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Abstract

At the Experimental Center of Gualaca, Chiriqui, Panama, it was studied during the rainy season (May-December) for three years the effect of applying 0, 60, 120 and 180 kg N/ha/yr (X₁) and of 0, 14, 28 and 42 days of resting period (X₂) in Faragua pastures. Experimental design was an incomplete factorial with the following nitrogen rates and days of resting periods respectively, 0-0, 0-42, 60-14, 60-28, 120-14, 120-28 and 180-42. There was a seven-day grazing period during the rainy season. Twenty four-month-old Braham steers were used with an average initial liveweight of 273 kg, providing three animals per treatment with an allocation of 5 kg DM/100 kg of liveweight in a system of variable stocking rate. Total production of annual dry matter yield was not significant affected (P>.01) by the variable in study; howere, mean yields ranged between 3398.6 and 7621.0 kg (DM/ha). Available dry matter per grazing kg DM/ha (DMA), and residual dry matter–kg DM/ha (DMR) – were also studied and significantly affected (P<.01) by the resting period factor mean while daily growth rate of the total biomas – kg DM/ha/day (TB) – was not affected (P>.01) by any of the variables. The resting period variable had a higher influence on grass avail ability than nitrogen fertilization. Therefore, this factor should receive more attention in management recommendations, an apropiate resting period ranging between 28 to 42 days.