Karina Guimarães Ribeiro

Características produtivas e qualitativas de ramas e raízes de batata-doce

A batata-doce e uma hortalica que se destaca pela versatilidade no uso, podendo ser empregada tanto na alimentacao humana como animal. Seu cultivo e relativamente facil e barato, o que, juntamente com sua adaptabilidade a variadas condicoes edafo-climaticas, viabiliza sua producao pelos agricultores familiares. Objetivou-se avaliar a producao de massa verde e massa seca da parte aerea para utilizacao na alimentacao animal e a produtividade e a qualidade das raizes tuberosas de clones de batata-doce para utilizacao na alimentacao humana. O delineamento experimental utilizado foi em blocos casualizados, com doze clones e quatro repeticoes. Foram avaliados clones de batata-doce pertencentes ao banco de germoplasma da UFVJM juntamente com as cultivares comerciais Brazlândia Roxa e Brazlândia Rosada, colhidos aos seis meses apos o plantio. Foram avaliadas a producao de massa verde e massa seca da parte aerea e a produtividade e qualidade das raizes tuberosas. O clone BD-45 destacou-se na producao de massa verde, producao de massa seca e nas produtividades total e comercial de raizes com valores de 19,7; 3,3; 32,9 e 29,5 t ha-1, respectivamente. A maioria dos genotipos avaliados apresentou raizes com formato proximo ao ideal para comercializacao e boa resistencia a insetos de solo com valores de notas proximos a 2,0. Foram observadas diferencas significativas entre os genotipos para os teores de amido e acucares totais e redutores. Os genotipos apresentaram composicao centesimal semelhante, exceto para o teor de cinzas. Os clones BD-67 e BD-56 apresentaram teores de cinzas mais elevados que o Cambraia, e semelhantes aos demais clones.

Potencial de silagens de ramas de batata-doce para alimentação animal

The objective was to evaluate the potential of silage derived from different clones of sweet potato for animal feed. The study was conducted at Forquilha Farm located in Batatal district, MG Diamantina in the period from 23/12/2007 to 23/06/2008. The experiment was conducted in split plot design in a randomized complete block. It was evaluated the green and dry matter yield, the chemical composition and the fermentative profile of silage harvested on three dates (days 120, 150 and 180), of eight clones of sweet potato. The dry matter yield did not vary according to the harvest time of the branches, resulting in an average of 6.01t ha-1. The dry matter content in the stems increased with the growth cycle, and there are average levels of 11.94, 12.16 and 19.62% on days 120, 150 and 180 after cutting, respectively. The raw potato silage showed high protein content and adequate energy fermentation and therefore, potential for use in animal feed, regardless of clones.

Produção e valor nutritivo do capim-coastcross sob doses de nitrogênio e idades de rebrotação

The production and nutritive value of the bermudagrass cv. coastcross under five different nitrogen doses (0, 100, 200, 300 and 400kg/ha.year) and two regrowth ages (28 and 42 days) were evaluated. The experiment was arranged in a factorial scheme in a complete randomized block design with three repetitions. The nitrogen (N) fertilization was performed in three applications right after harvest. Tiller population density showed quadratic response to N application. The forage production varied from 8.0 to 17.2t/ha.year at N doses ranging from 0 to 400kg/ha.year, showing positive linear response to nitrogen fertilization. The highest values of leaf:stem relation (LSR) were observed for later harvest in the absence of N fertilization. In general, as the N doses increased the LSR of grass decreased linearly. The crude protein contents increased linearly with nitrogen fertilization, showing higher efficiency at 28 days of regrowth. In vitro digestibility increases regarding the N fertilization occurred for younger plants at 28 days of regrowth. The neutral detergent fiber content decreased linearly with nitrogen fertilization. The nitrogen fertilization effect on the nutritional value of bermudagrass cv. coastcross depends on the regrowth age of this forage. When applying higher N doses under favorable growth conditions, the coastcross grass pasture should be managed to have defoliation each 28 days.

