Influence of processing comparative feed values

Studies continued for a second year on the potential for utilizing processed or “macerated” rice straw as a ration for cattle.  This mechanical treatment is intended to make straw more palatable to livestock in feedlots.

Scientists at the University of California’s Desert Research and Extension Center developed a large-scale macerator that runs straw between corrugated rollers at different speeds under high pressure.  In one trial 90 Holstein steers were segregated by weight into 18 pens and fed a diet consisting of processed sudangrass, rice straw or macerated rice straw supplemented with an enzyme. Results of this study showed maceration greatly enhanced the feeding value of rice straw by creating greater surface area and enhancing microbial activity.  Further, the combination of enzyme supplementation and maceration permitted greater energy intake and thus daily weight gain, a fact attributed to increased ruminal turnover in the animals’ digestive tract. A trial with eight Holstein calves is still under way.

Another part of this project sought to evaluate the influence of pelletizing on the feeding value of rice straw.  Crossbred steers were finished in two trials where the feed consisted of sudangrass, sudangrass hay and varying amounts of pelletized rice straw.  There were no observed treatment effects on daily weight gain.  However, increasing the percentage of pelletized rice straw showed mixed results on gain efficiency, DMI and dietary energy.