Sandra Galbeiro

Desempenho animal, produção de forragem e características estruturais dos capins marandu e xaraés submetidos a intensidades de pastejo

The objectives were to evaluate the forage yield, the structural characteristics, the herbage intake, the grazing behavior and beef cattle performance in the palisadegrass cvs. Marandu and Xaraes pastures submitted to three grazing intensities. The experiment was carried out at Embrapa Gado de Corte. The experimental period was from October 2005 to June 2006. The area was of 8 ha, divided in 12 paddocks of 0.67 ha. Two cultivars of palisadegrass, Marandu and Xaraes, and three grazing intensities, 15, 30, and 45 cm of sward height were evaluated. The experimental design was randomized block in a split plot arrangement and two replications. The main plot was constituted by cultivars and the subplot by the grazing intensities. The grazing was continuously stocking with variable stocking rate. Each paddock was grazed by three steers and regulating animals were utilized to adjust the sward heights. The sward heights were monitored twice per week. The grass was sampled each 28 days to estimate the herbage yield, herbage accumulation rate, pasture structural characteristics, and nutritive value. Animals were weighed each 28 days. The dry matter intake was estimated in the summer and the autumn, and the grazing behavior in the summer. Herbage accumulation and average daily gain decreased as the grazing intensities increased for both palisadegrass cvs. Xaraes and Marandu. The forage intake for the animals in xaraes grass pasture was limited by the variation in the sward structure. Based on the sward structural characteristics, forage intake and the productivity, these grasses require differentiated management. Marandu grass must be managed between 25 and 40 cm of height and xaraes grass at 40 cm.

Beef heifer production in Coastcross-1 and Arachis pintoi mixed pasture with or without nitrogen fertilization

Este trabalho foi realizado com o objetivo de avaliar a massa de forragem (MF), a taxa de acumulo diario (TAD), a oferta de forragem (OF), a taxa de lotacao (TL), a porcentagem de Arachis pintoi (PAR), o ganho medio diario (GMD) e o ganho por hectare (GPV/ha) de novilhas de corte em pastejo de Coastcross-1 consorciada com Arachis pintoi. Os consorcios avaliados foram: CA0 = coastcross + Arachis pintoi sem adubacao nitrogenada; CA100 = coastcross + Arachis pintoi com 100 kg de nitrogenio; CA200 = coastcross + Arachis pintoi com 200 kg de nitrogenio; e C200 = coastcross com 200 kg de nitrogenio, distribuidos em delineamento de blocos ao acaso, com duas repeticoes. O manejo do pasto foi o de lotacao continua com carga animal variavel utilizando-se novilhas mesticas com tres animais-testes por consorcio. A massa de forragem nas pastagens de coastcross + Arachis pintoi adubadas com 0, 100 e 200 kg de nitrogenio e na pastagem de coastcross adubada com 200 kg de nitrogenio foi de 2.641, 2.431, 2.760 e 2.704 kg de MS/ha, respectivamente. A taxa de acumulo diario foi semelhante (66,12 kg de MS/ha) entre as pastagens; o verao foi a estacao de maior producao, seguido da primavera, do outono, que nao diferiram entre si, e do inverno (108,6; 71,1; 54,2; 30,6 kg de MS/ha, respectivamente). Na associacao de coastcross + Arachis pintoi sem adubacao nitrogenada, foram obtidas a maior oferta de forragem e a menor taxa de lotacao (4,0 UA/ha). As maiores taxas de lotacao e as menores ofertas de forragem foram observadas com a adubacao nitrogenada. A porcentagem de Arachis pintoi foi maior na primavera e, na associacao coastcross + Arachis pintoi sem adubacao, as estimativas visuais foram sempre superiores as medidas, em virtude do baixo teor de materia seca dessa leguminosa. O ganho medio diario foi maior no cultivo em consorcio e adubacao com 200 kg de nitrogenio e na pastagem de coastcross em cultivo exclusivo com 200 kg de nitrogenio em comparacao aquelas de coastcross + Arachis adubada com 100 kg de nitrogenio e sem adubacao (0,51; 0,51; 0,42 e 0,38 kg/dia, respectivamente). Os ganhos anuais por hectare foram superiores a 1.000 kg/ha/ano e foram maiores no verao (221,4 kg/ha).

Valor nutritivo do capim-Tanzânia (Panicum maximum Jacq. cv. Tanzânia-1) pastejado em diferentes alturas

Crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg) and in vitro dry matter digestibility (IVDMD) contents were assessed in the leaf blade and stem + leaf sheath fractions of Tanzaniagrass (Panicum maximum Jacq. cv. Tanzania-1) managed at four sward heights (20, 40, 50 and 65 cm). The grazing method was the continuous stocking and variable stocking rate, and used Nelore steers with an average weight of 340 kg. The completely randomized experimental design was used with two replications, and five evaluations were performed during a period of 112 days. The CP, IVDMD, Ca, P and Mg contents decreased while NDF, ADF and K concentrations increased in the leaf blade and stem + leaf sheath fraction in response to grazing height as well as period of evaluation. Leaf blades exibited higher quality than stem + leaf sheath regardless of grazing height and evaluation time. Tanzaniagrass grazed to 40 and 50 cm presents good chemical composition and IVDMD.

Forage production of Tanzaniagrass (Panicum maximum Jacq. cv. Tanzania-1) grazed at different heights.

