Dried distiller’s grains improve the performance of beef cattle intensively grazing early summer bluestem pasture

Distiller's grains are byproducts of the production of ethanol from grains and are an excellent source of protein and energy for cattle. The most prevalent use of distiller's grains is in the finishing beef production sector. There is limited research available that has evaluated effectiveness of distiller's grains as a supplement for grazing beef cattle. Digestible protein content in grass begins to decrease in midsummer, resulting in lower average daily gains. The objective of this study was to measure the daily gain of yearling steers supplemented with different levels of dried distiller's grains while grazing doublestock Flint Hills pastures.

Dried distiller's grains improve the performance of beef cattle intensively grazing Dried distiller's grains improve the performance of beef cattle intensively grazing early summer bluestem pasture early summer bluestem pasture

Introduction
Distiller's grains are byproducts of the production of ethanol from grains and are an excellent source of protein and energy for cattle. The most prevalent use of distiller's grains is in the finishing beef production sector. There is limited research available that has evaluated effectiveness of distiller's grains as a supplement for grazing beef cattle. Digestible protein content in grass begins to decrease in midsummer, resulting in lower average daily gains. The objective of this study was to measure the daily gain of yearling steers supplemented with different levels of dried distiller's grains while grazing doublestock Flint Hills pastures.

Experimental Procedures
Three hundred forty-six steers (573 lbs ± 51.0 lbs) were used to evaluate performance of dried distiller's grains in an intensive Flint Hills grazing system (250 lbs/acre for 90 days). The dried distiller's grains were exclusively sorghum grain, pelleted for improved handling and shrink characteristics. All steers were backgrounded at a commercial yard between 30 and 45 days before arrival at the Beef Stocker Unit, Kansas State University, Manhattan, KS.
A single grazing period was used from May 1 to August 3, 2005. Pastures consisted of warm-season perennial grasses with big bluestem (Andropogon gerardii) and Indiangrass (Sorghastrum nutans) dominant forage species, as well as subdominant forage species of little bluestem (A. scoparius) and sideoats grama (Bouteloua curtipendual). The following four treatments were randomized over 16 pastures: No supplementation (CON), and sorghum dried distiller's grains supplemented at 0.25% (LOW), 0.50% (MED), and 0.75% (HIGH) of body weight (dry matter basis; Table 1). The dried distiller's grains were 34.6% crude protein and 8.8% crude fat (dry matter basis). Supplemental treatments were fed once daily from June 15 through August 3 in feed bunks located in each pasture. Cattle weights were estimated based on projected average daily gain of 1.8 lb/day from May 1 through June 14 (45 days). Supplements were adjusted every two weeks based on projected ADG of 2.0 lbs/day during the supplement period (June 15 through August 3). Freechoice mineral with a sub-therapeutic dose of oxytetracycline for control of foot rot and pinkeye was provided to all steers until mid-June. Salt in block form was provided to all cattle throughout the entire grazing period. On August 4 the steers were shipped to a commercial feedyard where final weights were taken. Steers were sorted into one of four pens according to dried distiller's grains treatment received on pasture. Grazing and feedyard performance were calculated for each treatment group (Table 2).
Forage quality throughout the grazing period was measured using four ruminally cannulated steers via the rumen evacuation procedure. Rumens were evacuated and rinsed three times, cattle were allowed to graze for 20 minutes, rumens were re-evacuated to obtain consumed forage, and then original rumen contents were put back into each steer. Four pastures, one from each dried distiller's grains treatment, were sampled. The sampling periods were as follows: May 24, June 28-29, and July 28-29. The same pastures were sampled each sampling period. Crude protein ( Figure  1) and ADF (i.e., digestibility; Figure 2) of the forage were analyzed.

Results and Discussion
All cattle fed dried distiller's grains had a significantly greater average daily gain than unsupplemented (Control) cattle (Table 2). In general, weight gain increased as levels of dried distiller's grains increased. However, subsequent performance in the feedyard was lowest for steers fed the highest level of dried distiller's grains during the grazing period.

Implications
Supplementation of dried distiller's grains increases average daily gain of steers in an intensive grazing system; however, subsequent performance in the feedyard appears to decrease.