Composição bromatológica de forragem de espécies arbóreas da Caatinga Paraibana em diferentes altitudes.

Abstract

The caatinga, a biome unique to Brazil, is characterized by a xerophilous vegetation composed of a highly diverse collection of trees, bushes and herbs. This study was carried out at Tapuio and Serra do Talhado Farms, in Santa Luzia - PB, Brazil, with the objective to evaluate the altitude effect on the bromatological composition of Capparis flexuosa L. (feijão bravo), Cnidoscollus phyllacanthus Muel. Arg. Pax et. K. Hoffm. (favela), Caesalpinia pyramidalis Tul. (catingueira), Mimosa tenuiflora (Willd) Poiret (Jurema preta) and Bauhinia cheilantha Bong. (mororó) forage collected in the Borborema Plateau and in the Sertão Northern Depression. These species were selected because they were considered good forage producers by local farmers and cattle raisers. Data were analyzed according to a randomized complete-block design, with five treatments (five tree species) and five replications (trees) of treatments in each block (plateau and depression blocks). Forage samples (550g) were collected at full growth stage and during the dormant period, for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF) and crude energy (CE) determination. Significant differences in DM, CP and NDF were observed anong species in the Borborema Plateau during the full growth stage, while CP and NDF were significantly affected in the dormant period (P<1%). There was block (altitude) effect (P<1%) on all bromatological characteristics during the dormant period. In the full growth stage, CP and CE contents were higher in the forage of all species, and DM was higher in Bauhinia cheilantha, Mimosa tenuiflora and Capparis flexuosa. In the dormant period, FDN was higher in forage from all species. It is concluded that: 1.CP content in the forage of the studied species is higher than the minimum demanded by ruminants; 2.forage collected in the dormant period showed a higher fiber content than the forage collected in the full growth stage; 3.composition of the studied forages suggests that they may be used in the maintenance diet of domestic ruminants; 4.forage can be collected at the full growth stage or in the dormant period, depending on rainfall regularity and species seasonality; 5.altitude affected CP content in the dormant period.