The objective of this study was to evaluate the morphogenetic and structural characteristics of tropical grasses managed under different regrowth periods. The experiment was conducted at the Federal Institute of Science and Technology Education of Rio Grande do Norte, located in the municipality of Apodi-RN, Brazil. The study design was in randomized blocks and the treatments were allocated in a 3x4 factorial arrangement, with three cultivars (Andropogon, Buffel and Massai) in four regrowth periods (21, 35, 49 and 63 days). The interaction between cultivar and age was significant for all studied variables, with the exception of leaf blade width and accumulation rate. The highest leaf appearance rates were observed in Buffel grass, regardless of the regrowth age. This characteristic was not influenced by age only in Andropogon grass. Higher stem elongation rates were observed in Buffel grass, while the lowest were observed in Massai grass until 35 days of regrowth, attributed to the presence of inflorescences. Canopy heights in Massai and Andropogon grass were greater than Buffel grass until 35 days of regrowth, Andropogon grass had higher height from 35 days of regrowth than the others. Andropogon grass showed higher rates of accumulation than Massai grass only at 21 days of regrowth, and no effects of regrowth age were observed for this variable. Buffel grass should be defoliated at 21 days, while Andropogon and Massai grass can be managed without losses between 21 and 63 days of regrowth.

Consumo de nutrientes, comportamento ingestivo e desempenho de ovinos alimentados com fenos de gramíneas tropicais em diferentes intervalos entre cortes

RESUMO: Objetivou-se avaliar o efeito do uso de adubos orgânicos e mineral na estrutura e na produção de forragem do Panicum maximum cv. Massai. O experimento foi desenvolvido na fazenda escola do Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, campus Apodi. Os tratamentos avaliados foram fontes orgânicas de nitrogênio (dejetos da suinocultura, da avicultura e da ovinocultura) e uma fonte mineral (ureia), fixados em 150 kg/ha de N. Avaliouse a produção de forragem e de componentes morfológicos, a altura do pasto, a interceptação luminosa, o índice de área foliar e o teor de clorofila, em cortes realizados a cada 60 dias. A altura do dossel foi afetada pelo tipo de adubo aplicado, e maior altura foi observada no pasto adubado com ureia (50,97 cm). A maior interceptação de luz (IL) pelo dossel foi observada nos pastos que receberam ureia, porém não alcançaram 95% de IL. O índice de área foliar nos pastos adubados com ureia foi maior que nos demais, e os valores observados nos pastos que receberam adubos orgânicos foram considerados muito baixos. As massas de forragem, de lâmina foliar, de colmo e de material morto foram afetadas pelo tipo de adubo, e foram maiores nos pastos que receberam ureia. Os teores de clorofila total nas lâminas foliares não diferiram entre os adubos avaliados. A estrutura e a produção de forragem em pastos de capim-massai não são afetadas pelo tipo de dejetos de produção animal utilizado como fonte de nitrogênio. A eficiência destes adubos orgânicos como fonte de nitrogênio é inferior à da adubação mineral. Os dejetos de produção animal avaliados podem ser utilizados como fonte de nitrogênio para pastos de capim-massai em condições de baixo custo e para diminuir os impactos ambientais.Palavras-chave: adubo orgânico, Panicum maximum, ureia. PRODUCTION AND STRUCTURE OF MASSAI GRASS PASTURES FERTILIZED WITH ANIMAL MANURESABSTRACT: The objective of this study was to evaluate the effect of organic and mineral fertilizers on the structure and production of Panicum maximum cv. Massai forage. The experiment was conducted at the teaching farm of Instituto Federal de Educação, Ciência e Tecnologia do Rio Grande do Norte, Apodi Campus. The treatments evaluated were organic sources of nitrogen (wastes of pig, poultry and sheep farming) and a mineral source (urea), set at 150 kg N/ha. Forage production, morphological components, pasture height, light interception, leaf area index, and chlorophyll content were evaluated in samples obtained at intervals of 60 days. Canopy height was affected by the type of fertilizer applied and the greatest height was observed for pasture fertilized with urea (50.97 cm). The highest light interception by the canopy was observed for pastures receiving urea, but 95% light interception was not reached. The leaf area index was higher for pastures fertilized with urea compared to the other treatments and the values obtained for pastures receiving organic fertilizers were considered very low. Forage, leaf blade, stem and dead material mass was affe...

