Browsing Rangeland Ecology & Management, Volume 61, Number 4 (July 2008) by Authors
Sphaeralcea angustifolia as a Substitute for Alfalfa for Growing GoatsMellado, Miguel; Salas, Gabriela; Pittroff, Wolfgang (Society for Range Management, 2008-07-01)Narrowleaf globemallow (Sphaeralcea angustifolia [Cav.] G. Don) occurs on millions of hectares of rangeland in the United States and Mexico, and it constitutes an important forage for herbivores. Forty 2-mo-old crossbred female goats (native 3 dairy goats; 9.4 +/- 2.2 kg) were randomly allotted to five dietary groups (two] goats per pen, four replications per ration) to evaluate the effects of feeding different levels of S. angustifolia in a complete ration on growth performance and diet digestibility. The rations were a total mixed control ration containing 0% S. angustifolia (T0) and four rations in which S. angustifolia progressively replaced alfalfa (25% [T25], 50% [T50], 75% [T75], and 100% [T100]). Grains and forage made up 70% and 30% of the dietary dry matter (DM) in all rations. Differences (P < 0.05) were observed between treatments in average daily gain (ADG; range 88-124 g d-1) and DM intake (DMI; range 3.3-4.0% body weight). Feed conversion ratio (DMI/ADG; range 4.0-4.8) was similar (P > 0.20) among treatments. Goats fed diets with any of the S. angustifolia levels had similar apparent nitrogen (N) digestion (range 67.6-69.8%) as those fed only alfalfa, but N retention was greater (P < 0.05) in goats on T25 and T50 diets compared to other diets. The apparent digestibilities of DM, neutral detergent fiber, and acid detergent fiber were greater (P < 0.05) for T25 and T50 than for other diets. Results indicate that S. angustifolia at the flowering stage was a savory and nutritious roughage, which could fully replace alfalfa hay in diets of growing goats. Considering that S. angustifolia is readily consumed by foraging animals, it is abundant enough that it is a significant source of forage, and has a sufficient quality to nutritionally satisfy herbivores, this forb is a potentially useful forage for pen-fed goats.