Avaliação de silagens de ramas de batata-doce

O presente trabalho teve como objetivo selecionar clones de batata-doce com potencial para uso na alimentacao animal. O experimento foi conduzido em blocos ao acaso, com 11 clones e quatro repeticoes. Os clones avaliados fazem parte do banco de germoplasma da Universidade Federal dos Vales do Jequitinhonha e Mucuri, sendo: BD-06, BD-25, BD-15, BD-38, Cambraia, BD-31-TO, BD-67, BD-45, BD-42, BD-54 e a cultivar Brazlândia Rosada. Nas ramas coletadas do experimento foram avaliados o teor de materia seca e as produtividades de massa verde e massa seca. Nas silagens de ramas foram avaliados o pH e os teores de materia seca (MS), proteina bruta (PB), fibra em detergente neutro (FDN), fibra em detergente acido (FDA), nutrientes digestiveis totais (NDT), fosforo, calcio e sodio. Nao houve diferenca significativa para a produtividade de massa verde e de massa seca das ramas entre os clones de batata-doce. As silagens produzidas caracterizam-se como volumosos de boa qualidade, apresentando teores satisfatorios de proteina bruta (11,59%), FDN (31,98 a 39,68%), FDA (29,65 a 35,45%) e NDT (62,90 a 66,91%), comprovando o potencial de utilizacao das ramas da batata-doce na forma de silagem.

Efeito da substituição de pré-secado de capim-tifton 85 por silagem de sorgo no consumo e na digestibilidade dos nutrientes e no desempenho de bovinos de corte

Intake, digestibility of nutrients, daily weight gain, and feed conversion were evaluated in beef cattle receiving diets containing the following ratios of sorghum silage:Tifton 85 haylage: 0:100; 32:68; 66:34; and 100:0. Diets were formulated to be isonitrogenous (12% crude protein) with a forage:concentrate ratio of 60:40, on DM basis. Twenty-four crossbred Holstein x Zebu steers averaging 360 kg of initial body weight were distributed in a completely randomized block design with 15 days for diet adaptation followed by three experimental periods of 28 days each. Indigestible acid detergent fiber (IADF) was used to estimate fecal output. Mean daily intakes of DM, OM, CP, EE, TC, and TDN all were not affected by treatments with mean values of: 9.46, 9.05, 1.20, 0.52, 7.4, and 6.23 kg/day, respectively. Significant quadratic effects were observed for the apparent total tract digestibilities of DM, OM, CP, and EE with estimated minimum digestibilities of 60.33, 61.58, 61.89, and 55.83% for the levels of 44.80, 47.18, 50.95, and 51.21% of sorghum silage in the forage portion of the diet, respectively. Mean daily weight gain and feed conversion also were affected quadratically by increasing the level of sorghum silage in the forage portion of the diet with estimated maximum and minimum values of 1.25 kg/day and 7.66 for the levels of 60.95 and 67.04% of sorghum silage, respectively. Results indicated that varying dietary ratios of Tifton 85 haylage and sorghum silage is a good alternative for feeding forage to finishing beef cattle. Inclusion of approximately 60% of sorghum silage in the total dietary forage resulted in the greatest estimated weight gain.

Intake, digestibility, and performance of steers fed diets based on two corn silage hybrids and two concentrate levels

A trial involving a 2x2 factorial arrangement of treatments was conducted to evaluate two corn silage hybrids (Agromen, AGN35-A42) and (Bayer, A3663) and concentrate levels (25 and 50%) on animal performance. Twenty-four Holstein x Zebu crossbred steers, averaging 335±30kg of BW, were distributed in six randomized blocks to evaluate intake, digestibility, and performance. Treatments consisted of 75% corn silage A + 25% concentrate, 50% corn silage A + 50% concentrate, 75% corn silage B + 25% concentrate, and 50% corn silage B + 50% concentrate (dry matter basis); formulated to be isonitrogenous (13% crude protein, dry matter basis). There were no differences in the daily intakes of dry matter (DM), organic matter (OM), and crude protein. Additionally, there was a concentrate effect on non-fiber carbohydrates and total digestible nutrients intakes, and on total apparent digestibility of DM and OM, with higher intakes for steers fed diets with 50% of concentrate. However, average daily gain (ADG) was not influenced by treatments. The utilization of both corn silage hybrids in association with 25% of concentrate is a good option to feed crossbred steers with ADG close to 1.0kg in order to reduce diet cost.

