Stocker Cattle Grazing Preference of Warm Season Perennial Grasses.

Fourteen introduced and native warm season perennial grasses were evaluated for yield, yield distribution and quality from 2004-2006.  Grasses were harvested at boot stage of reproductive development resulting in a range of cuttings from 1-4 per year dependent upon species and rainfall. Alamo switchgrass, touted for its biofuel potential, had the highest 2004-2005 average yield of 15800 lbs/ac. In 2006, a drought year, plots were harvested once and Alamo remained in the highest statistical grouping yielding 7091 lbs/ac.  Quality of the entries has been very similar. Over the three years of harvest data 53% of total yield for Alamo was produced in May and June.  This early production of Alamo could provide opportunities for it to be utilized for grazing or hay production followed by biomass for biofuel.  However, producers are often concerned with the perceived low palatability of Alamo which could potentially slow its adoption. To test this perception, a grazing preference study was conducted from 2007-2009 using stocker weight steers grazed across entries in two grazing cycles. Bite counts recorded by entry were used determine grazing preference.  Yield, quality, color, plant height, vegetative stage, and leaf to stem ratios for each entry were collected pre and post grazing. Grazing cycles occurred in June and July. Steers grazed each replicate in succession until each was grazed twice resulting in a six day cycle.  Daily grazing began at 6:30 a.m. and terminated when steers began rumination or stopped grazing.  Over the course of the study a total of 173,623 bite counts were recorded. Alamo switchgrass had the highest bite counts in years 1 and 3 while Midland 99 bermudagrass was highest in year 2. Correlations were run across entries to determine variables associated with bite count with bite counts being correlated to fiber and energy content of the grasses. These data indicate that cattle do not select against Alamo switchgrass and tend to prefer it over Blackwell switchgrass. Because of the yield stability of switchgrass it could have potential for both grazing and biofuel.