ARS | Publication request: Use of Gamagrass as Hay or Silage in animal Production Systems

Submitted to: Crop Science
Publication Type: Proceedings
Publication Acceptance Date: September 22, 2006
Publication Date: October 13, 2006
Citation: Burns, J.C., Fisher, D.S. 2006. Use of Gamagrass as Hay or Silage in animal Production Systems. Crop Science.96-105.

Interpretive Summary: Interest in sustainable farming systems with an emphasis on wildlife and plant diversity across the landscape has directed attention to native grasses. Gamagrass, a native grass indigenous to the Southeastern USA offers potential to accommodate these interest while providing either pasture or stored feed in ruminant production systems. Use of native grasses in animal production systems require the flexibility of being harvested and stored as feed. Because of the high frequency of summer thunderstorms the need exists to be able to direct cut gamagrass and immediately preserve it as silage. This study compares the potential of harvesting ‘Iuka’ and ‘Pete’ gamagrass and preserving them as hay and as silage. Generally, both cultivars ensiled well with a Ph between 4.1 and 4.5 with fermentation characteristics adequate for stable silage. Also, acetic and lactic acids predominated which is indicative of a desirable silage. Animals consumed all silages well two harvests taken in each of 2 yrs.), regardless of harvest date ( May, June, August, or September), but dry matter intake (lbs / 100 lbs body weight) was generally inferior for the same forage preserved as silage (1.51) vs. hay(1.96). This same trend was evident for dry matter digestion averaging 48.0% for silage vs. 58.8% for the same forage preserved as hay. Both Iuka and Pete gamagrass can be preserved as silage but quality is lost during the fermentation processed compared with hay. Also, both cultivars responded similarly to method of preservation and gave similar animal responses.

Technical Abstract: The use of native grasses to improve wildlife habitat is receiving consideration by conservation and wildlife interests. The potential use of native grasses in animal production systems, and particularly as conserved forage, has received little attention. Two experiments in each of 2 yr were conducted to determine the potential utility of gamagrass [Tripsacum dactyloides (L.) L.] as conserved forage. ‘Pete’ and ‘Iuka’ gamagrass were harvested and compared when preserved as either hay or silage. Both cultivars were readily ensiled with a pH generally ranging from 4.1 to 4.5. Dry matter consumption of the two cultivars conserved as silage did not differ as a percent of body weight per day (% BW/d) and ranged from 1.65 to 1.78 % BW/d among the four experiments. Intake was greater for hay (ranging from 1.89 to 2.03 % BW) compared with silage which ranged from 1.26 to 1.66 %BW/d. Further, dry matter digestion was greater for hay in all four experiments. Consequently, the decision to ensile gamagrass, attractive for risk reduction over hay harvest when faced with adverse weather, warrants careful consideration in light of its reduced quality.