ABSTRACT
The objective was to evaluate the effect of three stocking rates (2, 3.9, and 5.8 animal units ha−1) and three fertilization levels (0, 150, and 300 kg N ha−1 yr−1) on herbage mass and nutritive value of elephantgrass (Pennisetum purpureum Schum.) cv. IRI-381. The experiment was conducted from May to August of 2009 and 2010 in Itambé, PE, Brazil, during the rainy season. Treatments were allocated in a split-plot arrangement in a completely randomized block design. The variables measured included leaf mass (pre- and post-grazing), botanical composition, soil cover, leaf area index, light interception, leaf angle, and concentrations of dry matter, organic matter, N, and in vitro digestible dry matter. When fertilized with 300 kg N ha−1 yr−1, leaf mass reached 18,560 kg ha−1. Leaf area index decreased with increasing stocking rate. The relationship between sward height and light interception was R2 = 0.0126. Increased stocking rate resulted in greater contribution of signalgrass [Brachiaria decumbens (Stapf.) R.D. Webster] in the botanical composition, with a contribution up to 29% in 2010. Elephantgrass nutritive value is directly affected by the fertilization levels and stocking rate, with highest nutrient concentrations observed with 2 AU ha−1 and 300 kg N ha−1 yr−1.(AU)
Subject(s)
Animals , Pennisetum/physiology , Fertilizers/analysis , Animal Feed/analysis , Brazil , Pasture , Nutritive ValueABSTRACT
The objective of this research was to select elephantgrass clones for grazing conditions. A randomized complete block design was used, with 16 treatments and four replications. Each plot had a total area of 25m2, with the presence of animals. The following parameters were determined: leaf blade accumulation rate (LBAR) above 40cm height and total, stem accumulation rate (SAR), total forage accumulation rate (TFAR), dry matter concentration (%DM), crude protein concentration (%CP) and, neutral detergent fiber (%NDF). The results showed significant difference (P<0.05) between clones and evaluation periods for LBAR above 40cm, total LBAR and TFAR, with mean values of 28.08, 41.62 and 49.18kg/ha/day, respectively. Crude protein and NDF differences (P<0.05) were also found between the clones for all the different parts of the analyzed plant. The forage lost presented a similar chemical composition to the leaf blades above 40cm and to the post-grazing residue. The clones CE-08-AD and Venezuela AD presented a high performance considering the evaluated parameters and may be considered as promising materials.
Objetivando selecionar clones de capim-elefante para utilização sob pastejo, realizou-se experimento num delineamento em blocos ao acaso, com quatro repetições e 16 tratamentos, no período de 15/07/99 a 19/04/00. Em parcelas com 25m2, foram estudados a taxa de acúmulo de lâminas foliares (LF) e de colmos (C), teores de matéria seca (MS), proteína bruta (PB) e fibra em detergente neutro (FDN). Houve diferença significativa (p<0,05) entre clones e períodos de avaliação para produção de LF acima de 40cm, produção total de LF e produção total de forragem, com valores médios de 28,08; 41,62 e 49,18kg/ha/dia, respectivamente. Os teores de PB e FDN também foram diferentes (p<0,05) entre os clones em todas as frações da forragem. A fração perdas de forragem apresentou qualidade semelhante às frações LF acima de 40cm de altura de resíduo pós-pastejo. Os clones CE-08-AD e Venezuela AD destacaram-se para a maioria dos parâmetros avaliados, mostrando-se promissores.
ABSTRACT
The aim of this work was to evaluate the partial replacement of the soybean meal by urea plus forage cactus on the apparent digestibility of the nutrients. Eight Holstein cows were assigned in a two (4x4) latin square design. The urea represented 0.0%, 0.8%, 1.54%, and 2.40% of dry matter (DM) of the diets, corresponding to 2.32%, 4.65%, 6.66% and 8.02% of crude protein (CP) levels in the form of non-proteic nitrogen compounds (NPN). The digestibility of the crude protein, total carbohydrates, non-fiber carbohydrates, neutral detergent fiber, and acid detergent fiber was not affected by NPN levels (75.56%; 71.36%; 89.40%; 50.61%; the 57.30%, respectively). The apparent digestibility coefficients of dry matter, organic matter and ether extract decreased lineally. The TDN values determined in digestibility trial and the estimated by NRC (2001) presented high correlation (0.91).
O trabalho tem como objetivo avaliar a substituição parcial do farelo de soja por palma forrageira mais uréia, sobre a digestibilidade aparente dos nutrientes. Oito vacas da raça Holandesa foram distribuídas em 2 quadrados latinos (4X4). A uréia representou 0,0%; 0,8%; 1,54%; e 2,40% da MS da dieta, correspondendo a 2,31%; 4,65%; 6,66%; e 8,02% de proteína bruta na forma de compostos nitrogenados não-protéicos (NNP). Os coeficientes de digestibilidade aparente da proteína bruta, carboidratos totais, carboidratos não-fibrosos, fibra em detergente neutro e fibra em detergente ácido não foram influenciados pelos níveis de NNP (75,56%; 71,36%; 89,40%; 50,61%; e 57,30%, respectivamente). Os coeficientes de digestibilidade aparente de matéria seca, de matéria orgânica e do extrato etéreo diminuíram linearmente. Os teores de NDT, determinados no ensaio de digestibilidade, e os estimados pelo NRC (2001) apresentaram alta correlação (0,91).