Author: Eneas Reis Leite
Native pastures are the main sources of food for ruminants in Northeast Brazil. Considering that animal feeding represents 70% to 80% of total costs, it is justifiable to maximize the use of pastures. Their correct use allows the conversion of structural carbohydrates into proteins of high biological value at a relatively low cost.
Grasses from Brachiaria genus are the basis of animal production in the tropics, allowing extensive areas for livestock, including those being considered as marginal zones due to the low quality soils, which represent more than 40 million hectares in Brazil.
The morphogenic variables determine the structural characteristics of pastures, and the most important are the number and size of leaves and tiller density. These structural characteristics present high correlation with the intake plant species the animals will select, so that they constitute important factors for evaluation of pasture quality of grasses of economic interest..
The knowledge of morphological and physiological features of forage grasses represent the starting to the basic understanding of plant responses to cut or grazing. In Eneas Leite´s research from Department of Animal Science at Acacaú Valley University, in Brazil, published in American Journal of Plant Sciences 2014, vol. 5, deeper study on Mulato Grass (Brachiaria hibrida) have evaluated the effects of different heights of cuts, in four periods of the year, on structural characteristics of this forage species.
In general, it was concluded that the use of cutting at 10 cm causes a reduction in the total dry matter production of Mulato Grass. Cutting heights between 20 and 30 cm contributes positively to increasing the total number of leaves, the number of green leaves, the average size of the leaf blade and the total dry matter production. Cuttings near 40 cm are not recommended because they are responsible for the decrease in leaf/stem ratio and for the increasing in stem fractions and dry matter content, thus affecting the structure of the canopy. Further studies indicate the need of studying the structural characteristics together with the qualitative characteristics for a better understanding of this forage management.
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