ABSTRACT
Grazing management strategies affect not only herbage accumulation but also the efficiency of grazing. This study aimed to evaluate herbage accumulation (leaf, stem and dead material), grazing efficiency and losses of mulato grass (a Brachiaria ruziziensis × Brachiaria brizantha cv. Marandu hybrid) subjected to strategies of rotational stocking management. Treatments consisted of combinations between two post-grazing heights (15 and 20 cm) and two pre-grazing conditions (95 % and maximum canopy light interception (LI)) assigned to experimental units (1200-m² paddocks) according to a 2 × 2 factorial arrangement and a randomized complete block design, with four replications. The experiment was carried out from Jan 2008 to Mar 2009. Season of the year influenced almost all studied variables, resulting in a common pattern of response that was determined by pre- and post-grazing management targets. Herbage accumulation was greater on swards managed at 95 %, with higher accumulation of leaves and lower accumulation of stem and dead material in relation to those managed at maximum LI (99 %) during the entire experimental period. On the other hand, herbage removal by grazing was larger on swards managed at 99 % LI, which was compensated for by the smaller number of grazing cycles and larger losses due to grazing under those circumstances. Under rotational stocking, the pre-grazing LI of 95 % and post-grazing height of 20 cm resulted in efficient grazing and high producing leafy pastures, highlighting the potential of Mulato grass pastures for animal production.
ABSTRACT
Grazing management strategies affect not only herbage accumulation but also the efficiency of grazing. This study aimed to evaluate herbage accumulation (leaf, stem and dead material), grazing efficiency and losses of mulato grass (a Brachiaria ruziziensis × Brachiaria brizantha cv. Marandu hybrid) subjected to strategies of rotational stocking management. Treatments consisted of combinations between two post-grazing heights (15 and 20 cm) and two pre-grazing conditions (95 % and maximum canopy light interception (LI)) assigned to experimental units (1200-m² paddocks) according to a 2 × 2 factorial arrangement and a randomized complete block design, with four replications. The experiment was carried out from Jan 2008 to Mar 2009. Season of the year influenced almost all studied variables, resulting in a common pattern of response that was determined by pre- and post-grazing management targets. Herbage accumulation was greater on swards managed at 95 %, with higher accumulation of leaves and lower accumulation of stem and dead material in relation to those managed at maximum LI (99 %) during the entire experimental period. On the other hand, herbage removal by grazing was larger on swards managed at 99 % LI, which was compensated for by the smaller number of grazing cycles and larger losses due to grazing under those circumstances. Under rotational stocking, the pre-grazing LI of 95 % and post-grazing height of 20 cm resulted in efficient grazing and high producing leafy pastures, highlighting the potential of Mulato grass pastures for animal production.
ABSTRACT
This trial was carried out to evaluate the production and quality of leaf blade (LB), sheath + green stem (SGS), dead material (DE) forage structural constituents of Coastcross and Arachis pintoi whole plant (WPA) mixed pasture, under grazing, during February 2003 and June 2004. The treatments CA0 = Coastcross + Arachis without N; CA100 = Coastcross + Arachis with 100 kg of N; CA200 = Coastcross + Arachis with 200 kg of N and C200 = Coastcross with 200 kg of N were distributed in a randomly block design, with two replicates. Pasture management was done through continuous grazing with variable stocking rate. Analyses of crude protein (CP), neutral detergent fiber (NDF) and dry matter in vitro digestibility (DMIVD) were done to LB, SGS, and WPA. The production of structural constituents varied in agreement with total mass and forage. Coastcross SGS contributed for forage production, and the quality characteristics are acceptable for animal production. Treatments that received nitrogen presented the highest CP values, and similar NDF and DMIVD to treatments without nitrogen.
Objetivou-se, com este trabalho, avaliar a produção e composição química de forragem nos constituintes estruturais lâmina foliar (LF), bainha + colmo verde (BCV), material morto (MM) da Coastcross e da planta inteira de Arachis pintoi (AP) em consorciação sob pastejo no período de julho de 2003 a junho de 2004. Os tratamentos CA0=Coastcross + Arachis sem N; CA100=Coastcross + Arachis com 100 kg de N/ha/ano; CA200=Coastcross + Arachis com 200 kg de N/ha/ano e C200=Coastcross com 200 kg de N/ha/ano foram distribuídos em um delineamento em blocos ao acaso, com duas repetições. O manejo do pasto foi por meio de lotação contínua e carga animal variável. Foram realizadas as análises de proteína bruta (PB), fibra em detergente neutro (FDN) e digestibilidade in vitro da matéria seca (DIVMS) da pastagem para LF, BCV e AP. As produções dos constituintes estruturais variaram de acordo com os períodos experimentais, e os tratamentos com adubação apresentaram valores superiores de LF, principalmente nos períodos de primavera e verão. Além da melhor composição nutricional indicada pelas LF e AP, a BCV da Coastcross expressou características qualitativas aceitáveis para produção animal. Os tratamentos que receberam nitrogênio apresentaram maiores valores de PB e teores semelhantes de FDN e DIVMS ao tratamento sem nitrogênio.
ABSTRACT
This trial was carried out to evaluate the production and quality of leaf blade (LB), sheath + green stem (SGS), dead material (DE) forage structural constituents of Coastcross and Arachis pintoi whole plant (WPA) mixed pasture, under grazing, during February 2003 and June 2004. The treatments CA0 = Coastcross + Arachis without N; CA100 = Coastcross + Arachis with 100 kg of N; CA200 = Coastcross + Arachis with 200 kg of N and C200 = Coastcross with 200 kg of N were distributed in a randomly block design, with two replicates. Pasture management was done through continuous grazing with variable stocking rate. Analyses of crude protein (CP), neutral detergent fiber (NDF) and dry matter in vitro digestibility (DMIVD) were done to LB, SGS, and WPA. The production of structural constituents varied in agreement with total mass and forage. Coastcross SGS contributed for forage production, and the quality characteristics are acceptable for animal production. Treatments that received nitrogen presented the highest CP values, and similar NDF and DMIVD to treatments without nitrogen.
Objetivou-se, com este trabalho, avaliar a produção e composição química de forragem nos constituintes estruturais lâmina foliar (LF), bainha + colmo verde (BCV), material morto (MM) da Coastcross e da planta inteira de Arachis pintoi (AP) em consorciação sob pastejo no período de julho de 2003 a junho de 2004. Os tratamentos CA0=Coastcross + Arachis sem N; CA100=Coastcross + Arachis com 100 kg de N/ha/ano; CA200=Coastcross + Arachis com 200 kg de N/ha/ano e C200=Coastcross com 200 kg de N/ha/ano foram distribuídos em um delineamento em blocos ao acaso, com duas repetições. O manejo do pasto foi por meio de lotação contínua e carga animal variável. Foram realizadas as análises de proteína bruta (PB), fibra em detergente neutro (FDN) e digestibilidade in vitro da matéria seca (DIVMS) da pastagem para LF, BCV e AP. As produções dos constituintes estruturais variaram de acordo com os períodos experimentais, e os tratamentos com adubação apresentaram valores superiores de LF, principalmente nos períodos de primavera e verão. Além da melhor composição nutricional indicada pelas LF e AP, a BCV da Coastcross expressou características qualitativas aceitáveis para produção animal. Os tratamentos que receberam nitrogênio apresentaram maiores valores de PB e teores semelhantes de FDN e DIVMS ao tratamento sem nitrogênio.