organic matter (OM) and nutrients compared with mineral supplementation. No differences were found between dry matter intake and forage organic matter intake. The values of digestibility coefficients of DM, OM, ether extract, total carbohydrates and non-fiber carbohydrates were increased by concentrate supplementation. Regarding concentrations of rumen ammonia nitrogen, the interactions among time × treatment × day and day × treatment had effects on the measurements of ruminal pH. Plasma urea nitrogen, urinary urea excretion and urinary urea N excretion differed only between MM treatment and the others, with no interference of grain physical form and supplementation frequency on those variables. The millet grain processing does not alter forage intake, but improves digestibility. Daily supplementation increases digestibility of dry matter and neutral detergent fiber.

The objective of this study was to evaluate the effects of total digestible nutrient (TDN) levels in supplements on rumen pH, ruminal ammonia nitrogen concentration, intake and digestibility, nitrogen balance and microbial efficiency in beef cattle grazing on Marandu grass during the rainy season. The supplements comprised a mineral mixture, ground corn grain, soybean hulls, roasted soybeans and urea:ammonium sulfate. The mineral mix (MM) and supplements were supplied at 800, 1,600 and 2,400 g/animal/day, contained 500, 1,000 and 1,500 g of TDN, respectively, and were termed S500, S1000 and S1500. Supplemental crude protein (CP) was fixed at 300g animal/day for all supplementing strategies. Four crossbred rumen-fistulated steers, with an average weight of 512kg, were utilized. The animals were distributed in a 4×4 Latin square in four paddocks of 0.25 ha. The rumen nitrogen concentration was increased by 63% after four hours of supplementation. Supplements with increased TDN levels did not alter the total dry matter and forage intakes, although the TDN levels linearly increased the non-fibrous carbohydrates intake. Additionally, most supplements did not alter the digestibility of the diet nutrients.The nitrogen balance was similar in all treatments. However, supplements with the highest TDN levels linearly improved the microbial efficiency of finishing beef cattle that were pasture-grazed during the rainy season. Supplements with in creasing TDN levels improve the microbial efficiency during the rainy season.

O objetivo deste trabalho foi avaliar o efeito da substituição parcial do milho por fontes energéticas alternativas, em suplementos concentrados para bovinos de corte mantidos em pasto de Urochloa brizantha cultivar Marandu, durante o período das águas, no consumo e na digestibilidade aparente total dos alimentos. Foram utilizados cinco bovinos Nelore com peso médio corporal inicial de 367,8±4,31 kg. Utilizou-se o delineamento experimental quadrado latino 5x5, com cinco animais e cinco tratamentos. Foram avaliados: suplementos concentrados isoproteicos, com 30% de proteína bruta, formulados à base de grãos de milho, de milheto e de sorgo, e casca de soja; e um suplemento mineral (controle). Não foram observadas diferenças significativas no consumo de matéria seca (MS) total e de matéria orgânica (MO) entre os animais que receberam suplementação mineral e os que receberam suplementação concentrada; no entanto, estes últimos apresentaram menor (12,28%) consumo de MS de pasto. A suplementação concentrada aumentou o coeficiente de digestibilidade aparente total da MS, da MO, da proteína bruta e dos carboidratos não fibrosos que não foram influenciados pelas fontes de energia. Os grãos de milheto e de sorgo e a casca de soja podem ser utilizados em substituição parcial ao milho, na formulação de suplementos concentrados, sem prejudicar o consumo e a digestibilidade dos nutrientes da dieta.

O objetivo deste trabalho foi avaliar os efeitos da inclusão da torta de girassol na dieta de cordeiros em confinamento sobre o desempenho produtivo dos animais. Utilizaram-se 40 cordeiros sem raça definida, não castrados, com peso médio inicial de 20,17±2,66 kg, alimentados com 0, 7, 14, 21 e 28% de torta de girassol na dieta (base seca). O experimento foi conduzido em delineamento de blocos ao acaso. A inclusão de torta de girassol na dieta não alterou o consumo médio de matéria seca (883,58 g por dia), a conversão alimentar (4,40) e o consumo médio de água (2,59 L por dia). O aumento dos níveis de torta de girassol diminuiu linearmente o peso final, o ganho de peso total, o ganho de peso diário e a área de olho de lombo. O nível de inclusão de até 28% não afeta o consumo médio de matéria seca e de água, mas reduz o desempenho e a área de olho de lombo. Para obter o menor custo com a dieta, o nível de inclusão da torta de girassol pode atingir até 28% da matéria seca, quando o seu preço representar até 40% do preço da mistura entre milho e farelo de soja.

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.

Objetivou-se avaliar o processamento do grão de milheto inteiro ou triturado em suplementos fornecidos diariamente ou três vezes por semana para bovinos de corte em pastejo e seus efeitos sobre o desempenho produtivo e econômico e o comportamento ingestivo diurno durante o período da seca. Utilizaram-se 25 bovinos nelores não-castrados, com peso inicial de 350,92±31,7 kg, mantidos em cinco piquetes com área unitária de 1,45 ha formados por B. brizantha cv Marandu. Os animais foram distribuídos em delineamento inteiramente casualizado em esquema fatorial 2 × 2 + 1, composto de duas formas físicas do grão de milheto (inteiro ou triturado), duas frequências de suplementação (diária ou três vezes por semana) e um tratamento controle (mistura mineral). A suplementação concentrada promoveu ganho de peso, enquanto a suplementação apenas com minerais acarretou perdas de peso de 0,16 kg/animal/dia. A moagem do grão de milheto proporcionou maiores ganhos (0,36 e 0,38 kg/animal/dia nos grupos com suplementação 3 e 7 vezes por semana, respectivamente), em comparação ao fornecimento de grão inteiro (0,22 e 0,24 kg/animal/dia, 3 e 7 vezes por semana, respectivamente), enquanto as frequências de suplementação estudadas não promoveram diferenças nestas variáveis. Foi encontrado efeito significativo da interação dia × tratamento para tempo gasto com consumo de suplemento, pastejo e hidratação. Para o tempo em ócio, foi encontrada diferença entre o grupo controle e os demais. Maior retorno econômico foi obtido quando se ofertou milheto triturado e em menor frequência de suplementação (R$ 22,70/animal). A utilização de suplementos múltiplos, assim como o processamento do grão de milheto, possibilita maiores ganhos de peso, independentemente da frequência de suplementação estudada, sendo que o fornecimento de suplemento 3 vezes por semana reduz os custos da suplementação.The objective was to evaluate the processing of the grain of millet in supplements given daily or three times a week to grazing beef cattle on productive performance, economic and diurnal intake behavior during the drought period. Twenty-five non-castrated Nelore cattle with initial body weight of 350.92±31.7 kg were kept in five paddocks with unit area of 1.45 ha formed by B. brizantha cv. Marandu. The animals were distributed in a completely radomized design in a 2 × 2 + 1 factorial arrangement, as follows: two physical forms of the grain of millet (whole or ground), two frequencies of supplementation (daily or three times a week) and the control treatment (mineral mix). It was found that the concentrate supplementation promoted weight gains, while sole mineral supplementation resulted in weight loss of 0.16 kg/animal/day. Grinding the millet grain promoted higher gains (0.36 and 0.38 kg/animal/day for 3 and 7 times a week, respectively) when compared with the whole grain (0.22 and 0.24 kg/animal/day for 3 and 7 times a week, respectively), with no differences between the frequencies of supplementation. Significant effect of the day × treatment interaction was found for time in the trough, grazing and drinking water. For the resting time difference was found between the control treatment and the others. Greater economic return was achieved when ground millet was supplied at lower supplementation frequency (R$ 22,70/animal). The use of multiple supplements, as well as the processing of millet grain, enabled greater weight gain, regardless of the supplementation frequency studied. Providing supplement 3 times a week reduces the costs with supplementation.