This experiment was conducted out to evaluate the forage mass (FM), green leaf lamina mass (GLLM), green stem + leaf sheath mass (GSSM), mass of dead material (MDM), green forage mass (GMF), total forage mass (TFM), leaf/stem ratio (L/S), dry matter accumulation rate (DMAR), leaf area index (LAI), % of bare soil (BS) and litter cover percentage (LCP) in Tanzaniagrass pasture (Panicum maximum Jacq. cv. Tanzania-1) managed at four different sward heights (20, 40, 60 and 80 cm). The grazing method was the continuous stocking with variable stocking rate, and the grazing animals were Nellore steers with average weight of 340 kg. The completely randomized design was used with two replications and five evaluation periods were performed. The GLLM, GSSM, MDM, GMF, FM, LAI, DMAR, and TFM increased by increasing of the pasture height, the percentage of NCS, SCWL and dead material decreased with the pasture height. Tanzaniagrass management, based on the pasture height from 40 to 60 cmshowed good morphologic composition and high leaves availability for grazing, good ground cover and dry matter accumulation rate, while the heights of 20 and 80 cm shall not be recommended for the Tanzania grass management when the objective is high production of forage quality.

Concentrações e quantidades de macronutrientes na excreção de animais em pastagem de capim-mombaça fertilizada com fontes de fósforo

The objective of this experiment was to evalute the effects of phosphorus sources (Yoorin®, Ordinary Superphosphate (SS) + Triple Superphosphate (TS) and control) on the concentration and amount of N, P, K, and Ca in the excreta of crossbred steers under grazing conditions on mombaca grass (Panicum maximum Jacq. cv. mombaca) pasture. The grazing method was the continuous stocking with variable stocking rate, and the animals used were crossbred with average live weight of 300 kg. It was used a complete randomized design in split plot with four replications. Urine production and K concentration were high for animals grazing on Yoorin fertilized pastures compared to other treatments; urine production ranged from 7.2 to 20.4 L/animal/day and K urine concentration ranged from 180 to 310 g/L. Animals grazing on the control and SS + TS treatments presented greater N and P urine concentration than the ones grazing on Yoorin fertilized pastures, ranging from 154 to 195 g N/L and 0.2 to 0.29 g P/L, respectively. Average N and K amount excreted via urine was greater for animals grazing on Yoorin and SS + TS treatments compared to control treatment, ranging from 51 to 99 g N/animal/dia and 46 to 49 g K/animal/dia, respectively. Average Ca concentration and P and Ca amount excreted via urine were similar among treatments. Average fecal production and N, K, Ca concentrations and amounts were similar among treatments. Average P amount was greater for SS + TS and Yoorin treatments compared to the control, ranging from 7.5 to 11.6 g P/animal/day. Nutrient return via animal excreta contributed in the experimental period with 73, 87, 6, and 28 kg/ha of N, K, P, and Ca, respectively. Animals on Yoorin fertilized pastures presented greater urine production and greater K urine concentration and amount.

Características morfogênicas do capim-mombaça (Panicum maximum Jacq. cv. Mombaça) adubado com fontes de fósforo, sob pastejo

The experiment was carried out from December/2002 to April/2003 and aimed to evaluate the effects of two phosphorus sources (ordinary superphosphate + triple superphosphate and Yoorinâ magnesium thermophosphate), as a function of days (24) and evaluation period (summer and autumn) on leaf appearance interval (LAPI), leaf elongation rate (LER), leaf senescence (TLS), first and last ligule height (FLH; LLH), number of expanded leaves (NEL), number of leaves in expansion (NLE), total number of leaves (TNL), total number of live leaves (TNLL), and grazing return rate (GRR) on mombacagrass (Panicum maximum Jacq. cv. Mombaca). The experimental design was randomized blocks with three replications. There was no difference between phosphorus sources in all evaluated variables, except for leaf elongation rate, which was higher in tillers fertilized with the SPS+TSP treatment. Differences were found between evaluation periods, with summer showing higher leaf elongation rate and ligule height (first and last). The days evaluated indicated effect on first ligule height (FLH; LLH), number of expanded leaves (NEL), number of leaves in expansion (NFE), total number of leaves (TNL), total number of live leaves (TNLL), total number of senescent leaves (TLS), and grazing return rate (GRR). For days and period interactions only TNLL and TSL had positive linear correlations.

Produção de matéria seca e valor nutritivo do feno do tifton 85 adubado com nitrogênio e colhido com 35 dias

Objetivou-se avaliar as etapas de producao de feno de capim Tifton 85 adubado com cinco doses de nitrogenio apos cada corte sob a forma de ureia em cobertura. A desidratacao da primeira colheita ocorreu durante seis dias em galpao, em funcao das condicoes climaticas, e a desidratacao da segunda colheita ocorreu a campo durante dois dias. O delineamento experimental foi em blocos ao acaso com parcelas subdivididas no tempo, sendo as parcelas (5 m x 3 m) as doses de nitrogenio (0; 25; 50; 75 e 100 kg ha-1 colheita-1) e as subparcelas as etapas de producao de feno (corte, enfardamento e armazenamento). O nitrogenio aumentou a altura e producao de materia seca por hectare, os teores de proteina bruta (PB) e de proteina insoluvel em detergente acido (PIDA) e neutro (PIDN). A secagem em galpao durante seis dias foi insuficiente para que a forragem atingisse 850 g kg-1 de MS no momento de enfardar. Entre a etapa de corte e 30 dias de armazenamento, o feno desidratado em galpao aumentou os teores de fibra em detergente neutro, de fibra em detergente de acido, a PIDA, PIDN e a lignina e ocorreu um decrescimo de 18,9% nos teores de PB. Ocorreu reducao da digestibilidade in vitro da materia seca (DIVMS) em 32,72% entre a etapa de corte e 30 dias de armazenamento para o feno seco em galpao, enquanto que nao houve alteracao significativa na DIVMS e PB para o feno seco em dois dias a campo. Palavras-chave: Cynodon spp. Fenacao. Qualidade de volumosos.