Wednesday, November 4, 2009
Convention Center, Exhibit Hall BC, Second Floor
Brachiaria sp. cv. Mulato (a hybrid in the Brachiaria genus) is a new grass introduction for cattle grazing in Puerto Rico, but herbage mass and nutritive value declines in the dry season. The objective of this study was to assess Ubon Stylo (Stylosanthes guianensis var. vulgaris x var. pauciflora) or blue pea (Clitoria ternatea)-Mulato mixture effects on herbage mass (HM; Mg ha-1) and nutritive value [Crude protein (CP) and neutral detergent fiber (NDF)] during the dry season. Treatments consisted solid stands of Mulato, Ubon Stylo, Blue pea and 50:50 mixtures of either legume with Mulato in a randomized complete block. The Lajas substation has defined a dry season (from January to August). Both legumes and Mulato were seeded on a fine, smectic, isohyperthermic Typic Haplusterts (Fraternidad series) with a brillon seeder (September). After establishment (5-mo), all plots were stocked with dairy cows and grazed to 15-cm height. Thereafter, HM was estimated from clipping of grass-legumes (15-cm height) in three 1-m2 area in each pasture treatment every 42-d and experimental plots grazed. There was a treatment trend (P=0.068) on HM (ranging from 2.8 for Mulato to 3.6 Mg ha-1 for the mixed Ubon Stylo stands). There was, however, sampling date effects (P<0.05) attributed to rainfall pattern. There were difference (P<0.05) in CP and NDF among treatments. There was increased of five-percentage units on Mulato (5.6%), compared to mixed stands of Ubon Stylo or Bluepea , 10.3 and 12.6%, CP respectively. Mixed stands had lower ND than the solid stand Mulato, 68.7, 62.1 and 72.2%, for Mulato, Mulato-Ubon Stylo and Mualto-Bluepea, respectively. Mixtures of Ubon Stylo and Bluepea with Mulato increased HM, and also improved the nutritive value of Mulato during the dry season.