The ingestive behavior and performance of female lambs grazing on Marandu pasture submitted to different stocking rates during the rainy and transition season were evaluated. The experimental area with 4,500 m² was divided into 45 paddocks of 100 m². Twenty-seven Santa Ines female lambs (purebred) with 4 months age and 22 kg of initial body weight were distributed in a completely randomized design, with nine replicates. Lambs were divided into 9 groups with the same initial weight and submitted to three stocking rates: 2, 3 and 4 lambs/paddock, which corresponded to 40, 60 and 80 lambs/ha, respectively. Each group of animals had a module of five paddocks, managed on intermittent grazing system, with 7 days of occupation and 28 d of rest. Increase on time grazing and reduction on time ruminating and resting were observed as stocking rates increased. There was 14% raise in time grazing and 41% decline on time resting by lambs subjected to the highest stocking rate compared with those in the lower stocking rate. The number of animals/ha promoted linear effect on average daily gain, which was higher for animals in the lowest stocking rate of 90 g/d. For gain per area, the best result was obtained with 60 animals/ha featuring an average value of 426 kg/ha.

This study aimed to validate the estimates of the ruminal degradation of total carbohydrates (TC), ruminal and total digestion of fibrous carbohydrates (FC) and microbial nitrogen flow in the abomasum evaluated by in vitro gas production technique (IVGP). Six ruminally and abomasally cannulated steers arranged in a double 3 × 3 latin square were used to measure described parameters with indigestible neutral detergent fiber (INDF) utilization as marker. Total and fibrous carbohydrates degraded in the rumen were estimated through digestion rates obtained for fibrous (FC) and non fibrous carbohydrates (NFC) using in vitro gas production technique, corrected for its respective ruminal and postruminal passage rates. The estimation of the total digestion of FC was done by the sum of ruminal and post-ruminal digestion of these compounds. The microbial nitrogen flow in the abomasum was estimated by the calculating the microbial efficiency of bacteria that ferment FC and NFC, utilizing the microbial growth rate obtained by the ruminal digestion rate for carbohydrate fractions in IVGP. The utilization of the in vitro gas production technique allows obtaining accurate estimates of the ruminal digestion of total carbohydrates, total and ruminal digestion of fiber carbohydrates and microbial protein flow in the abomasum.

O objetivo deste trabalho foi avaliar o efeito da suplementação na resposta produtiva, no pH e no nitrogênio amoniacal ruminal, e no custo de produção de ovinos em pastagem de capim-marandu no período da seca. O experimento teve a duração de 84 dias. Utilizaram-se 20 cordeiros não castrados com idade e peso corporal inicial médios de quatro meses e 24,20 kg, respectivamente, para avaliação do desenvolvimento, distribuídos em cada um dos tratamentos que são os suplementos, mineral, energético, proteico e múltiplo, com cinco animais por tatamento, em área de 0,1 ha. Para avaliação dos parâmetros nutricionais, foram utilizados quatro ovinos fistulados no rúmen com 12 meses e 55 kg de peso corporal foram distribuídos em quatro piquetes de 0,1 ha. Avaliaram-se os suplementos mineral, energético, múltiplo e proteico. Os ganhos de peso foram de 0,017, -0,008, 0,024 e 0,077 kg por dia para os suplementos mineral, energético, múltiplo e proteico, respectivamente. Quatro horas após suplementação, os valores de pH ruminal foram de 6,30, 6,40, 6,18 e 6,24 para os suplementos mineral, energético, múltiplo e proteico, respectivamente. Os valores para nitrogênio amoniacal do líquido ruminal foram de 10,57, 7,36, 21,58 e 24,50 mg dL-1 para os suplementos mineral, energético, múltiplo e proteico, respectivamente. Os suplementos mineral e proteico produziram o ganho de peso com o menor custo. O uso de suplemento energético para cordeiros submetidos à forragem com baixo teor de proteína reduz o ganho de peso.

Objetivou-se avaliar o uso de suplementos de autocontrole de consumo sobre os parâmetros nutricionais de novilhos em pastagem de Brachiaria decumbens Stapf. No período de transição águas-seca. Utilizaram-se quatro novilhos mestiços fistulados no rúmen, abomaso e esôfago. Forneceram-se sal mineral (SAL) e suplementos à base de: mistura mineral, sal comum e milho grão triturado (MGS); mistura mineral, ureia e milho grão triturado (UMG); e mistura mineral, ureia, milho grão triturado e farelo de soja (UMGFS), com diferentes teores proteicos. Os suplementos não promoveram diferenças nos consumos de nutrientes, exceto proteína bruta, cujos maiores valores foram obtidos com a utilização dos suplementos com milho grão triturado e farelo de soja. Não houve efeito dos suplementos nos parâmetros de cinética de trânsito de partículas; os valores médios encontrados para taxa de passagem ruminal e tempo médio de retenção total no trato gastrintestinal foram de 0,018 h-1 e 106,93 horas, respectivamente. A suplementação influenciou a concentração de amônia ruminal, que foi maior quando fornecidos os suplementos contendo farelo de soja (31,25 mg/dL) e milho grão triturado (24,22 mg/dL). A suplementação não influenciou as digestibilidades aparente total, ruminal e intestinal de matéria seca, matéria orgânica, carboidratos totais, fibra em detergente neutro e carboidratos não-fibrosos, mas afetou a digestibilidade aparente da proteína bruta, que foi maior no animal que recebeu o suplemento com farelo de soja. Os suplementos com mistura mineral, ureia, milho grão triturado e farelo de soja promovem maiores excreções de N-ureia e maior eficiência microbiana.The aim of this study was to evaluate the use of self-control supplements on nutritional parameters of steers grazing Brachiaria decumbens Stapf. during the rainy-dry season transitional period. Four crossbred steers fistulated in rumen, abomasum and esophagus were used. Mineral salt (SAL) and supplements based on: mineral mix, salt, and ground corn grain (GCG); mineral mix, urea and ground corn grain (UGCG); and mineral mix, urea, grounded corn grain and soybean meal (UGCSM), with different protein contents were given. The supplements did not promote significant differences for intake of nutrients except for crude protein intake whose greater values were obtained with the use of supplements of ground corn grain and soybean meal. There was no effects of the supplements on transit kinetic parameters of the particles; the mean values found for rate of passage and mean retention time in the rumen and gastrointestinal tract were 0.018 h-1 and 106.93 hours, respectively. Supplementation changed ruminal ammonia concentration whose greatest values were obtained with the supplement containing soybean meal (31.25 mg/dL) and ground corn grain (24.22 mg/dL). There was no effect of supplementation on apparent total, ruminal and intestinal digestibility of dry matter, organic matter, total carbohydrates, neutral detergent fiber and neutral detergent fiber but it affected crude protein apparent digestibility which was the highest in the animals fed supplement with soybean meal. Supplements with mineral mixture, urea, ground corn grain and soybean meal promote the highest N-urea excretions and it shows more microbial efficiency.

