Evaluation of Robinia pseudoacacia L. as browse for meat goat production in the southeastern United States of America.

摘要

Demand for goat meat in the southeastern USA is steadily increasing as a result of preferences exhibited by expanding ethnic communities. Feeding systems can be developed to take advantage of the natural preference of goats for browse. A field study was undertaken in Raleigh, NC to measure the effects of spacing (1.0 or 0.5 m) and coppice height (0.25 or 0.5 m) of a 5-year old stand of black locust (BL; Robinia pseudoacacia L.) on growth characteristics such as herbage mass (HM), canopy height (H) and width, number and size of main branches, above ground woody biomass, and root collar diameter. A second objective was through regression analysis to identify one or more of the previously mentioned characteristics as a rapid method to estimate HM. The third objective was to determine the relationship between growing-degree-days (GDD) and HM, H, herbage quality indicators (N, in vitro true dry matter disappearance, neutral and acid detergent fiber (NDF and ADF), cellulose, and 72% sulfuric acid lignin) and anti-quality indicators (Folin-reactive phenolics, condensed and hydrolyzable tannins) of BL. The final objective was to evaluate the N metabolism of goats fed BL foliage. Results indicated that coppicing BL trees at 0.5 m and planting at the widest spacing (1.0 m) produced the greatest plant growth. Average HM (2,600 kg ha -1) was observed for the highest coppice height (0.5 m). The character most closely related to HM was size of main branches. In 1999, a dry year, there was a significant relationship between GDD and NDF, ADF (r 2 = 0.90 and 0.80, respectively). In 2000, a wet year, GDD was a poor predictor of NDF and ADF. For 1999 and 2000, GDD was a poor predictor of BL tannin concentrations. From the conclusions of the N metabolism trial, goats consuming BL had lower digestibilities and higher content of N in the feces. Overall, BL contributes well to a silvopastoral system.