R. S. Fontaneli

Yield and nutritive value of dual purpose winter cereals: green forage, silage or grain.

This study was carried out to evaluate 14 genotypes of six winter species for yield and nutritive value of early forage and silage or regrowth grain. The experiment was in a randomized complete block design with three replications, so that the plots consisted of seven 5.0 m-long rows spaced at 0.2 m. The seeding date was April in the three study years and fertilization followed the recommendations for the crops. During the tillering period and after cutting, urea was applied at the rate of 22.5 kg N/ha. Each plot was cut at a height of 7.0 cm from the soil to estimate the forage yield per genotype, when plants reached 30 cm height. Half the regrowth of each plot was used for silage and half for grain. Harvesting for silage was at the dough stage, from 30 to 35% DM. Nutritive value analyses were made using the near infrared spectroscopy (NIRS) technique. Rye BRS Serrano was superior for green forage, silage, and total forage yield (green forage + silage) and regrowth grain yield. However, for grain yield, BRS Serrano rye was similar to BRS 277 wheat, BRS 148 and BRS 203 triticales, UPF 18 oats, and BR 1 rye. It is possible to obtain early forage using genotypes of rye, wheat, barley, and triticale, producing equivalent forage yields to those obtained with black oats pasture. Embrapa 53 triticale and UPF 18 oats yielded more digestible green forage, but the silages had digestibility similar to barley silage.

Resposta de pastagens perenes à adubação com chorume suíno: cultivar Tifton 85

The work was carried out with the aim to verify the response of a cv. Tifton 85 pasture, in Depressao Central of Rio Grande do Sul state, to pig slurry (PS) fertilization, in the rates of 0, 15, 30 and 45 m3/ha/cutting, between October/03 and February/04, totalizing 0, 60, 120 e 180 m3/ha in the spring-summer. The PS was applied after cuttings, in: 15/10/2003 (uniformizing cutting), 11/24/2003, 1/10/2004 and 2/5/2004. The last cut was done in 4/10/2004 and then it was not applied PS. The highest production (2,232 kg DM/ha) was obtained in the second cutting (January/2004), with 30 m3/ha, a 347% higher than control. The total DM production response as function to PS was quadratic, being obtained 1,397 (without PS), 2,971 (15 m3), 4,696 (30 m3) and 4,714 (45 m3) kg/ha. The PS efficiency did not differ between the rates (24,5 kg DM/m3/ha) but it varied between cuttings, from 5.6 a 49.7 kg DM/m3/ha. The highest N extraction was 28 kg N/ha (30 m3) and the N recovery varied from 2% (fourth cutting) to 12% (second cutting). The CP and ADF content were affected by fertilization and cutting date, varying between 8.3 (without CS) to 10.7% (30 m3) in the first cutting and 45.9 (without PS) to 42.8% (45 m3) in the last cutting, respectively. The PS application is an alternative to increase the pasture production of cv. Tifton 85, being suggested the 30 m3/ha/cutting as reference-value.

Caracterização agronômica de genótipos de cornichão (Lotus corniculatus L.)

This work was carried out to characterize agronomically birdsfoot trefoil (Lotus corniculatus L.) genotypes, including eight populations derived from the cultivar Sao Gabriel, one rhizomatous cultivar (ARS-260) and one cultivar without rhizomes (Trueno). Individual plants were submitted to seven cuts under field conditions during one year, at Passo Fundo, Rio Grande do Sul, Brazil. The genotypes showed variability relative to internode lenght, height, diameter, legume lenght, forage production and nutritive value. On the average, the populations and the cv. Trueno were about 50% more productive than the cv. ARS-260. The genotypes presented a survival range from 80% to 100%. The crude protein content decreased from 21.8 (vegetative stage) to 11.2% (fruiting stage). The overall mean for acid detergent fiber was 24.2% and the neutral detergent fiber ranged from 55.3% to 58.8%.

Predição da composição química de bermudas (Cynodon spp.) pela espectroscopia de reflectância no infravermelho proximal

Many Cynodon dactylon cultivars have been cultivated in Rio Grande do Sul state to be used as pasture or hay to feed dairy cattle. Quick determination of the nutritional value of these forages would be valuable for management and diet planning. This work had the objective to develop calibration curves for analysis of the nutritional value of four Cynodon cultivars (Tifton 68, Tifton 85, Florakirk, Coastcross), using near infrared reflectance spectroscopy (NIRS). A total of 129 fresh samples of green pasture were collected and analyzed from 1998 to 2001. The determination coefficients for crude protein, neutral detergent fiber, acid detergent fiber, dry matter, calcium, phosphorus, potash and magnesium were, respectively, .98, .97, .99, 1, .92, .97, .99 and .72%. The calibration standard error for the same parameters were .38, .60, .35, .14, .02, .01, .05 and .01%, respectively. Obtained equations were considered of excellent resolution for all estimated parameters, indicating the accuracy of the method for the species studied.