Dois experimentos foram conduzidos com o objetivo de avaliar os efeitos da frequência de suplementação com duas fontes proteicas sobre o desempenho produtivo e econômico e o consumo e a digestibilidade dos nutrientes em bovinos em pastejo sob suplementação durante o período seco do ano. Foram utilizados 20 animais anelorados, não-castrados com 10 meses de idade e peso médio inicial de 208,43 kg, distribuídos em quatro piquetes de capim-marandu (Brachiaria brizantha, cv. Marandu), cada um com 1,6 ha. Ambos os experimentos foram estruturados em arranjo fatorial 2 × 2, com dois suplementos (com farelo de soja e com farelo de algodão de alta energia) e duas frequências de suplementação (diariamente ou três vezes por semana). Não houve interação fontes proteicas × frequências de suplementação para nenhuma das características de desempenho produtivo e econômico. As fontes proteicas não influenciaram o ganho médio diário, mas a frequência de fornecimento afetou o desempenho, que foi melhor nos animais sob suplementação três vezes/semana (0,670 kg/dia). O maior retorno econômico foi obtido com a oferta do suplemento com farelo de algodão três vezes por semana. A frequência de suplementação afetou o consumo de nutrientes, enquanto a fonte proteica do suplemento teve efeito somente sobre o consumo de extrato etéreo, que foi maior nos animais que consumiram o suplemento com farelo de algodão. O suplemento com farelo de algodão alta energia proporcionou maior digestibilidade da proteína bruta da dieta. O fornecimento de suplemento três vezes por semana, além de reduzir os custos da suplementação, possibilita desempenho superior ao obtido com a suplementação diária. A utilização do farelo de algodão de alta energia em suplementos múltiplos em substituição ao farelo de soja é satisfatória, principalmente do ponto de vista econômico.Two experiments were carried out with the objective of evaluating the effects of the frequency of supplementation with two proteins sources on productive and economical performance (experiment 1) and the nutrients digestibility of steers in supplemented pasture during the dry season over a year. It was used twenty weaned zebu calves at the age of 10 months and initial live weight (LW) of 208.43 kg, distributed in four paddocks of Brachiaria brizantha cv. Marandu, each one with 1.6 ha. Both experiments were structured in 2 × 2 factorial arrangement with two supplements (with soybean meal and high energy cottonseed meal). There was no protein sources × supplementation frequency interaction for any of the economical and productive performance traits. The protein sources didn't affect the daily average gain, but the frequency of supply affected performance, which was better in the animals under supplementation at three times a week (0.670 kg /day). The highest economic return was obtained with the offer of supplement with cottonseed meal three times a week. The frequency of supplementation affect the nutrients intake, while the protein source of the supplement had effect only on the ethereal extract intake, which was higher in the animals that consumed the supplement with cottonseed meal. The supplement with high energy cottonseed meal provided higher digestibility of diet crude protein. The supply of supplement three times a week, not only reduces the costs of supplementation, but it possibilities a higher performance than the one obtained with daily supplementation. The use of higher energy cottonseed meal in multiple supplements replacing soybean meal is satisfactory mainly under economical point of view.

Avaliou-se o efeito da inclusão de níveis crescentes de farelo de algodão alta energia (0; 8,7; 17,4; 26,1 e 34,8% da matéria seca) em substituição ao farelo de soja no concentrado de vacas no terço final de lactação sobre o consumo e a digestibilidade dos nutrientes, a eficiência na utilização do nitrogênio e a produção de leite. Foram utilizadas cinco vacas mestiças 5/8 Holandês × 3/8 Gir, em um delineamento quadrado latino 5 × 5, com cinco períodos de 18 dias (oito dias para adaptação e 10 dias para determinação do consumo e coleta de amostras). As dietas foram calculadas para terem teores proteicos semelhantes (14% de proteína bruta), com 60% de silagem de milho e 40% de concentrado na MS. Não houve efeito da inclusão de farelo de algodão alta energia sobre os consumos de matéria seca, matéria orgânica, proteína bruta, carboidratos totais e nutrientes digestíveis totais. O consumo de extrato etéreo aumentou com os níveis de 26,1 e 34,8% de farelo de algodão alta energia, enquanto o consumo de carboidratos não-fibrosos foi maior para os níveis de 0, 8,7 e 26,1%. A digestibilidade dos nutrientes não diferiu entre os níveis de farelo de algodão alta energia. A substituição do farelo de soja pelo farelo de algodão não influenciou a eficiência de utilização e o balanço de nitrogênio, ou o teor de nitrogênio ureico no leite e de nitrogênio ureico no soro. A produção média de leite (14,03 kg/dia) e a produção média de leite corrigida para 3,5% de gordura (14,68 kg/dia) não foram influenciadas pelos níveis de farelo de algodão alta energia na dieta nem houve diferença na eficiência alimentar. O farelo de algodão alta energia tem potencial para substituição do farelo de soja na dieta de vacas com capacidade de produção de 15 kg/dia.The effect of replacing increasing levels of high-energy cottonseed meal (0, 8.7, 17.4, 26.1 and 34,8% DM) with soybean meal in concentrate for cows in the final lactation third on intake, nutrient digestibility, nitrogen efficiency and milk yield was assessed. Five crossbred 5/8 Holstein × 3/8 Gir cows were allotted to a 5 × 5 Latin square design, with five 18-day periods (eight days for adaptation and 10 days to determine intake and collect samples). The diets were formulated to have similar protein contents (14% CP), with 60% corn silage and 40% on the DM. There was no effect of including high energy cottonseed meal on the intakes of DM, organic matter (OM), crude protein (CP), total carbohydrates (TCHO) and total digestible nutrients). The EE intake increased with levels of 26.1 and 34.8% of high energy cottonseed meal inclusion, while the non-fibrous carbohydrate (NFC) intake was higher for levels of 0, 8.7 and 26.1%. The digestibility coefficients of the nutrients did not differ among the high energy cottonseed meal levels experimental diets. Replacing soybean hulls levels with high energy cottonseed meal did not influence the nitrogen use efficiency or balance, or the milk urea nitrogen content (MUN) and blood urea nitrogen (BUN). Average milk yield (14.03 kg/day) and milk yield corrected for 3.5% fat milk fat (14.68 kg/day) were not influenced by the different levels of high-energy cottonseed meal in the diet and there was no difference for feed efficiency. High-energy cottonseed meal presents potential for replacing soybean meal in the diet of cows with 15 kg/day production capacity.