Spineless cactus (Nopalea cochenillifera) is widely used in animal feed in semi-arid regions, due to the adaptive characteristics to such conditions and for having high levels of soluble carbohydrates. This research article describes the effect of replacing grain maize with spineless cactus in the diet of dairy goats on dry matter intake, water intake, milk yield, milk physicochemical characteristics and diet production costs. Eight multiparous Anglo Nubian goats were fed diets in which grain maize was replaced with spineless cactus at four levels (0, 33, 66, and 100%) in a double 4 × 4 Latin square design. Milk yield was measured and samples collected in the last three days of each period for physicochemical analysis and for determining nutrient intake. Diet production costs were also determined. Replacing maize with spineless cactus did not influence dry matter intake. Water intake via the drinker decreased linearly in response to the increasing levels of spineless cactus in the diet. The replacement of maize with spineless cactus did not change milk yield or physicochemical parameters. Total feed cost and the percentage of revenue losses from feed decreased with the replacement. Therefore, spineless cactus can fully replace grain maize in the diet of dairy goats, as it does not change dry matter intake or milk yield, but rather reduces feed costs and the drinking-water intake of goats.

Objetivou-se avaliar o efeito do período de rebrotação e da altura de resíduo no crescimento do capim-buffel. Utilizou-se delineamento em blocos ao acaso, com três repetições. Os tratamentos consistiram em quatro alturas de resíduo (20, 30, 40 e 50 cm) e quatro períodos de descanso (15, 25, 35 e 45 dias), em arranjo fatorial 4x4. Foram determinados os teores de matéria seca e matéria mineral, a produção e a produtividade do capim. Os dados foram submetidos à análise de regressão a 5% de significância. Não houve interação entre altura de resíduo e o período de rebrotação para nenhuma das variáveis. A produtividade não diferiu em função de nenhuma das fontes de variações. Os teores de matéria mineral decresceram de forma linear em função do período de rebrotação e da altura de resíduo, atingindo 8,65 e 8,84% aos 45 dias e 50 cm de altura, respectivamente. A produção de forragem melhor se ajustou a equações lineares em função do período de rebrotação, alcançando médias de 8884,4 kg ha-1 de massa fresca e 2338,1 kg ha-1 de massa seca aos 45 dias. O capim-buffel manejado com 45 dias de rebrotação proporcionou maior produção de forragem por unidade de área. As menores alturas de resíduo e os períodos de rebrotação mais curtos proporcionaram maiores concentrações de minerais na forragem.

The objective of this study was to evaluate the chemical composition and protein and carbohydrate fractions in three forage species (Andropogon gayanus Kunth, Cenchrus ciliares L. and Panicum maximun x Panicum infestum) at four cutting ages: 21, 35, 49 and 63 days. Experiments were carried out at the Federal Institute of Education Science and Technology of Rio Grande do Norte - IFRN, located in the municipality of Apodi- RN, Potiguar West Meso-region. Materials collected in the field were analyzed in the Laboratory of Animal Nutrition (LANA), Federal Rural Semiarid University (UFERSA), Campus Mossoró, RN. Samples were processed, phenated, and analyzed. The analysis conducted included fractionation of nitrogen compounds and carbohydrates and chemical composition (dry matter, mineral matter, crude protein, lipids and fibers) was determined. The forages evaluated showed decreasing crude protein content with increasing cutting age, ranging between 14.9 and 6.2%. Andropogon grass showed the highest crude protein content. The fiber content increased with age. Fiber consisted of 62.4%–70.0% NDF and 30.07%–33.03% ADF. Highest fiber content was recorded for Massai grass, in which case, these two component species showed the highest fractions of intermediate degradation protein (B2), while Andropogon and Buffel Capins showed higher fractions of non-fibrous carbohydrates (A and B1). An increase in the concentration of cell-wall material in the detriment of the cellular content with increasing plant age was observed in the fodder studied. We also observed an increase in the indigestible fraction (C) of proteins and carbohydrates in the species studied.

The objective of this study was to evaluate the production and chemical composition of three forage species at different regrowth intervals. A 3 x 4 randomized-block factorial design with three forage species (Andropogon, Buffel, and Massai) and four regrowth intervals (21, 35, 49, and 63 days) was used. There was no interaction (p > 0.05) between forage species and regrowth interval on any of the chemical components evaluated. The crude protein content decreased but the contents of neutral detergent fiber, acid detergent fiber and hemicellulose increased with increasing regrowth interval (p > 0.05). Only the contents of crude protein and ether extract were similar (p > 0.05) among grasses. A significant interaction was observed (p < 0.05) between forage species and regrowth interval on forage mass. Andropogon grass had the highest forage mass at 63 days (3,270.1 kg ha-1 DM cut-1) and the highest productivity regardless of the regrowth interval (19.1 t ha-1 DM year-1). Therefore, Andropogon grass was the most productive forage among the tested species. Pastures should be managed with shorter growth intervals due to the highest crude protein level and the lowest contents of neutral detergent fiber and acid detergent fiber.