Validação do Método da Reflectância no Infravermelho Proximal para Análise de Silagem de Milho

Traditional analytical methods of assessing forage nutritional value are time-consuming and expensive. The near infrared reflectance method appears as an alternative that does not utilize chemicals, is not destructive and is extremely fast. However, in order to be used in a routinely basis, calibration curves have to be developed from laboratory results and mathematical equations. The objective of this paper was to develop calibration curves for corn silage, using a total of 246 samples collected in different regions of Rio Grande do Sul. The samples were analyzed using the reference methods to determine crude protein (CP), dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF) and minerals (Ca, K, Mg and P). The same samples were also analyzed by spectroscopy, using a wave length region that ranges from 1100 to 2500 nm. Data was mathematically treated by the Match program and then a regression model was fitted, having the results from the chemical analysis as independent variables and the results from the near infrared reflectance as dependent variables. The evaluation of the adjustment level was made through the determination coefficients (R2). The accuracy was elevated (R2 = 0.99) for CP, ADF, NDF and DM, indicating the validity of this method to predict such parameters in corn silage. Even though the R2 for minerals have ranged from 0.92 to 0.94, further research about the behavior of the spectrum is needed in order to evaluate the type of mineral complex formed and its relation with the chemical method. The averages for CP, NDF, ADF and DM were 7.86, 60.66, 29.87 and 94.17%, respectively. The averages for Ca, P, K and Mg were, respectively, 0.27, 0.21, 1.14 and 0.22%.

Caracterização morfofisiológica e agronômica de Paspalum dilatatum Poir. biótipo Virasoro e Festuca arundinacea Schreb: 2. Disponibilidade de forragem e valor nutritivo

Este trabalho foi conduzido com o objetivo de avaliar o potencial forrageiro de Paspalum dilatatum Poir. biotipo Virasoro e Festuca arundinacea Schreb., exotica e hibernal na regiao sul do Brasil. Foi colhida mensalmente a parte aerea de plantas individuais, cultivadas no campo durante 12 meses e avaliadas quanto a disponibilidade de massa seca (DMS), proteina bruta (PB), fibra detergente neutro (FDN) e fibra detergente acido (FDA). O virasoro apresentou ciclo estacional, com a maior DMS na primavera/verao (98 g MS/planta), enquanto a festuca teve a maior DMS no inverno/primavera (100 g MS/planta). O virasoro mostrou teores mais elevados de PB nas folhas (19,09%) em relacao a festuca (17,8%), mas essa apresentou menor conteudo de FDA (29%) em relacao ao virasoro (43%); para FDN nas folhas nao houve diferenca entre as especies, com medias de 62%. No colmo, as diferencas foram apenas no outono (festuca=19,9%; virasoro=73,9%). O biotipo Virasoro nao foi infectado por Claviceps paspali, que comumente ocorre em P. dilatatum, indicando resistencia ao fungo. O biotipo Virasoro detem caracteristicas desejaveis como planta forrageira, sendo uma boa opcao para a estacao quente.

Valor nutritivo da forragem de genótipos de cereais de inverno de duplo propósito

The objective of this research was to evaluate the nutritive value of the forage of 12 genotypes of six double purpose (forage and grains) winter cereal species submitted to harvest in the region of Depressao Central in Rio Grande do Sul state. The species and genotypes tested were: wheat (BRS 277, BRS Guatambu, BRS Taruma and BRS Umbu); black oat (Agro Zebu, UPFA 21 - Moreninha and Commom black-oat); white-oat (UPF 18); rye (BR 1 and BRS Serrano); barley (BRS Marciana); and triticale (BRS 148). The genotypes were distributed in 36 experimental plots in completely randomized experimental design, with 12 treatments and three replications. Analysis of nutritive value and mineral composition were performed by the near infrared spectroscopy (NIRS) in samples of stratum greater than 10 cm height of forage. Oat genotypes and BRS Umbu wheat presented the best nutritive value results. Mineral composition presented small variability among the genotypes tested. The results demonstrate that winter cereals produce high nutritive value forage.