Objetivou-se avaliar o consumo, a digestibilidade, o pH e a concentração de amônia do líquido ruminal, a concentração de nitrogênio sérico e urinário e a síntese microbiana em novilhos recebendo suplemento durante o período da seca. Utilizaram-se quatro novilhos mestiços Zebu × Holandês, castrados, com peso médio inicial de 430 kg, fistulados no esôfago, rúmen e abomaso e distribuídos em quatro piquetes de Brachiaria decumbens, cada um com 0,40 ha. Cada animal recebeu 4,0 kg/dia de suplemento, constituído de milho moído, farelo de algodão, mistura mineral e uréia/sulfato de amônia em quatro níveis (0; 1,2; 2,4 e 3,6% na matéria natural). Os consumos de matéria seca total, 2,0% (10,9 kg/dia), e de pasto, 2,3% (7,1 kg/dia), matéria orgânica, 2,2% (9,7 kg/dia), matéria orgânica do pasto, 2,3% (6,3 kg/dia), proteína bruta, 1,9% (1,3 kg/dia), extrato etéreo, 3,6% (0,4 kg/dia), fibra em detergente neutro, 1,9% (5,8 kg/dia), carboidratos totais, 2,3% (8,2 kg/dia), e carboidratos não-fibrosos, 2,9% (4,1 kg/dia), foram influenciados de forma quadrática pelos níveis de uréia nos suplementos. Apenas a digestibilidade total da matéria orgânica foi afetada, de forma linear positiva, pelos níveis de uréia no suplemento. Não foram observados efeitos dos níveis de uréia no suplemento sobre o pH ruminal, entretanto as concentrações de amônia aumentaram linearmente de acordo com os níveis de uréia, ocasionando aumento linear na excreção de nitrogênio sérico e urinário. A eficiência microbiana, em qualquer forma de expressão, não diferiu entre os níveis de uréia.Four Zebu × Holstein steers were fistulated in rumen, abomasums and esophagus, with 430 kg of live weight grazing in four paddocks of Brachiaria decumbens (.40 ha), feed supplements were used to evaluate intake, digestibility, pH and ammonia ruminal concentration, nitrogen in serum and urine and microbial yield. The animals received 4.0 kg/animal/day of supplement based on grounded corn grain, cottonseed meal, mineral mix (MM), ammonium sulfate and urea in four levels (0, 1.2, 2.4 and 3.6%) as fed basis. The intake of total (TDM) and pasture (DMP) dry matter, organic matter (OM), OM from pasture, crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), total carbohydrate (TO) and non-fiber carbohydrate (NFC) presented quadratic behavior. The maximum responses on the urea levels were: 2.0% (10.9 kg/day), 2.3% (7.1 kg/day), 2.2% (9.7 kg/day), 2.3% (6.3 kg/day), 1.9% (1.3 kg/day), 3.6% (0.4 kg/day), 1.9% (5.8 kg/day), 2.3% (8.2 kg/day) and 2.9% (4.1 kg/day), respectively, for TDM, DMP, OM, OMP, CP, EE, NFD, TC and NFC. The OM digestibility was affected with a linear behavior. No differences were observed for the pH values. However, ammonia concentration increased linearly as the urea level in the supplement increased. The urea level in supplement increased linearly the nitrogen in serum and urinary excretion of nitrogen from urea. No effect from the urea level on the microbial efficiency, expressed by different forms, was observed.

Avaliou-se o uso de suplementos de autocontrole de consumo sobre o desempenho de 24 novilhos mestiços com idade e pesos médios iniciais de 12 meses e 172 kg, respectivamente, recriados em pastagem de Brachiaria decumbens Stapf. durante o período das águas, com disponibilidade média de 10,82 ton./ha. Forneceu-se sal mineral (SAL) e suplementos à base de: uréia, mistura mineral, milho grão triturado e farelo de soja (MFS); uréia, mistura mineral, farelo de soja e farelo de glúten de milho (FGFS); e, uréia, mistura mineral, farelo de trigo e farelo de soja (FTFS), com teor protéico médio de 53,60% de PB. Não se verificou efeito da suplementação sobre os ganhos médios diários (P>0,05), que foram de: 0,820; 0,950; 1,020 e 0,970 kg/animal/dia, respectivamente, para SAL, MFS, FGFS e FTFS. Contudo, foram obtidos ganhos adicionais em torno de 20%, os quais são de grande relevância na intensificação da pecuária de ciclo curto em pastagens.Twenty four crossbred steers, with average initial age and weight of 12 months and 172 kg, respectively, grazing Brachiaria decumbens Stapf., in the rainy season (10.82 ton. Dry matter/ha), were used in the performance assay to evaluate the effect of supplements of self feed. Mineral salt (SAL) and supplements based on: urea, mineral mix, grounded corn grain and soybean meal (MFS); urea, mineral mix, soybean meal and corn gluten meal (FGFS); and urea, mineral mix, wheat bran and soybean meal (FTFS), with average protein content of 53.60% CP, were fed. It was not observed effect (P>0.05) of supplementation on the average daily gain, of 0.820, 0.950, 1.020 and 0.970 kg/animal/day, respectively, for SAL, MFS, FGFS and FTFS. However, significant additional gains (20%) were observed for supplemented steers.

Objetivou-se avaliar a utilização de quatro níveis de casca de soja (0; 8,0; 16,0 ou 24,0%) em substituição ao fubá de milho (0, 25, 50 e 75%) em dietas para ovinos em confinamento. Avaliaram-se o consumo e a digestibilidade dos nutrientes, o desempenho animal, a conversão alimentar e os custos com a dieta. Vinte cordeiros da raça Santa Inês com peso vivo médio inicial de 32,96 kg foram distribuídos em delineamento inteiramente casualizado com quatro tratamentos e cinco repetições. A dieta foi composta de 50% de volumoso (50% de silagem de milho e 50% de cana-de-açúcar picada) e 50% de concentrado. Os concentrados foram compostos de fubá de milho, farelo de soja, mistura mineral e uréia, de modo que o fubá de milho foi gradativamente substituído pela casca de soja. Os animais foram mantidos em baias individuais com comedouro e bebedouro. Não foram observados efeitos dos níveis de casca de soja da dieta sobre o consumo de nutrientes, exceto o de FDN, que aumentou linearmente de acordo com o nível de casca de soja na dieta. Os níveis de casca de soja não influenciaram a digestibilidade dos nutrientes, o ganho de peso (0,215 kg/animal/dia) e a conversão alimentar dos animais (6,20 kg MS/kg peso ganho). O aumento do nível de casca de soja de 0 e 75% na dieta reduziu os gastos com alimentação e aumentou a margem bruta de R$ 10,89 para R$ 18,63 por animal. A substituição de até 75% do fubá de milho por casca de soja na dieta não afeta o desempenho de ovinos em terminação em confinamento.The objective was to evaluate the use of four levels of soybean hulls (0.0, 8.0, 16.0 and 24.0%) to replace the corn meal (0.0, 25, 50 and 75%) in the diet of sheep in feedlot. Performance, nutrient digestibilities and feeding costs were evaluated. Twenty Santa Inez breed lambs with 32.96 kg BW were distributed to a completely randomized design with four diets and five replications. The diet was composed of 50% forage (50% of corn silage and 50% of sugar cane) and 50% concentrate. The concentrates were composed of corn meal, soybean meal, mineral mix and urea, so corn meal was gradually replaced by soybean hulls. No effect was observed in the levels of soybean hulls of diet on feed intake of nutrients, except for NDF, which linearly increased according to soybean hulls level in the diet. Soybean hulls levels did not affect digestibility of nutrients, weight gain (0.215 kg/anim.day) and feed conversion ratio of the animals (6.20 kg DM/kg weight gain). Increasing of soybean hulls levels in the diet reduced feeding cost and increased the gross margin from R$ 10.89 to R$ 18.63 per animal in the 0 and 75% of replacement levels, respectively. The replacement of up to 75% of corn meal by soybean hulls in the diet does not affect performance of sheep finished in feedlot.

