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Ciência Rural

Print version ISSN 0103-8478

Abstract

SILVA NETO, Benedito; SCHNEIDER, Mariane  and  VIEGAS, Julio. Simulation model of rotative and continuous grazing systems of ryegrass (Lolium multiflorum Lam.) in bovine cattle. Cienc. Rural [online]. 2006, vol.36, n.4, pp. 1272-1277. ISSN 0103-8478.  http://dx.doi.org/10.1590/S0103-84782006000400035.

The main objective of the paper is to propose a dynamic systems simulation model for the analysis of pasture management seeking to maximize animal intake. The forage used was annual ryegrass, grazed by bovine adults. The variables considered were: animal stocking density, forage growth rate, animal apprehension rate, first entrance of the animals in the pasture (beginning of grazing) and rotation cycle (period of grazing plus period of rest of the pasture). To simulate the pasture growth the Verhulst equation was used. The computational model was programmed using software Berkeley Madonna. Simulations with this software showed that when grazing started early (until the 73 days) the rotative system provided greater animal dry matter intake than the continuous grazing system. When the grazing started between 74 and 95 days the continuous system provided greater animal dry matter intake than the rotative system. The simulations also showed that when the rotative system started early (60 days), the cycle of 30 days (a day of grazing and 29 of rest) provided greater animal dry matter intake. When the rotative system started later (75 days), variations of the grazing cycle length had little influence on dry matter intake.

Keywords : dynamic systems simulation; forage production; Verhulst model.

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