Efeito da substituição de feno de capim-tifton 85 por silagem de milho no consumo, na digestibilidade dos nutrientes e no desempenho de novilhos mestiços Limousin

Avaliaram-se o consumo e a digestibilidade dos nutrientes, o ganho de peso e a conversao alimentar de bovinos de corte recebendo dietas contendo feno de capim-tifton 85 e silagem de milho nas proporcoes 100:0; 68:32; 35:65 e 0:100, com base na MS. Foram utilizados 19 animais mesticos Limousin x Zebu, nao-castrados, com PV inicial de 301 kg, distribuidos em um delineamento inteiramente casualizado. A relacao volumoso:concentrado foi de 58:42, com base na MS. O ensaio teve duracao de 99 dias, sendo 15 dias de adaptacao e tres periodos de 28 dias para avaliacoes. Para determinacao da excrecao fecal, utilizou-se a fibra em detergente acido indigestivel (FDAi) como indicador. Os consumos medios de MS, MO, PB, CT e FDN apresentaram efeito quadratico em funcao de niveis crescentes de silagem de milho. Para os consumos de MS e MO, estimaram-se valores maximos de 7,52 e 7,08 kg/dia para os niveis de 61,13 e 61,78%, respectivamente, de silagem de milho no volumoso. As digestibilidades aparentes de MS, MO e FDN nao foram influenciadas pelos niveis de silagem de milho no volumoso. O ganho de peso medio diario aumentou de forma linear e a conversao alimentar decresceu, tambem de forma linear, com o incremento da proporcao de silagem de milho no volumoso das dietas. A silagem de milho como constituinte do volumoso da dieta, na proporcao de 61%, proporcionou maximo consumo de MS. O ganho de peso aumentou 4,82 g/dia para cada unidade de silagem de milho adicionada ao volumoso da dieta para novilhos mesticos Limousin.

Consumo, digestibilidade e parâmetros ruminais em bovinos de corte alimentados com dietas contendo silagem de sorgo e pré-secado de capim-tifton 85

Avaliaram-se o consumo e as digestibilidades total e parcial dos nutrientes, a eficiencia microbiana, o balanco de nitrogenio, a taxa de passagem da digesta ruminal, o pH e a concentracao de amonia ruminal em bovinos de corte alimentados com dietas contendo como fonte de volumoso pre-secado de capim-tifton 85 e silagem de sorgo nas seguintes proporcoes: 100:0; 68:32; 34:66 e 0:100, respectivamente, com base na MS. Foram utilizados quatro animais mesticos Holandes × Zebu (H × Z), fistulados no rumen e abomaso, com peso medio de 364 kg, distribuidos em um quadrado latino 4 × 4. A relacao volumoso:concentrado foi de 60:40, na base da MS. Os consumos de MS, MO, PB, carboidratos totais (CT), assim como as digestibilidades totais da PB, EE, CNF e FDN nao foram influenciados pelas dietas, registrando-se valores medios de 6,01; 5,69; 0,76 e 4,64 kg/dia e 67,94; 82,42; 84,43 e 53,57%, respectivamente. Os consumos de EE, CNF, FDN e NDT e as digestibilidades aparentes totais da MS, MO e CT aumentaram linearmente com o incremento da proporcao de silagem de sorgo no volumoso. As digestibilidades ruminais e intestinais de MS, CT, CNF e FDN nao foram influenciadas pelas dietas. O pH nao foi alterado pelos tempos de coleta nem pelas dietas. A concentracao de amonia foi influenciada pelos tempos de coleta, estimando-se valor maximo de 13,14 mg/100 mL, as 2,90 horas apos a alimentacao. Para as dietas contendo 0; 32; 66 e 100% de silagem de sorgo no volumoso estimaram-se taxas de passagem da digesta ruminal da ordem de 4,10: 4,22; 4,27 e 5,30%/hora, respectivamente. A eficiencia microbiana nao foi afetada pelo nivel de silagem de sorgo na dieta. O uso de silagem pre-secada de capim tifton 85 associada a silagem de sorgo mostrou-se uma boa alternativa de volumoso para bovinos de corte.

