Characteristics of nutritional quality and production of genotypes of guineagrass harvested in three maturity stages

Revista Brasileira de Zootecnia

Stabile, Samuel dos Santos²  Rennó, Francisco Palma²  Salazar, Diego Reynaga²  Jank, Liana¹  Silva, Luís Felipe Prada e² 

[1] Embrapa Gado de Corte, Campo Grande;USP, Pirassununga

关键词: animal nutrition;    cell wall;    digestibility;    lignin;    Panicum maximum;    tropical grasses    Introdução No Brasil;    a produção de bovinos de corte ocorre predominantemente a pasto;    onde as pastagens tropicais são as principais fontes de alimento para os ruminantes;    sendo sensivelmente mais econômica em relação aos concentrados (Aguiar et al;   

DOI  :  10.1590/S1516-35982010000700004

学科分类：兽医学

来源: Universidade Federal de Vicosa

【 摘 要 】

This study aimed to verify the existence of genetic variation among guineagrass cultivars regarding the effect of maturity on chemical composition and digestibility, and to classify the genotypes according to productive characteristics and nutritional quality. A randomized block design, with split- plots and three replications, was used. Dates of the cuts were considered as the plots, and the genotypes were considered as the sub- plots. Dry matter yield differed among the genotypes only at 90 days of growth, but the percentage of leaves, stems, and senesced material changed at 60 days of growth, as well as at 90 days of growth. Differently from what was observed for the leaves, chemical composition and digestibility of stem showed great variability among genotypes. The stem showed higher concentrations of neutral detergent fiber, acid detergent fiber, and lignin, and lower values of crude protein, when compared to the leaves. It also presented higher digestibility of dry matter at 60 days of growth, and higher digestibility of neutral detergent fiber at 30, and at 60 days of growth. Clustering of the cultivars identified the PM39 and PM47 genotypes as the most promising ones in the breeding program, because they showed high productivity and high nutritional quality. Maturity has little effect on leaf digestibility when compared to the stem. When participation of the stem increases in the total of dry matter, this component becomes the major factor limiting quality of forage plants. Therefore, breeding program must consider, in addition to leaf:stem ratio, the in vitro digestibility of neutral detergent fiber of the stem when selecting genotypes.

【 授权许可】

CC BY-NC