Effects of species and maturity stage on nutritional and fermentation characteristics of Sarcobatus species

The aim of this paper was to investigate the effect of maturity stage and species on nutritional and rumen fermentation characteristics of two species of greasewood, Black [Sarcobatus vermiculatus (Hook) Torr], and Bailey [Sarcobatus baileyi (Coville) Jepson]. Crude protein (CP) content of both species for all stages ranged from 114.1 to 204.8 g/kg, which is greater than the maintenance requirement of cattle. Highest CP content (204.8 g/kg, P = 0.045) was observed for Black greasewood pre-bloom. Highest acid detergent fiber (ADF) and lignin (sa) fractions (311.3 and 103.9 g/kg, P < 0.05, respectively) were recorded for Bailey post-bloom, while the lowest ADF and Lignin (sa) fractions (163.4 g/kg and 36.3 g/kg, P < 0.05, respectively) were obtained for Black greasewood pre-bloom stage. In vitro dry matter (IVDMD) and organic matter (IVOMD) disappearance, ammonia nitrogen (NH3N), and volatile fatty acid (VFA) content were determined at the end of a 48 h incubation period. Black greasewood was higher (409.0 vs. 366.1 g/kg; P = 0.006) in IVOMD than Bailey greasewood. The pre-bloom stage yielded more (P = 0.015) IVOMD than the bloom and post-bloom stages. No IVOMD difference was observed between bloom and post-bloom stages. Rumen ammonia nitrogen was highest (32.13 mg/100 ml; P = 0.005) for Black greasewood pre-bloom. Total VFA was significantly affected by species and maturity. The highest total VFA content was observed for both species pre-bloom. Total VFA remained the same for Black greasewood at bloom and post-bloom stages, while it declined significantly with increased maturity for Bailey. Based on this study Black greasewood has greater potential than Bailey greasewood as a late summer and early fall forage source in salt desert shrub plant communities of the Great Basin.