Objetivou-se avaliar em ovinos o consumo e a digestibilidade de nutrientes de dietas contendo grão de capim-pé-de-galinha (Eleusine coracana). Foram utilizados 20 ovinos com peso vivo inicial de 18,90 kg, em delineamento inteiramente casualizado, com cinco tratamentos e quatro repetições. Os animais foram alimentados com dietas isoprotéicas formuladas com 50% de volumoso e 50% de concentrado contendo 0; 16,0; 32,5; 48,0 ou 67,0% de grão de capim-pé-de-galinha em substituição ao fubá de milho. Utilizou-se a fibra indigestível em detergente neutro (FDNi) como indicador para estimativa da excreção fecal. Os níveis de grão de pé-de-galinha não influenciaram os consumos de MS, NDT e FDN. Os valores médios de consumo de matéria seca foram de 1,2 kg/animal/dia e 3,2% do peso vivo. O coeficiente de digestibilidade da matéria seca (CDMS) e o NDT reduziram linearmente em 0,1425 e 0,1612%, respectivamente, a cada 1% de grão de capim-pé-de-galinha no concentrado, o que está relacionado aos maiores teores de FDN e FDNi desse alimento. Os coeficientes de digestibilidade de MO e FDN apresentaram valores máximos de 57,64 e 53,60% nos níveis de 42,36 e 39,56% de grão de capim-pé-de-galinha no concentrado. Os valores médios de digestibilidade aparente de PB e EE foram 56,90 e 66,86%, respectivamente. A substituição do fubá de milho por grão do capim pé-de-galinha na dieta de ovinos não influenciou o consumo de matéria seca dos nutrientes, mas reduziu o coeficiente de digestibilidade da matéria seca, da matéria orgânica, dos carboidratos totais e os nutrientes digestíveis totais, logo, esse ingrediente pode substituir até 50% do fubá de milho no concentrado para ovinos.The objective was to evaluate in sheep the intake and apparent digestibility of nutrients diets containing finger millet grain (Eleusine coracana). Twenty lambs were used with average initial 18.90 kg BW, in a completely randomized design, with five diets and four replications. The animals were fed isoprotein diets formulated with 0.0, 16.0, 32.5, 48.0 e 67.0% of finger millet grain in substitution of corn meal, with 50:50 forage to concentrate ratio (%DM). The levels of finger millet grain did not affect the intake of DM, TDN and NDF. Dry matter intake was 1.2 kg/anim/d and 3.2% of BW. The coefficient of apparent digestibility of DM and NDT linearly decreased in 0.1425 and 0.1612%, respectively, for each 1% of finger millet grain in the concentrate, which is related to higher levels of NDF and NDFi in this feed. The digestibility coefficients OM and NDF showed maximum values of 57.64 and 53.60% in the levels of 42.36 and 39.56% of finger millet grain in the concentrate. Apparent digestibility of CP and EE were 56.90 and 66.86% respectively. The replacement of corn meal per finger millet grain in the diet of sheep does not affected dry matter intake of nutrients, but reduced the digestibility of DM, OM, total carbohydrates and TDN. Then, this ingredient could replace up to 50% of corn meal in the concentrate for sheep.

Objetivou-se com este trabalho determinar o fluxo de compostos nitrogenados no abomaso, a degradação ruminal dos carboidratos totais e da matéria orgânica, a eficiência microbiana, a concentração de N-NH3 e o pH ruminal em bovinos alimentados com dietas à base de silagem de milho, silagem de capim-elefante ou feno de capim-tifton 85. Foram utilizados seis bovinos fistulados no rúmen e abomaso em um delineamento quadrado latino 3 × 3 duplo. Os fluxos de matéria seca da digesta e da matéria seca microbiana no abomaso foram determinados a partir da utilização de fibra em detergente neutro indigestível e das bases purinas como indicador microbiano, respectivamente. As concentrações de NH3 e o pH ruminal foram determinados antes e 2, 4 e 8 horas após a alimentação. As dietas à base de silagem de milho e de feno de capim-tifton 85 proporcionaram os maiores fluxos de compostos nitrogenados no abomaso. As bactérias isoladas do rúmen apresentaram em média 8,89% de N total e 18,40 para a relação N-RNA:N-total. A dieta à base de silagem de milho promoveu maior degradação ruminal da matéria orgânica (2,96 kg/dia) e dos carboidratos totais (3,07 kg/dia) e maior fluxo de massa microbiana para o abomaso (788,28 g/dia). As dietas à base de feno de capim-tifton 85 e de silagem de capim-elefante resultaram em maior eficiência microbiana, cujos valores foram 28,10 e 30,39 g de N microbiano/kg de carboidratos degradados no rúmen. As menores concentrações de NH3 e pH ruminal, considerando o tempo após a alimentação, ocorreram quando fornecida a dieta à base de silagem de milho, o que possivelmente afetou negativamente a eficiência microbiana.The objectives of the present work were to determine nitrogen compounds flow into the abomasum, total carbohydrate and organic matter ruminal degradation, microbial efficiency, N-NH3 concentration and ruminal pH in cattle fed with diets based on corn silage, elephant grass silage and Tifton-85 bermudagrass hay. Six ruminal and abomasal fistulated cattle were utilized in a double 3 × 3 latin square. Abomasal digesta dry matter of and microbial dry matter flows were determined by use of indigestible neutral detergent fiber and base purines as microbial marker, respectively. The N-NH3 concentration and ruminal pH were determined before and 2, 4 and 8 hours after feeding. The diets based on corn silage and Tifton-85 bermudagrass hay provided higher nitrogen compounds flow into abomasum. Isolated bacteria from rumen averaged 8.89% of total N and had an N-RNA:N-total ration of 18.40. The corn silage diet provided higher ruminal degradation of organic matter (2.96 kg/day) and of total carbohydrates (3.07 kg/day) and higher microbial matter flow to the abomasum (788.28 g/day). The Tifton-85 bermudagrass hay and elephant grass silage diets had the greatest microbial efficiencies, which values were 28.10 and 30.39 g of microbial N/kg of rumen degradable carbohydrates. The corn silage diet showed lower N-NH3 concentration and ruminal pH after feeding, possibly indicating reduction of microbial efficiency.

Objetivou-se determinar os consumos de MS, PB, EE, CT, FDN e CNF e as digestibilidades aparentes totais e parciais desses nutrientes em bovinos alimentados com dietas à base de silagens de milho e de capim-elefante e feno de capim-Tifton 85. Os volumosos compuseram 90% da MS das dietas, as quais foram suplementadas com 10% de farelo de soja. Foram utilizados seis bovinos fistulados no rúmen e abomaso (peso inicial de 351 kg) em um delineamento em quadrado latino 3 x 3 duplo, simultâneos. Cada período experimental constou de 16 dias, sendo os 10 primeiros destinados à adaptação dos animais e os seis dias restantes para coleta de amostras de fezes e digesta abomasal. Utilizou-se a fibra em detergente neutro indigestível (FDNi) como indicador do fluxo de MS abomasal e fecal. Embora as dietas à base de silagem de milho e de feno de capim-Tifton 85 não tenham diferido quanto à ingestão de MS, a dieta à base de silagem de milho permitiu maior ingestão de NDT. A dieta de feno de capim-Tifton 85 promoveu promoveu maior consumo de FDN (4,52 kg/dia), enquanto aquela com silagem de milho resultou em maior ingestão de CNF (1,95 kg/dia). A dieta com silagem de milho proporcionou maior digestibilidade aparente total de MS (66,3%), MO (68,9%), FDN (55,7%) e CT (68,2%). O rúmen foi o principal local de digestão dos carboidratos totais e da FDN para todas as dietas. Considerando a relação inversa entre a digestibilidade total da matéria seca e a ingestão de FDNi, pode-se inferir que essa última fração pode ser utilizada na estimativa da digestibilidade de gramíneas tropicais. A estimativa da digestão verdadeira dos CNF foi de 96,6% para as dietas avaliadas.The objective of this trial was to investigate the effects of diets containing corn silage, bermudagrass hay, or elephantgrass silage on intake and apparent total tract and partial digestibilities of nutrients in cattle. A forage to concentrate (soybean meal) ratio of 90:10 was used. Six ruminally and omasally fistulated bovines averaging 351 kg of initial body weight were used in two replicated 3 x 3 Latin squares. Each experimental period lasted 16 days with 10 days for animal adaptation and six days for samples collection. The internal marker indigestible neutral detergent fiber (INDF) was used to estimate abomasal DM flow and fecal DM excretion. No significant difference in DM intake was observed between corn silage and bermudagrass hay diets. However, total digestible nutrient intake was greater on corn silage than bermudagrass hay. Animals fed the bermudagrass hay diet had the greatest NDF intake (4.52 kg/day) while those fed corn silage showed the highest NFC intake (1.95 kg/day). In addition, the corn silage diet also resulted in the greatest apparent total tract digestibilities of DM (66.3%), OM (68.9%), NDF (55.7%), and total carbohydrates (68.2%). Rumen was the main site for digestion of total carbohydrates and NDF in all four diets. It was observed an inverse relationship between apparent total tract DM digestibility and INDF intake. Therefore, forage INDF content can be used to estimate digestibility of tropical grasses. Estimated NFC true digestibility averaged 96.6% across diets in the present study.

