Comportamento ingestivo de novilhas de corte submetidas a estratégias de suplementação em pastagens de aveia e azevém

Abstract

It was evaluated the ingestive behavior of beef heifers on black oats (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.) pastures under different strategies of supplementation and continuous stocking system. The treatments evaluated were: 'no supplement'- animals on black oats (BO) and Italian ryegrass (IR) pasture; 'increasing' - animals on BO and IR pasture receiving increasing levels (0.3, 0.6, and 0.9% of live weight - LW) of supplement; 'fixed' - animals on BO and IR pasture receiving 0.9% of LW of supplement; and 'decreasing' - animals on BO and IR pasture receiving decreasing (1.5, 1.2, and 0.9% of LW) levels of supplement. Structural sward characteristics (herbage mass, green herbage mass, herbage allowance, leaf blade allowance, leaf:stem ratio, and proportion of oats leaf blade and stem + sheath and proportion of ryegrass leaf blade and stem + sheath) and nutritive value (crude protein concentration, in vitro organic matter digestibility, total digestible nutrients, and neutral detergent fiber) were similar among strategies of supplementation and varied with pasture utilization periods. Daily grazing time, ruminating time, idling time, time spent near the trough (min/day), and bite mass (g OM/bite) varied with strategies of supplementation and sward characteristics. The biting rate/min was influenced only by grazing cycle. © 2008 Sociedade Brasileira de Zootecnia.