Suplementação da Silagem de Sorgo com Diferentes Fontes de Proteína para Bovinos de Corte

Soybean meal (SBM), feather meal (FTM) and treated soybean meal (TSBM) with 0.17% of formaldehyde were used as supplement of sorghum silage to evaluate the effect on intake, performance and nutrient digestibilities with young bulls. Treatment of soybean meal with formaldehyde did not differ from soybean not treated, for all studied parameters. Feather meal supplement presented lower digestibility coefficients for DM, OM, CP, NDF and ADF (63.0, 65.5, 61.8, 56.4, and 50.9%, versus 65.1, 67.0, 66.8, 58.5, and 53.6% for soybean meal and 66.7, 68.7, 67.2, 61.9 and 57.5% for treated soybean meal, respectively). It also showed lower metabolizable energy intake by unit of metabolic weight (214 kcal/MW for FTM, 234 kcal/MW for SBM and 240 kcal/MW for TSBM). Even if differences were observed for all parameters, it was not possible to detect differences in live weight gain (1.5, 1.6 and 1.7 kg/d for FTM, SBM and TSBM).

Utilização de cama sobreposta de suínos e sobressemeadura de leguminosas para aumento da produção e qualidade de pastagem natural

Este trabalho foi conduzido com o objetivo de verificar o efeito da fertilizacao com dois tipos de camas sobrepostas de suinos (CSS), a base de casca de arroz (CA) e maravalha (MA), sobre a producao de uma pastagem natural, com predominio de Axonopus sp. e Paspalum sp., sobressemeada com leguminosas (cornichao e trevo-branco). As camas sobrepostas foram aplicadas em quantidades equivalentes a 180, 360, 540 e 720 kg/ha de P2O5, constituindo quatro niveis de cama de casca de arroz (30, 60, 90 ou 120 t/ha) e quatro niveis de cama de maravalha (20,6; 41,2; 62,2 ou 82,8 t/ha). Foram incluidos dois tratamentos-testemunha: 180 kg/ha de superfosfato triplo (SFT) e ausencia de adubacao (AA). A sobressemeadura das leguminosas foi realizada em maio de 2004 e, a partir de agosto de 2004, foram realizados nove cortes da pastagem, a cada seis semanas. As maiores producoes de materia seca (MS) anuais (setembro/2004 a agosto/2005) com as aplicacoes de cama de casca de arroz foram obtidas nos niveis 30 e 60 t/ha e, com cama de maravalha, nos niveis 62,2 e 82,8 t/ha, que resultaram em producoes de MS de 8.083 e 8.276 kg/ha, superiores as obtidas com superfosfato triplo (4.091 kg MS/ha) e sem adubacao (3.071 MS kg/ha). A producao de MS de trevo-branco aumentou linearmente no outono e no inverno, de acordo com os niveis de adubacao com cama de maravalha, mas nao variaram com a adubacao com cama de casca de arroz. O efeito fertilizante varia entre os tipos de cama sobreposta, que podem influenciar a composicao botânica de pastagens mistas de leguminosas-gramineas.

Produção de forragem de gramíneas anuais semeadas no verão

In the Rio Grande do Sul (RS) state, southern Brazil, the forage foundation of beef and dairy cattle operations is pasture of warm-season grasses, with high nutritive value (NV) during spring and part of summer seasons, if managed frequently. However, during cool-season, forage NV is very low and worsen by frosts. A 2-yr split-plot experiment on randomized complete block design with three replications compared yield, yield distribution, and nutritive value in three seeding dates (January, February, and March) allocated on main plots, and five forage grasses cultivars (common pearl millet, teosinte, sudangrass, and BRS 800 and AG 2501C sorghum hybrids) on subplots. The two first seeding dates had the highest forage yield, about 6.0Mg ha-1 of DM than March seeding date of high nutritive value forage (>150g kg-1 MS). Sorghum-hybrids genotypes yield more than teosinte and sudangrass. Pearl millet, sudangrass and teosinte had more tillering. Pearl millet had high CP (200g kg-1 DM), and lower FDA (350g kg-1 DM) concentrations on leaf blades compared to sorghums and teosinte. It is possible minimize fall forage shortage seeding annual forage grasses until end of February in the Planalto region of RS state, and extend the productive period, an additional 30 to 60-d, during a time of year when warm-season perennial grasses have low forage allowance or low nutritive value, and annual winter forages are not established.