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%.

Objetivou-se neste estudo avaliar as digestibilidades total e parcial dos compostos nitrogenados insolúveis em detergente ácido (NIDA) em bovinos em pastejo. Foram utilizados cinco novilhos mestiços Holandês x Zebu (24 meses de idade e 304 kg de PV), canulados no esôfago, rúmen e abomaso, manejados em cinco piquetes de Brachiaria decumbens (0,34 ha), recebendo ou não suplementação com concentrado. O experimento foi realizado em quatro períodos experimentais de 21 dias, entre agosto e novembro de 2000. A avaliação da forragem selecionada pelos animais foi feita em amostras de extrusa esofágica e a estimativa do consumo e dos fluxos fecais e abomasais de MS e NIDA, foram estimados por intermédio de indicadores interno e externo. A avaliação estatística da digestibilidade do NIDA foi conduzida por ajustamento de equação de regressão linear, desconsiderando o parâmetro intercepto e utilizando-se como variáveis independente e dependente as estimativas de influxo e efluxo de NIDA, respectivamente. Os desvios do coeficiente de regressão a partir do valor paramétrico 1,0 foram considerados estimativas de digestibilidade. A comparação entre o consumo e os fluxos abomasal e fecal de NIDA indicou haver digestibilidade desta fração em nível total, atribuída exclusivamente a eventos intestinais (30,7%), uma vez que não foi observada digestibilidade no compartimento ruminal. Esse comportamento indica que o teor de NIDA de um alimento é somente indicador, e não preditor, da digestibilidade potencial dos compostos nitrogenados totais.The objective of this trial was to investigate ruminal, intestinal and total tract digestibility of acid detergent insoluble nitrogen (ADIN) in grazing cattle. Five Holstein x Zebu steers averaging 304 kg of body weight and 24 months of age and fitted with esophageal, ruminal and abomasal cannulas were used in this study. Animals were maintained in five 0.34-ha paddocks of Brachiaria decumbens with or without concentrate supplementation. The experiment was conducted from August to November of 2000 using four 21-days experimental periods. Evaluation of the forage ingested by the animals was done by collecting esophageal extrusa samples. The flow of fecal and abomasal dry matter was estimated by using both internal and external markers. Statistical analysis of ADIN digestibility was conducted by adjustment of the linear regression equation with no intercept in the model and using ADIN inflow as independent variable and ADIN outflow as dependent variable. The deviation of the regression coefficient from the parametrical value 1.0 was considered to be digestible matter. Comparison between intake and abomasum and fecal flows of ADIN indicated that the observed total tract digestibility (30.7%) of this nitrogen fraction occurred exclusively in the intestine. Therefore, ADIN content of feeds can be considered only as an indicator but not as a predictor of nitrogen compounds potential digestibility.

Dois experimentos foram realizados com o objetivo de avaliar diferentes fontes protéicas e energéticas em suplementos múltiplos para bovinos. No primeiro experimento, estudou-se o desempenho de novilhos em fase de recria em pastagem de Brachiaria brizantha, no período da seca. Utilizaram-se 20 novilhos mestiços Holandês x Zebu, não-castrados (17 meses de idade e 265±18 kg de peso vivo inicial), distribuídos em quatro piquetes de 1,5 ha. Os suplementos foram fornecidos diariamente na proporção de 0,75% do PV. Empregou-se como fonte protéica grão de soja (GS) ou caroço de algodão (CA) inteiros e farelo de trigo (FT) ou farelo de arroz (FA) como fonte de energia, em esquema fatorial 2 x 2. Não foram verificadas diferenças no ganho médio diário (GMD), no peso vivo final (PVF) e no ganho de peso total (GPT). A suplementação propiciou aos animais GMD de 0,589; 0,530; 0,620 e 0,606 kg/dia, respectivamente, nos tratamentos GS/FT, GS/FA, CA/FT e CA/FA. No segundo experimento, determinaram-se as frações dos carboidratos da pastagem e dos ingredientes utilizados na formulação dos suplementos e estimaram-se as respectivas taxas de digestão das frações pela técnica de produção de gás. A forragem apresentou altos teores da fração indigestível (C) e baixos da potencialmente digestível (B2). Entre os concentrados, o FA apresentou menor fração C. O GS e o FT destacaram-se pela elevada proporção de CNF. O CA, embora tenha demonstrado fração C superior aos demais, apresentou rápida taxa de digestão da fração B2. As taxas de digestão dos CNF foram 35,06; 14,86; 17,83 e 58,80, respectivamente, para FA, FT, GS e CA. A opção por uma das fontes protéicas ou energéticas estudadas depende, portanto, do preço e da disponibilidade no mercado, pois não influenciou o desempenho dos animais. Os carboidratos estruturais (B2 e C) são responsáveis pelo alto teor de carboidratos totais presentes na Brachiaria brizantha no período da seca, pois correspondem a aproximadamente 80% de sua composição. Observaram-se variações entre as frações dos carboidratos, assim como na taxa de degradação das fontes energéticas e protéicas estudadas.Two trials were conducted to investigate different protein and energy sources in multiple supplements fed to growing crossbred bulls. In the first experiment, performance of 20 crossbred growing bulls averaging 17 months of age and 265±18 kg of body weight was evaluated in the dry season. Animals were maintained in 1.5 ha paddocks of Brachiaria brizantha with supplements being offered daily in a proportion of 0.75% of the body weight. A completely randomized design with a 2 x 2 factorial arrangement was used. Supplements contained whole soybean (WSB) or whole cottonseed (WCS) as the protein sources and rice bran (RB) or wheat bran (WB) as the energy sources. No significant differences on the average daily weight gain (ADG), final body weight (FBW), and total weight gain were observed among diets in this trial. The ADG and FBW averaged 0.589 and 318.2, 0.530 and 317.2, 0.620 and 319.6 and 0.606 kg/day and 323.6 kg for animals fed supplements containing WSB/WB, WSB/RB, WCS/WB, and WCS/RB, respectively. The objective of the second study was to estimate the carbohydrate fractions of the pasture and that of the feeds used in multiple supplements as well as their digestion rates using the gas production technique. Forage had higher indigestible fraction (C) and lower potentially degradable fraction (B2) compared to the supplements. Among supplements, WCS had the lowest C fraction while WSB and WB had the highest proportion of non-fiber carbohydrates (NFC). Although WCS had the highest content of C fraction, it also showed the fastest rate of digestion of the B2 fraction. Digestion rate of NFC were: 35.06, 14.86, 17.83 and 58.80, respectively for RB, WB, WSB and WCS. The choice of each protein and energy source will depend on market price and availability because there were no significant differences among treatments. The structural carbohydrates (B2 e C) are responsible for the high concentrations of total carbohydrates in Brachiaria brizantha during the dry season, which averaged 80%. It was observed variations in the carbohydrate fractions as well as in the degradation rates across supplements.