Effects of roughage sources produced in a tropical environment on forage intake, and ruminal and microbial parameters

Our objective was to study the effect of different roughage sources produced in a tropical environment on intake, digestibility, and ruminal parameters of crossbred bulls. Five rumen-fistulated 30-mo-old Holstein × Bos indicus bulls (average BW =459 ± 32.5 kg) were utilized in a 5 × 5 randomized Latin square design. The experiment consisted of five 19-d experimental periods (10 d for adaptation and 9 d for data collection) and 5 treatments. Experimental diets consisted of corn (Zea mays L.) silage (CS), Brachiaria grass (Brachiaria decumbens Stapf.) silage (BGS), elephant grass (Pennisetum purpureum Schumach.) silage(EGS), Tifton 85 (Cynodon spp.) hay (T85), and fresh sugarcane (Saccharum officinarum L.; SC). Diets were formulated to have approximately 11% CP (DM basis)using a mixture of urea and ammonium sulfate (9:1 ratio) that was diluted in water and then mixed with roughage. Intake, ruminal outflow, digestibility coefficients,ruminal pool, intake, passage (kp) and digestion rates, microbial parameters, and pH data were assessed.D ry matter intake was greater (P < 0.01) for CS compared with SC. Among treatments, lesser (P < 0.01)potentially digestible NDF, ash- and protein-free NDF(apNDF), and digestible ash- and protein-free NDF intake values were observed for SC. Ruminal outflows of DM and nonfibrous carbohydrates were lesser (P <0.01) for SC compared with other treatments. Dry matter apparent digestibility and ruminal digestibility did not differ (P > 0.27) among treatments. No differences (P = 0.11) were observed for ruminal apNDF pool and ruminal kp of apNDF (P = 0.06) among treatments. No treatment effect (P > 0.28) was observed for DM and nitrogen of rumen-isolated bacteria, and microbial efficiency was greater (P = 0.02) for BGS among treatments.A treatment × time interaction (P < 0.01) was found for ruminal pH, with a quadratic pattern in terms of time for CS, BGS, EGS, and T85, whereas pH values for CA linearly decreased as a function of time. In summary, these roughages, when supplemented with an additional nitrogen sources, show similar overall apparent digestibility and ruminal pool values, but conversely, bulls fed sugarcane had less overall nutrient intake and lower ruminal outflow and digestion rate values. We conclude that fresh-cut sugarcane, when provided with urea, can affect digestion rate and, consequently, impact nutrient intake.

Produção de silagem, composição bromatológica e capacidade fermentativa de ramas de batata-doce emurchecidas

The variation in the availability of forage throughout the year and the need to use low-cost food for ruminants contributed to an increase in the search for new food alternatives. This study aimed to evaluate the yield of the dry mass of vines and the effect of wilting on the chemical composition and fermentative capacity of sweet potato vines for silage production. The evaluated genotypes were BD-08, BD-23, BD-25, BD-31TO, BD-38, BD-43 and Brazlândia Roxa, using a 7x2 factorial arrangement (genotype x wilted vines or not), in a randomized block design, with four replications. We determined the dry matter yield (PMS) and dry matter (MS), crude protein (PB), neutral detergent fiber (FDN), acid detergent fiber (FDA), cellulose, hemicellulose, lignin, ash, water soluble carbohydrates (CS), acid detergent insoluble nitrogen (NIDA), buffering capacity (CT) and fermentative capacity (CF) of fresh and wilted vines. The MS of vines ranged from 4.2 to 7.9 t ha-1, with emphasis on BD-25, BD-08 and BD-23 with yields higher than 7.0 t ha-1. Wilting promoted increase in MS (15.7 to 25.7%), PB (11.0 to 11.9%), FDA (29.2 to 41.7%), lignin (8.6 to 15.5%), cellulose (19.3 to 24.3%), ash (8.9 to 10.0%) and NIDA (9.7 to 32.8%), and reduced levels of CS (15.0 to 7.6%), making the wilted branches of poorer quality. Wilting did not affect the CF of the vines (average 37.2) and promoted an increase in FDN differently for each genotype. The highest levels of MS in wilted vines offset the lower level of CS, making similar the CF of vines.The sweet potato vines of all genotypes presented high potential for silage.