Objetivou-se avaliar o efeito da utilização da soja em diferentes formas físicas em suplementos múltiplos para terminação de bovinos em pastejo sobre o ganho médio diário (GMD), o ganho de peso total (GT), o rendimento de carcaça (RC), o pH e a amônia ruminal. Os tratamentos consistiram da suplementação com grão de soja moído (GSM), grão de soja inteiro (GSI) e farelo de soja + milho moído (FSM), fornecidos três vezes/semana, e do fornecimento de mistura mineral (controle). Para avaliar o desempenho, utilizaram-se 16 novilhos mestiços Holandês-Zebu, não-castrados, com 19 meses de idade e peso médio inicial de 316 kg. Os valores de pH e as concentrações de amônia ruminal foram obtidos utilizando-se quatro novilhos mestiços Holandês-Zebu fistulados no rúmen. Os suplementos GSM, FSM e GSI proporcionaram ganhos adicionais de 143,0; 142,0 e 135,0 g/animal/dia, respectivamente, ocasionando redução no período de terminação dos bovinos em pastejo. O rendimento de carcaça e os valores de pH (média de 6,51) não foram influenciados pelos tratamentos. A concentração de amônia ruminal dos bovinos do tratamento sem suplementação foi inferior à observada nos animais sob suplementação.The objective of this trial was to evaluate the effects of different physical forms of soybean on average daily weight gain (ADWG), final body weight (FBW), carcass yield (CY), ruminal pH, and ruminal ammonia concentration on crossbred steers fineshed at pasture. Animals were fed three times per week a supplement containing a mineral mix and one of the following protein sources: ground whole soybean (GWS), whole soybean (WSB) or soybean meal and ground corn (SMGC); steers on control treatment received only a mineral mix. Sixteen crossbreed steers averaging 19 months of age and initial body weight of 316 kg were used in this study. Four steers fitted with ruminal cannulas were used to measure ruminal pH and concentration of ruminal ammonia. Supplementing steers with GWS, SMGC, or WSB yielded additional weight gains of 143.0, 142.0, and 135.0 g/animal/day, respectively, when compared to control animals suggesting a reduced time to finishing protein-supplemented steers at pasture. No significant differences in CY were observed across treatments in this trial. Ruminal pH also did not differ averaging 6.51 among supplements. Conversely, concentration of ruminal ammonia was lower on animals receiving only mineral mix than on those fed protein supplements.

Objetivou-se simular e validar a degradação ruminal dos carboidratos e o fluxo nitrogenado microbiano, estimados a partir de parâmetros da cinética de degradação ruminal de amostras de extrusa esofágica e de suplementos obtidos pela técnica in vitro de produção de gases. As estimativas in vivo foram obtidas em experimento de campo, no qual foram utilizados cinco novilhos mestiços Holandês x Zebu com idade e peso médios iniciais de 24 meses e 304 kg, manejados em cinco piquetes de B. decumbens (0,34 ha). Foram fornecidos suplementos (4 kg/animal/dia) constituídos por fubá de milho, grão de soja integral, uréia, sulfato de amônia e mistura mineral, formulados para apresentarem níveis de 12, 16, 20 e 24% de proteína bruta, com base na matéria natural. O experimento foi conduzido em quatro períodos experimentais de 21 dias, em delineamento em quadrado latino 4 x 4. O quinto animal foi mantido sem suplementação, sendo utilizado como medida de comparação descritiva. A avaliação estatística foi feita por meio do ajustamento de equação de regressão linear simples de valores preditos in vitro sobre valores observados in vivo. A utilização das taxas de digestão específica obtidas in vitro implicou em sub e superestimação da degradação ruminal de carboidratos fibrosos (CF) e não-fibrosos (CNF), cujos vícios globais do processo de de estimação foram de -25,27% e +33,58%, respectivamente. Os valores preditos de eficiência microbiana não mostraram relação significativa com os valores observados, refletindo falta de relação entre valores preditos e observados para o fluxo abomasal de nitrogênio microbiano. A avaliação de alimentos separadamente subestima a taxa de digestão específica de CF.The objective of this trial was simulate and validate the ruminal degradation of carbohydrates and the flow of microbial nitrogen, estimated from samples of esophageal extrusa and supplements, using an in vitro gas production technique. In vivo estimates were obtained from five Holstein x Zebu steers averaging 304 kg of body weight and 24 months of age that were grazing on five paddocks of Brachiaria decumbens (0.34 ha). The supplements fed to the steers (4 kg/animal/day) contained: grounded corn, whole soybean, urea, ammonium sulfate, and mineral salt and the following crude protein levels: 12, 16, 20, or 24% on as-fed basis. Statistical analyses were performed as a 4 x 4 Latin square design with 21-days periods. The fifth animal was not supplemented and was used only for descriptive comparisons. Data were obtained by regression of values predicted in vitro on values observed in vivo. Use of digestion rates obtained in vitro resulted in under- and over-estimation of the ruminal degradation of fiber (FC) and nonfiber (NFC) carbohydrates with overall biases of -25.27% and +33.58%, respectively. No significant relationship was found between predicted versus observed values for microbial efficiency showing lack of relationship between predicted and observed values for the abomasum flow of microbial nitrogen. Results showed that the ruminal incubation of feeds separately underestimates the digestion rate of FC.

Avaliaram-se aspectos das digestibilidades aparente total e parcial e parâmetros do metabolismo ruminal e dos compostos nitrogenados em novilhos mestiços suplementados durante a fase de transição entre os períodos seco e chuvoso. Foram utilizados cinco novilhos mestiços holandês x zebu com idade e peso médios iniciais de 24 meses e 304 kg, manejados em cinco piquetes de B. decumbens (0,34 ha). Foram fornecidos suplementos (4 kg/animal/dia) constituídos por fubá de milho, grão de soja integral, uréia, sulfato de amônia e mistura mineral, sendo formulados para apresentarem níveis de 12; 16; 20 e 24% de proteína bruta (PB), com base na matéria natural. O experimento foi conduzido em quatro períodos experimentais de 21 dias, sendo analisado por delineamento em quadrado latino 4x4. O quinto animal foi mantido sem suplementação e utilizado como medida de comparação descritiva (SAL). Não foram observados efeitos da composição dos suplementos sobre a digestibilidade total e parcial da matéria seca, matéria orgânica (MO) e fibra em detergente neutro e sobre os fluxos abomasais de nitrogênio (N) total, amoniacal e microbiano (NMIC). Os níveis de N amoniacal ruminal foram incrementados linearmente pela elevação dos níveis de PB dos suplementos. A eficiência de síntese microbiana apresentou valor médio de 17,5 g NMIC/kg MO fermentada no rúmen (MOFR) para os suplementos, sendo superior a SAL (10,6 g NMIC/kg MOFR). A elevação dos níveisThe objective of this trial was to evaluate ruminal, intestinal, and total tract apparent digestibilities of nutrients as well as metabolism of ruminal and nitrogenous compounds in supplemented finishing cattle during the drought to rainy transition season. Five Holstein x Zebu steers averaging 304 kg of live weight and 24 months of age located in five paddocks (0.34 ha each) of Brachiaria decumbens were used in this trial. The supplements fed (4 kg/animal/day) contained ground corn, whole soybean, urea, ammonium sulfate, and minerals and were formulated to yield, on as fed basis, 12, 16, 20, and 24% of crude protein (CP). Four animals were assigned to a 4 x 4 Latin square with experimental periods lasting 21 days. The remaining animal was not supplemented and was used for comparative purposes (CONT). No significant differences in ruminal, intestinal, and total tract apparent digestibilities of dry matter, organic matter, and neutral detergent fiber were observed by increasing the CP contents of the supplements. Similarly, abomasal flows of total nitrogen, ammonia nitrogen, and microbial nitrogen (MICN) did not differ when the CP contents of the supplements were increased. However, concentration of ruminal ammonia nitrogen increased linearly by incrementing the CP content of the supplement from 12 to 24%. Microbial efficiency averaged 17.5 g of MICN/kg of organic matter fermented in the rumen (OMFR) across supplements and was higher than that of the CONT (10.6 g of MICN/kg of OMFR). In addition, it was observed a significant cubic effect for urinary excretion of urea by increasing the CP contents of the supplements.

Avaliaram-se o consumo e os parâmetros da cinética de trânsito de partículas em bovinos suplementados durante a fase de transição entre os períodos seco e chuvoso. Foram utilizados cinco novilhos Holandês x Zebu com idade e peso médios iniciais de 24 meses e 304 kg, respectivamente, manejados em cinco piquetes de Brachiaria decumbens (0,34 ha). Foram fornecidos suplementos (4 kg/animal/dia), constituídos por fubá de milho, grão de soja integral, uréia, sulfato de amônia e mistura mineral, formulados para apresentarem níveis de 12, 16, 20 e 24% de proteína bruta (PB), com base na matéria natural. O experimento foi conduzido em quatro períodos experimentais de 21 dias e analisado por delineamento em quadrado latino 4 x 4. O quinto animal, mantido sem suplementação (controle), foi utilizado como medida de comparação descritiva. A forragem selecionada pelos animais apresentou teores médios de PB e fibra em detergente neutro (FDN) de 109,9 e 564,4 g/kg de matéria seca (MS), respectivamente. A variação do nível de PB dos suplementos não alterou os consumos de MS, de matéria orgânica e de FDN. O fornecimento de suplementos reduziu o consumo de pastagem e ampliou o consumo de MS total em relação ao controle, com coeficiente médio de substituição de 0,41. O nível de PB dos suplementos não afetou a taxa de passagem ruminal das partículas, cujo valor médio (0,034 h-1), foi superior ao observado no controle (0,029 h-1).The objective of this trial was to evaluate the voluntary intake and ruminal passage of particles in supplemented finishing cattle during the drought to rainy transition season. Five Holstein x Zebu steers averaging 304 kg of live weight and 24 months of age located in five paddocks (0.34 ha each) of Brachiaria decumbens were used in this trial. The supplements fed (4 kg/animal/day) contained ground corn, whole soybean, urea, ammonium sulfate, and minerals and were formulated to yield, on as-fed basis, 12, 16, 20, and 24% of crude protein (CP). Four animals were assigned to a 4 x 4 Latin square with experimental periods lasting 21 days. The remaining animal was not supplemented and was used for comparative purposes (CONT). Forage grazed by the animals had average contents of CP and neutral detergent fiber (NDF) of 109.9 and 564.4 g/kg of dry matter (DM), respectively. No significant differences in the intakes of DM, organic matter, and NDF were observed by increasing the CP contents of the supplements. Supplementation reduced consumption of forage but total DM intake was greater in the supplemented than in the CONT animal. Increasing the CP content of the supplements did not change the ruminal passage rate of particles that averaged 0.034 h-1 for the supplemented steers and was higher than that of the CONT animal (0.029 h-1).

O objetivo deste trabalho foi determinar os parâmetros cinéticos da degradação, in situ, da matéria seca, da proteína bruta e da fibra em detergente neutro das silagens de milho e de capim-elefante, do feno de capim-Tifton 85 e do farelo de soja. Foram utilizados três bovinos adultos, fistulados no rúmen, com peso vivo médio de 400 kg. Os alimentos foram pesados em sacos de náilon, incubados todos de uma vez e retirados nos tempos 0, 2, 4, 8, 16, 24, 48 e 72 horas, após a incubação dos volumosos, e 0, 2, 4, 8, 16, 24 e 48 horas, após incubação do farelo de soja. Os resíduos dos sacos foram analisados quanto ao conteúdo de matéria seca, proteína bruta e fibra em detergente neutro. A matéria seca e a proteína bruta do farelo de soja apresentaram potencial de degradação elevado, assim como a proteína bruta da silagem de milho. Destacou-se a elevada fração não-degradável da fibra em detergente neutro do feno de capim-Tifton 85 e, portanto, sua baixa degradabilidade potencial da matéria seca. O teor de fibra em detergente neutro e suas características cinéticas exercem acentuado efeito sobre a digestão dos alimentos.The objective of this work was to determine the kinetic parameters of the dry matter in situ degradation, crude protein and neutral detergent fiber for corn silage, elephant-grass silage, Tifton-85 grass hay and soybean meal. Three rumen canulated cattle were used, with mean liveweight of 400 kg. Feeds were weighted in naylon bags, and incubated in the rumen at once. Roughages were removed at 0, 2, 4, 8, 16, 24, 48 and 72 hours, and soybean meal at 0, 2, 4, 8, 16, 24 and 48 hours after incubation. Residues in the bags were analyzed for dry matter, crude protein and neutral detergent fiber. Dry matter and crude protein of soybean meal presented highly degradable potential, as well as crude protein of corn silage. Tifton-85 grass hay presented high indigestible neutral detergent fiber fraction and therefore, low potential dry matter degradation. Amount of the neutral detergent fiber and its kinetic characteristic has a marked effect on digestion of feeds.

Objetivou-se avaliar o efeito de diferentes fontes energéticas em suplementos múltiplos de auto-regulação de consumo sobre o ganho médio diário (GMD), ganho de peso total (GPT), pH e a concentração de amônia ruminal em novilhos recriados em pastejo no período das águas. Foram avaliados suplementos contendo grão de milho moído (GMM), milho desintegrado com palha e sabugo (MDPS), sorgo moído (SM) e tratamento controle (mistura mineral - MM). Utilizaram-se 16 novilhos mestiços Holandês-Zebu, não-castrados, com 12 meses de idade e peso médio inicial de 265 kg para avaliar o desempenho. Os parâmetros ruminais foram obtidos utilizando-se quatro novilhos mestiços Holandês-Zebu fistulados no rúmen. O pH do líquido ruminal variou de 6,43 a 6,62 (média de 6,55), não sendo influenciado pelas quantidades de sal e de suplemento consumidas. As concentrações de amônia foram de 9,61; 25,71; 24,45 e 26,04 mg/dL, respectivamente para os tratamentos MM, GMM, MDPS, SM. Não se verificou diferença entre os tratamentos, contudo o suplemento MDPS proporcionou ganhos adicionais em torno de 220 g/animal/dia. Maiores concentrações de amônia ruminal foram observadas nos animais suplementados.The effect of different energy sources in multiple supplements of self-feed on the average daily gain (ADG), total weight gain (TWG), pH and ruminal ammonia concentration of steers grazed at pasture in the wet season was evaluated. Treatments were supplements containing ground corn grain (GCG), corn, ears and cob (CEC), ground sorghum (GS) and control treatment (mineral mix - MM). Sixteen crossbreed steers with initial age and weight of 12 months old and 265 kg were used. Ruminal parameters were obtained from four crossbreed steers fistulated in the rumen. The pH values ranged from 6.43 to 6.62, with an average of 6.55 not having effect for the amounts of salt and supplement consumed. Concentrations were 9.61, 25.71, 24.45 and 26.04 mg/dL, respectively, for MM, GCG, CEC and GS treatments. It was not found differences between treatments, although the supplement CEC provided additional gains of 220 g/animal/day. Higher concentrations of ruminal ammonia were observed in the supplemented animals.